update

Reviewed-on: #51

.github/workflows/release.yml

@@ -152,11 +152,23 @@ jobs:
           echo "Artifacts structure:"
           find artifacts -type f -exec ls -la {} \;
 
+      - name: Generate SHA256SUMS
+        run: |
+          # One `<sha256>  <path>` line per artifact. The in-app updater reads
+          # this to verify a download before installing it, so it must be
+          # published alongside every release. Written outside the directory
+          # being hashed so the checksums file never includes itself.
+          find artifacts -type f ! -name SHA256SUMS -print0 \
+            | sort -z \
+            | xargs -0 sha256sum > SHA256SUMS.raw
+          mv SHA256SUMS.raw artifacts/SHA256SUMS
+          cat artifacts/SHA256SUMS
+
       - name: Create draft release
         id: create_release
         uses: akkuman/gitea-release-action@v1
         with:
-          server_url: "https://git.reya.su/"
+          server_url: "https://git.reya.info/"
           repository: "reya/coop"
           token: ${{ secrets.GITEA_TOKEN }}
           draft: true

.gitignore

@@ -19,8 +19,8 @@ dist/
 
 # Useless stuffs
 .DS_Store
-# Added by goreleaser init:
-.intentionally-empty-file.o
 
 .cargo/
 vendor/
+wasm/
+node_modules/

AGENTS.md

@@ -0,0 +1,150 @@
+# Rust coding guidelines
+
+* Prioritize code correctness and clarity. Speed and efficiency are secondary priorities unless otherwise specified.
+* Do not write organizational or comments that summarize the code. Comments should only be written in order to explain "why" the code is written in some way in the case there is a reason that is tricky / non-obvious.
+* Prefer implementing functionality in existing files unless it is a new logical component. Avoid creating many small files.
+* Avoid using functions that panic like `unwrap()`, instead use mechanisms like `?` to propagate errors.
+* Be careful with operations like indexing which may panic if the indexes are out of bounds.
+* Never silently discard errors with `let _ =` on fallible operations. Always handle errors appropriately:
+  - Propagate errors with `?` when the calling function should handle them
+  - Use `.log_err()` or similar when you need to ignore errors but want visibility
+  - Use explicit error handling with `match` or `if let Err(...)` when you need custom logic
+  - Example: avoid `let _ = client.request(...).await?;` - use `client.request(...).await?;` instead
+* When implementing async operations that may fail, ensure errors propagate to the UI layer so users get meaningful feedback.
+* Avoid creative additions unless explicitly requested
+* Use full words for variable names (no abbreviations like "q" for "queue")
+* Use variable shadowing to scope clones in async contexts for clarity, minimizing the lifetime of borrowed references.
+  Example:
+  ```rust
+  executor.spawn({
+      let task_ran = task_ran.clone();
+      async move {
+          *task_ran.borrow_mut() = true;
+      }
+  });
+  ```
+
+# Timers in tests
+
+* In GPUI tests, prefer GPUI executor timers over `smol::Timer::after(...)` when you need timeouts, delays, or to drive `run_until_parked()`:
+  - Use `cx.background_executor().timer(duration).await` (or `cx.background_executor.timer(duration).await` in `TestAppContext`) so the work is scheduled on GPUI's dispatcher.
+  - Avoid `smol::Timer::after(...)` for test timeouts when you rely on `run_until_parked()`, because it may not be tracked by GPUI's scheduler and can lead to "nothing left to run" when pumping.
+
+# GPUI
+
+GPUI is a UI framework which also provides primitives for state and concurrency management.
+
+## Context
+
+Context types allow interaction with global state, windows, entities, and system services. They are typically passed to functions as the argument named `cx`. When a function takes callbacks they come after the `cx` parameter.
+
+* `App` is the root context type, providing access to global state and read and update of entities.
+* `Context<T>` is provided when updating an `Entity<T>`. This context dereferences into `App`, so functions which take `&App` can also take `&Context<T>`.
+* `AsyncApp` and `AsyncWindowContext` are provided by `cx.spawn` and `cx.spawn_in`. These can be held across await points.
+
+## `Window`
+
+`Window` provides access to the state of an application window. It is passed to functions as an argument named `window` and comes before `cx` when present. It is used for managing focus, dispatching actions, directly drawing, getting user input state, etc.
+
+## Entities
+
+An `Entity<T>` is a handle to state of type `T`. With `thing: Entity<T>`:
+
+* `thing.entity_id()` returns `EntityId`
+* `thing.downgrade()` returns `WeakEntity<T>`
+* `thing.read(cx: &App)` returns `&T`.
+* `thing.read_with(cx, |thing: &T, cx: &App| ...)` returns the closure's return value.
+* `thing.update(cx, |thing: &mut T, cx: &mut Context<T>| ...)` allows the closure to mutate the state, and provides a `Context<T>` for interacting with the entity. It returns the closure's return value.
+* `thing.update_in(cx, |thing: &mut T, window: &mut Window, cx: &mut Context<T>| ...)` takes a `AsyncWindowContext` or `VisualTestContext`. It's the same as `update` while also providing the `Window`.
+
+Within the closures, the inner `cx` provided to the closure must be used instead of the outer `cx` to avoid issues with multiple borrows.
+
+Trying to update an entity while it's already being updated must be avoided as this will cause a panic.
+
+`WeakEntity<T>` is a weak handle. It has `read_with`, `update`, and `update_in` methods that work the same, but always return an `anyhow::Result` so that they can fail if the entity no longer exists. This can be useful to avoid memory leaks - if entities have mutually recursive handles to each other they will never be dropped.
+
+## Concurrency
+
+All use of entities and UI rendering occurs on a single foreground thread.
+
+`cx.spawn(async move |cx| ...)` runs an async closure on the foreground thread. Within the closure, `cx` is `&mut AsyncApp`.
+
+When the outer cx is a `Context<T>`, the use of `spawn` instead looks like `cx.spawn(async move |this, cx| ...)`, where `this: WeakEntity<T>` and `cx: &mut AsyncApp`.
+
+To do work on other threads, `cx.background_spawn(async move { ... })` is used. Often this background task is awaited on by a foreground task which uses the results to update state.
+
+Both `cx.spawn` and `cx.background_spawn` return a `Task<R>`, which is a future that can be awaited upon. If this task is dropped, then its work is cancelled. To prevent this one of the following must be done:
+
+* Awaiting the task in some other async context.
+* Detaching the task via `task.detach()` or `task.detach_and_log_err(cx)`, allowing it to run indefinitely.
+* Storing the task in a field, if the work should be halted when the struct is dropped.
+
+A task which doesn't do anything but provide a value can be created with `Task::ready(value)`.
+
+## Elements
+
+The `Render` trait is used to render some state into an element tree that is laid out using flexbox layout. An `Entity<T>` where `T` implements `Render` is sometimes called a "view".
+
+Example:
+
+```
+struct TextWithBorder(SharedString);
+
+impl Render for TextWithBorder {
+    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
+        div().border_1().child(self.0.clone())
+    }
+}
+```
+
+Since `impl IntoElement for SharedString` exists, it can be used as an argument to `child`. `SharedString` is used to avoid copying strings, and is either an `&'static str` or `Arc<str>`.
+
+UI components that are constructed just to be turned into elements can instead implement the `RenderOnce` trait, which is similar to `Render`, but its `render` method takes ownership of `self` and receives `&mut App` instead of `&mut Context<Self>`. Types that implement this trait can use `#[derive(IntoElement)]` to use them directly as children.
+
+The style methods on elements are similar to those used by Tailwind CSS.
+
+If some attributes or children of an element tree are conditional, `.when(condition, |this| ...)` can be used to run the closure only when `condition` is true. Similarly, `.when_some(option, |this, value| ...)` runs the closure when the `Option` has a value.
+
+## Input events
+
+Input event handlers can be registered on an element via methods like `.on_click(|event, window, cx: &mut App| ...)`.
+
+Often event handlers will want to update the entity that's in the current `Context<T>`. The `cx.listener` method provides this - its use looks like `.on_click(cx.listener(|this: &mut T, event, window, cx: &mut Context<T>| ...)`.
+
+## Actions
+
+Actions are dispatched via user keyboard interaction or in code via `window.dispatch_action(SomeAction.boxed_clone(), cx)` or `focus_handle.dispatch_action(&SomeAction, window, cx)`.
+
+Actions with no data are defined with the `actions!(some_namespace, [SomeAction, AnotherAction])` macro call. Otherwise the `Action` derive macro is used. Doc comments on actions are displayed to the user.
+
+Action handlers can be registered on an element via the event handler `.on_action(|action, window, cx| ...)`. Like other event handlers, this is often used with `cx.listener`.
+
+## Notify
+
+When a view's state has changed in a way that may affect its rendering, it should call `cx.notify()`. This will cause the view to be rerendered. It will also cause any observe callbacks registered for the entity with `cx.observe` to be called.
+
+## Entity events
+
+While updating an entity (`cx: Context<T>`), it can emit an event using `cx.emit(event)`. Entities register which events they can emit by declaring `impl EventEmitter<EventType> for EntityType {}`.
+
+Other entities can then register a callback to handle these events by doing `cx.subscribe(other_entity, |this, other_entity, event, cx| ...)`. This will return a `Subscription` which deregisters the callback when dropped.  Typically `cx.subscribe` happens when creating a new entity and the subscriptions are stored in a `_subscriptions: Vec<Subscription>` field.
+
+# Pull request hygiene
+
+When an agent opens or updates a pull request, it must:
+
+- Use a clear, correctly capitalized, imperative PR title (for example, `fix crash in project panel`).
+- Avoid conventional commit prefixes in PR titles (`fix:`, `feat:`, `docs:`, etc.).
+- Avoid trailing punctuation in PR titles.
+- Optionally prefix the title with a crate name when one crate is the clear scope (for example, `workspace: add history view`).
+- Include a `Release Notes:` section as the final section in the PR body.
+- Use one bullet under `Release Notes:`:
+  - `- Added ...`, `- Fixed ...`, or `- Improved ...` for user-facing changes, or
+  - `- N/A` for docs-only and other non-user-facing changes.
+- Format release notes exactly with a blank line after the heading, for example:
+
+```
+Release Notes:
+
+- N/A
+```

Cargo.toml

@@ -4,31 +4,50 @@ members = ["crates/*", "desktop", "web"]
 default-members = ["desktop"]
 
 [workspace.package]
-version = "1.0.0-beta5"
+version = "1.0.2"
 edition = "2024"
 publish = false
 
 [workspace.dependencies]
-# GPUI
-gpui = { git = "https://github.com/zed-industries/zed" }
-gpui_platform = { git = "https://github.com/zed-industries/zed", features = ["font-kit", "x11", "wayland"] }
-gpui_linux = { git = "https://github.com/zed-industries/zed" }
-gpui_windows = { git = "https://github.com/zed-industries/zed" }
-gpui_macos = { git = "https://github.com/zed-industries/zed" }
-gpui_tokio = { git = "https://github.com/zed-industries/zed" }
-reqwest_client = { git = "https://github.com/zed-industries/zed" }
+# GPUI. The `gpui-pre` family is upstream zed's gpui republished unchanged, so these
+# aliases keep every `use gpui::..` site as it is while moving off the zed git pin.
+gpui = { package = "gpui-pre", version = "0.3.5" }
+gpui_platform = { package = "gpui-pre-platform", version = "0.3.5", features = ["font-kit", "x11", "wayland"] }
+gpui_linux = { package = "gpui-pre-linux", version = "0.3.5" }
+gpui_windows = { package = "gpui-pre-windows", version = "0.3.5" }
+gpui_macos = { package = "gpui-pre-macos", version = "0.3.5" }
+gpui_web = { package = "gpui-pre-web", version = "0.3.5" }
+gpui_util = { package = "gpui-pre-util", version = "0.3.5" }
+sum_tree = { package = "gpui-pre-sum-tree", version = "0.3.5" }
+reqwest_client = { package = "gpui-pre-reqwest-client", version = "0.3.5" }
+gpui_tokio = { path = "crates/gpui_tokio" }
+
+# Unstyled behavior, state, and infrastructure from GPUI Kit
+gpui-base = "0.6.1"
 
 # Nostr
-nostr-lmdb = { git = "https://github.com/rust-nostr/nostr", }
-nostr-connect = { git = "https://github.com/rust-nostr/nostr" }
+nostr-lmdb = { git = "https://github.com/rust-nostr/nostr" }
+nostr-memory = { git = "https://github.com/rust-nostr/nostr" }
 nostr-blossom = { git = "https://github.com/rust-nostr/nostr" }
 nostr-gossip-memory = { git = "https://github.com/rust-nostr/nostr" }
+nostr-connect = { git = "https://github.com/rust-nostr/nostr" }
 nostr-sdk = { git = "https://github.com/rust-nostr/nostr" }
 nostr = { git = "https://github.com/rust-nostr/nostr", features = [ "nip59", "nip49", "nip44" ] }
 
+# Crypto (NIP-17 encrypted file messages)
+aes-gcm = "0.10"
+sha2 = "0.10"
+data-encoding = "2"
+hkdf = "0.12"
+# Pinned to the instances `nostr` already builds: the NIP-44 message-key disclosure
+chacha20 = "0.9"
+hmac = "0.12"
+# Pinned to the instance `nostr-sdk` already builds, so NIP-44 nonces share it
+rand = { version = "0.10", default-features = false, features = [ "std", "sys_rng" ] }
+
 # Others
 anyhow = "1.0.44"
-chrono = "0.4.38"
+chrono = { version = "0.4.38", features = ["wasmbind"] }
 futures = "0.3"
 itertools = "0.13.0"
 log = "0.4"
@@ -40,9 +59,15 @@ serde_json = "1.0"
 schemars = "1"
 smallvec = "1.14.0"
 smol = "2"
-tracing = "0.1.40"
 webbrowser = "1.0.4"
-tracing-subscriber = { version = "0.3.18", features = ["fmt", "env-filter"] }
+tracing-subscriber = { version = "0.3.18", features = ["fmt"] }
+errno = { version = "0.3.14", default-features = false }
+instant = "0.1"
+ureq = { version = "3", default-features = false, features = ["rustls", "platform-verifier", "json"] }
+
+[patch.crates-io]
+# Use stacker's psm version which may have better WASM support
+psm = { git = "https://github.com/rust-lang/stacker", branch = "master" }
 
 [profile.release]
 strip = true

README.md

@@ -1,125 +1,5 @@
-![Coop](/docs/coop.png)
-
-<p>
-    <a href="https://github.com/reyakov/coop/actions/workflows/rust.yml">
-      <img alt="Actions" src="https://github.com/reyakov/coop/actions/workflows/rust.yml/badge.svg">
-    </a>
-    <img alt="GitHub repo size" src="https://img.shields.io/github/repo-size/reyakov/coop">
-    <img alt="GitHub issues" src="https://img.shields.io/github/issues-raw/reyakov/coop">
-    <img alt="GitHub pull requests" src="https://img.shields.io/github/issues-pr/reyakov/coop">
-</p>
-
 Coop is a simple, fast, and reliable nostr client for secure messaging across all platforms.
 
-### Screenshots
-
-<p float="left">
-  <img src="/docs/mac_01.png" width="250" />
-  <img src="/docs/mac_02.png" width="250" />
-  <img src="/docs/mac_03.png" width="250" />
-  <img src="/docs/mac_04.png" width="250" />
-  <img src="/docs/mac_05.png" width="250" />
-  <img src="/docs/mac_06.png" width="250" />
-  <img src="/docs/mac_07.png" width="250" />
-  <img src="/docs/mac_08.png" width="250" />
-  <img src="/docs/mac_09.png" width="250" />
-  <img src="/docs/linux_01.png" width="250" />
-  <img src="/docs/linux_02.png" width="250" />
-  <img src="/docs/linux_03.png" width="250" />
-  <img src="/docs/linux_04.png" width="250" />
-  <img src="/docs/linux_05.png" width="250" />
-</p>
-
-### Installation
-
-To install Coop, follow these steps:
-
-1. **Download the Latest Release**:
-
-   - Visit the [Coop Releases page on GitHub](https://github.com/reyakov/coop/releases).
-   - Download the package that matches your operating system (Windows, macOS, or Linux).
-
-2. **Install**:
-
-   - **Windows**: Run the downloaded `.exe` installer and follow the on-screen instructions.
-   - **macOS**: Open the downloaded `.dmg` file and drag Coop to your Applications folder.
-   - **Linux**: Run the downloaded `.flatpak` or `.snap` installer and follow the on-screen instructions.
-
-3. **Run Coop**:
-   - Launch Coop from your Applications folder (macOS) or by double-clicking the executable (Windows/Linux).
-
-For more detailed instructions, refer to the [Release Notes](#) on GitHub.
-
-### Developing Coop
-
-Coop is built using Rust and GPUI. All Nostr related stuffs handled by [Rust Nostr SDK](https://github.com/rust-nostr/nostr)
-
-#### Prerequisites
-
-- **Rust Toolchain**: Ensure you have Rust installed. If not, you can install it using [rustup](https://rustup.rs/).
-- **Cargo**: Rust's package manager, which comes bundled with the Rust installation.
-- **Git**: To clone the repository and manage version control.
-
-#### Setting Up the Development Environment
-
-1. Clone the repository:
-
-   ```bash
-   git clone https://github.com/reyakov/coop.git
-   cd coop
-   ```
-
-2.1 Install Linux dependencies:
-
-   ```bash
-   ./script/linux
-   ```
-
-2.2 Install FreeBSD dependencies:
-
-   ```bash
-   ./script/freebsd
-   ```
-
-3. Install Rust dependencies:
-
-   ```bash
-   cargo build
-   ```
-
-4. Run the app:
-   ```bash
-   cargo run
-   ```
-
-#### Building for Production
-
-To build Coop for production, use the following command:
-
-```bash
-cargo build --release
-```
-
-This will generate an optimized binary in the `target/release` directory.
-
-#### Contributing Code
-
-If you'd like to contribute to Coop, please follow these steps:
-
-1. Fork the repository.
-2. Create a new branch for your feature or bugfix.
-3. Make your changes and ensure all tests pass.
-4. Submit a pull request with a detailed description of your changes.
-
-For more information, see the [Contributing](#contributing) section.
-
-#### Additional Resources
-
-- [Rust Nostr](https://github.com/rust-nostr/nostr/)
-- [GPUI](https://www.gpui.rs/)
-- [GPUI Components](https://github.com/longbridge/gpui-component/)
-- [Coop Issue Tracker](https://github.com/reyakov/coop/issues/)
-
 ### License
 
 Copyright (C) 2025 Ren Amamiya & other Coop contributors

assets/icons/compass.svg

@@ -0,0 +1,3 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none">
+<circle cx="12" cy="12" r="9.25" stroke="currentColor" stroke-width="1.5"/><ellipse cx="12" cy="12" rx="3.5" ry="9.25" stroke="currentColor" stroke-width="1.5"/><path d="M3.5 9.25H20.5" stroke="currentColor" stroke-width="1.5"/><path d="M3.5 14.75H20.5" stroke="currentColor" stroke-width="1.5"/>
+</svg>

assets/icons/folder.svg

@@ -0,0 +1,3 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none">
+<path d="M2.75 5.75V17.25C2.75 18.3546 3.64543 19.25 4.75 19.25H19.25C20.3546 19.25 21.25 18.3546 21.25 17.25V8.75C21.25 7.64543 20.3546 6.75 19.25 6.75H13.0704C12.4017 6.75 11.7772 6.4158 11.4063 5.8594L10.5937 4.6406C10.2228 4.0842 9.59834 3.75 8.92963 3.75H4.75C3.64543 3.75 2.75 4.64543 2.75 5.75Z" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+</svg>

assets/icons/lock.svg

@@ -0,0 +1,3 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none">
+<path d="M12 8.75003C11.1716 8.75003 10.5 9.4216 10.5 10.25C10.5 11.0785 11.1716 11.75 12 11.75C12.8284 11.75 13.5 11.0785 13.5 10.25C13.5 9.4216 12.8284 8.75003 12 8.75003ZM12 8.75003V14.75M20.25 11.9124V6.94155C20.25 6.08069 19.6991 5.31641 18.8825 5.04418L12.6325 2.96085C12.2219 2.824 11.7781 2.824 11.3675 2.96085L5.11754 5.04418C4.30086 5.31641 3.75 6.08069 3.75 6.94155V11.9124C3.75 16.8848 8 19.25 12 21.4079C16 19.25 20.25 16.8848 20.25 11.9124Z" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+</svg>

assets/icons/message.svg

@@ -0,0 +1,3 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none">
+<path d="M21.75 12C21.75 6.84375 17.9583 3.75 12 3.75C6.04167 3.75 2.25 6.84375 2.25 12C2.25 13.3368 3.17054 15.6055 3.3145 15.9522C3.32742 15.9833 3.34021 16.0117 3.3518 16.0433C3.45089 16.3136 3.85722 17.7527 2.25 19.8828C4.41667 20.914 6.71766 19.2188 6.71766 19.2188C8.30963 20.0597 10.2038 20.25 12 20.25C17.9583 20.25 21.75 17.1562 21.75 12Z" stroke="currentColor" stroke-width="1.5" stroke-linecap="square" stroke-linejoin="round"/>
+</svg>

assets/themes/aurora.json

@@ -2,7 +2,7 @@
   "id": "aurora",
   "name": "Aurora",
   "author": "Coop",
-  "url": "https://github.com/lumehq/coop",
+  "url": "https://coopchat.xyz",
   "light": {
     "background": "#fdfcfeff",
     "surface_background": "#f8f8ffff",

assets/themes/forest.json

@@ -2,7 +2,7 @@
   "id": "forest",
   "name": "Forest",
   "author": "Coop",
-  "url": "https://github.com/lumehq/coop",
+  "url": "https://coopchat.xyz",
   "light": {
     "background": "#fbfefcff",
     "surface_background": "#f4fbf6ff",

assets/themes/ocean.json

@@ -2,7 +2,7 @@
   "id": "ocean",
   "name": "Ocean",
   "author": "Coop",
-  "url": "https://github.com/lumehq/coop",
+  "url": "https://coopchat.xyz",
   "light": {
     "background": "#fafefeff",
     "surface_background": "#f2fbfaff",

crates/auto_update/Cargo.toml

@@ -5,17 +5,11 @@ edition.workspace = true
 publish.workspace = true
 
 [dependencies]
-common = { path = "../common" }
-
 gpui.workspace = true
-gpui_tokio.workspace = true
-anyhow.workspace = true
-smol.workspace = true
+instant.workspace = true
 log.workspace = true
-smallvec.workspace = true
-serde = { workspace = true, features = ["derive"] }
+serde.workspace = true
 serde_json.workspace = true
+ureq.workspace = true
 
-semver = "1.0.27"
-tempfile = "3.23.0"
-futures.workspace = true
+gpui-updater-core = { git = "https://github.com/AprilNEA/gpui-updater" }

crates/auto_update/src/lib.rs

@@ -1,561 +1,326 @@
-use std::ffi::OsString;
-use std::path::{Path, PathBuf};
+#![cfg(not(target_arch = "wasm32"))]
+
 use std::sync::Arc;
-use std::time::Duration;
+use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
 
-use anyhow::{Context as AnyhowContext, Error, anyhow};
-use gpui::http_client::{AsyncBody, HttpClient};
-use gpui::{
-    App, AppContext, AsyncApp, BackgroundExecutor, Context, Entity, Global, Subscription, Task,
-    Window,
-};
-use semver::Version;
-use serde::Deserialize;
-use smallvec::{SmallVec, smallvec};
-use smol::fs::File;
-use smol::io::AsyncReadExt;
-use smol::process::Command;
+use gpui::{App, AppContext, Context, Entity, Global, SharedString, Task, Window};
+use gpui_updater_core::{EngineConfig, Release, UpdateEngine, UpdateStatus, Verification, Version};
+use instant::Duration;
+
+use crate::source::{AssetFilter, GiteaSource, asset_filter_for};
+
+mod source;
+
+pub use gpui_updater_core::UpdateStatus as AutoUpdateStatus;
+
+const GITEA_API_BASE: &str = "https://git.reya.info/api/v1";
+const GITEA_REPO_OWNER: &str = "reya";
+const GITEA_REPO_NAME: &str = "coop";
+
+/// Delay before the automatic check that runs on startup.
+const AUTO_CHECK_DELAY: Duration = Duration::from_secs(120);
+/// How long a failure stays visible before the status reverts to "Up to date".
+const ERROR_DISPLAY_DURATION: Duration = Duration::from_secs(5);
 
-const GITHUB_API_URL: &str = "https://api.github.com";
 const COOP_UPDATE_EXPLANATION: &str = "COOP_UPDATE_EXPLANATION";
+const COOP_BUNDLE_TYPE: &str = "COOP_BUNDLE_TYPE";
 
-fn get_github_repo_owner() -> String {
-    std::env::var("COOP_GITHUB_REPO_OWNER").unwrap_or_else(|_| "reyakov".to_string())
-}
-
-fn get_github_repo_name() -> String {
-    std::env::var("COOP_GITHUB_REPO_NAME").unwrap_or_else(|_| "coop".to_string())
-}
-
-fn is_flatpak_installation() -> bool {
-    // Check if app is installed via Flatpak
-    std::env::var("FLATPAK_ID").is_ok() || std::env::var(COOP_UPDATE_EXPLANATION).is_ok()
+fn uses_managed_updates() -> bool {
+    // The Flatpak runtime exports `FLATPAK_ID` inside the sandbox.
+    std::env::var("FLATPAK_ID").is_ok()
+        // Allow opting out of in-app updates via an explicit environment variable.
+        || std::env::var(COOP_UPDATE_EXPLANATION).is_ok()
+        // The Snap package sets `COOP_BUNDLE_TYPE=snap` (see snapcraft.yaml.in).
+        || std::env::var(COOP_BUNDLE_TYPE).is_ok_and(|value| value == "snap")
 }
 
+/// Initialize the auto-update system.
 pub fn init(window: &mut Window, cx: &mut App) {
-    // Skip auto-update initialization if installed via Flatpak
-    if is_flatpak_installation() {
-        log::info!("Skipping auto-update initialization: App is installed via Flatpak");
+    if uses_managed_updates() {
+        log::info!(
+            "Skipping auto-update initialization: updates are managed by the installed distribution channel (Flatpak/Snap)"
+        );
         return;
     }
 
-    AutoUpdater::set_global(cx.new(|cx| AutoUpdater::new(window, cx)), cx);
+    let (os, arch) = (std::env::consts::OS, std::env::consts::ARCH);
+
+    let Some(filter) = asset_filter_for(os, arch) else {
+        log::info!(
+            "Skipping auto-update initialization: no installable release artifact is published for {os}/{arch}"
+        );
+        return;
+    };
+
+    let Ok(version) = Version::parse(env!("CARGO_PKG_VERSION")) else {
+        log::error!(
+            "Skipping auto-update initialization: crate version {:?} is not valid semver",
+            env!("CARGO_PKG_VERSION")
+        );
+        return;
+    };
+
+    AutoUpdater::set_global(
+        cx.new(|cx| AutoUpdater::new(window, version, filter, cx)),
+        cx,
+    );
 }
 
 struct GlobalAutoUpdater(Entity<AutoUpdater>);
 
 impl Global for GlobalAutoUpdater {}
 
-#[cfg(not(target_os = "windows"))]
-struct InstallerDir(tempfile::TempDir);
-
-#[cfg(not(target_os = "windows"))]
-impl InstallerDir {
-    async fn new() -> Result<Self, Error> {
-        Ok(Self(
-            tempfile::Builder::new()
-                .prefix("coop-auto-update")
-                .tempdir()?,
-        ))
-    }
-
-    fn path(&self) -> &Path {
-        self.0.path()
-    }
-}
-
-#[cfg(target_os = "windows")]
-struct InstallerDir(PathBuf);
-
-#[cfg(target_os = "windows")]
-impl InstallerDir {
-    async fn new() -> Result<Self, Error> {
-        let installer_dir = std::env::current_exe()?
-            .parent()
-            .context("No parent dir for Coop.exe")?
-            .join("updates");
-
-        if smol::fs::metadata(&installer_dir).await.is_ok() {
-            smol::fs::remove_dir_all(&installer_dir).await?;
-        }
-
-        smol::fs::create_dir(&installer_dir).await?;
-
-        Ok(Self(installer_dir))
-    }
-
-    fn path(&self) -> &Path {
-        self.0.as_path()
-    }
-}
-
-struct MacOsUnmounter<'a> {
-    mount_path: PathBuf,
-    background_executor: &'a BackgroundExecutor,
-}
-
-impl Drop for MacOsUnmounter<'_> {
-    fn drop(&mut self) {
-        let mount_path = std::mem::take(&mut self.mount_path);
-
-        self.background_executor
-            .spawn(async move {
-                let unmount_output = Command::new("hdiutil")
-                    .args(["detach", "-force"])
-                    .arg(&mount_path)
-                    .output()
-                    .await;
-
-                match unmount_output {
-                    Ok(output) if output.status.success() => {
-                        log::info!("Successfully unmounted the disk image");
-                    }
-                    Ok(output) => {
-                        log::error!(
-                            "Failed to unmount disk image: {:?}",
-                            String::from_utf8_lossy(&output.stderr)
-                        );
-                    }
-                    Err(error) => {
-                        log::error!("Error while trying to unmount disk image: {:?}", error);
-                    }
-                }
-            })
-            .detach();
-    }
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
-pub enum AutoUpdateStatus {
-    Idle,
-    Checking,
-    Checked { download_url: String },
-    Installing,
-    Updated,
-    Errored { msg: Box<String> },
-}
-
-impl AsRef<AutoUpdateStatus> for AutoUpdateStatus {
-    fn as_ref(&self) -> &AutoUpdateStatus {
-        self
-    }
-}
-
-impl AutoUpdateStatus {
-    pub fn is_updating(&self) -> bool {
-        matches!(self, Self::Checked { .. } | Self::Installing)
-    }
-
-    pub fn is_updated(&self) -> bool {
-        matches!(self, Self::Updated)
-    }
-
-    pub fn checked(download_url: String) -> Self {
-        Self::Checked { download_url }
-    }
-
-    pub fn error(e: String) -> Self {
-        Self::Errored { msg: Box::new(e) }
-    }
-}
-
-#[derive(Debug, Deserialize)]
-pub struct GitHubRelease {
-    pub tag_name: String,
-    pub assets: Vec<GitHubAsset>,
-}
-
-#[derive(Debug, Deserialize)]
-pub struct GitHubAsset {
-    pub name: String,
-    pub browser_download_url: String,
-}
-
-#[derive(Debug)]
 pub struct AutoUpdater {
-    /// Current status of the auto updater
-    pub status: AutoUpdateStatus,
-
-    /// Current version of the application
+    /// The blocking engine, driven on the background executor.
+    engine: Arc<UpdateEngine<GiteaSource>>,
+    status: UpdateStatus,
+    /// The newer release found by the last successful check, if any.
+    available: Option<Release>,
+    /// Currently running app version.
     pub version: Version,
-
-    /// Event subscriptions
-    _subscriptions: SmallVec<[Subscription; 1]>,
-
-    /// Background tasks
-    tasks: Vec<Task<Result<(), Error>>>,
+    /// The in-flight check or download, if any.
+    task: Option<Task<()>>,
 }
 
 impl AutoUpdater {
-    /// Retrieve the global auto updater instance
+    /// Whether auto-update is available for this installation.
+    pub fn is_available(cx: &App) -> bool {
+        cx.try_global::<GlobalAutoUpdater>().is_some()
+    }
+
+    /// Retrieve the global auto updater instance, if one was initialized.
+    pub fn try_global(cx: &App) -> Option<Entity<Self>> {
+        cx.try_global::<GlobalAutoUpdater>()
+            .map(|global| global.0.clone())
+    }
+
+    /// Retrieve the global auto updater instance.
     pub fn global(cx: &App) -> Entity<Self> {
         cx.global::<GlobalAutoUpdater>().0.clone()
     }
 
-    /// Set the global auto updater instance
     fn set_global(state: Entity<Self>, cx: &mut App) {
         cx.set_global(GlobalAutoUpdater(state));
     }
 
-    fn new(window: &mut Window, cx: &mut Context<Self>) -> Self {
-        let version = Version::parse(env!("CARGO_PKG_VERSION")).unwrap();
-        let mut subscriptions = smallvec![];
+    fn new(
+        window: &mut Window,
+        version: Version,
+        filter: AssetFilter,
+        cx: &mut Context<Self>,
+    ) -> Self {
+        let source = GiteaSource::new(GITEA_API_BASE, GITEA_REPO_OWNER, GITEA_REPO_NAME, filter);
+        let config = EngineConfig::new(version.clone()).verification(Verification::Checksum);
+        let engine = Arc::new(UpdateEngine::new(source, config));
 
-        subscriptions.push(
-            // Observe the status
-            cx.observe_self(|this, cx| {
-                if let AutoUpdateStatus::Checked { download_url } = this.status.clone() {
-                    this.download_and_install(&download_url, cx);
-                }
-            }),
-        );
-
-        // Run at the end of current cycle
-        cx.defer_in(window, |this, _window, cx| {
-            this.check(cx);
+        // Schedule an auto-check after a 2-minute delay
+        cx.defer_in(window, |_this, _window, cx| {
+            cx.spawn(async move |this, cx| {
+                cx.background_executor().timer(AUTO_CHECK_DELAY).await;
+                this.update(cx, |this, cx| this.check(cx)).ok();
+            })
+            .detach();
         });
 
         Self {
-            status: AutoUpdateStatus::Idle,
+            engine,
+            status: UpdateStatus::Idle,
+            available: None,
             version,
-            tasks: vec![],
-            _subscriptions: subscriptions,
+            task: None,
         }
     }
 
-    fn set_status(&mut self, status: AutoUpdateStatus, cx: &mut Context<Self>) {
-        self.status = status;
-        cx.notify();
+    /// Whether nothing is happening, so the UI can hide the status line.
+    pub fn idle(&self) -> bool {
+        matches!(self.status, UpdateStatus::Idle)
     }
 
-    fn check(&mut self, cx: &mut Context<Self>) {
-        let version = self.version.clone();
-        let duration = Duration::from_secs(120);
-        let task = self.check_for_updates(version, cx);
+    /// Whether a verified update is installed and waiting for a restart.
+    pub fn staged(&self) -> bool {
+        matches!(self.status, UpdateStatus::Staged(_))
+    }
 
-        // Check for updates after 2 minutes
-        self.tasks.push(cx.spawn(async move |this, cx| {
-            cx.background_executor().timer(duration).await;
-
-            // Update the status to checking
-            this.update(cx, |this, cx| {
-                this.set_status(AutoUpdateStatus::Checking, cx);
-            })?;
-
-            match task.await {
-                Ok(download_url) => {
-                    // Update the status to checked with download URL
-                    this.update(cx, |this, cx| {
-                        this.set_status(AutoUpdateStatus::checked(download_url), cx);
-                    })?;
-                }
-                Err(e) => {
-                    log::warn!("Failed to check for updates: {e}");
-                    this.update(cx, |this, cx| {
-                        this.set_status(AutoUpdateStatus::Idle, cx);
-                    })?;
+    /// A short, human-readable description of the current status.
+    pub fn status(&self) -> SharedString {
+        match &self.status {
+            UpdateStatus::Idle | UpdateStatus::UpToDate => "Up to date".into(),
+            UpdateStatus::Checking => "Checking for updates…".into(),
+            UpdateStatus::Available(version) => format!("Version {version} available").into(),
+            UpdateStatus::Downloading { downloaded, total } => {
+                let total_mb = total.map(|t| t as f64 / 1_048_576.0);
+                let downloaded_mb = *downloaded as f64 / 1_048_576.0;
+                match total_mb {
+                    Some(t) => format!("Downloading {downloaded_mb:.1} / {t:.1} MB").into(),
+                    None => format!("Downloading {downloaded_mb:.1} MB").into(),
                 }
             }
+            UpdateStatus::Installing => "Installing update…".into(),
+            UpdateStatus::Staged(version) => {
+                format!("Version {version} ready — restart to apply").into()
+            }
+            UpdateStatus::Errored(message) => format!("Update failed: {message}").into(),
+        }
+    }
 
-            Ok(())
+    /// Check the release host for a newer version, then download and install it.
+    pub fn check(&mut self, cx: &mut Context<Self>) {
+        if self.status.is_busy() {
+            return;
+        }
+        self.set_status(UpdateStatus::Checking, cx);
+
+        let engine = self.engine.clone();
+
+        self.task = Some(cx.spawn(async move |this, cx| {
+            let result = cx
+                .background_executor()
+                .spawn(async move { engine.check() })
+                .await;
+
+            this.update(cx, |this, cx| {
+                this.task = None;
+                match result {
+                    Ok(Some(release)) => {
+                        log::info!("Update {} is available", release.version);
+                        let version = release.version.clone();
+                        this.available = Some(release);
+                        this.set_status(UpdateStatus::Available(version), cx);
+                        this.download_and_install(cx);
+                    }
+                    Ok(None) => this.set_status(UpdateStatus::UpToDate, cx),
+                    Err(error) => {
+                        log::warn!("Update check failed: {error}");
+                        this.set_status(UpdateStatus::Errored(error.to_string()), cx);
+                    }
+                }
+            })
+            .ok();
         }));
     }
 
-    fn check_for_updates(&self, version: Version, cx: &App) -> Task<Result<String, Error>> {
-        let http_client = cx.http_client();
-        let repo_owner = get_github_repo_owner();
-        let repo_name = get_github_repo_name();
+    /// Download the available update, verify it, and swap it into place.
+    fn download_and_install(&mut self, cx: &mut Context<Self>) {
+        if self.status.is_busy() {
+            return;
+        }
+        let Some(release) = self.available.clone() else {
+            return;
+        };
 
-        cx.background_spawn(async move {
-            let url = format!(
-                "{}/repos/{}/{}/releases/latest",
-                GITHUB_API_URL, repo_owner, repo_name
-            );
+        let engine = self.engine.clone();
+        self.set_status(
+            UpdateStatus::Downloading {
+                downloaded: 0,
+                total: None,
+            },
+            cx,
+        );
 
-            let async_body = AsyncBody::default();
-            let mut body = Vec::new();
-            let mut response = http_client.get(&url, async_body, false).await?;
+        self.task = Some(cx.spawn(async move |this, cx| {
+            let downloaded = Arc::new(AtomicU64::new(0));
+            let total = Arc::new(AtomicU64::new(0)); // 0 = unknown
+            let done = Arc::new(AtomicBool::new(false));
 
-            // Read the response body into a vector
-            response.body_mut().read_to_end(&mut body).await?;
+            let download_task = {
+                let (engine, release) = (engine.clone(), release.clone());
+                let (downloaded, total, done) = (downloaded.clone(), total.clone(), done.clone());
+                cx.background_executor().spawn(async move {
+                    let result = engine.download(&release, |got, expected| {
+                        downloaded.store(got, Ordering::Relaxed);
+                        total.store(expected.unwrap_or(0), Ordering::Relaxed);
+                    });
+                    done.store(true, Ordering::Relaxed);
+                    result
+                })
+            };
 
-            if !response.status().is_success() {
-                return Err(anyhow!("GitHub API returned error: {}", response.status()));
-            }
-
-            // Parse the response body as JSON
-            let release: GitHubRelease = serde_json::from_slice(&body)?;
-
-            // Parse version from tag (remove 'v' prefix if present)
-            let tag_version = release.tag_name.trim_start_matches('v');
-            let new_version = Version::parse(tag_version).context(format!(
-                "Failed to parse version from tag: {}",
-                release.tag_name
-            ))?;
-
-            if new_version > version {
-                // Find the appropriate asset for the current platform
-                let current_os = std::env::consts::OS;
-                let asset_name = match current_os {
-                    "macos" => "Coop.dmg",
-                    "linux" => "coop.tar.gz",
-                    "windows" => "Coop.exe",
-                    _ => return Err(anyhow!("Unsupported OS: {}", current_os)),
-                };
-
-                let download_url = release
-                    .assets
-                    .iter()
-                    .find(|asset| asset.name == asset_name)
-                    .map(|asset| asset.browser_download_url.clone())
-                    .context(format!(
-                        "No {} asset found in release {}",
-                        asset_name, release.tag_name
-                    ))?;
-
-                Ok(download_url)
-            } else {
-                Err(anyhow!(
-                    "No update available. Current: {}, Latest: {}",
-                    version,
-                    new_version
-                ))
-            }
-        })
-    }
-
-    fn download_and_install(&mut self, download_url: &str, cx: &mut Context<Self>) {
-        let http_client = cx.http_client();
-        let download_url = download_url.to_string();
-
-        let task: Task<Result<(InstallerDir, PathBuf), Error>> = cx.background_spawn(async move {
-            let installer_dir = InstallerDir::new().await?;
-            let target_path = Self::target_path(&installer_dir).await?;
-
-            // Download the release
-            download(&download_url, &target_path, http_client).await?;
-
-            Ok((installer_dir, target_path))
-        });
-
-        self.tasks.push(
-            // Install the new release
-            cx.spawn(async move |this, cx| {
+            loop {
+                let got = downloaded.load(Ordering::Relaxed);
+                let total = total.load(Ordering::Relaxed);
                 this.update(cx, |this, cx| {
-                    this.set_status(AutoUpdateStatus::Installing, cx);
-                })?;
+                    this.set_status(
+                        UpdateStatus::Downloading {
+                            downloaded: got,
+                            total: (total != 0).then_some(total),
+                        },
+                        cx,
+                    );
+                })
+                .ok();
+                if done.load(Ordering::Relaxed) {
+                    break;
+                }
+                cx.background_executor()
+                    .timer(Duration::from_millis(120))
+                    .await;
+            }
 
-                match task.await {
-                    Ok((installer_dir, target_path)) => {
-                        if Self::install(installer_dir, target_path, cx).await.is_ok() {
-                            // Update the status to updated
-                            this.update(cx, |this, cx| {
-                                this.set_status(AutoUpdateStatus::Updated, cx);
-                            })?;
+            let artifact = match download_task.await {
+                Ok(artifact) => artifact,
+                Err(error) => {
+                    log::warn!("Update download failed: {error}");
+                    this.update(cx, |this, cx| {
+                        this.task = None;
+                        this.set_status(UpdateStatus::Errored(error.to_string()), cx);
+                    })
+                    .ok();
+                    return;
+                }
+            };
+
+            let _ = this.update(cx, |this, cx| this.set_status(UpdateStatus::Installing, cx));
+
+            let installed = {
+                let engine = engine.clone();
+                cx.background_executor()
+                    .spawn(async move { engine.install(&artifact) })
+                    .await
+            };
+
+            this.update(cx, |this, cx| {
+                this.task = None;
+                match installed {
+                    Ok(installed) => {
+                        if let Some(path) = installed.restart_path {
+                            cx.set_restart_path(path);
                         }
+                        let version = release.version.clone();
+                        this.set_status(UpdateStatus::Staged(version), cx);
                     }
-                    Err(e) => {
-                        // Update the status to error including the error message
-                        this.update(cx, |this, cx| {
-                            this.set_status(AutoUpdateStatus::error(e.to_string()), cx);
-                        })?;
+                    Err(error) => {
+                        this.set_status(UpdateStatus::Errored(error.to_string()), cx);
                     }
                 }
-
-                Ok(())
-            }),
-        );
+            })
+            .ok();
+        }));
     }
 
-    async fn target_path(installer_dir: &InstallerDir) -> Result<PathBuf, Error> {
-        let filename = match std::env::consts::OS {
-            "macos" => anyhow::Ok("Coop.dmg"),
-            "linux" => Ok("coop.tar.gz"),
-            "windows" => Ok("Coop.exe"),
-            unsupported_os => anyhow::bail!("not supported: {unsupported_os}"),
-        }?;
-
-        Ok(installer_dir.path().join(filename))
-    }
-
-    async fn install(
-        installer_dir: InstallerDir,
-        target_path: PathBuf,
-        cx: &AsyncApp,
-    ) -> Result<(), Error> {
-        match std::env::consts::OS {
-            "macos" => install_release_macos(&installer_dir, target_path, cx).await,
-            "linux" => install_release_linux(&installer_dir, target_path, cx).await,
-            "windows" => install_release_windows(target_path).await,
-            unsupported_os => anyhow::bail!("Not supported: {unsupported_os}"),
+    /// Relaunch into the staged update.
+    pub fn restart(&mut self, cx: &mut Context<Self>) {
+        if !self.staged() {
+            log::warn!("Ignoring restart request: no update is staged");
+            return;
         }
+        cx.restart();
     }
-}
 
-async fn download(
-    url: &str,
-    target_path: &std::path::Path,
-    client: Arc<dyn HttpClient>,
-) -> Result<(), Error> {
-    let body = AsyncBody::default();
-    let mut target_file = File::create(&target_path).await?;
-    let mut response = client.get(url, body, true).await?;
+    fn set_status(&mut self, status: UpdateStatus, cx: &mut Context<Self>) {
+        let errored = matches!(status, UpdateStatus::Errored(_));
+        self.status = status;
 
-    // Copy the response body to the target file
-    smol::io::copy(response.body_mut(), &mut target_file).await?;
-
-    Ok(())
-}
-
-async fn install_release_macos(
-    temp_dir: &InstallerDir,
-    downloaded_dmg: PathBuf,
-    cx: &AsyncApp,
-) -> Result<(), Error> {
-    let running_app_path = cx.update(|cx| cx.app_path())?;
-    let running_app_filename = running_app_path
-        .file_name()
-        .with_context(|| format!("invalid running app path {running_app_path:?}"))?;
-
-    let mount_path = temp_dir.path().join("Coop");
-    let mut mounted_app_path: OsString = mount_path.join(running_app_filename).into();
-
-    mounted_app_path.push("/");
-
-    let output = Command::new("hdiutil")
-        .args(["attach", "-nobrowse"])
-        .arg(&downloaded_dmg)
-        .arg("-mountroot")
-        .arg(temp_dir.path())
-        .output()
-        .await?;
-
-    anyhow::ensure!(
-        output.status.success(),
-        "failed to mount: {:?}",
-        String::from_utf8_lossy(&output.stderr)
-    );
-
-    // Create an MacOsUnmounter that will be dropped (and thus unmount the disk) when this function exits
-    let _unmounter = MacOsUnmounter {
-        mount_path: mount_path.clone(),
-        background_executor: cx.background_executor(),
-    };
-
-    let output = Command::new("rsync")
-        .args(["-av", "--delete"])
-        .arg(&mounted_app_path)
-        .arg(&running_app_path)
-        .output()
-        .await?;
-
-    anyhow::ensure!(
-        output.status.success(),
-        "failed to copy app: {:?}",
-        String::from_utf8_lossy(&output.stderr)
-    );
-
-    Ok(())
-}
-
-async fn install_release_linux(
-    temp_dir: &InstallerDir,
-    downloaded_tar_gz: PathBuf,
-    cx: &AsyncApp,
-) -> Result<(), Error> {
-    let running_app_path = cx.update(|cx| cx.app_path())?;
-
-    // Extract the tar.gz file
-    let extracted = temp_dir.path().join("coop");
-    smol::fs::create_dir_all(&extracted)
-        .await
-        .context("failed to create directory to extract update")?;
-
-    let output = Command::new("tar")
-        .arg("-xzf")
-        .arg(&downloaded_tar_gz)
-        .arg("-C")
-        .arg(&extracted)
-        .output()
-        .await?;
-
-    anyhow::ensure!(
-        output.status.success(),
-        "failed to extract {:?} to {:?}: {:?}",
-        downloaded_tar_gz,
-        extracted,
-        String::from_utf8_lossy(&output.stderr)
-    );
-
-    // Find the extracted app directory
-    let mut entries = smol::fs::read_dir(&extracted).await?;
-    let mut app_dir = None;
-
-    use smol::stream::StreamExt;
-
-    while let Some(entry) = entries.next().await {
-        let entry = entry?;
-        let path = entry.path();
-        if path.is_dir() {
-            app_dir = Some(path);
-            break;
+        if errored {
+            cx.spawn(async move |this, cx| {
+                cx.background_executor().timer(ERROR_DISPLAY_DURATION).await;
+                this.update(cx, |this, cx| {
+                    this.set_status(UpdateStatus::Idle, cx);
+                })
+                .ok();
+            })
+            .detach();
         }
+
+        cx.notify();
     }
-
-    let from = app_dir.context("No app directory found in archive")?;
-
-    // Copy to the current installation directory
-    let output = Command::new("rsync")
-        .args(["-av", "--delete"])
-        .arg(&from)
-        .arg(
-            running_app_path
-                .parent()
-                .context("No parent directory for app")?,
-        )
-        .output()
-        .await?;
-
-    anyhow::ensure!(
-        output.status.success(),
-        "failed to copy app from {:?} to {:?}: {:?}",
-        from,
-        running_app_path.parent(),
-        String::from_utf8_lossy(&output.stderr)
-    );
-
-    Ok(())
-}
-
-async fn install_release_windows(downloaded_installer: PathBuf) -> Result<(), Error> {
-    //const CREATE_NO_WINDOW: u32 = 0x08000000;
-
-    let system_root = std::env::var("SYSTEMROOT");
-    let powershell_path = system_root.as_ref().map_or_else(
-        |_| "powershell.exe".to_string(),
-        |p| format!("{p}\\System32\\WindowsPowerShell\\v1.0\\powershell.exe"),
-    );
-
-    let mut installer_path = std::ffi::OsString::new();
-    installer_path.push("\"");
-    installer_path.push(&downloaded_installer);
-    installer_path.push("\"");
-
-    let output = Command::new(powershell_path)
-        //.creation_flags(CREATE_NO_WINDOW)
-        .args(["-NoProfile", "-WindowStyle", "Hidden"])
-        .args(["Start-Process"])
-        .arg(installer_path)
-        .arg("-ArgumentList")
-        .args(["/P", "/R"])
-        .output()
-        .await?;
-
-    anyhow::ensure!(
-        output.status.success(),
-        "failed to start installer: {:?}",
-        String::from_utf8_lossy(&output.stderr)
-    );
-
-    Ok(())
 }

crates/auto_update/src/source.rs

@@ -0,0 +1,369 @@
+use gpui_updater_core::{Asset, Error, Release, Result, UpdateSource, parse_tag};
+use serde::Deserialize;
+
+const CHECKSUMS_ASSET: &str = "SHA256SUMS";
+const RELEASE_PAGE_SIZE: usize = 20;
+
+/// Which published artifact belongs to a target platform.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct AssetFilter {
+    extension: &'static str,
+    arch: &'static str,
+}
+
+impl AssetFilter {
+    /// Whether `name` is the installable artifact for this target.
+    fn matches(&self, name: &str) -> bool {
+        let name = name.to_ascii_lowercase();
+        name.ends_with(self.extension) && name.contains(self.arch)
+    }
+}
+
+pub fn asset_filter_for(os: &str, arch: &str) -> Option<AssetFilter> {
+    let extension = match os {
+        "macos" => ".dmg",
+        "linux" => ".tar.gz",
+        _ => return None,
+    };
+
+    let arch = match (os, arch) {
+        // cargo-packager names the disk images `aarch64`/`x64`.
+        ("macos", "aarch64") => "aarch64",
+        ("macos", "x86_64") => "x64",
+        // `script/bundle-linux` names the tarballs `aarch64`/`x86_64`.
+        ("linux", "aarch64") => "aarch64",
+        ("linux", "x86_64") => "x86_64",
+        _ => return None,
+    };
+
+    Some(AssetFilter { extension, arch })
+}
+
+/// Reads releases from a Gitea repository's Releases.
+pub struct GiteaSource {
+    api_base: String,
+    owner: String,
+    repo: String,
+    filter: AssetFilter,
+}
+
+impl GiteaSource {
+    /// Build a source for `owner/repo` on the Gitea instance at `api_base`
+    /// (e.g. `https://git.reya.info/api/v1`).
+    pub fn new(
+        api_base: impl Into<String>,
+        owner: impl Into<String>,
+        repo: impl Into<String>,
+        filter: AssetFilter,
+    ) -> Self {
+        Self {
+            api_base: api_base.into().trim_end_matches('/').to_string(),
+            owner: owner.into(),
+            repo: repo.into(),
+            filter,
+        }
+    }
+
+    fn releases_url(&self) -> String {
+        format!(
+            "{}/repos/{}/{}/releases?limit={RELEASE_PAGE_SIZE}",
+            self.api_base, self.owner, self.repo
+        )
+    }
+}
+
+impl UpdateSource for GiteaSource {
+    fn fetch_latest(&self) -> Result<Release> {
+        let releases: Vec<GiteaRelease> = http::get_json(&self.releases_url())?;
+        let release = newest_published(&releases)
+            .ok_or_else(|| Error::Parse("repository has no published releases".to_string()))?;
+
+        let asset = release
+            .assets
+            .iter()
+            .find(|asset| self.filter.matches(&asset.name))
+            .ok_or(Error::NoMatchingAsset {
+                target_os: std::env::consts::OS,
+                target_arch: std::env::consts::ARCH,
+            })?;
+
+        // Resolve the published checksum so the engine can reject a truncated or substituted download.
+        let sha256 = release
+            .assets
+            .iter()
+            .find(|candidate| candidate.name.eq_ignore_ascii_case(CHECKSUMS_ASSET))
+            .map(|sums| http::get_string(&sums.browser_download_url))
+            .transpose()?
+            .and_then(|sums| sha256_for(&sums, &asset.name));
+
+        Ok(Release {
+            version: parse_tag(&release.tag_name)?,
+            notes: release
+                .body
+                .clone()
+                .filter(|body| !body.trim().is_empty())
+                .or_else(|| release.name.clone()),
+            asset: Asset {
+                name: asset.name.clone(),
+                url: asset.browser_download_url.clone(),
+                size: asset.size,
+            },
+            signature: None,
+            signature_url: None,
+            sha256,
+        })
+    }
+}
+
+fn newest_published(releases: &[GiteaRelease]) -> Option<&GiteaRelease> {
+    releases
+        .iter()
+        .filter(|release| !release.draft && !release.prerelease)
+        .filter_map(|release| {
+            parse_tag(&release.tag_name)
+                .ok()
+                .map(|version| (version, release))
+        })
+        .max_by(|(left, _), (right, _)| left.cmp(right))
+        .map(|(_, release)| release)
+}
+
+/// The SHA-256 recorded for `asset_name` in a `shasum`-style checksums file.
+fn sha256_for(sums: &str, asset_name: &str) -> Option<String> {
+    sums.lines().find_map(|line| {
+        let mut parts = line.split_whitespace();
+        let (hash, path) = (parts.next()?, parts.next()?);
+        let path = path.strip_prefix('*').unwrap_or(path);
+        let base = path.rsplit(['/', '\\']).next().unwrap_or(path);
+        (base == asset_name).then(|| hash.to_ascii_lowercase())
+    })
+}
+
+/// A release as returned by the Gitea API.
+#[derive(Debug, Deserialize)]
+struct GiteaRelease {
+    tag_name: String,
+    #[serde(default)]
+    name: Option<String>,
+    #[serde(default)]
+    body: Option<String>,
+    #[serde(default)]
+    draft: bool,
+    #[serde(default)]
+    prerelease: bool,
+    #[serde(default)]
+    assets: Vec<GiteaAsset>,
+}
+
+/// A release asset as returned by the Gitea API.
+#[derive(Debug, Deserialize)]
+struct GiteaAsset {
+    name: String,
+    browser_download_url: String,
+    #[serde(default)]
+    size: u64,
+}
+
+/// Blocking HTTP helpers for release metadata.
+mod http {
+    use std::time::Duration;
+
+    use gpui_updater_core::{Error, Result};
+    use serde::de::DeserializeOwned;
+    use ureq::Agent;
+    use ureq::tls::{RootCerts, TlsConfig};
+
+    const USER_AGENT: &str = concat!("coop-updater/", env!("CARGO_PKG_VERSION"));
+    const CONNECT_TIMEOUT: Duration = Duration::from_secs(15);
+    const RESPONSE_TIMEOUT: Duration = Duration::from_secs(30);
+
+    fn agent() -> Agent {
+        Agent::config_builder()
+            .user_agent(USER_AGENT)
+            .tls_config(
+                TlsConfig::builder()
+                    .root_certs(RootCerts::PlatformVerifier)
+                    .build(),
+            )
+            .timeout_resolve(Some(CONNECT_TIMEOUT))
+            .timeout_connect(Some(CONNECT_TIMEOUT))
+            .timeout_recv_response(Some(RESPONSE_TIMEOUT))
+            .build()
+            .into()
+    }
+
+    fn get_bytes(url: &str) -> Result<Vec<u8>> {
+        let mut response = agent().get(url).call().map_err(|error| match error {
+            ureq::Error::StatusCode(code) => Error::Http(format!("GET {url} -> {code}")),
+            other => Error::Http(other.to_string()),
+        })?;
+
+        response
+            .body_mut()
+            .read_to_vec()
+            .map_err(|error| Error::Http(format!("GET {url} -> {error}")))
+    }
+
+    pub(super) fn get_json<T: DeserializeOwned>(url: &str) -> Result<T> {
+        serde_json::from_slice(&get_bytes(url)?).map_err(|error| Error::Parse(error.to_string()))
+    }
+
+    pub(super) fn get_string(url: &str) -> Result<String> {
+        String::from_utf8(get_bytes(url)?).map_err(|error| Error::Parse(error.to_string()))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use gpui_updater_core::Version;
+
+    use super::*;
+
+    const PUBLISHED: &[&str] = &[
+        "Coop_1.0.1_aarch64.dmg",
+        "Coop_1.0.1_x64.dmg",
+        "coop-linux-aarch64.tar.gz",
+        "coop-linux-x86_64.tar.gz",
+        "coop_1.0.1_aarch64.snap",
+        "coop_1.0.1_arm64-setup.exe",
+        "coop_1.0.1_x64-setup.exe",
+        "coop_1.0.1_x86_64.snap",
+        "su.reya.coop_aarch64.flatpak",
+        "su.reya.coop_x86_64.flatpak",
+    ];
+
+    fn selected(os: &str, arch: &str) -> Option<&'static str> {
+        let filter = asset_filter_for(os, arch)?;
+        PUBLISHED.iter().copied().find(|name| filter.matches(name))
+    }
+
+    #[test]
+    fn picks_the_artifact_matching_os_and_architecture() {
+        assert_eq!(selected("macos", "aarch64"), Some("Coop_1.0.1_aarch64.dmg"));
+        assert_eq!(selected("macos", "x86_64"), Some("Coop_1.0.1_x64.dmg"));
+        assert_eq!(
+            selected("linux", "aarch64"),
+            Some("coop-linux-aarch64.tar.gz")
+        );
+        assert_eq!(
+            selected("linux", "x86_64"),
+            Some("coop-linux-x86_64.tar.gz")
+        );
+    }
+
+    #[test]
+    fn has_no_target_for_windows_or_unknown_platforms() {
+        assert_eq!(asset_filter_for("windows", "x86_64"), None);
+        assert_eq!(asset_filter_for("freebsd", "x86_64"), None);
+        assert_eq!(asset_filter_for("macos", "riscv64"), None);
+    }
+
+    #[test]
+    fn ignores_package_formats_and_sidecars_that_are_not_the_artifact() {
+        let macos = asset_filter_for("macos", "aarch64").unwrap();
+        assert!(!macos.matches("coop_1.0.1_aarch64.snap"));
+        assert!(!macos.matches("su.reya.coop_aarch64.flatpak"));
+        assert!(!macos.matches("Coop_1.0.1_aarch64.dmg.minisig"));
+
+        let linux = asset_filter_for("linux", "x86_64").unwrap();
+        assert!(!linux.matches("coop_1.0.1_x64-setup.exe"));
+        assert!(!linux.matches("coop_1.0.1_x86_64.snap"));
+    }
+
+    #[test]
+    fn reads_checksums_by_basename_ignoring_directory_prefix() {
+        let sums = "\
+abcdef  macos-arm64-artifacts/Coop_1.0.1_aarch64.dmg
+123456  *linux-x64-artifacts/coop-linux-x86_64.tar.gz
+789abc  SHA256SUMS
+";
+        assert_eq!(
+            sha256_for(sums, "Coop_1.0.1_aarch64.dmg").as_deref(),
+            Some("abcdef")
+        );
+        assert_eq!(
+            sha256_for(sums, "coop-linux-x86_64.tar.gz").as_deref(),
+            Some("123456")
+        );
+        assert_eq!(sha256_for(sums, "coop_1.0.1_x64-setup.exe"), None);
+    }
+
+    #[test]
+    fn newest_published_skips_drafts_prereleases_and_bad_tags() {
+        let releases: Vec<GiteaRelease> = serde_json::from_str(
+            r#"[
+                {
+                    "tag_name": "v1.0.2",
+                    "draft": true,
+                    "assets": []
+                },
+                {
+                    "tag_name": "v2.0.0-rc.1",
+                    "prerelease": true,
+                    "assets": []
+                },
+                {
+                    "tag_name": "nightly",
+                    "assets": []
+                },
+                {
+                    "tag_name": "v1.0.0",
+                    "assets": [
+                        {
+                            "name": "coop-linux-x86_64.tar.gz",
+                            "browser_download_url": "https://git.reya.info/reya/coop/releases/download/v1.0.0/coop-linux-x86_64.tar.gz",
+                            "size": 26160329
+                        }
+                    ]
+                },
+                {
+                    "tag_name": "v1.0.1",
+                    "name": "v1.0.1",
+                    "body": "Fixed app panic on flatpak installations",
+                    "assets": [
+                        {
+                            "name": "coop-linux-x86_64.tar.gz",
+                            "browser_download_url": "https://git.reya.info/reya/coop/releases/download/v1.0.1/coop-linux-x86_64.tar.gz",
+                            "size": 26160329
+                        }
+                    ]
+                }
+            ]"#,
+        )
+        .unwrap();
+
+        let newest = newest_published(&releases).unwrap();
+        assert_eq!(newest.tag_name, "v1.0.1");
+        assert_eq!(parse_tag(&newest.tag_name).unwrap().to_string(), "1.0.1");
+        assert_eq!(newest.assets.len(), 1);
+        assert_eq!(newest.assets[0].size, 26160329);
+    }
+
+    #[test]
+    #[ignore = "requires network access to the release host"]
+    fn live_release_source_resolves_the_running_platform() {
+        let filter = asset_filter_for(std::env::consts::OS, std::env::consts::ARCH)
+            .expect("this platform should be supported");
+        let source = GiteaSource::new("https://git.reya.info/api/v1", "reya", "coop", filter);
+
+        let release = source
+            .fetch_latest()
+            .expect("release lookup should succeed");
+
+        assert!(
+            release.version >= Version::new(1, 0, 0),
+            "unexpected version {}",
+            release.version
+        );
+        assert!(
+            source.filter.matches(&release.asset.name),
+            "unexpected artifact {}",
+            release.asset.name
+        );
+        assert!(
+            release.asset.url.starts_with("https://"),
+            "{} ",
+            release.asset.url
+        );
+    }
+}

crates/browser-signer-proxy/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "browser-signer-proxy"
+version = "0.1.0"
+edition.workspace = true
+description = "Nostr browser signer (NIP-07) proxy using smol async runtime"
+license = "MIT"
+repository = "https://github.com/nostrdevkit/nostr"
+publish = false
+
+[dependencies]
+atomic-destructor = "0.2"
+event-listener = "5"
+nostr.workspace = true
+opaquerr = { version = "0.1", features = ["alloc"] }
+serde.workspace = true
+serde_json.workspace = true
+smol.workspace = true
+tracing = { version = "0.1", features = ["std"] }
+uuid = { version = "1.23", features = ["serde", "v4"] }

crates/browser-signer-proxy/README.md

@@ -0,0 +1,55 @@
+# browser-signer-proxy
+
+Proxy to use Nostr Browser signer ([NIP-07](https://github.com/nostr-protocol/nips/blob/master/07.md)) in native applications.
+
+This is a re-implementation of [`nostr-browser-signer-proxy`](https://github.com/nostrdevkit/nostr/tree/master/signer/nostr-browser-signer-proxy)
+using the [`smol`](https://github.com/smol-rs/smol) async runtime instead of tokio.
+
+## Description
+
+This crate provides a local HTTP proxy that communicates with a NIP-07 browser extension
+(e.g., Alby, nos2x) running in a browser tab. Native applications can use this proxy to
+request public keys, sign events, and perform NIP-04/NIP-44 encryption/decryption through
+the browser extension.
+
+The HTTP server is implemented with a minimal, dependency-free approach using `smol::net::TcpListener`
+and manual HTTP/1.1 parsing — avoiding heavy HTTP framework dependencies entirely.
+
+## Usage
+
+```rust
+use browser_signer_proxy::prelude::*;
+
+async fn example() -> Result<(), Error> {
+    // Create the proxy with default options (localhost:7400)
+    let proxy = BrowserSignerProxy::new(BrowserSignerProxyOptions::default());
+
+    // Open the proxy URL in a browser
+    webbrowser::open(&proxy.url())?;
+
+    // Start the proxy server
+    proxy.start().await?;
+
+    // Use it as an async Nostr signer
+    let public_key = proxy.get_public_key_async().await?;
+    println!("Connected with public key: {public_key}");
+
+    Ok(())
+}
+```
+
+## Differences from the tokio-based version
+
+| Feature | tokio (original) | smol (this crate) |
+|---|---|---|
+| Async runtime | `tokio` | `smol` |
+| HTTP server | `hyper` | `smol::net::TcpListener` + manual HTTP/1.1 |
+| Mutex | `tokio::sync::Mutex` | `smol::lock::Mutex` |
+| Shutdown signal | `tokio::sync::Notify` | `event_listener::Event` |
+| Request-response channel | `tokio::sync::oneshot` | `smol::channel::bounded(1)` |
+| Timeout | `tokio::time::timeout` | `smol::future::or` + `smol::Timer` |
+| Task spawning | `tokio::spawn` | `smol::spawn` |
+
+## License
+
+This project is distributed under the MIT software license.

crates/browser-signer-proxy/index.html

@@ -0,0 +1,185 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Coop — Web Signer Proxy</title>
+    <link rel="preconnect" href="https://fonts.googleapis.com">
+    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
+    <link href="https://fonts.googleapis.com/css2?family=Nunito:wght@800;900&display=swap" rel="stylesheet">
+    <style>
+        :root {
+            --brand: #F8FF37;
+            --ink: #111111;
+            --ink-soft: #333333;
+            --muted: #666666;
+            --paper: #FFFFFF;
+            --edge: rgba(17, 17, 17, 0.14);
+            --radius-sm: 1rem;
+            --radius-md: 1.5rem;
+            --radius-lg: 2.5rem;
+            --green: #2E8B57;
+            --red: #D32F2F;
+        }
+
+        * {
+            box-sizing: border-box;
+        }
+
+        html, body {
+            margin: 0;
+            min-height: 100%;
+        }
+
+        body {
+            font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
+            color: var(--ink);
+            background: var(--brand);
+            -webkit-font-smoothing: antialiased;
+            display: flex;
+            align-items: center;
+            justify-content: center;
+            min-height: 100vh;
+            padding: 2rem;
+        }
+
+        .card {
+            background: var(--paper);
+            border-radius: var(--radius-md);
+            padding: 2.5rem;
+            max-width: 440px;
+            width: 100%;
+            box-shadow: 0 8px 0 rgba(17, 17, 17, 0.12), 0 2px 20px rgba(17, 17, 17, 0.06);
+        }
+
+        .logo {
+            display: flex;
+            align-items: center;
+            gap: 0.6rem;
+            margin-bottom: 1.75rem;
+        }
+
+        .logo__mark {
+            width: 2.5rem;
+            height: 2.5rem;
+            background: var(--ink);
+            border-radius: var(--radius-sm);
+            display: flex;
+            align-items: center;
+            justify-content: center;
+            font-family: "Nunito", system-ui, sans-serif;
+            font-weight: 900;
+            font-size: 1.2rem;
+            color: var(--brand);
+            letter-spacing: -0.02em;
+        }
+
+        .logo__text {
+            font-family: "Nunito", system-ui, sans-serif;
+            font-weight: 900;
+            font-size: 1.3rem;
+            letter-spacing: -0.02em;
+        }
+
+        .heading {
+            font-family: "Nunito", system-ui, sans-serif;
+            font-weight: 900;
+            font-size: 1.6rem;
+            letter-spacing: -0.03em;
+            line-height: 1.15;
+            margin: 0 0 0.6rem;
+        }
+
+        .subtitle {
+            font-size: 0.95rem;
+            color: var(--ink-soft);
+            margin: 0 0 1.75rem;
+            line-height: 1.5;
+        }
+
+        .status {
+            display: flex;
+            align-items: center;
+            gap: 0.75rem;
+            padding: 1rem 1.25rem;
+            border-radius: var(--radius-sm);
+            font-weight: 600;
+            font-size: 0.95rem;
+            transition: background 300ms ease, color 300ms ease;
+        }
+
+        .status--checking {
+            background: rgba(17, 17, 17, 0.05);
+            color: var(--muted);
+        }
+
+        .status--connected {
+            background: rgba(46, 139, 87, 0.1);
+            color: var(--green);
+        }
+
+        .status--error {
+            background: rgba(211, 47, 47, 0.08);
+            color: var(--red);
+        }
+
+        .status__dot {
+            width: 0.7rem;
+            height: 0.7rem;
+            border-radius: 50%;
+            flex-shrink: 0;
+        }
+
+        .status--checking .status__dot {
+            background: var(--muted);
+            animation: pulse 1.2s ease-in-out infinite;
+        }
+
+        .status--connected .status__dot {
+            background: var(--green);
+        }
+
+        .status--error .status__dot {
+            background: var(--red);
+        }
+
+        @keyframes pulse {
+            0%, 100% { opacity: 0.4; transform: scale(0.85); }
+            50%      { opacity: 1;   transform: scale(1); }
+        }
+
+        .hint {
+            margin-top: 1.5rem;
+            padding-top: 1.25rem;
+            border-top: 1px solid var(--edge);
+            font-size: 0.8rem;
+            color: var(--muted);
+            line-height: 1.5;
+        }
+
+        .hint strong {
+            color: var(--ink-soft);
+        }
+    </style>
+</head>
+<body>
+    <div class="card">
+        <h1 class="heading">Web Signer</h1>
+
+        <p class="subtitle">
+            This page connects the app to your Nostr Web Signer extension so you can sign in and use Coop securely.
+        </p>
+
+        <div id="nip07-status" class="status status--checking">
+            <div class="status__dot"></div>
+            <span id="nip07-status-text">Checking extension…</span>
+        </div>
+
+        <div class="hint">
+            <strong>Keep this tab open</strong> while using the app — it automatically handles sign-in requests in the background.
+        </div>
+    </div>
+
+    <script src="proxy.js"></script>
+</body>
+</html>

crates/browser-signer-proxy/proxy.js

@@ -0,0 +1,156 @@
+let isPolling = false;
+
+async function pollForRequests() {
+    if (isPolling) return;
+    isPolling = true;
+
+    try {
+        const response = await fetch('/api/pending');
+        const data = await response.json();
+
+        console.log('Polled for requests, got:', data);
+
+        // Process any new requests
+        if (data.requests && data.requests.length > 0) {
+            console.log(`Processing ${data.requests.length} requests`);
+            for (const request of data.requests) {
+                await handleNip07Request(request);
+            }
+        }
+    } catch (error) {
+        console.error('Polling error:', error);
+        updateStatus('Error: ' + error.message, 'error');
+    }
+
+    isPolling = false;
+}
+
+async function handleNip07Request(request) {
+    console.log('Handling request:', request);
+
+    try {
+        let result;
+
+        if (!window.nostr) {
+            throw new Error('NIP-07 extension not available');
+        }
+
+        switch (request.method) {
+            case 'get_public_key':
+                console.log('Calling nostr.getPublicKey()');
+                result = await window.nostr.getPublicKey();
+                console.log('Got public key:', result);
+                break;
+
+            case 'sign_event':
+                console.log('Calling nostr.signEvent() with:', request.params);
+                result = await window.nostr.signEvent(request.params);
+                console.log('Got signed event:', result);
+                break;
+
+            case 'nip04_encrypt':
+                console.log('Calling nostr.nip04.encrypt()');
+                result = await window.nostr.nip04.encrypt(
+                    request.params.public_key,
+                    request.params.content
+                );
+                break;
+
+            case 'nip04_decrypt':
+                console.log('Calling nostr.nip04.decrypt()');
+                result = await window.nostr.nip04.decrypt(
+                    request.params.public_key,
+                    request.params.content
+                );
+                break;
+
+            case 'nip44_encrypt':
+                console.log('Calling nostr.nip44.encrypt()');
+                result = await window.nostr.nip44.encrypt(
+                    request.params.public_key,
+                    request.params.content
+                );
+                break;
+
+            case 'nip44_decrypt':
+                console.log('Calling nostr.nip44.decrypt()');
+                result = await window.nostr.nip44.decrypt(
+                    request.params.public_key,
+                    request.params.content
+                );
+                break;
+
+
+            default:
+                throw new Error(`Unknown method: ${request.method}`);
+        }
+
+        // Send response back to server
+        const responsePayload = {
+            id: request.id,
+            result: result,
+            error: null
+        };
+
+        console.log('Sending response:', responsePayload);
+
+        await fetch('/api/response', {
+            method: 'POST',
+            headers: {
+                'Content-Type': 'application/json',
+            },
+            body: JSON.stringify(responsePayload)
+        });
+
+        console.log('Response sent successfully');
+        updateStatus('Request processed successfully', 'connected');
+
+    } catch (error) {
+        console.error('Error handling request:', error);
+
+        // Send error response back to server
+        const errorPayload = {
+            id: request.id,
+            result: null,
+            error: error.message
+        };
+
+        console.log('Sending error response:', errorPayload);
+
+        await fetch('/api/response', {
+            method: 'POST',
+            headers: {
+                'Content-Type': 'application/json',
+            },
+            body: JSON.stringify(errorPayload)
+        });
+
+        updateStatus('Error: ' + error.message, 'error');
+    }
+}
+
+function updateStatus(message, state) {
+    const container = document.getElementById('nip07-status');
+    const textEl = document.getElementById('nip07-status-text');
+    if (container && textEl) {
+        container.className = 'status status--' + state;
+        textEl.textContent = message;
+    }
+}
+
+// Start polling when page loads
+window.addEventListener('load', () => {
+    console.log('NIP-07 Proxy loaded');
+
+    // Check if NIP-07 extension is available
+    if (window.nostr) {
+        console.log('NIP-07 extension detected');
+        updateStatus('Connected — ready', 'connected');
+    } else {
+        console.log('NIP-07 extension not found');
+        updateStatus('No NIP-07 extension found', 'error');
+    }
+
+    // Start polling every 500 ms
+    setInterval(pollForRequests, 500);
+});

crates/browser-signer-proxy/src/error.rs

@@ -0,0 +1,51 @@
+// Copyright (c) 2022-2023 Yuki Kishimoto
+// Copyright (c) 2023-2025 Rust Nostr Developers
+// Distributed under the MIT software license
+
+//! Error types for the browser signer proxy.
+
+opaquerr::define_kind! {
+    /// Nostr browser signer proxy error kind.
+    pub ErrorKind {
+        /// Nostr protocol error.
+        Protocol => "nostr protocol error",
+        /// I/O error.
+        IO => "I/O error",
+        /// JSON error.
+        Json => "JSON error",
+        /// The operation timed out.
+        Timeout => "timeout",
+        /// The operation cannot be completed in the current state.
+        State => "invalid state",
+        /// Anything not covered by the stable categories above.
+        Other => "other error",
+    }
+}
+
+opaquerr::define_error! {
+    /// Nostr browser signer proxy error.
+    pub Error(ErrorKind)
+
+    from {
+        nostr::error::Error => ErrorKind::Protocol,
+        std::io::Error => ErrorKind::IO,
+        serde_json::Error => ErrorKind::Json,
+    }
+}
+
+impl Error {
+    pub(crate) fn generic<S>(message: S) -> Self
+    where
+        S: Into<String>,
+    {
+        Self::new(ErrorKind::Other, message.into())
+    }
+
+    pub(crate) fn timeout() -> Self {
+        Self::simple(ErrorKind::Timeout)
+    }
+
+    pub(crate) fn shutdown() -> Self {
+        Self::with_static_message(ErrorKind::State, "server is shutdown")
+    }
+}

crates/browser-signer-proxy/src/lib.rs

@@ -0,0 +1,764 @@
+use std::collections::HashMap;
+use std::future::Future;
+use std::net::{IpAddr, Ipv4Addr, SocketAddr, SocketAddrV4};
+use std::pin::Pin;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
+
+use atomic_destructor::{AtomicDestroyer, AtomicDestructor};
+use event_listener::Event as ShutdownEvent;
+use nostr::prelude::*;
+use serde::de::DeserializeOwned;
+use serde::{Deserialize, Serialize, Serializer};
+use serde_json::{Value, json};
+use smol::channel;
+use smol::io::{AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufReader};
+use smol::lock::Mutex;
+use smol::net::{TcpListener, TcpStream};
+use uuid::Uuid;
+
+mod error;
+pub mod prelude;
+
+pub use self::error::Error;
+
+const DEFAULT_HTML: &str = include_str!("../index.html");
+const JS: &str = include_str!("../proxy.js");
+
+type PendingResponseMap = HashMap<Uuid, channel::Sender<Result<Value, String>>>;
+
+#[derive(Debug, Deserialize)]
+struct Message {
+    id: Uuid,
+    error: Option<String>,
+    result: Option<Value>,
+}
+
+impl Message {
+    fn into_result(self) -> Result<Value, String> {
+        if let Some(error) = self.error {
+            Err(error)
+        } else {
+            Ok(self.result.unwrap_or(Value::Null))
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+enum RequestMethod {
+    GetPublicKey,
+    SignEvent,
+    Nip04Encrypt,
+    Nip04Decrypt,
+    Nip44Encrypt,
+    Nip44Decrypt,
+}
+
+impl RequestMethod {
+    fn as_str(&self) -> &str {
+        match self {
+            Self::GetPublicKey => "get_public_key",
+            Self::SignEvent => "sign_event",
+            Self::Nip04Encrypt => "nip04_encrypt",
+            Self::Nip04Decrypt => "nip04_decrypt",
+            Self::Nip44Encrypt => "nip44_encrypt",
+            Self::Nip44Decrypt => "nip44_decrypt",
+        }
+    }
+}
+
+impl Serialize for RequestMethod {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_str(self.as_str())
+    }
+}
+
+#[derive(Debug, Clone, Serialize)]
+struct RequestData {
+    id: Uuid,
+    method: RequestMethod,
+    params: Value,
+}
+
+impl RequestData {
+    #[inline]
+    fn new(method: RequestMethod, params: Value) -> Self {
+        Self {
+            id: Uuid::new_v4(),
+            method,
+            params,
+        }
+    }
+}
+
+#[derive(Serialize)]
+struct Requests<'a> {
+    requests: &'a [RequestData],
+}
+
+impl<'a> Requests<'a> {
+    #[inline]
+    fn new(requests: &'a [RequestData]) -> Self {
+        Self { requests }
+    }
+
+    #[inline]
+    fn len(&self) -> usize {
+        self.requests.len()
+    }
+}
+
+/// Params for NIP-04 and NIP-44 encryption/decryption
+#[derive(Serialize)]
+struct CryptoParams<'a> {
+    public_key: &'a PublicKey,
+    content: &'a str,
+}
+
+impl<'a> CryptoParams<'a> {
+    #[inline]
+    fn new(public_key: &'a PublicKey, content: &'a str) -> Self {
+        Self {
+            public_key,
+            content,
+        }
+    }
+}
+
+#[derive(Debug)]
+struct ProxyState {
+    /// Requests waiting to be picked up by browser
+    pub outgoing_requests: Mutex<Vec<RequestData>>,
+    /// Map of request ID to response sender
+    pub pending_responses: Mutex<PendingResponseMap>,
+    /// Last time the client asked for the pending requests
+    pub last_pending_request: Arc<AtomicU64>,
+}
+
+/// Configuration options for [`BrowserSignerProxy`].
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct BrowserSignerProxyOptions {
+    /// Request timeout for the signer extension. Default is 30 seconds.
+    pub timeout: Duration,
+    /// Proxy server IP address and port. Default is `127.0.0.1:7400`.
+    pub addr: SocketAddr,
+    /// Custom HTML page.
+    // NOTE: not `Option` to move it between threads without reference counter
+    pub custom_html: &'static str,
+}
+
+#[derive(Debug, Clone)]
+struct InnerBrowserSignerProxy {
+    /// Configuration options for the proxy
+    options: BrowserSignerProxyOptions,
+    /// Internal state of the proxy including request queues
+    state: Arc<ProxyState>,
+    /// Notification trigger for graceful shutdown
+    shutdown: Arc<ShutdownEvent>,
+    /// Flag to indicate if the server is shutdown
+    is_shutdown: Arc<AtomicBool>,
+    /// Flag indicating if the server is started
+    is_started: Arc<AtomicBool>,
+}
+
+impl AtomicDestroyer for InnerBrowserSignerProxy {
+    fn on_destroy(&self) {
+        self.shutdown();
+    }
+}
+
+impl InnerBrowserSignerProxy {
+    #[inline]
+    fn is_shutdown(&self) -> bool {
+        self.is_shutdown.load(Ordering::SeqCst)
+    }
+
+    fn shutdown(&self) {
+        // Mark the server as shutdown
+        self.is_shutdown.store(true, Ordering::SeqCst);
+
+        // Notify all waiters that the proxy is shutting down
+        self.shutdown.notify(usize::MAX);
+    }
+}
+
+/// Nostr Browser Signer Proxy
+///
+/// Proxy to use Nostr Browser signer (NIP-07) in native applications.
+#[derive(Debug, Clone)]
+pub struct BrowserSignerProxy {
+    inner: AtomicDestructor<InnerBrowserSignerProxy>,
+}
+
+impl Default for BrowserSignerProxyOptions {
+    fn default() -> Self {
+        Self {
+            timeout: Duration::from_secs(30),
+            // 7 for NIP-07 and 400 because the NIP title is 40 bytes :)
+            addr: SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::LOCALHOST, 7400)),
+            custom_html: "",
+        }
+    }
+}
+
+impl BrowserSignerProxyOptions {
+    /// Sets the timeout duration.
+    pub const fn timeout(mut self, timeout: Duration) -> Self {
+        self.timeout = timeout;
+        self
+    }
+
+    /// Sets the IP address.
+    pub const fn ip_addr(mut self, new_ip: IpAddr) -> Self {
+        self.addr = SocketAddr::new(new_ip, self.addr.port());
+        self
+    }
+
+    /// Sets the port number.
+    pub const fn port(mut self, new_port: u16) -> Self {
+        self.addr = SocketAddr::new(self.addr.ip(), new_port);
+        self
+    }
+
+    /// Sets a custom html page.
+    ///
+    /// The page must include `/proxy.js` script (`<script src="/proxy.js"></script>`)
+    /// which will handle communication with the server and update the element
+    /// with id `nip07-proxy-status` with the status.
+    pub const fn custom_html_page(mut self, custom_html: &'static str) -> Self {
+        self.custom_html = custom_html;
+        self
+    }
+}
+
+impl BrowserSignerProxy {
+    /// Construct a new browser signer proxy
+    pub fn new(options: BrowserSignerProxyOptions) -> Self {
+        let state = ProxyState {
+            outgoing_requests: Mutex::new(Vec::new()),
+            pending_responses: Mutex::new(HashMap::new()),
+            last_pending_request: Arc::new(AtomicU64::new(0)),
+        };
+
+        Self {
+            inner: AtomicDestructor::new(InnerBrowserSignerProxy {
+                options,
+                state: Arc::new(state),
+                shutdown: Arc::new(ShutdownEvent::new()),
+                is_shutdown: Arc::new(AtomicBool::new(false)),
+                is_started: Arc::new(AtomicBool::new(false)),
+            }),
+        }
+    }
+
+    /// Indicates whether the server is currently running.
+    #[inline]
+    pub fn is_started(&self) -> bool {
+        self.inner.is_started.load(Ordering::SeqCst)
+    }
+
+    /// Checks if there is an open browser tab ready to respond to requests by
+    /// verifying the time since the last pending request.
+    #[inline]
+    pub fn is_session_active(&self) -> bool {
+        current_time() - self.inner.state.last_pending_request.load(Ordering::SeqCst) < 2
+    }
+
+    /// Get the signer proxy webpage URL
+    #[inline]
+    pub fn url(&self) -> String {
+        format!("http://{}", self.inner.options.addr)
+    }
+
+    /// Start the proxy server.
+    ///
+    /// If this is not called explicitly, the server will be automatically
+    /// started on the first interaction with the signer.
+    pub async fn start(&self) -> Result<(), Error> {
+        // Ensure is not shutdown
+        if self.inner.is_shutdown() {
+            return Err(Error::shutdown());
+        }
+
+        // Mark the proxy as started and check if was already started
+        let is_started: bool = self.inner.is_started.swap(true, Ordering::SeqCst);
+
+        // Immediately return if already started
+        if is_started {
+            return Ok(());
+        }
+
+        let listener: TcpListener = match TcpListener::bind(self.inner.options.addr).await {
+            Ok(listener) => listener,
+            Err(e) => {
+                // Undo the started flag if binding fails
+                self.inner.is_started.store(false, Ordering::SeqCst);
+                return Err(Error::from(e));
+            }
+        };
+
+        let addr: SocketAddr = self.inner.options.addr;
+        let state: Arc<ProxyState> = self.inner.state.clone();
+        let custom_html: &'static str = self.inner.options.custom_html;
+        let shutdown: Arc<ShutdownEvent> = self.inner.shutdown.clone();
+
+        smol::spawn(async move {
+            tracing::info!("Starting proxy server on {addr}");
+
+            loop {
+                // Race between accepting a new connection and shutdown signal
+                let shutdown_listener = shutdown.listen();
+
+                enum AcceptEvent {
+                    Connection(Result<(TcpStream, SocketAddr), std::io::Error>),
+                    Shutdown,
+                }
+
+                let event = smol::future::or(
+                    async { AcceptEvent::Connection(listener.accept().await) },
+                    async {
+                        shutdown_listener.await;
+                        AcceptEvent::Shutdown
+                    },
+                )
+                .await;
+
+                match event {
+                    AcceptEvent::Connection(Ok((stream, _))) => {
+                        let state: Arc<ProxyState> = state.clone();
+                        let shutdown: Arc<ShutdownEvent> = shutdown.clone();
+
+                        smol::spawn(async move {
+                            let shutdown_listener = shutdown.listen();
+
+                            smol::future::or(
+                                async {
+                                    handle_connection(stream, state, custom_html).await;
+                                },
+                                async {
+                                    shutdown_listener.await;
+                                    tracing::debug!(
+                                        "Closing connection, proxy server is shutting down."
+                                    );
+                                },
+                            )
+                            .await;
+                        })
+                        .detach();
+                    }
+                    AcceptEvent::Connection(Err(e)) => {
+                        tracing::error!("Failed to accept connection: {e}");
+                    }
+                    AcceptEvent::Shutdown => break,
+                }
+            }
+
+            tracing::info!("Proxy server shut down.");
+        })
+        .detach();
+
+        Ok(())
+    }
+
+    #[inline]
+    async fn store_pending_response(&self, id: Uuid, tx: channel::Sender<Result<Value, String>>) {
+        let mut pending_responses = self.inner.state.pending_responses.lock().await;
+        pending_responses.insert(id, tx);
+    }
+
+    #[inline]
+    async fn store_outgoing_request(&self, request: RequestData) {
+        let mut outgoing_requests = self.inner.state.outgoing_requests.lock().await;
+        outgoing_requests.push(request);
+    }
+
+    async fn request<T>(&self, method: RequestMethod, params: Value) -> Result<T, Error>
+    where
+        T: DeserializeOwned,
+    {
+        // Start the proxy if not already started
+        self.start().await?;
+
+        // Construct the request
+        let request: RequestData = RequestData::new(method, params);
+
+        // Create a bounded channel of size 1 as a oneshot replacement
+        let (tx, rx) = channel::bounded::<Result<Value, String>>(1);
+
+        // Store the response sender
+        self.store_pending_response(request.id, tx).await;
+
+        // Add to outgoing requests queue
+        self.store_outgoing_request(request).await;
+
+        // Wait for response with timeout
+        let response = race_timeout(self.inner.options.timeout, rx.recv()).await;
+
+        match response {
+            Ok(Ok(res)) => Ok(serde_json::from_value(res)?),
+            Ok(Err(error)) => Err(Error::generic(error)),
+            Err(TimeoutError) => Err(Error::timeout()),
+        }
+    }
+
+    #[inline]
+    async fn _get_public_key(&self) -> Result<PublicKey, Error> {
+        self.request(RequestMethod::GetPublicKey, json!({})).await
+    }
+
+    #[inline]
+    async fn _sign_event(&self, event: UnsignedEvent) -> Result<Event, Error> {
+        let event: Event = self
+            .request(RequestMethod::SignEvent, serde_json::to_value(event)?)
+            .await?;
+        event.verify()?;
+        Ok(event)
+    }
+
+    #[inline]
+    async fn _nip04_encrypt(&self, public_key: &PublicKey, content: &str) -> Result<String, Error> {
+        let params = CryptoParams::new(public_key, content);
+        self.request(RequestMethod::Nip04Encrypt, serde_json::to_value(params)?)
+            .await
+    }
+
+    #[inline]
+    async fn _nip04_decrypt(&self, public_key: &PublicKey, content: &str) -> Result<String, Error> {
+        let params = CryptoParams::new(public_key, content);
+        self.request(RequestMethod::Nip04Decrypt, serde_json::to_value(params)?)
+            .await
+    }
+
+    #[inline]
+    async fn _nip44_encrypt(&self, public_key: &PublicKey, content: &str) -> Result<String, Error> {
+        let params = CryptoParams::new(public_key, content);
+        self.request(RequestMethod::Nip44Encrypt, serde_json::to_value(params)?)
+            .await
+    }
+
+    #[inline]
+    async fn _nip44_decrypt(&self, public_key: &PublicKey, content: &str) -> Result<String, Error> {
+        let params = CryptoParams::new(public_key, content);
+        self.request(RequestMethod::Nip44Decrypt, serde_json::to_value(params)?)
+            .await
+    }
+}
+
+impl AsyncGetPublicKey for BrowserSignerProxy {
+    type Error = Error;
+
+    #[inline]
+    fn get_public_key_async(
+        &self,
+    ) -> Pin<Box<dyn Future<Output = Result<PublicKey, Self::Error>> + Send + '_>> {
+        Box::pin(async move { self._get_public_key().await })
+    }
+}
+
+impl AsyncSignEvent for BrowserSignerProxy {
+    type Error = Error;
+
+    #[inline]
+    fn sign_event_async(
+        &self,
+        unsigned: UnsignedEvent,
+    ) -> Pin<Box<dyn Future<Output = Result<Event, Self::Error>> + Send + '_>> {
+        Box::pin(async move { self._sign_event(unsigned).await })
+    }
+}
+
+impl AsyncNip04 for BrowserSignerProxy {
+    type Error = Error;
+
+    fn nip04_encrypt_async<'a>(
+        &'a self,
+        public_key: &'a PublicKey,
+        content: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, Self::Error>> + Send + 'a>> {
+        Box::pin(async move { self._nip04_encrypt(public_key, content).await })
+    }
+
+    fn nip04_decrypt_async<'a>(
+        &'a self,
+        public_key: &'a PublicKey,
+        encrypted_content: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, Self::Error>> + Send + 'a>> {
+        Box::pin(async move { self._nip04_decrypt(public_key, encrypted_content).await })
+    }
+}
+
+impl AsyncNip44 for BrowserSignerProxy {
+    type Error = Error;
+
+    fn nip44_encrypt_async<'a>(
+        &'a self,
+        public_key: &'a PublicKey,
+        content: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, Self::Error>> + Send + 'a>> {
+        Box::pin(async move { self._nip44_encrypt(public_key, content).await })
+    }
+
+    fn nip44_decrypt_async<'a>(
+        &'a self,
+        public_key: &'a PublicKey,
+        payload: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, Self::Error>> + Send + 'a>> {
+        Box::pin(async move { self._nip44_decrypt(public_key, payload).await })
+    }
+}
+
+// ── Minimal HTTP server ──────────────────────────────────────────────────
+
+/// Handle a single HTTP connection.
+async fn handle_connection(stream: TcpStream, state: Arc<ProxyState>, custom_html: &'static str) {
+    let mut reader = BufReader::new(stream);
+
+    // Read the request line
+    let mut request_line = String::new();
+    if reader.read_line(&mut request_line).await.is_err() {
+        return;
+    }
+    let request_line = request_line.trim_end().to_string();
+
+    // Parse method, path, and HTTP version from request line
+    let parts: Vec<&str> = request_line.split_whitespace().collect();
+    if parts.len() < 2 {
+        send_response(&mut reader, 400, "Bad Request", "", "").await;
+        return;
+    }
+    let method = parts[0].to_uppercase();
+    let path = parts[1].to_string();
+
+    // Read headers until empty line
+    let mut headers = Vec::new();
+    let mut content_length: usize = 0;
+    loop {
+        let mut line = String::new();
+        if reader.read_line(&mut line).await.is_err() {
+            return;
+        }
+        let line = line.trim_end().to_string();
+        if line.is_empty() {
+            break;
+        }
+        if let Some(value) = line.strip_prefix("content-length:") {
+            content_length = value.trim().parse().unwrap_or(0);
+        } else if let Some(value) = line.strip_prefix("Content-Length:") {
+            content_length = value.trim().parse().unwrap_or(0);
+        }
+        headers.push(line);
+    }
+
+    match (method.as_str(), path.as_str()) {
+        // Serve the HTML proxy page
+        ("GET", "/") => {
+            let html = if custom_html.is_empty() {
+                DEFAULT_HTML
+            } else {
+                custom_html
+            };
+            send_response(&mut reader, 200, "OK", "text/html", html).await;
+        }
+        // Serve the JS proxy script
+        ("GET", "/proxy.js") => {
+            send_response(&mut reader, 200, "OK", "application/javascript", JS).await;
+        }
+        // Browser polls this endpoint to get pending requests
+        ("GET", "/api/pending") => {
+            state
+                .last_pending_request
+                .store(current_time(), Ordering::SeqCst);
+
+            let mut outgoing = state.outgoing_requests.lock().await;
+
+            let requests = Requests::new(&outgoing);
+            let json = match serde_json::to_string(&requests) {
+                Ok(j) => j,
+                Err(e) => {
+                    tracing::error!("Failed to serialize pending requests: {e}");
+                    send_response(&mut reader, 500, "Internal Server Error", "", "").await;
+                    return;
+                }
+            };
+
+            tracing::debug!("Sending {} pending requests to browser", requests.len());
+
+            // Clear the outgoing requests after sending them
+            outgoing.clear();
+
+            send_response_cors_json(&mut reader, 200, "OK", &json).await;
+        }
+        // Receive response from browser extension
+        ("POST", "/api/response") => {
+            let mut body_bytes = vec![0u8; content_length];
+            if content_length > 0 && reader.read_exact(&mut body_bytes).await.is_err() {
+                send_response(&mut reader, 400, "Bad Request", "", "").await;
+                return;
+            }
+
+            let message: Message = match serde_json::from_slice(&body_bytes) {
+                Ok(json) => json,
+                Err(e) => {
+                    tracing::error!("Failed to parse response body: {e}");
+                    send_response(&mut reader, 400, "Invalid JSON", "", "").await;
+                    return;
+                }
+            };
+
+            tracing::debug!("Received response from browser: {message:?}");
+
+            let id: Uuid = message.id;
+            let mut pending = state.pending_responses.lock().await;
+
+            match pending.remove(&id) {
+                Some(sender) => {
+                    // Use try_send since we already hold the lock
+                    let _ = sender.try_send(message.into_result());
+                    tracing::info!("Forwarded response for request {id}");
+                }
+                None => tracing::warn!("No pending request found for {id}"),
+            }
+
+            send_response_cors(&mut reader, 200, "OK", "text/plain", "OK").await;
+        }
+        // CORS preflight
+        ("OPTIONS", _) => {
+            let response = "HTTP/1.1 200 OK\r\n\
+                Access-Control-Allow-Origin: *\r\n\
+                Access-Control-Allow-Methods: GET, POST, OPTIONS\r\n\
+                Access-Control-Allow-Headers: Content-Type\r\n\
+                Content-Length: 0\r\n\
+                Connection: close\r\n\
+                \r\n";
+            let _ = reader.get_mut().write_all(response.as_bytes()).await;
+            let _ = reader.get_mut().flush().await;
+        }
+        // 404 - not found
+        _ => {
+            send_response(&mut reader, 404, "Not Found", "", "").await;
+        }
+    }
+}
+
+/// Write an HTTP response to the stream.
+async fn send_response(
+    stream: &mut (impl AsyncWriteExt + Unpin),
+    status: u16,
+    status_text: &str,
+    content_type: &str,
+    body: &str,
+) {
+    let mut response = format!("HTTP/1.1 {status} {status_text}\r\n");
+
+    if !content_type.is_empty() {
+        response.push_str(&format!("Content-Type: {content_type}\r\n"));
+    }
+
+    response.push_str(&format!("Content-Length: {}\r\n", body.len()));
+    response.push_str("Access-Control-Allow-Origin: *\r\n");
+    response.push_str("Connection: close\r\n");
+    response.push_str("\r\n");
+    response.push_str(body);
+
+    let _ = stream.write_all(response.as_bytes()).await;
+    let _ = stream.flush().await;
+}
+
+/// Write a response with CORS headers and JSON content type.
+async fn send_response_cors_json(
+    stream: &mut (impl AsyncWriteExt + Unpin),
+    status: u16,
+    status_text: &str,
+    body: &str,
+) {
+    let mut response = format!("HTTP/1.1 {status} {status_text}\r\n");
+    response.push_str("Content-Type: application/json\r\n");
+    response.push_str(&format!("Content-Length: {}\r\n", body.len()));
+    response.push_str("Access-Control-Allow-Origin: *\r\n");
+    response.push_str("Connection: close\r\n");
+    response.push_str("\r\n");
+    response.push_str(body);
+
+    let _ = stream.write_all(response.as_bytes()).await;
+    let _ = stream.flush().await;
+}
+
+/// Write a response with CORS headers.
+async fn send_response_cors(
+    stream: &mut (impl AsyncWriteExt + Unpin),
+    status: u16,
+    status_text: &str,
+    content_type: &str,
+    body: &str,
+) {
+    let mut response = format!("HTTP/1.1 {status} {status_text}\r\n");
+
+    if !content_type.is_empty() {
+        response.push_str(&format!("Content-Type: {content_type}\r\n"));
+    }
+
+    response.push_str(&format!("Content-Length: {}\r\n", body.len()));
+    response.push_str("Access-Control-Allow-Origin: *\r\n");
+    response.push_str("Connection: close\r\n");
+    response.push_str("\r\n");
+    response.push_str(body);
+
+    let _ = stream.write_all(response.as_bytes()).await;
+    let _ = stream.flush().await;
+}
+
+// ── Timeout helper ───────────────────────────────────────────────────────
+
+/// An error indicating that an operation timed out.
+#[derive(Debug)]
+struct TimeoutError;
+
+/// Races a channel receive against a duration.
+///
+/// Returns the channel value on success, or [`TimeoutError`] if the duration
+/// elapses first or the channel is closed.
+async fn race_timeout<T>(
+    duration: Duration,
+    recv: impl Future<Output = Result<T, channel::RecvError>>,
+) -> Result<T, TimeoutError> {
+    enum Event<T> {
+        Value(T),
+        ChannelClosed,
+        Timeout,
+    }
+
+    let event = smol::future::or(
+        async {
+            match recv.await {
+                Ok(value) => Event::Value(value),
+                Err(_) => Event::ChannelClosed,
+            }
+        },
+        async {
+            smol::Timer::after(duration).await;
+            Event::Timeout
+        },
+    )
+    .await;
+
+    match event {
+        Event::Value(value) => Ok(value),
+        Event::ChannelClosed | Event::Timeout => Err(TimeoutError),
+    }
+}
+
+// ── Utility ──────────────────────────────────────────────────────────────
+
+/// Gets the current time in seconds since the Unix epoch (1970-01-01). If the
+/// time is before the epoch, returns 0.
+#[inline]
+fn current_time() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|d| d.as_secs())
+        .unwrap_or_default()
+}

crates/browser-signer-proxy/src/prelude.rs

@@ -0,0 +1,14 @@
+// Copyright (c) 2022-2023 Yuki Kishimoto
+// Copyright (c) 2023-2025 Rust Nostr Developers
+// Distributed under the MIT software license
+
+//! Prelude
+
+#![allow(unknown_lints)]
+#![allow(ambiguous_glob_reexports)]
+#![doc(hidden)]
+
+pub use nostr::prelude::*;
+
+pub use crate::error::{Error, ErrorKind};
+pub use crate::*;

crates/chat/Cargo.toml

@@ -13,15 +13,16 @@ settings = { path = "../settings" }
 
 gpui.workspace = true
 nostr-sdk.workspace = true
+instant.workspace = true
 
 anyhow.workspace = true
 itertools.workspace = true
 smallvec.workspace = true
-smol.workspace = true
 log.workspace = true
-futures.workspace = true
 flume.workspace = true
-serde.workspace = true
-serde_json.workspace = true
 
+futures.workspace = true
 fuzzy-matcher = "0.3.7"
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+smol.workspace = true

crates/chat/src/message.rs

@@ -4,6 +4,9 @@ use std::ops::Range;
 use common::{EventExt, NostrParser, extract_and_remove_media_urls};
 use gpui::{SharedString, SharedUri};
 use nostr_sdk::prelude::*;
+use state::FileAttachment;
+
+pub const KIND_FILE_MESSAGE: Kind = Kind::Custom(15);
 
 /// Rendered message.
 #[derive(Debug, Clone)]
@@ -21,61 +24,90 @@ pub struct Message {
     pub mentions: Vec<Mention>,
     /// List of event of the message this message is a reply to
     pub replies_to: Vec<EventId>,
+    /// Encrypted file attachment
+    pub file: Option<FileAttachment>,
 }
 
 impl From<&Event> for Message {
     fn from(val: &Event) -> Self {
-        let mentions = extract_mentions(&val.content);
-        let replies_to = extract_reply_ids(&val.tags);
-        let (media, string) = extract_and_remove_media_urls(&val.content);
-
-        Self {
-            id: val.id,
-            author: val.pubkey,
-            content: string,
-            media,
-            created_at: val.created_at,
-            mentions,
-            replies_to,
-        }
+        from_parts(
+            val.id,
+            val.pubkey,
+            val.created_at,
+            val.kind,
+            &val.content,
+            &val.tags,
+        )
     }
 }
 
 impl From<&UnsignedEvent> for Message {
     fn from(val: &UnsignedEvent) -> Self {
-        let mentions = extract_mentions(&val.content);
-        let replies_to = extract_reply_ids(&val.tags);
-        let (media, string) = extract_and_remove_media_urls(&val.content);
-
-        Self {
+        from_parts(
             // Event ID must be known
-            id: val.id.unwrap(),
-            author: val.pubkey,
-            content: string,
-            media,
-            created_at: val.created_at,
-            mentions,
-            replies_to,
-        }
+            val.id.unwrap(),
+            val.pubkey,
+            val.created_at,
+            val.kind,
+            &val.content,
+            &val.tags,
+        )
     }
 }
 
 impl From<&NewMessage> for Message {
     fn from(val: &NewMessage) -> Self {
-        let mentions = extract_mentions(&val.rumor.content);
-        let replies_to = extract_reply_ids(&val.rumor.tags);
-        let (media, string) = extract_and_remove_media_urls(&val.rumor.content);
-
-        Self {
+        from_parts(
             // Event ID must be known
-            id: val.rumor.id.unwrap(),
-            author: val.rumor.pubkey,
-            content: string,
-            media,
-            created_at: val.rumor.created_at,
-            mentions,
-            replies_to,
-        }
+            val.rumor.id.unwrap(),
+            val.rumor.pubkey,
+            val.rumor.created_at,
+            val.rumor.kind,
+            &val.rumor.content,
+            &val.rumor.tags,
+        )
+    }
+}
+
+fn from_parts(
+    id: EventId,
+    author: PublicKey,
+    created_at: Timestamp,
+    kind: Kind,
+    content: &str,
+    tags: &Tags,
+) -> Message {
+    let file = if kind == KIND_FILE_MESSAGE {
+        FileAttachment::from_tags(content, tags)
+    } else {
+        None
+    };
+    let has_file = file.is_some();
+
+    let replies_to = extract_reply_ids(tags);
+
+    // For file messages `.content` is the encrypted blob URL, not text or media
+    let mentions = if has_file {
+        Vec::new()
+    } else {
+        extract_mentions(content)
+    };
+
+    let (media, content) = if has_file {
+        (Vec::new(), String::new())
+    } else {
+        extract_and_remove_media_urls(content)
+    };
+
+    Message {
+        id,
+        author,
+        content,
+        media,
+        created_at,
+        mentions,
+        replies_to,
+        file,
     }
 }
 
@@ -105,6 +137,17 @@ impl Hash for Message {
     }
 }
 
+impl Message {
+    /// Single-line representation for reply previews, notifications and copy.
+    pub fn preview(&self) -> SharedString {
+        if let Some(file) = &self.file {
+            return format!("[File] {}", file.display_name()).into();
+        }
+
+        self.content.clone().into()
+    }
+}
+
 /// New message.
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub struct NewMessage {

crates/chat/src/room.rs

@@ -1,18 +1,18 @@
 use std::cmp::Ordering;
 use std::hash::{Hash, Hasher};
-use std::time::Duration;
 
 use anyhow::{Error, anyhow};
 use common::EventExt;
 use device::DeviceRegistry;
 use gpui::{App, AppContext, Context, EventEmitter, SharedString, Task};
+use instant::Duration;
 use itertools::Itertools;
 use nostr_sdk::prelude::*;
 use person::{Person, PersonRegistry};
 use settings::{RoomConfig, SignerKind};
-use state::{NostrRegistry, TIMEOUT};
+use state::{NostrRegistry, TIMEOUT, UniversalSigner};
 
-use crate::NewMessage;
+use crate::{FileAttachment, KIND_FILE_MESSAGE, NewMessage};
 
 const NO_DEKEY: &str = "User hasn't set up a decoupled encryption key yet.";
 const USER_NO_DEKEY: &str = "You haven't set up a decoupled encryption key or it's not available.";
@@ -271,8 +271,8 @@ impl Room {
     }
 
     /// Returns the members of the room
-    pub fn members(&self) -> Vec<PublicKey> {
-        self.members.clone()
+    pub fn members(&self) -> &[PublicKey] {
+        &self.members
     }
 
     /// Checks if the room has more than two members (group)
@@ -289,12 +289,21 @@ impl Room {
         }
     }
 
-    /// Gets the display image for the room
-    pub fn display_image(&self, cx: &App) -> SharedString {
-        if !self.is_group() {
-            self.display_member(cx).avatar()
+    /// Gets the display picture for the room, if it has one
+    pub fn display_image(&self, cx: &App) -> Option<SharedString> {
+        if self.is_group() {
+            None
         } else {
-            SharedString::from("brand/group.png")
+            self.display_member(cx).avatar()
+        }
+    }
+
+    /// A stable seed for the room's generated avatar
+    pub fn display_image_seed(&self, cx: &App) -> SharedString {
+        if self.is_group() {
+            SharedString::from(self.id.to_string())
+        } else {
+            self.display_member(cx).avatar_seed()
         }
     }
 
@@ -356,29 +365,38 @@ impl Room {
     pub fn connect(&self, cx: &App) -> Task<Result<(), Error>> {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
-        let members = self.members();
+        let members = self.members().to_vec();
 
         cx.background_spawn(async move {
             let opts = SubscribeAutoCloseOptions::default()
                 .exit_policy(ReqExitPolicy::ExitOnEOSE)
                 .timeout(Some(Duration::from_secs(TIMEOUT)));
 
-            for public_key in members.into_iter() {
-                let inbox = Filter::new()
-                    .author(public_key)
-                    .kind(Kind::InboxRelays)
-                    .limit(1);
+            let tasks: Vec<_> = members
+                .into_iter()
+                .map(|public_key| {
+                    let client = client.clone();
+                    async move {
+                        let inbox = Filter::new()
+                            .author(public_key)
+                            .kind(Kind::InboxRelays)
+                            .limit(1);
 
-                let announcement = Filter::new()
-                    .author(public_key)
-                    .kind(Kind::Custom(10044))
-                    .limit(1);
+                        let announcement = Filter::new()
+                            .author(public_key)
+                            .kind(Kind::Custom(10044))
+                            .limit(1);
 
-                // Subscribe to the target
-                client
-                    .subscribe(vec![inbox, announcement])
-                    .close_on(opts)
-                    .await?;
+                        client
+                            .subscribe(vec![inbox, announcement])
+                            .close_on(opts)
+                            .await
+                    }
+                })
+                .collect();
+
+            for result in futures::future::join_all(tasks).await {
+                result?;
             }
 
             Ok(())
@@ -389,12 +407,12 @@ impl Room {
     pub fn get_messages(&self, cx: &App) -> Task<Result<Vec<UnsignedEvent>, Error>> {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
-        let conversation_id = self.id.to_string();
+        let room_id = self.id.to_string();
 
         cx.background_spawn(async move {
             let filter = Filter::new()
                 .kind(Kind::ApplicationSpecificData)
-                .custom_tag(SingleLetterTag::lowercase(Alphabet::C), conversation_id);
+                .custom_tag(SingleLetterTag::LOWERCASE_R, room_id);
 
             let messages = client
                 .database()
@@ -402,10 +420,6 @@ impl Room {
                 .await?
                 .into_iter()
                 .filter_map(|event| UnsignedEvent::from_json(&event.content).ok())
-                .filter(|event| {
-                    // Only process private direct messages and file messages
-                    event.kind == Kind::PrivateDirectMessage || event.kind == Kind::Custom(15)
-                })
                 .sorted_by_key(|message| message.created_at)
                 .collect();
 
@@ -414,28 +428,71 @@ impl Room {
     }
 
     // Construct a rumor event for direct message
-    pub fn rumor<S, I>(&self, content: S, replies: I, cx: &App) -> Option<UnsignedEvent>
+    pub fn rumor<S, I>(
+        &self,
+        content: S,
+        replies: I,
+        reaction: bool,
+        cx: &App,
+    ) -> Option<UnsignedEvent>
     where
         S: Into<String>,
         I: IntoIterator<Item = EventId>,
     {
-        let kind = Kind::PrivateDirectMessage;
+        let kind = if reaction {
+            Kind::Reaction
+        } else {
+            Kind::PrivateDirectMessage
+        };
+
         let content: String = content.into();
         let replies: Vec<EventId> = replies.into_iter().collect();
 
-        let persons = PersonRegistry::global(cx);
+        // Get current user's public key
         let nostr = NostrRegistry::global(cx);
+        let sender = nostr.read(cx).current_user()?;
+
+        // Construct a direct message rumor event
+        // WARNING: never sign and send this event to relays
+        let mut event = EventBuilder::new(kind, content)
+            .tags(self.conversation_tags(&replies, sender, cx))
+            .finalize_unsigned(sender);
+
+        // Ensure that the ID is set
+        event.ensure_id();
+
+        Some(event)
+    }
+
+    // Construct a rumor event for an encrypted file message (NIP-17 kind 15)
+    pub fn file_rumor<I>(&self, file: FileAttachment, replies: I, cx: &App) -> Option<UnsignedEvent>
+    where
+        I: IntoIterator<Item = EventId>,
+    {
+        let replies: Vec<EventId> = replies.into_iter().collect();
 
         // Get current user's public key
-        let sender = nostr.read(cx).signer_pubkey(cx)?;
+        let nostr = NostrRegistry::global(cx);
+        let sender = nostr.read(cx).current_user()?;
 
-        // Get all members, excluding the sender
-        let members: Vec<Person> = self
-            .members
-            .iter()
-            .filter(|public_key| public_key != &&sender)
-            .map(|member| persons.read(cx).get(member, cx))
-            .collect();
+        let mut tags = self.conversation_tags(&replies, sender, cx);
+        tags.extend(file.tags());
+
+        // Construct a file message rumor event
+        // WARNING: never sign and send this event to relays
+        let mut event = EventBuilder::new(KIND_FILE_MESSAGE, file.url.to_string())
+            .tags(tags)
+            .finalize_unsigned(sender);
+
+        // Ensure that the ID is set
+        event.ensure_id();
+
+        Some(event)
+    }
+
+    // Build the `subject` + reply `e` tags + receiver `p` tags (excluding `sender`)
+    fn conversation_tags(&self, replies: &[EventId], sender: PublicKey, cx: &App) -> Vec<Tag> {
+        let persons = PersonRegistry::global(cx);
 
         // Construct event's tags
         let mut tags = vec![];
@@ -446,31 +503,44 @@ impl Room {
         }
 
         // Add all reply tags
-        for id in replies.into_iter() {
-            tags.push(Tag::event(id))
+        for id in replies {
+            tags.push(Tag::event(*id))
         }
 
-        // Add all receiver tags
-        for member in members.into_iter() {
-            tags.push(
-                Nip01Tag::PublicKey {
-                    public_key: member.public_key(),
-                    relay_hint: member.messaging_relay_hint(),
+        // Add all receiver tags (no intermediate allocation)
+        for public_key in self.members.iter().filter(|pk| *pk != &sender) {
+            let member = persons.read(cx).get(public_key, cx);
+            tags.push(Tag::from(Nip01Tag::PublicKey {
+                public_key: member.public_key(),
+                relay_hint: member.messaging_relay_hint(),
+            }));
+        }
+
+        tags
+    }
+
+    /// Select the appropriate signer based on signer kind and available keys.
+    fn select_signer(
+        signer_kind: &SignerKind,
+        has_announcement: bool,
+        encryption_signer: &Option<UniversalSigner>,
+        user_signer: &UniversalSigner,
+    ) -> UniversalSigner {
+        match signer_kind {
+            SignerKind::Auto => {
+                if has_announcement {
+                    encryption_signer
+                        .clone()
+                        .unwrap_or_else(|| user_signer.clone())
+                } else {
+                    user_signer.clone()
                 }
-                .to_tag(),
-            );
+            }
+            SignerKind::Encryption => encryption_signer
+                .clone()
+                .expect("encryption signer must be set"),
+            SignerKind::User => user_signer.clone(),
         }
-
-        // Construct a direct message rumor event
-        // WARNING: never sign and send this event to relays
-        let mut event = EventBuilder::new(kind, content)
-            .tags(tags)
-            .finalize_unsigned(sender);
-
-        // Ensure that the ID is set
-        event.ensure_id();
-
-        Some(event)
     }
 
     /// Send rumor event to all members's messaging relays
@@ -482,13 +552,12 @@ impl Room {
 
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
+        let user_signer = nostr.read(cx).signer();
+        let current_user = nostr.read(cx).current_user()?;
 
-        // Get current user's public key
-        let user_signer = nostr.read(cx).signer(cx)?;
-        let public_key = nostr.read(cx).signer_pubkey(cx)?;
-
+        // Get sender's profile
         let persons = PersonRegistry::global(cx);
-        let sender = persons.read(cx).get(&public_key, cx);
+        let sender = persons.read(cx).get(&current_user, cx);
 
         // Get all members (excluding sender)
         let members: Vec<Person> = self
@@ -526,23 +595,12 @@ impl Room {
                 }
 
                 // Determine the signer to use
-                let signer = match signer_kind {
-                    SignerKind::Auto => {
-                        if announcement.is_some()
-                            && let Some(encryption_signer) = encryption_signer.clone()
-                        {
-                            // Safe to unwrap due to earlier checks
-                            encryption_signer
-                        } else {
-                            user_signer.clone()
-                        }
-                    }
-                    SignerKind::Encryption => {
-                        // Safe to unwrap due to earlier checks
-                        encryption_signer.as_ref().unwrap().clone()
-                    }
-                    SignerKind::User => user_signer.clone(),
-                };
+                let signer = Self::select_signer(
+                    signer_kind,
+                    announcement.is_some(),
+                    &encryption_signer,
+                    &user_signer,
+                );
 
                 // Send the gift wrap event and collect the report
                 match send_gift_wrap(&client, &signer, &member, &rumor, signer_kind).await {
@@ -562,23 +620,12 @@ impl Room {
                 let public_key = sender.public_key();
 
                 // Determine the signer to use
-                let signer = match signer_kind {
-                    SignerKind::Auto => {
-                        if sender.announcement().is_some()
-                            && let Some(encryption_signer) = encryption_signer.clone()
-                        {
-                            // Safe to unwrap due to earlier checks
-                            encryption_signer
-                        } else {
-                            user_signer.clone()
-                        }
-                    }
-                    SignerKind::Encryption => {
-                        // Safe to unwrap due to earlier checks
-                        encryption_signer.as_ref().unwrap().clone()
-                    }
-                    SignerKind::User => user_signer.clone(),
-                };
+                let signer = Self::select_signer(
+                    signer_kind,
+                    sender.announcement().is_some(),
+                    &encryption_signer,
+                    &user_signer,
+                );
 
                 match send_gift_wrap(&client, &signer, &sender, &rumor, signer_kind).await {
                     Ok(report) => reports.push(report),
@@ -597,12 +644,12 @@ impl Room {
 // Helper function to send a gift-wrapped event
 async fn send_gift_wrap(
     client: &Client,
-    signer: &Keys,
+    signer: &UniversalSigner,
     receiver: &Person,
     rumor: &UnsignedEvent,
     config: &SignerKind,
 ) -> Result<SendReport, Error> {
-    let k_tag = Tag::custom("k", vec!["14"]);
+    let k_tag = Tag::custom("k", [rumor.kind.to_string()]);
     let mut extra_tags = vec![k_tag];
 
     // Determine the receiver public key based on the config

crates/chat_ui/Cargo.toml

@@ -14,19 +14,16 @@ chat = { path = "../chat" }
 settings = { path = "../settings" }
 
 gpui.workspace = true
-gpui_tokio.workspace = true
-
 nostr-sdk.workspace = true
 anyhow.workspace = true
 itertools.workspace = true
 smallvec.workspace = true
-smol.workspace = true
 flume.workspace = true
+futures.workspace = true
 log.workspace = true
 serde.workspace = true
-serde_json.workspace = true
 
-once_cell = "1.19.0"
-regex = "1"
 linkify = "0.10.0"
 pulldown-cmark = "0.13.1"
+regex = "1"
+

crates/chat_ui/src/file.rs

@@ -0,0 +1,32 @@
+use std::path::{Path, PathBuf};
+
+use chat::FileAttachment;
+use gpui::SharedString;
+use nostr_sdk::prelude::*;
+
+/// A file attachment that has been uploaded, but not sent yet.
+///
+/// The local `path` is kept around so the composer can preview
+/// the file without downloading and decrypting it again.
+pub(crate) struct PendingFile {
+    pub file: FileAttachment,
+    pub path: PathBuf,
+}
+
+/// State of the encrypted file attachment of a message
+pub(crate) enum DecryptedFile {
+    Loading,
+    Ready(PathBuf),
+    Failed(SharedString),
+}
+
+/// Result of an upload, either plain or encrypted
+pub(crate) enum Uploaded {
+    Url(Url),
+    File(FileAttachment, PathBuf),
+}
+
+/// A `file://` url for a decrypted file, so it can be opened by the OS
+pub(crate) fn file_url(path: &Path) -> String {
+    format!("file://{}", path.display())
+}

crates/chat_ui/src/text.rs

@@ -1,17 +1,19 @@
 use std::ops::Range;
-use std::sync::Arc;
+use std::sync::{Arc, LazyLock};
 
 use chat::Mention;
-use common::RangeExt;
 use gpui::{
     AnyElement, App, ElementId, Entity, FontStyle, FontWeight, HighlightStyle, InteractiveText,
     IntoElement, SharedString, StrikethroughStyle, StyledText, UnderlineStyle, Window,
 };
 use person::PersonRegistry;
+use regex::Regex;
 use theme::ActiveTheme;
 
+/// Matches `http://` and `https://` URLs. Only these are treated as clickable links.
+static WEB_URL: LazyLock<Regex> = LazyLock::new(|| Regex::new(r"(?i)^https?://").unwrap());
+
 #[allow(clippy::enum_variant_names)]
-#[allow(dead_code)]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Highlight {
     Code,
@@ -39,25 +41,61 @@ impl RenderedText {
         content: &str,
         mentions: &[Mention],
         persons: &Entity<PersonRegistry>,
+        markdown: bool,
         cx: &App,
+    ) -> Self {
+        Self::render(content, mentions, markdown, |mention| {
+            format!("@{}", persons.read(cx).get(&mention.public_key, cx).name())
+        })
+    }
+
+    fn render(
+        content: &str,
+        mentions: &[Mention],
+        markdown: bool,
+        resolve_mention: impl Fn(&Mention) -> String,
     ) -> Self {
         let mut text = String::new();
         let mut highlights = Vec::new();
         let mut link_ranges = Vec::new();
         let mut link_urls = Vec::new();
 
-        render_plain_text_mut(
+        render_text_mut(
             content,
             mentions,
             &mut text,
             &mut highlights,
             &mut link_ranges,
             &mut link_urls,
-            persons,
-            cx,
+            markdown,
+            resolve_mention,
         );
 
-        text.truncate(text.trim_end().len());
+        // Trim trailing whitespace and adjust highlight and link ranges.
+        let trimmed_len = text.trim_end().len();
+
+        // Retain highlights and link ranges that are within the trimmed text.
+        if trimmed_len < text.len() {
+            highlights.retain_mut(|(range, _)| {
+                range.end = range.end.min(trimmed_len);
+                range.start < range.end
+            });
+
+            let mut ix = 0;
+
+            while ix < link_ranges.len() {
+                let range = &mut link_ranges[ix];
+                range.end = range.end.min(trimmed_len);
+                if range.start < range.end {
+                    ix += 1;
+                } else {
+                    link_ranges.remove(ix);
+                    link_urls.remove(ix);
+                }
+            }
+
+            text.truncate(trimmed_len);
+        }
 
         RenderedText {
             text: SharedString::from(text),
@@ -70,55 +108,71 @@ impl RenderedText {
     pub fn element(&self, id: ElementId, window: &Window, cx: &App) -> AnyElement {
         let code_background = cx.theme().elevated_surface_background;
         let color = cx.theme().text_accent;
+        let code_font = if cfg!(target_os = "macos") {
+            "Menlo"
+        } else if cfg!(target_os = "windows") {
+            "Consolas"
+        } else {
+            "monospace"
+        };
 
         InteractiveText::new(
             id,
-            StyledText::new(self.text.clone()).with_default_highlights(
-                &window.text_style(),
-                self.highlights.iter().map(|(range, highlight)| {
-                    (
-                        range.clone(),
-                        match highlight {
-                            Highlight::Code => HighlightStyle {
-                                background_color: Some(code_background),
-                                ..Default::default()
-                            },
-                            Highlight::InlineCode(link) => {
-                                if *link {
-                                    HighlightStyle {
-                                        background_color: Some(code_background),
-                                        underline: Some(UnderlineStyle {
-                                            thickness: 1.0.into(),
+            StyledText::new(self.text.clone())
+                .with_default_highlights(
+                    &window.text_style(),
+                    self.highlights.iter().map(|(range, highlight)| {
+                        (
+                            range.clone(),
+                            match highlight {
+                                Highlight::Code => HighlightStyle {
+                                    background_color: Some(code_background),
+                                    ..Default::default()
+                                },
+                                Highlight::InlineCode(link) => {
+                                    if *link {
+                                        HighlightStyle {
+                                            background_color: Some(code_background),
+                                            underline: Some(UnderlineStyle {
+                                                thickness: 1.0.into(),
+                                                ..Default::default()
+                                            }),
                                             ..Default::default()
-                                        }),
-                                        ..Default::default()
-                                    }
-                                } else {
-                                    HighlightStyle {
-                                        background_color: Some(code_background),
-                                        ..Default::default()
+                                        }
+                                    } else {
+                                        HighlightStyle {
+                                            background_color: Some(code_background),
+                                            ..Default::default()
+                                        }
                                     }
                                 }
-                            }
-                            Highlight::Mention => HighlightStyle {
-                                color: Some(color),
-                                underline: Some(UnderlineStyle {
-                                    thickness: 1.0.into(),
+                                Highlight::Mention => HighlightStyle {
+                                    color: Some(color),
+                                    underline: Some(UnderlineStyle {
+                                        thickness: 1.0.into(),
+                                        ..Default::default()
+                                    }),
                                     ..Default::default()
-                                }),
-                                ..Default::default()
+                                },
+                                Highlight::Highlight(highlight) => *highlight,
                             },
-                            Highlight::Highlight(highlight) => *highlight,
-                        },
-                    )
-                }),
-            ),
+                        )
+                    }),
+                )
+                .with_font_family_overrides(self.highlights.iter().filter_map(
+                    |(range, highlight)| match highlight {
+                        Highlight::Code | Highlight::InlineCode(_) => {
+                            Some((range.clone(), code_font.into()))
+                        }
+                        _ => None,
+                    },
+                )),
         )
         .on_click(self.link_ranges.clone(), {
             let link_urls = self.link_urls.clone();
             move |ix, _, cx| {
                 let url = &link_urls[ix];
-                if url.starts_with("http") {
+                if WEB_URL.is_match(url) {
                     cx.open_url(url);
                 }
             }
@@ -128,15 +182,15 @@ impl RenderedText {
 }
 
 #[allow(clippy::too_many_arguments)]
-fn render_plain_text_mut(
+fn render_text_mut(
     block: &str,
     mut mentions: &[Mention],
     text: &mut String,
     highlights: &mut Vec<(Range<usize>, Highlight)>,
     link_ranges: &mut Vec<Range<usize>>,
     link_urls: &mut Vec<String>,
-    persons: &Entity<PersonRegistry>,
-    cx: &App,
+    markdown: bool,
+    resolve_mention: impl Fn(&Mention) -> String,
 ) {
     use pulldown_cmark::{Event, Options, Parser, Tag, TagEnd};
 
@@ -145,34 +199,58 @@ fn render_plain_text_mut(
     let mut strikethrough_depth = 0;
     let mut link_url = None;
     let mut list_stack = Vec::new();
+    let mut code_block = false;
 
-    let mut options = Options::all();
-    options.remove(pulldown_cmark::Options::ENABLE_DEFINITION_LIST);
+    // Only enable the extensions that make sense for chat messages. Notably this leaves
+    // out smart punctuation, tables, math and footnotes: they rewrite or swallow text.
+    let events: Box<dyn Iterator<Item = (Event<'_>, Range<usize>)> + '_> = if markdown {
+        Box::new(Parser::new_ext(block, Options::ENABLE_STRIKETHROUGH).into_offset_iter())
+    } else {
+        Box::new(std::iter::once((Event::Text(block.into()), 0..block.len())))
+    };
 
-    for (event, source_range) in Parser::new_ext(block, options).into_offset_iter() {
+    for (event, source_range) in events {
         let prev_len = text.len();
 
         match event {
             Event::Text(t) => {
-                // Process text with mention replacements
+                if code_block {
+                    text.push_str(t.as_ref());
+                    highlights.push((prev_len..text.len(), Highlight::Code));
+                    continue;
+                }
+
                 let t_str = t.as_ref();
                 let mut last_processed = 0;
 
                 while let Some(mention) = mentions.first() {
-                    if !source_range.contains_inclusive(&mention.range) {
+                    if mention.range.start >= source_range.end {
                         break;
                     }
 
-                    // Calculate positions within the current text
-                    let mention_start_in_text = mention.range.start - source_range.start;
-                    let mention_end_in_text = mention.range.end - source_range.start;
+                    mentions = &mentions[1..];
+                    if mention.range.start < source_range.start
+                        || mention.range.end > source_range.end
+                    {
+                        continue;
+                    }
+
+                    let Some(token) = block.get(mention.range.clone()) else {
+                        continue;
+                    };
+
+                    let Some(offset) = t_str[last_processed..].find(token) else {
+                        continue;
+                    };
+
+                    let mention_start_in_text = last_processed + offset;
+                    let mention_end_in_text = mention_start_in_text + token.len();
 
                     // Add text before this mention
                     if mention_start_in_text > last_processed {
                         let before_mention = &t_str[last_processed..mention_start_in_text];
                         process_text_segment(
                             before_mention,
-                            prev_len + last_processed,
                             bold_depth,
                             italic_depth,
                             strikethrough_depth,
@@ -185,9 +263,7 @@ fn render_plain_text_mut(
                     }
 
                     // Process the mention replacement
-                    let profile = persons.read(cx).get(&mention.public_key, cx);
-                    let replacement_text = format!("@{}", profile.name());
-
+                    let replacement_text = resolve_mention(mention);
                     let replacement_start = text.len();
                     text.push_str(&replacement_text);
                     let replacement_end = text.len();
@@ -195,7 +271,6 @@ fn render_plain_text_mut(
                     highlights.push((replacement_start..replacement_end, Highlight::Mention));
 
                     last_processed = mention_end_in_text;
-                    mentions = &mentions[1..];
                 }
 
                 // Add any remaining text after the last mention
@@ -203,7 +278,6 @@ fn render_plain_text_mut(
                     let remaining_text = &t_str[last_processed..];
                     process_text_segment(
                         remaining_text,
-                        prev_len + last_processed,
                         bold_depth,
                         italic_depth,
                         strikethrough_depth,
@@ -234,11 +308,14 @@ fn render_plain_text_mut(
                 }
                 Tag::CodeBlock(_kind) => {
                     new_paragraph(text, &mut list_stack);
+                    code_block = true;
                 }
                 Tag::Emphasis => italic_depth += 1,
                 Tag::Strong => bold_depth += 1,
                 Tag::Strikethrough => strikethrough_depth += 1,
-                Tag::Link { dest_url, .. } => link_url = Some(dest_url.to_string()),
+                Tag::Link { dest_url, .. } => {
+                    link_url = WEB_URL.is_match(&dest_url).then(|| dest_url.to_string());
+                }
                 Tag::List(number) => {
                     list_stack.push((number, false));
                 }
@@ -264,6 +341,7 @@ fn render_plain_text_mut(
                 _ => {}
             },
             Event::End(tag) => match tag {
+                TagEnd::CodeBlock => code_block = false,
                 TagEnd::Heading(_) => bold_depth -= 1,
                 TagEnd::Emphasis => italic_depth -= 1,
                 TagEnd::Strong => bold_depth -= 1,
@@ -272,6 +350,11 @@ fn render_plain_text_mut(
                 TagEnd::List(_) => drop(list_stack.pop()),
                 _ => {}
             },
+            Event::Html(t) | Event::InlineHtml(t) => text.push_str(t.as_ref()),
+            Event::Rule => {
+                new_paragraph(text, &mut list_stack);
+                text.push_str("────────\n");
+            }
             Event::HardBreak => text.push('\n'),
             Event::SoftBreak => text.push('\n'),
             _ => {}
@@ -282,7 +365,6 @@ fn render_plain_text_mut(
 #[allow(clippy::too_many_arguments)]
 fn process_text_segment(
     segment: &str,
-    segment_start: usize,
     bold_depth: i32,
     italic_depth: i32,
     strikethrough_depth: i32,
@@ -307,7 +389,8 @@ fn process_text_segment(
         });
     }
 
-    // Add the text
+    // Ranges always refer to the rendered text, including replaced mentions.
+    let segment_start = text.len();
     text.push_str(segment);
     let text_end = text.len();
 
@@ -330,7 +413,10 @@ fn process_text_segment(
         finder.kinds(&[linkify::LinkKind::Url]);
         let mut last_link_pos = 0;
 
-        for link in finder.links(segment) {
+        for link in finder
+            .links(segment)
+            .filter(|link| WEB_URL.is_match(link.as_str()))
+        {
             let start = link.start();
             let end = link.end();
 
@@ -375,6 +461,7 @@ fn process_text_segment(
 
 fn new_paragraph(text: &mut String, list_stack: &mut [(Option<u64>, bool)]) {
     let mut is_subsequent_paragraph_of_list = false;
+
     if let Some((_, has_content)) = list_stack.last_mut() {
         if *has_content {
             is_subsequent_paragraph_of_list = true;
@@ -390,9 +477,11 @@ fn new_paragraph(text: &mut String, list_stack: &mut [(Option<u64>, bool)]) {
         }
         text.push('\n');
     }
+
     for _ in 0..list_stack.len().saturating_sub(1) {
         text.push_str("  ");
     }
+
     if is_subsequent_paragraph_of_list {
         text.push_str("  ");
     }

crates/common/Cargo.toml

@@ -7,17 +7,14 @@ publish.workspace = true
 [dependencies]
 gpui.workspace = true
 nostr.workspace = true
+instant.workspace = true
 nostr-sdk.workspace = true
 
-anyhow.workspace = true
 itertools.workspace = true
 chrono.workspace = true
-smallvec.workspace = true
-smol.workspace = true
 futures.workspace = true
 log.workspace = true
 
 dirs = "5.0"
 qrcode = "0.14.1"
-bech32 = "0.11.1"
 regex = "1.10"

crates/common/src/caching.rs

@@ -1,135 +0,0 @@
-use std::collections::{HashMap, VecDeque};
-use std::mem::take;
-
-use futures::FutureExt;
-use gpui::{
-    App, AppContext, Asset, AssetLogger, ElementId, Entity, ImageAssetLoader, ImageCache,
-    ImageCacheItem, ImageCacheProvider, ImageSource, Resource, hash,
-};
-
-pub fn coop_cache(id: impl Into<ElementId>, max_items: usize) -> CoopImageCacheProvider {
-    CoopImageCacheProvider {
-        id: id.into(),
-        max_items,
-    }
-}
-
-pub struct CoopImageCacheProvider {
-    id: ElementId,
-    max_items: usize,
-}
-
-impl ImageCacheProvider for CoopImageCacheProvider {
-    fn provide(&mut self, window: &mut gpui::Window, cx: &mut App) -> gpui::AnyImageCache {
-        window
-            .with_global_id(self.id.clone(), |id, window| {
-                window.with_element_state(id, |cache, _| {
-                    let cache = cache.unwrap_or_else(|| CoopImageCache::new(self.max_items, cx));
-                    (cache.clone(), cache)
-                })
-            })
-            .into()
-    }
-}
-
-pub struct CoopImageCache {
-    max_items: usize,
-    usage_list: VecDeque<u64>,
-    cache: HashMap<u64, (ImageCacheItem, Resource)>,
-}
-
-impl CoopImageCache {
-    pub fn new(max_items: usize, cx: &mut App) -> Entity<Self> {
-        cx.new(|cx| {
-            log::info!("Creating CoopImageCache");
-            cx.on_release(|this: &mut Self, cx| {
-                for (ix, (mut image, resource)) in take(&mut this.cache) {
-                    if let Some(Ok(image)) = image.get() {
-                        log::info!("Dropping image {ix}");
-                        cx.drop_image(image, None);
-                    }
-                    ImageSource::Resource(resource).remove_asset(cx);
-                }
-            })
-            .detach();
-
-            CoopImageCache {
-                max_items,
-                usage_list: VecDeque::with_capacity(max_items),
-                cache: HashMap::with_capacity(max_items),
-            }
-        })
-    }
-}
-
-impl ImageCache for CoopImageCache {
-    fn load(
-        &mut self,
-        resource: &Resource,
-        window: &mut gpui::Window,
-        cx: &mut gpui::App,
-    ) -> Option<Result<std::sync::Arc<gpui::RenderImage>, gpui::ImageCacheError>> {
-        let hash = hash(resource);
-
-        if let Some(item) = self.cache.get_mut(&hash) {
-            let current_idx = self
-                .usage_list
-                .iter()
-                .position(|item| *item == hash)
-                .expect("cache has an item usage_list doesn't");
-
-            self.usage_list.remove(current_idx);
-            self.usage_list.push_front(hash);
-
-            return item.0.get();
-        }
-
-        let load_future = AssetLogger::<ImageAssetLoader>::load(resource.clone(), cx);
-        let task = cx.background_executor().spawn(load_future).shared();
-
-        if self.usage_list.len() >= self.max_items {
-            log::info!("Image cache is full, evicting oldest item");
-
-            if let Some(oldest) = self.usage_list.pop_back() {
-                let mut image = self
-                    .cache
-                    .remove(&oldest)
-                    .expect("usage_list has an item cache doesn't");
-
-                if let Some(Ok(image)) = image.0.get() {
-                    log::info!("requesting image to be dropped");
-                    cx.drop_image(image, Some(window));
-                }
-
-                ImageSource::Resource(image.1).remove_asset(cx);
-            }
-        }
-
-        self.cache.insert(
-            hash,
-            (
-                gpui::ImageCacheItem::Loading(task.clone()),
-                resource.clone(),
-            ),
-        );
-        self.usage_list.push_front(hash);
-
-        let entity = window.current_view();
-
-        window
-            .spawn(cx, async move |cx| {
-                let result = task.await;
-
-                if let Err(err) = result {
-                    log::error!("error loading image into cache: {:?}", err);
-                }
-
-                cx.on_next_frame(move |_, cx| {
-                    cx.notify(entity);
-                });
-            })
-            .detach();
-
-        None
-    }
-}

crates/common/src/debounced_delay.rs

@@ -1,5 +1,5 @@
 use std::marker::PhantomData;
-use std::time::Duration;
+use instant::Duration;
 
 use futures::channel::oneshot;
 use futures::FutureExt;

crates/common/src/lib.rs

@@ -1,4 +1,3 @@
-pub use caching::*;
 pub use debounced_delay::*;
 pub use display::*;
 pub use event::*;
@@ -7,7 +6,6 @@ pub use parser::*;
 pub use paths::*;
 pub use range::*;
 
-mod caching;
 mod debounced_delay;
 mod display;
 mod event;

crates/community/Cargo.toml

@@ -1,21 +1,22 @@
 [package]
-name = "relay_auth"
+name = "community"
 version.workspace = true
 edition.workspace = true
 publish.workspace = true
 
 [dependencies]
+concord = { path = "../concord" }
 state = { path = "../state" }
-settings = { path = "../settings" }
-common = { path = "../common" }
-theme = { path = "../theme" }
-ui = { path = "../ui" }
 
 gpui.workspace = true
 nostr-sdk.workspace = true
 
 anyhow.workspace = true
-smallvec.workspace = true
-smol.workspace = true
 flume.workspace = true
 log.workspace = true
+serde_json.workspace = true
+smallvec.workspace = true
+
+[dev-dependencies]
+nostr-memory.workspace = true
+smol.workspace = true

crates/community/src/community.rs

@@ -0,0 +1,129 @@
+use std::collections::{BTreeMap, BTreeSet};
+
+use anyhow::Result;
+use concord::cord02::ControlFold;
+use concord::store::{ChannelKeyRef, CommunityState};
+use concord::{ChannelId, CommunityId, Epoch};
+use gpui::{AppContext, Context, EventEmitter, Task};
+use nostr_sdk::prelude::*;
+use state::NostrRegistry;
+
+use crate::sync::{self, Snapshot};
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SubscriptionKey {
+    control_pks: BTreeMap<u64, PublicKey>,
+    channels: Vec<(ChannelId, Epoch, bool)>,
+    relays: Vec<RelayUrl>,
+}
+
+impl SubscriptionKey {
+    fn of(state: &CommunityState) -> Self {
+        Self {
+            control_pks: state.control_pks.clone(),
+            channels: state
+                .channels
+                .iter()
+                .map(|channel| (channel.id, channel.epoch, channel.private))
+                .collect(),
+            relays: state.relays.clone(),
+        }
+    }
+
+    pub(crate) fn relays(&self) -> &[RelayUrl] {
+        &self.relays
+    }
+}
+
+#[derive(Debug, Clone)]
+pub enum CommunityEvent {
+    Updated(CommunityId),
+    Error(String),
+}
+
+pub struct Community {
+    state: CommunityState,
+    control: ControlFold,
+    members: BTreeSet<PublicKey>,
+    dirty: bool,
+    refresh_task: Option<Task<Result<()>>>,
+}
+
+impl EventEmitter<CommunityEvent> for Community {}
+
+impl Community {
+    pub fn new(state: CommunityState) -> Self {
+        Self {
+            state,
+            control: ControlFold::default(),
+            members: BTreeSet::new(),
+            dirty: false,
+            refresh_task: None,
+        }
+    }
+
+    pub fn id(&self) -> CommunityId {
+        self.state.id
+    }
+
+    pub fn state(&self) -> &CommunityState {
+        &self.state
+    }
+
+    pub fn control(&self) -> &ControlFold {
+        &self.control
+    }
+
+    pub fn members(&self) -> &BTreeSet<PublicKey> {
+        &self.members
+    }
+
+    pub fn channels(&self) -> &[ChannelKeyRef] {
+        &self.state.channels
+    }
+
+    pub fn subscription_key(&self) -> SubscriptionKey {
+        SubscriptionKey::of(&self.state)
+    }
+
+    /// Rebuilds the community from the wraps in the local database.
+    pub fn refresh(&mut self, cx: &mut Context<Self>) {
+        if self.refresh_task.is_some() {
+            self.dirty = true;
+            return;
+        }
+
+        let nostr = NostrRegistry::global(cx);
+        let client = nostr.read(cx).client();
+
+        let state = self.state.clone();
+        let folded = cx.background_spawn(async move { sync::fold(&client, &state).await });
+
+        self.refresh_task = Some(cx.spawn(async move |this, cx| {
+            let result = folded.await;
+            this.update(cx, |this, cx| this.apply(result, cx))?;
+            Ok(())
+        }));
+    }
+
+    fn apply(&mut self, result: Result<Option<Snapshot>>, cx: &mut Context<Self>) {
+        self.refresh_task = None;
+
+        match result {
+            Ok(Some(snapshot)) => {
+                self.state = snapshot.state;
+                self.control = snapshot.control;
+                self.members = snapshot.members;
+                cx.emit(CommunityEvent::Updated(self.state.id));
+                cx.notify();
+            }
+            Ok(None) => {}
+            Err(error) => cx.emit(CommunityEvent::Error(error.to_string())),
+        }
+
+        if self.dirty {
+            self.dirty = false;
+            self.refresh(cx);
+        }
+    }
+}

crates/community/src/lib.rs

@@ -0,0 +1,323 @@
+use std::collections::HashMap;
+
+use anyhow::Result;
+use concord::CommunityId;
+use concord::cord01::KIND_WRAP;
+use concord::store::CommunityState;
+use gpui::{App, AppContext, Context, Entity, EventEmitter, Global, Subscription, Task, Window};
+use nostr_sdk::prelude::*;
+use smallvec::{SmallVec, smallvec};
+use state::NostrRegistry;
+
+mod community;
+mod sync;
+
+pub use community::*;
+pub use sync::*;
+
+pub fn init(window: &mut Window, cx: &mut App) {
+    CommunityRegistry::set_global(cx.new(|cx| CommunityRegistry::new(window, cx)), cx);
+}
+
+struct GlobalCommunityRegistry(Entity<CommunityRegistry>);
+
+impl Global for GlobalCommunityRegistry {}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+enum Signal {
+    Event(CommunityId),
+}
+
+impl EventEmitter<CommunityEvent> for CommunityRegistry {}
+
+pub struct CommunityRegistry {
+    communities: Vec<Entity<Community>>,
+    index: HashMap<CommunityId, Entity<Community>>,
+    /// The plane set each community was last subscribed with
+    synced: HashMap<CommunityId, SubscriptionKey>,
+    /// One observer per tracked community, dropped on reset
+    observers: Vec<Subscription>,
+    signal_tx: flume::Sender<Signal>,
+    signal_rx: flume::Receiver<Signal>,
+    tasks: SmallVec<[Task<Result<()>>; 2]>,
+    /// Notification listener task (cancelled on signer change)
+    notification_listener: Option<Task<Result<()>>>,
+    /// Signal consumer task (cancelled on signer change)
+    signal_consumer: Option<Task<Result<()>>>,
+    _subscriptions: SmallVec<[Subscription; 2]>,
+}
+
+impl CommunityRegistry {
+    pub fn global(cx: &App) -> Entity<Self> {
+        cx.global::<GlobalCommunityRegistry>().0.clone()
+    }
+
+    fn set_global(state: Entity<Self>, cx: &mut App) {
+        cx.set_global(GlobalCommunityRegistry(state));
+    }
+
+    fn new(window: &mut Window, cx: &mut Context<Self>) -> Self {
+        let nostr = NostrRegistry::global(cx);
+        let (tx, rx) = flume::bounded::<Signal>(256);
+        let mut subscriptions = smallvec![];
+
+        subscriptions.push(cx.subscribe(&nostr, |this, _nostr, event, cx| {
+            if event.signer_changed() {
+                this.reset(cx);
+                this.handle_notifications(cx);
+                this.load(cx);
+            }
+        }));
+
+        cx.defer_in(window, move |this, _window, cx| {
+            this.handle_notifications(cx);
+
+            if nostr.read(cx).current_user().is_some() {
+                this.load(cx);
+            }
+        });
+
+        Self {
+            communities: Vec::new(),
+            index: HashMap::new(),
+            synced: HashMap::new(),
+            observers: Vec::new(),
+            signal_tx: tx,
+            signal_rx: rx,
+            tasks: smallvec![],
+            notification_listener: None,
+            signal_consumer: None,
+            _subscriptions: subscriptions,
+        }
+    }
+
+    pub fn communities(&self) -> &[Entity<Community>] {
+        &self.communities
+    }
+
+    pub fn community(&self, id: &CommunityId) -> Option<Entity<Community>> {
+        self.index.get(id).cloned()
+    }
+
+    /// Forget the current account and cancel everything in flight.
+    pub fn reset(&mut self, cx: &mut Context<Self>) {
+        self.notification_listener = None;
+        self.signal_consumer = None;
+        self.tasks.clear();
+        self.observers.clear();
+
+        let nostr = NostrRegistry::global(cx);
+        let client = nostr.read(cx).client();
+        let ids: Vec<CommunityId> = self.index.keys().copied().collect();
+
+        for id in ids {
+            let client = client.clone();
+            let subscription = sync::subscription_id(&id);
+
+            self.tasks.push(cx.background_spawn(async move {
+                client.unsubscribe(&subscription).await?;
+                Ok(())
+            }));
+        }
+
+        self.communities.clear();
+        self.index.clear();
+        self.synced.clear();
+        cx.notify();
+    }
+
+    /// Discover the account's communities in the local database.
+    fn load(&mut self, cx: &mut Context<Self>) {
+        let nostr = NostrRegistry::global(cx);
+        let signer = nostr.read(cx).signer();
+        let client = nostr.read(cx).client();
+
+        let task = cx.background_spawn(async move {
+            let self_pk = signer.get_public_key_async().await?;
+            sync::load(&client, &signer, self_pk).await
+        });
+
+        self.tasks.push(cx.spawn(async move |this, cx| {
+            match task.await {
+                Ok(states) => {
+                    this.update(cx, |this, cx| this.track(states, cx))?;
+                }
+                Err(error) => {
+                    this.update(cx, |_this, cx| {
+                        cx.emit(CommunityEvent::Error(error.to_string()));
+                    })?;
+                }
+            }
+
+            Ok(())
+        }));
+    }
+
+    /// Replace the tracked communities with a freshly loaded set.
+    fn track(&mut self, states: Vec<CommunityState>, cx: &mut Context<Self>) {
+        self.observers.clear();
+        self.communities.clear();
+        self.index.clear();
+        self.synced.clear();
+
+        for state in states {
+            let id = state.id;
+            let community = cx.new(|_| Community::new(state));
+
+            self.observers
+                .push(cx.observe(&community, |this, _community, cx| {
+                    this.sync_subscriptions(cx);
+                }));
+            self.index.insert(id, community.clone());
+            self.communities.push(community);
+        }
+
+        self.sync_subscriptions(cx);
+
+        // A backlog already in the database produces no notification, so fold it once.
+        for community in self.communities.clone() {
+            community.update(cx, |community, cx| community.refresh(cx));
+        }
+
+        cx.notify();
+    }
+
+    fn refresh(&mut self, id: CommunityId, cx: &mut Context<Self>) {
+        let Some(community) = self.index.get(&id).cloned() else {
+            return;
+        };
+
+        community.update(cx, |community, cx| community.refresh(cx));
+    }
+
+    /// Re-subscribe every community whose held planes moved.
+    fn sync_subscriptions(&mut self, cx: &mut Context<Self>) {
+        let nostr = NostrRegistry::global(cx);
+        let client = nostr.read(cx).client();
+
+        for community in self.communities.clone() {
+            let (id, key, state) = {
+                let community = community.read(cx);
+                (
+                    community.id(),
+                    community.subscription_key(),
+                    community.state().clone(),
+                )
+            };
+
+            if self.synced.get(&id) == Some(&key) {
+                continue;
+            }
+
+            let planes = match sync::planes(&state) {
+                Ok(planes) => planes,
+                Err(error) => {
+                    cx.emit(CommunityEvent::Error(error.to_string()));
+                    continue;
+                }
+            };
+
+            let subscription = sync::subscription_id(&id);
+            let filter = sync::subscription_filter(&planes);
+            let relays = key.relays().to_vec();
+            self.synced.insert(id, key);
+
+            let client = client.clone();
+            self.tasks.push(cx.spawn(async move |this, cx| {
+                if let Err(error) = subscribe(&client, &subscription, &relays, filter).await {
+                    this.update(cx, |_this, cx| {
+                        cx.emit(CommunityEvent::Error(error.to_string()));
+                    })?;
+                }
+
+                Ok(())
+            }));
+        }
+    }
+
+    fn handle_notifications(&mut self, cx: &mut Context<Self>) {
+        self.notification_listener = None;
+        self.signal_consumer = None;
+
+        let nostr = NostrRegistry::global(cx);
+        let client = nostr.read(cx).client();
+
+        let tx = self.signal_tx.clone();
+        let rx = self.signal_rx.clone();
+
+        self.notification_listener = Some(cx.background_spawn(async move {
+            let mut notifications = client.notifications();
+
+            while let Some(notification) = notifications.next().await {
+                let ClientNotification::Event {
+                    subscription_id,
+                    event,
+                    ..
+                } = notification
+                else {
+                    continue;
+                };
+
+                if event.kind != Kind::from(KIND_WRAP) {
+                    continue;
+                }
+
+                let Some(id) = sync::community_of(&subscription_id) else {
+                    continue;
+                };
+
+                tx.send_async(Signal::Event(id)).await?;
+            }
+
+            Ok(())
+        }));
+
+        self.signal_consumer = Some(cx.spawn(async move |this, cx| {
+            while let Ok(Signal::Event(id)) = rx.recv_async().await {
+                this.update(cx, |this, cx| this.refresh(id, cx))?;
+            }
+
+            Ok(())
+        }));
+    }
+}
+
+async fn subscribe(
+    client: &Client,
+    id: &SubscriptionId,
+    relays: &[RelayUrl],
+    filter: Filter,
+) -> Result<()> {
+    client.unsubscribe(id).await?;
+
+    for url in relays {
+        if let Err(error) = client.add_relay(url).and_connect().await {
+            log::warn!("community {id}: failed to add relay {url}: {error}");
+        }
+    }
+
+    // Concord wraps share kind 1059 with NIP-59 gift wraps, so an automatic
+    // target sends gossip after the plane authors as if they were DM peers.
+    // The community's own relays are the routing relays, so target them.
+    let target = if relays.is_empty() {
+        ReqTarget::auto(vec![filter])
+    } else {
+        ReqTarget::manual(
+            relays
+                .iter()
+                .map(|url| (url.clone(), vec![filter.clone()]))
+                .collect::<Vec<_>>(),
+        )
+    };
+
+    let output = client.subscribe(target).with_id(id.clone()).await?;
+
+    if !output.failed.is_empty() {
+        log::warn!(
+            "community {id}: {} relay(s) rejected the subscription",
+            output.failed.len()
+        );
+    }
+
+    Ok(())
+}

crates/community/src/sync.rs

@@ -0,0 +1,261 @@
+use std::collections::{BTreeMap, BTreeSet};
+
+use anyhow::Result;
+use concord::cord01::KIND_WRAP;
+use concord::cord02::list::{CommunityList, KIND_COMMUNITY_LIST};
+use concord::cord02::{self, ControlFold};
+use concord::cord04::AuthorityCitation;
+use concord::cord04::roles::{Permissions, citation_ok};
+use concord::derive::{channel_group_key, control_group_key, guestbook_group_key};
+use concord::store::{self, CommunityState};
+use concord::{ChannelId, CommunityId, Epoch, GroupKey};
+use nostr_sdk::prelude::*;
+use state::UniversalSigner;
+
+const SUBSCRIPTION_PREFIX: &str = "concord/";
+const STATE_PREFIX: &str = "concord/";
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum PlaneKind {
+    Control(Epoch),
+    Guestbook,
+    Channel(ChannelId, Epoch),
+}
+
+#[derive(Debug, Clone)]
+pub struct Plane {
+    pub kind: PlaneKind,
+    /// The wrap's author: the control signer for Control, the group's own key otherwise.
+    pub address: PublicKey,
+    pub group: GroupKey,
+}
+
+pub fn planes(state: &CommunityState) -> Result<Vec<Plane>> {
+    let mut planes = Vec::new();
+
+    for (epoch, address) in &state.control_pks {
+        let epoch = Epoch(*epoch);
+        let group = control_group_key(&state.community_root, &state.id, epoch)?;
+        planes.push(Plane {
+            kind: PlaneKind::Control(epoch),
+            address: *address,
+            group,
+        });
+    }
+
+    let group = guestbook_group_key(&state.community_root, &state.id, state.root_epoch)?;
+    planes.push(Plane {
+        kind: PlaneKind::Guestbook,
+        address: group.pk(),
+        group,
+    });
+
+    for channel in &state.channels {
+        if channel.private {
+            continue;
+        }
+
+        let group = channel_group_key(&state.community_root, &channel.id, channel.epoch)?;
+        planes.push(Plane {
+            kind: PlaneKind::Channel(channel.id, channel.epoch),
+            address: group.pk(),
+            group,
+        });
+    }
+
+    Ok(planes)
+}
+
+/// One `Filter` covering every held plane. The address is the event author,
+/// not a `p` tag: a Concord wrap's `p` tag carries a random ephemeral key.
+pub fn subscription_filter(planes: &[Plane]) -> Filter {
+    Filter::new()
+        .kinds([Kind::from(KIND_WRAP)])
+        .authors(planes.iter().map(|plane| plane.address))
+}
+
+pub fn subscription_id(id: &CommunityId) -> SubscriptionId {
+    SubscriptionId::new(format!("{SUBSCRIPTION_PREFIX}{}", id.to_hex()))
+}
+
+pub fn community_of(subscription_id: &SubscriptionId) -> Option<CommunityId> {
+    subscription_id
+        .as_str()
+        .strip_prefix(SUBSCRIPTION_PREFIX)?
+        .parse()
+        .ok()
+}
+
+#[derive(Debug, Clone)]
+pub struct Snapshot {
+    pub state: CommunityState,
+    pub control: ControlFold,
+    pub members: BTreeSet<PublicKey>,
+}
+
+/// Discovers the current account's communities from the local database.
+pub async fn load(
+    client: &Client,
+    signer: &UniversalSigner,
+    self_pk: PublicKey,
+) -> Result<Vec<CommunityState>> {
+    let filter = Filter::new().kind(Kind::ApplicationSpecificData);
+    let mut newest: BTreeMap<CommunityId, Event> = BTreeMap::new();
+
+    for event in client.database().query(filter).await? {
+        let Some(id) = state_document_of(&event) else {
+            continue;
+        };
+
+        match newest.get(&id) {
+            Some(existing) if existing.created_at >= event.created_at => {}
+            _ => {
+                newest.insert(id, event);
+            }
+        }
+    }
+
+    let mut states = Vec::with_capacity(newest.len());
+
+    for event in newest.into_values() {
+        match serde_json::from_str::<CommunityState>(&event.content) {
+            Ok(state) => states.push(state),
+            Err(error) => log::warn!("ignoring malformed community state {}: {error}", event.id),
+        }
+    }
+
+    if let Some(list) = load_list(client, signer, self_pk).await? {
+        states.retain(|state| list.is_live(&state.id));
+    }
+
+    Ok(states)
+}
+
+fn state_document_of(event: &Event) -> Option<CommunityId> {
+    let identifier = event.tags.identifier()?;
+    let hex = identifier.strip_prefix(STATE_PREFIX)?;
+    hex.parse().ok()
+}
+
+async fn load_list(
+    client: &Client,
+    signer: &UniversalSigner,
+    self_pk: PublicKey,
+) -> Result<Option<CommunityList>> {
+    let filter = Filter::new()
+        .kind(Kind::Custom(KIND_COMMUNITY_LIST))
+        .author(self_pk)
+        .limit(1);
+
+    let Some(event) = client.database().query(filter).await?.into_iter().next() else {
+        return Ok(None);
+    };
+
+    let json = signer.nip44_decrypt_async(&self_pk, &event.content).await?;
+
+    Ok(Some(serde_json::from_str(&json)?))
+}
+
+/// Rebuilds a community from the wraps already in the local database.
+pub async fn fold(client: &Client, state: &CommunityState) -> Result<Option<Snapshot>> {
+    let planes = planes(state)?;
+
+    if planes.is_empty() {
+        return Ok(None);
+    }
+
+    let wraps = client
+        .database()
+        .query(subscription_filter(&planes))
+        .await?;
+
+    let mut editions = Vec::new();
+    let mut observed: BTreeMap<PublicKey, u64> = BTreeMap::new();
+    let mut guestbook_rumors = Vec::new();
+
+    for wrap in &wraps {
+        let Some(plane) = planes.iter().find(|plane| plane.address == wrap.pubkey) else {
+            continue;
+        };
+
+        match plane.kind {
+            PlaneKind::Control(_) => {
+                if let Ok(edition) = cord02::open_edition(wrap, &plane.group, &plane.address, true)
+                {
+                    editions.push(edition);
+                }
+            }
+            PlaneKind::Guestbook => {
+                if let Ok((_, rumor)) = cord02::guestbook::open(wrap, &plane.group) {
+                    observe(&mut observed, rumor.author, rumor.at_ms);
+                    guestbook_rumors.push(rumor);
+                }
+            }
+            PlaneKind::Channel(channel, epoch) => {
+                if let Ok((opened, rumor)) =
+                    concord::cord03::open(wrap, &plane.group, &channel, epoch)
+                {
+                    store::cache_rumor(client, &channel, &opened).await?;
+                    observe(&mut observed, rumor.author, rumor.at_ms);
+                }
+            }
+        }
+    }
+
+    if editions.is_empty() {
+        return Ok(None);
+    }
+
+    let control = cord02::fold_control(
+        &state.owner,
+        &state.id,
+        &editions,
+        &state.floors(),
+        &state.banned,
+    );
+
+    let granted: BTreeSet<PublicKey> = control
+        .roles
+        .grants()
+        .filter(|grant| !grant.role_ids.is_empty())
+        .map(|grant| grant.member)
+        .collect();
+
+    let floors = state.floors();
+    let can_kick = |actor: &PublicKey, target: &PublicKey, citation: Option<&AuthorityCitation>| {
+        citation_ok(&state.owner, &state.id, actor, citation, &floors)
+            && control
+                .roles
+                .can_act_on_member(actor, &state.owner, target, Permissions::KICK)
+    };
+
+    let now_ms = Timestamp::now().as_secs().saturating_mul(1000);
+    let coalesced = cord02::guestbook::coalesce(&guestbook_rumors, now_ms, None, can_kick);
+    let mut members = cord02::guestbook::complete_memberlist(
+        &coalesced,
+        &observed,
+        &granted,
+        &control.banned,
+        &BTreeMap::new(),
+    );
+
+    // The roster has no grant for the owner, so membership is stated here.
+    members.insert(state.owner);
+
+    let mut state = state.clone();
+    state.apply_fold(&control);
+    store::save_state(client, &state).await?;
+
+    Ok(Some(Snapshot {
+        state,
+        control,
+        members,
+    }))
+}
+
+fn observe(observed: &mut BTreeMap<PublicKey, u64>, author: PublicKey, at_ms: u64) {
+    observed
+        .entry(author)
+        .and_modify(|seen| *seen = (*seen).max(at_ms))
+        .or_insert(at_ms);
+}

crates/concord/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "concord"
+version.workspace = true
+edition.workspace = true
+publish.workspace = true
+
+[dependencies]
+nostr.workspace = true
+nostr-sdk.workspace = true
+
+hkdf.workspace = true
+sha2.workspace = true
+chacha20.workspace = true
+hmac.workspace = true
+data-encoding.workspace = true
+rand.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+anyhow.workspace = true
+
+[dev-dependencies]
+nostr-memory.workspace = true
+smol.workspace = true

crates/concord/src/cords/cord01.rs

@@ -0,0 +1,700 @@
+use std::fmt;
+
+use data_encoding::BASE64;
+use nostr::nips::nip44::v2::{ConversationKey, decrypt_to_bytes, encrypt_to_bytes_with_nonce};
+use nostr_sdk::prelude::{
+    Event, EventBuilder, EventId, FinalizeEvent, Keys, Kind, PublicKey, Tag, Timestamp,
+    UnsignedEvent,
+};
+
+use crate::derive::GroupKey;
+use crate::{ChannelId, Epoch};
+
+pub const KIND_WRAP: u16 = 1059;
+pub const KIND_WRAP_EPHEMERAL: u16 = 21059;
+pub const KIND_SEAL_ENCRYPTED: u16 = 20013;
+pub const KIND_SEAL_PLAINTEXT: u16 = 20014;
+pub const NIP44_MAX_PLAINTEXT: usize = 65_535;
+
+const TAG_MS: &str = "ms";
+const TAG_CHANNEL: &str = "channel";
+const TAG_EPOCH: &str = "epoch";
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum SealForm {
+    Encrypted,
+    Plaintext,
+}
+
+impl SealForm {
+    pub fn kind(self) -> u16 {
+        match self {
+            SealForm::Encrypted => KIND_SEAL_ENCRYPTED,
+            SealForm::Plaintext => KIND_SEAL_PLAINTEXT,
+        }
+    }
+
+    fn from_kind(kind: u16) -> Option<Self> {
+        match kind {
+            KIND_SEAL_ENCRYPTED => Some(SealForm::Encrypted),
+            KIND_SEAL_PLAINTEXT => Some(SealForm::Plaintext),
+            _ => None,
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum StreamError {
+    Sign(String),
+    Encrypt(String),
+    Decrypt(String),
+    Parse(String),
+    Oversize(usize),
+    BadWrapKind(u16),
+    WrongStream,
+    BadWrapSignature,
+    BadSealKind(u16),
+    BadSealSignature,
+    AuthorMismatch,
+    BadRumorId,
+    BadMs,
+    ChannelMismatch,
+    EpochMismatch,
+    MissingTag(&'static str),
+    DuplicateTag(&'static str),
+    NotRewrappable,
+}
+
+impl fmt::Display for StreamError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            StreamError::Sign(error) => write!(f, "sign: {error}"),
+            StreamError::Encrypt(error) => write!(f, "encrypt: {error}"),
+            StreamError::Decrypt(error) => write!(f, "decrypt: {error}"),
+            StreamError::Parse(error) => write!(f, "parse: {error}"),
+            StreamError::Oversize(len) => write!(f, "plaintext {len} bytes exceeds NIP-44 cap"),
+            StreamError::BadWrapKind(kind) => write!(f, "not a wrap kind: {kind}"),
+            StreamError::WrongStream => write!(f, "wrap author is not this stream"),
+            StreamError::BadWrapSignature => write!(f, "restricted wrap signature invalid"),
+            StreamError::BadSealKind(kind) => write!(f, "not a seal kind: {kind}"),
+            StreamError::BadSealSignature => write!(f, "seal signature invalid"),
+            StreamError::AuthorMismatch => write!(f, "rumor pubkey != seal pubkey"),
+            StreamError::BadRumorId => write!(f, "rumor id != computed hash"),
+            StreamError::BadMs => write!(f, "ms is not a canonical decimal in 0..=999"),
+            StreamError::ChannelMismatch => write!(f, "channel binding mismatch"),
+            StreamError::EpochMismatch => write!(f, "epoch binding mismatch"),
+            StreamError::MissingTag(name) => write!(f, "missing rumor tag: {name}"),
+            StreamError::DuplicateTag(name) => write!(f, "duplicate rumor tag: {name}"),
+            StreamError::NotRewrappable => write!(f, "only plaintext seals survive re-wrapping"),
+        }
+    }
+}
+
+impl std::error::Error for StreamError {}
+
+#[derive(Debug, Clone)]
+pub struct OpenedStream {
+    pub rumor_id: EventId,
+    pub author: PublicKey,
+    pub seal_form: SealForm,
+    pub seal: Event,
+    pub wrapper_id: EventId,
+    pub at_ms: u64,
+    pub rumor: UnsignedEvent,
+}
+
+pub fn split_ms(at_ms: u64) -> (u64, u16) {
+    (at_ms / 1000, (at_ms % 1000) as u16)
+}
+
+/// Build a rumor carrying a full epoch-ms time: seconds in `created_at`, the remainder as `["ms", 0..=999]`.
+pub fn build_rumor_ms(
+    kind: u16,
+    author: PublicKey,
+    content: &str,
+    mut tags: Vec<Tag>,
+    at_ms: u64,
+) -> UnsignedEvent {
+    let (seconds, offset) = split_ms(at_ms);
+    tags.push(Tag::custom(TAG_MS, [offset.to_string()]));
+    build_rumor_secs(kind, author, content, tags, seconds)
+}
+
+/// Build a rumor with a plain seconds timestamp and no `ms` tag.
+pub fn build_rumor_secs(
+    kind: u16,
+    author: PublicKey,
+    content: &str,
+    tags: Vec<Tag>,
+    at_secs: u64,
+) -> UnsignedEvent {
+    let mut rumor = UnsignedEvent::new(
+        author,
+        Timestamp::from_secs(at_secs),
+        Kind::Custom(kind),
+        tags,
+        content,
+    );
+    rumor.ensure_id();
+    rumor
+}
+
+pub fn resolve_ms_strict(rumor: &UnsignedEvent) -> Result<u64, StreamError> {
+    let seconds = rumor.created_at.as_secs().saturating_mul(1000);
+    let mut tag: Option<Option<String>> = None;
+
+    for candidate in rumor.tags.iter() {
+        let fields = candidate.as_slice();
+        if fields.first().map(String::as_str) == Some(TAG_MS) {
+            tag = Some(fields.get(1).cloned());
+            break;
+        }
+    }
+
+    let Some(raw) = tag else {
+        return Ok(seconds);
+    };
+    let raw = raw.ok_or(StreamError::BadMs)?;
+
+    if raw.is_empty() || !raw.bytes().all(|byte| byte.is_ascii_digit()) {
+        return Err(StreamError::BadMs);
+    }
+
+    let offset: u64 = raw.parse().map_err(|_| StreamError::BadMs)?;
+
+    if offset > 999 || (raw.len() > 1 && raw.starts_with('0')) {
+        return Err(StreamError::BadMs);
+    }
+
+    Ok(seconds.saturating_add(offset))
+}
+
+pub fn seal_content(
+    rumor: &UnsignedEvent,
+    form: SealForm,
+    group: &GroupKey,
+) -> Result<String, StreamError> {
+    let json = rumor.as_json();
+    check_plaintext_cap(json.len())?;
+
+    match form {
+        SealForm::Plaintext => Ok(json),
+        SealForm::Encrypted => seal_bytes(group.conversation(), json.as_bytes()),
+    }
+}
+
+pub fn seal_bytes(conversation: &ConversationKey, plaintext: &[u8]) -> Result<String, StreamError> {
+    check_plaintext_cap(plaintext.len())?;
+    Ok(BASE64.encode(&encrypt(conversation, plaintext)?))
+}
+
+pub fn open_bytes(conversation: &ConversationKey, content: &str) -> Result<Vec<u8>, StreamError> {
+    let payload = BASE64
+        .decode(content.as_bytes())
+        .map_err(|error| StreamError::Decrypt(error.to_string()))?;
+
+    decrypt_to_bytes(conversation, &payload)
+        .map_err(|error| StreamError::Decrypt(error.to_string()))
+}
+
+/// A member's own document (the Community List, the Invite List): NIP-44 to self.
+pub fn seal_to_self(keys: &Keys, plaintext: &[u8]) -> Result<String, StreamError> {
+    seal_bytes(
+        &ConversationKey::derive(keys.secret_key(), &keys.public_key())
+            .map_err(|error| StreamError::Encrypt(error.to_string()))?,
+        plaintext,
+    )
+}
+
+pub fn open_to_self(keys: &Keys, content: &str) -> Result<Vec<u8>, StreamError> {
+    open_bytes(
+        &ConversationKey::derive(keys.secret_key(), &keys.public_key())
+            .map_err(|error| StreamError::Decrypt(error.to_string()))?,
+        content,
+    )
+}
+
+pub fn build_seal(
+    rumor: &UnsignedEvent,
+    form: SealForm,
+    group: &GroupKey,
+    author: &Keys,
+) -> Result<Event, StreamError> {
+    let content = seal_content(rumor, form, group)?;
+    EventBuilder::new(Kind::Custom(form.kind()), content)
+        .custom_created_at(rumor.created_at)
+        .finalize(author)
+        .map_err(|error| StreamError::Sign(error.to_string()))
+}
+
+pub fn wrap_seal(
+    seal: &Event,
+    group: &GroupKey,
+    wrap_kind: u16,
+    at: Timestamp,
+    extra: &[Tag],
+) -> Result<(Event, Keys), StreamError> {
+    wrap_seal_with(
+        seal,
+        group.conversation(),
+        group.keys(),
+        wrap_kind,
+        at,
+        extra,
+    )
+}
+
+pub fn wrap_seal_with(
+    seal: &Event,
+    conversation: &ConversationKey,
+    signer: &Keys,
+    wrap_kind: u16,
+    at: Timestamp,
+    extra: &[Tag],
+) -> Result<(Event, Keys), StreamError> {
+    if wrap_kind != KIND_WRAP && wrap_kind != KIND_WRAP_EPHEMERAL {
+        return Err(StreamError::BadWrapKind(wrap_kind));
+    }
+
+    let json = seal.as_json();
+    check_plaintext_cap(json.len())?;
+
+    let content = BASE64.encode(&encrypt(conversation, json.as_bytes())?);
+    let ephemeral = Keys::generate();
+
+    let mut tags = vec![Tag::public_key(ephemeral.public_key())];
+    tags.extend_from_slice(extra);
+
+    let wrap = EventBuilder::new(Kind::Custom(wrap_kind), content)
+        .tags(tags)
+        .custom_created_at(at)
+        .finalize(signer)
+        .map_err(|error| StreamError::Sign(error.to_string()))?;
+
+    Ok((wrap, ephemeral))
+}
+
+pub fn rewrap_seal(
+    seal: &Event,
+    read: &GroupKey,
+    signer: &GroupKey,
+    at: Timestamp,
+) -> Result<(Event, Keys), StreamError> {
+    if seal.kind.as_u16() != KIND_SEAL_PLAINTEXT {
+        return Err(StreamError::NotRewrappable);
+    }
+
+    wrap_seal_with(seal, read.conversation(), signer.keys(), KIND_WRAP, at, &[])
+}
+
+pub fn open_wrap(wrap: &Event, group: &GroupKey) -> Result<OpenedStream, StreamError> {
+    open_wrap_at(wrap, &group.pk(), group.conversation(), false)
+}
+
+pub fn open_wrap_at(
+    wrap: &Event,
+    address: &PublicKey,
+    conversation: &ConversationKey,
+    verify_wrap_signature: bool,
+) -> Result<OpenedStream, StreamError> {
+    let wrap_kind = wrap.kind.as_u16();
+
+    if wrap_kind != KIND_WRAP && wrap_kind != KIND_WRAP_EPHEMERAL {
+        return Err(StreamError::BadWrapKind(wrap_kind));
+    }
+
+    if wrap.pubkey != *address {
+        return Err(StreamError::WrongStream);
+    }
+
+    if verify_wrap_signature && wrap.verify().is_err() {
+        return Err(StreamError::BadWrapSignature);
+    }
+
+    let seal: Event = Event::from_json(decode_content(conversation, &wrap.content)?)
+        .map_err(|error| StreamError::Parse(error.to_string()))?;
+    let seal_kind = seal.kind.as_u16();
+    let seal_form = SealForm::from_kind(seal_kind).ok_or(StreamError::BadSealKind(seal_kind))?;
+    seal.verify().map_err(|_| StreamError::BadSealSignature)?;
+
+    let rumor_json = match seal_form {
+        SealForm::Plaintext => seal.content.clone(),
+        SealForm::Encrypted => decode_content(conversation, &seal.content)?,
+    };
+
+    let mut rumor: UnsignedEvent = UnsignedEvent::from_json(rumor_json.as_bytes())
+        .map_err(|error| StreamError::Parse(error.to_string()))?;
+
+    if rumor.pubkey != seal.pubkey {
+        return Err(StreamError::AuthorMismatch);
+    }
+
+    let computed = rumor.compute_id();
+    if let Some(claimed) = rumor.id
+        && claimed != computed
+    {
+        return Err(StreamError::BadRumorId);
+    }
+    rumor.id = Some(computed);
+
+    let at_ms = resolve_ms_strict(&rumor)?;
+
+    Ok(OpenedStream {
+        rumor_id: computed,
+        author: seal.pubkey,
+        seal_form,
+        seal,
+        wrapper_id: wrap.id,
+        at_ms,
+        rumor,
+    })
+}
+
+pub fn channel_binding_tags(channel: &ChannelId, epoch: Epoch) -> Vec<Tag> {
+    vec![
+        Tag::custom(TAG_CHANNEL, [channel.to_hex()]),
+        Tag::custom(TAG_EPOCH, [epoch.0.to_string()]),
+    ]
+}
+
+pub fn check_channel_binding(
+    rumor: &UnsignedEvent,
+    channel: &ChannelId,
+    epoch: Epoch,
+) -> Result<(), StreamError> {
+    match unique_tag(rumor, TAG_CHANNEL)? {
+        Some(value) if value == channel.to_hex() => {}
+        Some(_) => return Err(StreamError::ChannelMismatch),
+        None => return Err(StreamError::MissingTag(TAG_CHANNEL)),
+    }
+
+    match unique_tag(rumor, TAG_EPOCH)? {
+        Some(value) if value == epoch.0.to_string() => {}
+        Some(_) => return Err(StreamError::EpochMismatch),
+        None => return Err(StreamError::MissingTag(TAG_EPOCH)),
+    }
+
+    Ok(())
+}
+
+fn encrypt(conversation: &ConversationKey, plaintext: &[u8]) -> Result<Vec<u8>, StreamError> {
+    let mut nonce = [0u8; 32];
+
+    crate::fill_random(&mut nonce).map_err(|error| StreamError::Encrypt(error.to_string()))?;
+
+    encrypt_to_bytes_with_nonce(conversation, plaintext, nonce)
+        .map_err(|error| StreamError::Encrypt(error.to_string()))
+}
+
+fn decode_content(conversation: &ConversationKey, content: &str) -> Result<String, StreamError> {
+    let plaintext = open_bytes(conversation, content)?;
+
+    String::from_utf8(plaintext).map_err(|error| StreamError::Parse(error.to_string()))
+}
+
+fn check_plaintext_cap(len: usize) -> Result<(), StreamError> {
+    if len > NIP44_MAX_PLAINTEXT {
+        return Err(StreamError::Oversize(len));
+    }
+
+    Ok(())
+}
+
+fn unique_tag(rumor: &UnsignedEvent, name: &'static str) -> Result<Option<String>, StreamError> {
+    let mut found: Option<String> = None;
+
+    for tag in rumor.tags.iter() {
+        let fields = tag.as_slice();
+        if fields.len() >= 2 && fields[0] == name {
+            if found.is_some() {
+                return Err(StreamError::DuplicateTag(name));
+            }
+            found = Some(fields[1].clone());
+        }
+    }
+
+    Ok(found)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::derive::channel_group_key;
+
+    const SECRET: [u8; 32] = [0x07u8; 32];
+    const OTHER_SECRET: [u8; 32] = [0x08u8; 32];
+
+    fn channel() -> ChannelId {
+        ChannelId::from_bytes([0xabu8; 32])
+    }
+
+    fn group(epoch: u64) -> GroupKey {
+        channel_group_key(&SECRET, &channel(), Epoch(epoch)).expect("derives")
+    }
+
+    fn wrapper_p_tag(wrap: &Event) -> Option<String> {
+        wrap.tags
+            .iter()
+            .find(|tag| tag.as_slice().first().map(String::as_str) == Some("p"))
+            .and_then(|tag| tag.as_slice().get(1).cloned())
+    }
+
+    fn bound_rumor(content: &str, author: PublicKey, at_ms: u64) -> UnsignedEvent {
+        build_rumor_ms(
+            9,
+            author,
+            content,
+            channel_binding_tags(&channel(), Epoch(0)),
+            at_ms,
+        )
+    }
+
+    fn sealed(rumor: &UnsignedEvent, form: SealForm, author: &Keys) -> Event {
+        build_seal(rumor, form, &group(0), author).expect("seals")
+    }
+
+    fn wrapped(seal: &Event, kind: u16, at_secs: u64) -> Event {
+        wrap_seal(seal, &group(0), kind, Timestamp::from_secs(at_secs), &[])
+            .expect("wraps")
+            .0
+    }
+
+    fn encrypted_wrap(content: &str, author: &Keys, at_ms: u64, kind: u16) -> Event {
+        let rumor = bound_rumor(content, author.public_key(), at_ms);
+        wrapped(
+            &sealed(&rumor, SealForm::Encrypted, author),
+            kind,
+            at_ms / 1000,
+        )
+    }
+
+    #[test]
+    fn both_seal_forms_round_trip() {
+        let author = Keys::generate();
+        let at_ms = 1_686_840_217_417;
+        let wrap = encrypted_wrap("Hey chat!", &author, at_ms, KIND_WRAP);
+
+        assert_eq!(wrap.kind, Kind::GiftWrap, "the durable wrap is kind 1059");
+        assert_eq!(wrap.pubkey, group(0).pk(), "the stream key signs the wrap");
+
+        let opened = open_wrap(&wrap, &group(0)).expect("opens");
+        assert_eq!(opened.author, author.public_key());
+        assert_eq!(opened.rumor.content, "Hey chat!");
+        assert_eq!(opened.rumor_id, opened.rumor.id.expect("id is set"));
+        assert_eq!(opened.wrapper_id, wrap.id);
+        assert_eq!(opened.at_ms, at_ms);
+        assert_eq!(opened.seal_form, SealForm::Encrypted);
+        check_channel_binding(&opened.rumor, &channel(), Epoch(0)).expect("binding holds");
+
+        // The wrap's `p` tag must identify neither the stream nor the author.
+        let p = wrapper_p_tag(&wrap).expect("the wrap carries a p tag");
+        assert_ne!(p, group(0).pk_hex());
+        assert_ne!(p, author.public_key().to_hex());
+
+        // Ephemeral actions ride the same structure at a kind relays must drop.
+        let typing = encrypted_wrap("typing", &author, 5_000, KIND_WRAP_EPHEMERAL);
+        assert_eq!(typing.kind.as_u16(), 21059);
+        assert_eq!(
+            open_wrap(&typing, &group(0)).expect("opens").rumor.content,
+            "typing"
+        );
+
+        // The plaintext form carries the rumor's bytes verbatim, which is what
+        // lets a compaction re-wrap the signed edition into a later epoch.
+        let edition = build_rumor_secs(
+            3308,
+            author.public_key(),
+            "an edition",
+            vec![],
+            1_700_000_000,
+        );
+        let seal = sealed(&edition, SealForm::Plaintext, &author);
+        assert_eq!(seal.content, edition.as_json(), "the rumor rides verbatim");
+
+        let opened = open_wrap(&wrapped(&seal, KIND_WRAP, 1), &group(0)).expect("opens");
+        assert_eq!(opened.seal_form, SealForm::Plaintext);
+
+        let (rewrapped, _) =
+            rewrap_seal(&opened.seal, &group(1), &group(1), Timestamp::from_secs(2))
+                .expect("rewraps");
+        let reopened = open_wrap(&rewrapped, &group(1)).expect("opens");
+        assert_eq!(reopened.rumor_id, opened.rumor_id, "the rumor id survives");
+        assert_eq!(reopened.author, author.public_key());
+        assert_eq!(
+            reopened.seal.sig, opened.seal.sig,
+            "the signature rides whole"
+        );
+        assert_ne!(reopened.wrapper_id, opened.wrapper_id);
+
+        assert!(matches!(
+            rewrap_seal(
+                &sealed(&edition, SealForm::Encrypted, &author),
+                &group(1),
+                &group(1),
+                Timestamp::from_secs(2)
+            ),
+            Err(StreamError::NotRewrappable)
+        ));
+    }
+
+    #[test]
+    fn hostile_wraps_are_dropped_in_order() {
+        let author = Keys::generate();
+        let impostor = Keys::generate();
+
+        // Kind and address are settled before any decryption is attempted.
+        let mut wrong_kind = encrypted_wrap("x", &author, 1_000, KIND_WRAP);
+        wrong_kind.kind = Kind::Custom(1058);
+        assert!(matches!(
+            open_wrap(&wrong_kind, &group(0)),
+            Err(StreamError::BadWrapKind(1058))
+        ));
+
+        let foreign = channel_group_key(&OTHER_SECRET, &channel(), Epoch(0)).expect("derives");
+        let wrap = encrypted_wrap("x", &author, 1_000, KIND_WRAP);
+        assert!(matches!(
+            open_wrap(&wrap, &foreign),
+            Err(StreamError::WrongStream)
+        ));
+
+        // A flipped ciphertext byte fails the NIP-44 MAC.
+        let mut payload = BASE64
+            .decode(wrap.content.as_bytes())
+            .expect("content is base64");
+        payload[40] ^= 0x01;
+        let mut tampered = wrap.clone();
+        tampered.content = BASE64.encode(&payload);
+        assert!(matches!(
+            open_wrap(&tampered, &group(0)),
+            Err(StreamError::Decrypt(_))
+        ));
+
+        // A seal claiming an author it holds no signature for.
+        let seal = sealed(
+            &bound_rumor("spoof", author.public_key(), 1_000),
+            SealForm::Encrypted,
+            &impostor,
+        );
+        let mut swapped: serde_json::Value = serde_json::from_str(&seal.as_json()).expect("json");
+        swapped["pubkey"] = serde_json::Value::String(author.public_key().to_hex());
+        let seal = Event::from_json(swapped.to_string()).expect("a swapped pubkey still parses");
+        assert!(matches!(
+            open_wrap(&wrapped(&seal, KIND_WRAP, 1), &group(0)),
+            Err(StreamError::BadSealSignature)
+        ));
+
+        // A seal that does not vouch for the rumor's author.
+        let seal = sealed(
+            &bound_rumor("spoof", impostor.public_key(), 1_000),
+            SealForm::Encrypted,
+            &author,
+        );
+        assert!(matches!(
+            open_wrap(&wrapped(&seal, KIND_WRAP, 1), &group(0)),
+            Err(StreamError::AuthorMismatch)
+        ));
+
+        // A claimed id the rumor's own bytes do not hash to. The plaintext seal
+        // smuggles the forgery through verbatim.
+        let rumor = bound_rumor("real", author.public_key(), 1_000);
+        let mut forged: serde_json::Value = serde_json::from_str(&rumor.as_json()).expect("json");
+        forged["id"] = serde_json::Value::String("00".repeat(32));
+        let seal = EventBuilder::new(Kind::Custom(KIND_SEAL_PLAINTEXT), forged.to_string())
+            .custom_created_at(rumor.created_at)
+            .finalize(&author)
+            .expect("seals");
+        assert!(matches!(
+            open_wrap(&wrapped(&seal, KIND_WRAP, 1), &group(0)),
+            Err(StreamError::BadRumorId)
+        ));
+
+        // Binding splices: another channel, another epoch, a duplicate or none.
+        let doubled = vec![channel_binding_tags(&channel(), Epoch(0)); 2].concat();
+        let rumor = bound_rumor("x", author.public_key(), 1_000);
+
+        assert!(matches!(
+            check_channel_binding(&rumor, &ChannelId::from_bytes([0xcdu8; 32]), Epoch(0)),
+            Err(StreamError::ChannelMismatch)
+        ));
+
+        assert!(matches!(
+            check_channel_binding(&rumor, &channel(), Epoch(1)),
+            Err(StreamError::EpochMismatch)
+        ));
+
+        let duplicate = build_rumor_ms(9, author.public_key(), "x", doubled, 1_000);
+        assert!(matches!(
+            check_channel_binding(&duplicate, &channel(), Epoch(0)),
+            Err(StreamError::DuplicateTag(_))
+        ));
+
+        let unbound = build_rumor_ms(9, author.public_key(), "x", vec![], 1_000);
+        assert!(matches!(
+            check_channel_binding(&unbound, &channel(), Epoch(0)),
+            Err(StreamError::MissingTag(_))
+        ));
+
+        let oversize = build_rumor_ms(
+            9,
+            author.public_key(),
+            &"x".repeat(NIP44_MAX_PLAINTEXT + 1),
+            vec![],
+            1_000,
+        );
+        assert!(matches!(
+            seal_content(&oversize, SealForm::Encrypted, &group(0)),
+            Err(StreamError::Oversize(_))
+        ));
+    }
+
+    #[test]
+    fn ms_is_a_drop_gate() {
+        let author = Keys::generate();
+
+        let absent = build_rumor_secs(9, author.public_key(), "x", vec![], 1_000);
+        assert_eq!(resolve_ms_strict(&absent).expect("resolves"), 1_000_000);
+
+        let highest = build_rumor_ms(9, author.public_key(), "x", vec![], 1_000_999);
+        assert_eq!(resolve_ms_strict(&highest).expect("resolves"), 1_000_999);
+
+        for malformed in ["1000", "007", "abc", "+5", ""] {
+            let rumor = build_rumor_secs(
+                9,
+                author.public_key(),
+                "x",
+                vec![Tag::custom(TAG_MS, [malformed.to_string()])],
+                1_000,
+            );
+            assert!(
+                matches!(resolve_ms_strict(&rumor), Err(StreamError::BadMs)),
+                "{malformed:?} must be malformed"
+            );
+        }
+
+        // Present but valueless is malformed, not an offset-0 default.
+        let valueless = build_rumor_secs(
+            9,
+            author.public_key(),
+            "x",
+            vec![Tag::custom(TAG_MS, Vec::<String>::new())],
+            1_000,
+        );
+        assert!(matches!(
+            resolve_ms_strict(&valueless),
+            Err(StreamError::BadMs)
+        ));
+
+        // A valued duplicate takes the first, matching Armada.
+        let repeated = build_rumor_secs(
+            9,
+            author.public_key(),
+            "x",
+            vec![
+                Tag::custom(TAG_MS, ["1".to_string()]),
+                Tag::custom(TAG_MS, ["2".to_string()]),
+            ],
+            1_000,
+        );
+        assert_eq!(resolve_ms_strict(&repeated).expect("resolves"), 1_000_001);
+    }
+}

crates/concord/src/cords/cord02/guestbook.rs

@@ -0,0 +1,890 @@
+use std::cmp::Reverse;
+use std::collections::{BTreeMap, BTreeSet};
+use std::fmt;
+
+use anyhow::Result;
+use data_encoding::HEXLOWER;
+use nostr_sdk::prelude::*;
+
+use crate::cord01::{
+    KIND_WRAP, OpenedStream, SealForm, StreamError, build_rumor_ms, build_seal, open_wrap,
+    wrap_seal,
+};
+use crate::cord04::{
+    AuthorityCitation, TAG_CITATION, canonical_decimal, citation_from, citation_tag,
+};
+use crate::{GroupKey, decode_hex_32};
+
+pub const KIND_JOIN_LEAVE: u16 = 3306;
+pub const KIND_KICK: u16 = 3309;
+pub const KIND_SNAPSHOT: u16 = 3312;
+
+pub const MAX_SNAPSHOT_CHUNK: usize = 400;
+pub const MAX_FUTURE_SKEW_MS: u64 = 60 * 60 * 1000;
+
+const TAG_INVITE: &str = "invite";
+const TAG_TARGET: &str = "p";
+const TAG_SNAP: &str = "snap";
+const TAG_CONTENT: &str = "content";
+const CONTENT_JOIN: &str = "join";
+const CONTENT_LEAVE: &str = "leave";
+
+#[derive(Debug)]
+pub enum GuestbookError {
+    Stream(StreamError),
+    NotEncryptedSealed,
+    UnknownKind(u16),
+    MissingTag(&'static str),
+    DuplicateTag(&'static str),
+    BadTag(&'static str),
+}
+
+impl fmt::Display for GuestbookError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            GuestbookError::Stream(error) => write!(f, "stream: {error}"),
+            GuestbookError::NotEncryptedSealed => {
+                write!(f, "guestbook rumor must ride an encrypted seal")
+            }
+            GuestbookError::UnknownKind(kind) => {
+                write!(f, "not a guestbook rumor kind: {kind}")
+            }
+            GuestbookError::MissingTag(name) => write!(f, "missing guestbook tag: {name}"),
+            GuestbookError::DuplicateTag(name) => write!(f, "duplicate guestbook tag: {name}"),
+            GuestbookError::BadTag(name) => write!(f, "malformed guestbook tag: {name}"),
+        }
+    }
+}
+
+impl std::error::Error for GuestbookError {}
+
+impl From<StreamError> for GuestbookError {
+    fn from(error: StreamError) -> Self {
+        GuestbookError::Stream(error)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum GuestbookEntry {
+    Join {
+        member: PublicKey,
+        at_ms: u64,
+        /// The `(creator, label)` an invite attributed the join to.
+        invited_by: Option<(String, String)>,
+    },
+    Leave {
+        member: PublicKey,
+        at_ms: u64,
+    },
+    Kick {
+        actor: PublicKey,
+        target: PublicKey,
+        at_ms: u64,
+        citation: Option<AuthorityCitation>,
+    },
+    Snapshot {
+        refounder: PublicKey,
+        members: Vec<PublicKey>,
+        snapshot_id: [u8; 32],
+        chunk: (u32, u32),
+        at_ms: u64,
+    },
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct GuestbookRumor {
+    pub id: EventId,
+    pub author: PublicKey,
+    pub kind: Kind,
+    pub at_ms: u64,
+    pub entry: GuestbookEntry,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum MemberState {
+    Joined {
+        at_ms: u64,
+        invited_by: Option<(String, String)>,
+    },
+    Left {
+        at_ms: u64,
+    },
+    Kicked {
+        at_ms: u64,
+        actor: PublicKey,
+    },
+}
+
+pub fn build_join(
+    member: PublicKey,
+    invited_by: Option<(&str, &str)>,
+    at_ms: u64,
+) -> UnsignedEvent {
+    let mut tags = Vec::new();
+
+    if let Some((creator, label)) = invited_by {
+        tags.push(Tag::custom(TAG_INVITE, [creator, label]));
+    }
+
+    build_rumor_ms(KIND_JOIN_LEAVE, member, CONTENT_JOIN, tags, at_ms)
+}
+
+pub fn build_leave(member: PublicKey, at_ms: u64) -> UnsignedEvent {
+    build_rumor_ms(KIND_JOIN_LEAVE, member, CONTENT_LEAVE, Vec::new(), at_ms)
+}
+
+pub fn build_kick(
+    actor: PublicKey,
+    target: &PublicKey,
+    citation: Option<&AuthorityCitation>,
+    at_ms: u64,
+) -> UnsignedEvent {
+    let mut tags = vec![Tag::custom(TAG_TARGET, [target.to_hex()])];
+
+    if let Some(citation) = citation {
+        tags.push(citation_tag(citation));
+    }
+
+    build_rumor_ms(KIND_KICK, actor, "", tags, at_ms)
+}
+
+pub fn build_snapshot_chunks(
+    refounder: PublicKey,
+    members: &[PublicKey],
+    snapshot_id: [u8; 32],
+    at_ms: u64,
+) -> Vec<UnsignedEvent> {
+    let chunks: Vec<&[PublicKey]> = members.chunks(MAX_SNAPSHOT_CHUNK).collect();
+    let total = chunks.len() as u32;
+
+    chunks
+        .iter()
+        .enumerate()
+        .map(|(index, chunk)| {
+            let hex: Vec<String> = chunk.iter().map(PublicKey::to_hex).collect();
+            let content = format!(
+                "[{}]",
+                hex.iter()
+                    .map(|member| format!("\"{member}\""))
+                    .collect::<Vec<_>>()
+                    .join(",")
+            );
+            let tags = vec![Tag::custom(
+                TAG_SNAP,
+                [
+                    HEXLOWER.encode(&snapshot_id),
+                    (index as u32 + 1).to_string(),
+                    total.to_string(),
+                ],
+            )];
+
+            build_rumor_ms(KIND_SNAPSHOT, refounder, &content, tags, at_ms)
+        })
+        .collect()
+}
+
+pub fn seal_rumor(
+    rumor: &UnsignedEvent,
+    group: &GroupKey,
+    author: &Keys,
+) -> Result<(Event, Keys), GuestbookError> {
+    let kind = rumor.kind.as_u16();
+
+    if !is_guestbook_kind(kind) {
+        return Err(GuestbookError::UnknownKind(kind));
+    }
+
+    let seal = build_seal(rumor, SealForm::Encrypted, group, author)?;
+
+    Ok(wrap_seal(&seal, group, KIND_WRAP, rumor.created_at, &[])?)
+}
+
+pub fn open(
+    wrap: &Event,
+    group: &GroupKey,
+) -> Result<(OpenedStream, GuestbookRumor), GuestbookError> {
+    let opened = open_wrap(wrap, group)?;
+
+    if opened.seal_form != SealForm::Encrypted {
+        return Err(GuestbookError::NotEncryptedSealed);
+    }
+
+    let entry = entry_of(&opened)?;
+    let rumor = GuestbookRumor {
+        id: opened.rumor_id,
+        author: opened.author,
+        kind: opened.rumor.kind,
+        at_ms: opened.at_ms,
+        entry,
+    };
+
+    Ok((opened, rumor))
+}
+
+pub fn coalesce(
+    rumors: &[GuestbookRumor],
+    now_ms: u64,
+    snapshot_authority: Option<&PublicKey>,
+    can_kick: impl Fn(&PublicKey, &PublicKey, Option<&AuthorityCitation>) -> bool,
+) -> BTreeMap<PublicKey, MemberState> {
+    let mut states: BTreeMap<PublicKey, (u64, Reverse<EventId>, MemberState)> = BTreeMap::new();
+    let horizon = now_ms.saturating_add(MAX_FUTURE_SKEW_MS);
+
+    for rumor in rumors {
+        if rumor.at_ms > horizon {
+            continue;
+        }
+
+        match &rumor.entry {
+            GuestbookEntry::Join {
+                member,
+                at_ms,
+                invited_by,
+            } => offer(
+                &mut states,
+                *member,
+                *at_ms,
+                rumor.id,
+                MemberState::Joined {
+                    at_ms: *at_ms,
+                    invited_by: invited_by.clone(),
+                },
+            ),
+            GuestbookEntry::Leave { member, at_ms } => offer(
+                &mut states,
+                *member,
+                *at_ms,
+                rumor.id,
+                MemberState::Left { at_ms: *at_ms },
+            ),
+            GuestbookEntry::Kick {
+                actor,
+                target,
+                at_ms,
+                citation,
+            } => {
+                if !can_kick(actor, target, citation.as_ref()) {
+                    continue;
+                }
+
+                offer(
+                    &mut states,
+                    *target,
+                    *at_ms,
+                    rumor.id,
+                    MemberState::Kicked {
+                        at_ms: *at_ms,
+                        actor: *actor,
+                    },
+                );
+            }
+            GuestbookEntry::Snapshot {
+                refounder,
+                members,
+                at_ms,
+                ..
+            } => {
+                if snapshot_authority != Some(refounder) {
+                    continue;
+                }
+
+                for member in members {
+                    offer(
+                        &mut states,
+                        *member,
+                        *at_ms,
+                        rumor.id,
+                        MemberState::Joined {
+                            at_ms: *at_ms,
+                            invited_by: None,
+                        },
+                    );
+                }
+            }
+        }
+    }
+
+    states
+        .into_iter()
+        .map(|(member, (_, _, state))| (member, state))
+        .collect()
+}
+
+pub fn complete_memberlist(
+    coalesced: &BTreeMap<PublicKey, MemberState>,
+    observed: &BTreeMap<PublicKey, u64>,
+    granted: &BTreeSet<PublicKey>,
+    banned: &BTreeSet<PublicKey>,
+    banned_at: &BTreeMap<PublicKey, u64>,
+) -> BTreeSet<PublicKey> {
+    let mut candidates: BTreeSet<&PublicKey> = coalesced.keys().collect();
+    candidates.extend(observed.keys());
+    candidates.extend(granted.iter());
+
+    let mut members = BTreeSet::new();
+
+    for member in candidates {
+        let mut inclusion = observed.get(member).copied();
+
+        if let Some(state) = coalesced.get(member) {
+            match state {
+                MemberState::Joined { at_ms, .. } => {
+                    inclusion = Some(inclusion.map_or(*at_ms, |seen| seen.max(*at_ms)));
+                }
+                MemberState::Left { .. } | MemberState::Kicked { .. } => {}
+            }
+        }
+
+        if inclusion.is_none() && granted.contains(member) {
+            inclusion = Some(0);
+        }
+
+        let mut exclusion = match coalesced.get(member) {
+            Some(MemberState::Left { at_ms }) | Some(MemberState::Kicked { at_ms, .. }) => {
+                Some(*at_ms)
+            }
+            _ => None,
+        };
+
+        if banned.contains(member) {
+            exclusion = Some(match banned_at.get(member) {
+                Some(at_ms) => exclusion.map_or(*at_ms, |seen| seen.max(*at_ms)),
+                None => u64::MAX,
+            });
+        }
+
+        if let Some(inclusion) = inclusion
+            && exclusion.is_none_or(|exclusion| inclusion > exclusion)
+        {
+            members.insert(*member);
+        }
+    }
+
+    members
+}
+
+fn offer(
+    states: &mut BTreeMap<PublicKey, (u64, Reverse<EventId>, MemberState)>,
+    member: PublicKey,
+    at_ms: u64,
+    id: EventId,
+    state: MemberState,
+) {
+    let candidate = (at_ms, Reverse(id));
+
+    if let Some(existing) = states.get(&member)
+        && (existing.0, existing.1) >= candidate
+    {
+        return;
+    }
+
+    states.insert(member, (at_ms, Reverse(id), state));
+}
+
+fn is_guestbook_kind(kind: u16) -> bool {
+    matches!(kind, KIND_JOIN_LEAVE | KIND_KICK | KIND_SNAPSHOT)
+}
+
+fn entry_of(opened: &OpenedStream) -> Result<GuestbookEntry, GuestbookError> {
+    let rumor = &opened.rumor;
+    let author = opened.author;
+    let at_ms = opened.at_ms;
+
+    match rumor.kind.as_u16() {
+        KIND_JOIN_LEAVE => match rumor.content.as_str() {
+            CONTENT_JOIN => Ok(GuestbookEntry::Join {
+                member: author,
+                at_ms,
+                invited_by: invite_of(rumor),
+            }),
+            CONTENT_LEAVE => Ok(GuestbookEntry::Leave {
+                member: author,
+                at_ms,
+            }),
+            _ => Err(GuestbookError::BadTag(TAG_CONTENT)),
+        },
+        KIND_KICK => Ok(GuestbookEntry::Kick {
+            actor: author,
+            target: tagged_pubkey(rumor, TAG_TARGET)?,
+            at_ms,
+            citation: optional_citation(rumor)?,
+        }),
+        KIND_SNAPSHOT => {
+            let (snapshot_id, chunk) = snapshot_of(rumor)?;
+            let members = members_of(&rumor.content)?;
+
+            Ok(GuestbookEntry::Snapshot {
+                refounder: author,
+                members,
+                snapshot_id,
+                chunk,
+                at_ms,
+            })
+        }
+        other => Err(GuestbookError::UnknownKind(other)),
+    }
+}
+
+fn invite_of(rumor: &UnsignedEvent) -> Option<(String, String)> {
+    rumor.tags.iter().find_map(|candidate| {
+        let fields = candidate.as_slice();
+
+        (fields.len() >= 3 && fields[0] == TAG_INVITE)
+            .then(|| (fields[1].clone(), fields[2].clone()))
+    })
+}
+
+fn members_of(content: &str) -> Result<Vec<PublicKey>, GuestbookError> {
+    let entries: Vec<String> =
+        serde_json::from_str(content).map_err(|_| GuestbookError::BadTag(TAG_CONTENT))?;
+
+    if entries.len() > MAX_SNAPSHOT_CHUNK {
+        return Err(GuestbookError::BadTag(TAG_SNAP));
+    }
+
+    entries
+        .iter()
+        .map(|entry| pubkey(entry, TAG_CONTENT))
+        .collect()
+}
+
+fn snapshot_of(rumor: &UnsignedEvent) -> Result<([u8; 32], (u32, u32)), GuestbookError> {
+    let fields = required(rumor, TAG_SNAP)?;
+
+    if fields.len() != 4 {
+        return Err(GuestbookError::BadTag(TAG_SNAP));
+    }
+
+    let snapshot_id = decode_hex_32(&fields[1]).map_err(|_| GuestbookError::BadTag(TAG_SNAP))?;
+    let index = decimal(&fields[2])?;
+    let total = decimal(&fields[3])?;
+
+    if index == 0 || index > total {
+        return Err(GuestbookError::BadTag(TAG_SNAP));
+    }
+
+    Ok((snapshot_id, (index, total)))
+}
+
+fn optional_citation(rumor: &UnsignedEvent) -> Result<Option<AuthorityCitation>, GuestbookError> {
+    let Some(fields) = tag(rumor, TAG_CITATION)? else {
+        return Ok(None);
+    };
+
+    citation_from(fields)
+        .map(Some)
+        .ok_or(GuestbookError::BadTag(TAG_CITATION))
+}
+
+fn decimal(raw: &str) -> Result<u32, GuestbookError> {
+    canonical_decimal(raw)
+        .and_then(|value| u32::try_from(value).ok())
+        .ok_or(GuestbookError::BadTag(TAG_SNAP))
+}
+
+fn required<'a>(
+    rumor: &'a UnsignedEvent,
+    name: &'static str,
+) -> Result<&'a [String], GuestbookError> {
+    tag(rumor, name)?.ok_or(GuestbookError::MissingTag(name))
+}
+
+fn tagged_pubkey(rumor: &UnsignedEvent, name: &'static str) -> Result<PublicKey, GuestbookError> {
+    pubkey(value(required(rumor, name)?, name)?, name)
+}
+
+fn tag<'a>(
+    rumor: &'a UnsignedEvent,
+    name: &'static str,
+) -> Result<Option<&'a [String]>, GuestbookError> {
+    let mut found: Option<&[String]> = None;
+
+    for candidate in rumor.tags.iter() {
+        let fields = candidate.as_slice();
+
+        if fields.first().map(String::as_str) != Some(name) {
+            continue;
+        }
+
+        if found.is_some() {
+            return Err(GuestbookError::DuplicateTag(name));
+        }
+
+        found = Some(fields);
+    }
+
+    Ok(found)
+}
+
+fn value<'a>(fields: &'a [String], name: &'static str) -> Result<&'a str, GuestbookError> {
+    fields
+        .get(1)
+        .map(String::as_str)
+        .ok_or(GuestbookError::BadTag(name))
+}
+
+fn pubkey(hex: &str, name: &'static str) -> Result<PublicKey, GuestbookError> {
+    let bytes = decode_hex_32(hex).map_err(|_| GuestbookError::BadTag(name))?;
+
+    PublicKey::from_slice(&bytes).map_err(|_| GuestbookError::BadTag(name))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::cord01::build_rumor_secs;
+    use crate::derive::guestbook_group_key;
+    use crate::{CommunityId, Epoch};
+
+    const ROOT: [u8; 32] = [0x5au8; 32];
+    const AT: u64 = 1_700_000_000_000;
+
+    fn community() -> CommunityId {
+        CommunityId::from_bytes([0x11u8; 32])
+    }
+
+    fn group() -> GroupKey {
+        guestbook_group_key(&ROOT, &community(), Epoch(0)).expect("derives")
+    }
+
+    fn citation() -> AuthorityCitation {
+        AuthorityCitation {
+            entity: [0x33u8; 32],
+            version: 1,
+            hash: [0x44u8; 32],
+        }
+    }
+
+    fn publish(rumor: &UnsignedEvent, author: &Keys) -> GuestbookRumor {
+        let wrap = seal_rumor(rumor, &group(), author).expect("seals").0;
+
+        open(&wrap, &group()).expect("opens").1
+    }
+
+    #[test]
+    fn join_leave_kick_and_snapshot_converge_to_one_memberlist() {
+        let alice = Keys::generate();
+        let bob = Keys::generate();
+        let carol = Keys::generate();
+        let dave = Keys::generate();
+        let frank = Keys::generate();
+        let grace = Keys::generate();
+        let owner = Keys::generate();
+
+        let survivors: Vec<PublicKey> = (0..401).map(|_| Keys::generate().public_key()).collect();
+
+        let mut rumors = vec![
+            publish(
+                &build_join(
+                    alice.public_key(),
+                    Some((&"ab".repeat(32), "Reddit")),
+                    AT + 1_000,
+                ),
+                &alice,
+            ),
+            publish(&build_join(bob.public_key(), None, AT + 2_000), &bob),
+            publish(&build_leave(bob.public_key(), AT + 3_000), &bob),
+            publish(&build_join(dave.public_key(), None, AT + 4_000), &dave),
+            publish(
+                &build_kick(
+                    carol.public_key(),
+                    &dave.public_key(),
+                    Some(&citation()),
+                    AT + 5_000,
+                ),
+                &carol,
+            ),
+            publish(&build_join(frank.public_key(), None, AT + 7_000), &frank),
+        ];
+
+        let snapshot_id = "77".repeat(32);
+        let chunks =
+            build_snapshot_chunks(carol.public_key(), &survivors, [0x77u8; 32], AT + 6_000);
+        assert_eq!(chunks.len(), 2, "401 survivors chunk into two events");
+        for (index, chunk) in chunks.iter().enumerate() {
+            assert!(chunk.tags.iter().any(|tag| tag.as_slice()
+                == [
+                    TAG_SNAP,
+                    snapshot_id.as_str(),
+                    &(index + 1).to_string(),
+                    "2"
+                ]));
+            rumors.push(publish(chunk, &carol));
+        }
+
+        let can_kick =
+            |actor: &PublicKey, target: &PublicKey, citation: Option<&AuthorityCitation>| {
+                citation.is_some() && actor == &carol.public_key() && target != &owner.public_key()
+            };
+
+        let states = coalesce(&rumors, AT + 8_000, Some(&carol.public_key()), can_kick);
+
+        assert_eq!(
+            states.get(&alice.public_key()),
+            Some(&MemberState::Joined {
+                at_ms: AT + 1_000,
+                invited_by: Some(("ab".repeat(32), "Reddit".to_owned())),
+            })
+        );
+        assert_eq!(
+            states.get(&bob.public_key()),
+            Some(&MemberState::Left { at_ms: AT + 3_000 })
+        );
+        assert_eq!(
+            states.get(&dave.public_key()),
+            Some(&MemberState::Kicked {
+                at_ms: AT + 5_000,
+                actor: carol.public_key(),
+            })
+        );
+        assert!(
+            survivors
+                .iter()
+                .all(|member| matches!(states.get(member), Some(MemberState::Joined { .. }))),
+            "every chunk seeds its own members"
+        );
+
+        let reversed: Vec<GuestbookRumor> = rumors.iter().rev().cloned().collect();
+        assert_eq!(
+            coalesce(&reversed, AT + 8_000, Some(&carol.public_key()), can_kick),
+            states,
+            "arrival order cannot change the fold"
+        );
+
+        let observed = BTreeMap::from([
+            (bob.public_key(), AT + 9_000),
+            (carol.public_key(), AT + 5_000),
+        ]);
+        let granted = BTreeSet::from([grace.public_key()]);
+        let banned = BTreeSet::from([frank.public_key()]);
+        let banned_at = BTreeMap::from([(frank.public_key(), AT + 8_000)]);
+
+        let members = complete_memberlist(&states, &observed, &granted, &banned, &banned_at);
+
+        let mut expected = BTreeSet::from([
+            alice.public_key(),
+            bob.public_key(),
+            carol.public_key(),
+            grace.public_key(),
+        ]);
+        expected.extend(survivors.iter().copied());
+
+        assert_eq!(members, expected);
+        assert!(
+            !members.contains(&dave.public_key()),
+            "a kicked member is out"
+        );
+        assert!(
+            !members.contains(&frank.public_key()),
+            "a ban wins over a later join"
+        );
+    }
+
+    #[test]
+    fn a_kick_or_snapshot_without_authority_is_dropped() {
+        let moderator = Keys::generate();
+        let outsider = Keys::generate();
+        let owner = Keys::generate();
+        let kicked = Keys::generate();
+        let uncited = Keys::generate();
+        let unranked = Keys::generate();
+        let refounder = Keys::generate();
+        let impostor = Keys::generate();
+        let seeded = Keys::generate();
+        let smuggled = Keys::generate();
+
+        let can_kick = |actor: &PublicKey,
+                        target: &PublicKey,
+                        citation: Option<&AuthorityCitation>| {
+            citation.is_some() && actor == &moderator.public_key() && target != &owner.public_key()
+        };
+
+        let rumors = vec![
+            publish(
+                &build_kick(
+                    moderator.public_key(),
+                    &kicked.public_key(),
+                    Some(&citation()),
+                    AT,
+                ),
+                &moderator,
+            ),
+            publish(
+                &build_kick(moderator.public_key(), &uncited.public_key(), None, AT),
+                &moderator,
+            ),
+            publish(
+                &build_kick(
+                    outsider.public_key(),
+                    &unranked.public_key(),
+                    Some(&citation()),
+                    AT,
+                ),
+                &outsider,
+            ),
+            publish(
+                &build_kick(
+                    moderator.public_key(),
+                    &owner.public_key(),
+                    Some(&citation()),
+                    AT,
+                ),
+                &moderator,
+            ),
+        ];
+
+        let states = coalesce(&rumors, AT + 1_000, None, can_kick);
+
+        assert_eq!(
+            states.get(&kicked.public_key()),
+            Some(&MemberState::Kicked {
+                at_ms: AT,
+                actor: moderator.public_key(),
+            })
+        );
+        assert!(
+            !states.contains_key(&uncited.public_key()),
+            "a kick cites the Grant it acts under"
+        );
+        assert!(
+            !states.contains_key(&unranked.public_key()),
+            "a kick needs KICK"
+        );
+        assert!(
+            !states.contains_key(&owner.public_key()),
+            "nobody kicks the owner"
+        );
+
+        let by_refounder = build_snapshot_chunks(
+            refounder.public_key(),
+            &[seeded.public_key()],
+            [0x77u8; 32],
+            AT,
+        )
+        .remove(0);
+        let by_impostor = build_snapshot_chunks(
+            impostor.public_key(),
+            &[smuggled.public_key()],
+            [0x88u8; 32],
+            AT,
+        )
+        .remove(0);
+
+        for authority in [None, Some(refounder.public_key())] {
+            let states = coalesce(
+                &[
+                    publish(&by_refounder, &refounder),
+                    publish(&by_impostor, &impostor),
+                ],
+                AT + 1_000,
+                authority.as_ref(),
+                |_, _, _| true,
+            );
+
+            assert_eq!(
+                states.contains_key(&seeded.public_key()),
+                authority.is_some(),
+                "only the epoch's refounder seeds, and there is no owner fallback"
+            );
+            assert!(
+                !states.contains_key(&smuggled.public_key()),
+                "a foreign snapshot never seeds"
+            );
+        }
+    }
+
+    #[test]
+    fn a_future_entry_a_bad_ms_and_a_malformed_snapshot_are_dropped() {
+        let member = Keys::generate();
+        let moderator = Keys::generate();
+        let target = Keys::generate();
+
+        let future = publish(
+            &build_join(member.public_key(), None, AT + MAX_FUTURE_SKEW_MS + 1),
+            &member,
+        );
+        let horizon = publish(
+            &build_join(member.public_key(), None, AT + MAX_FUTURE_SKEW_MS),
+            &member,
+        );
+        assert!(
+            coalesce(&[future], AT, None, |_, _, _| true).is_empty(),
+            "an entry more than an hour ahead is dropped"
+        );
+        assert_eq!(
+            coalesce(&[horizon], AT, None, |_, _, _| true).len(),
+            1,
+            "the horizon itself is skew, not forgery"
+        );
+
+        let bad_ms = build_rumor_secs(
+            KIND_JOIN_LEAVE,
+            member.public_key(),
+            CONTENT_JOIN,
+            vec![Tag::custom("ms", ["1000"])],
+            AT / 1000,
+        );
+        assert!(matches!(
+            open(
+                &seal_rumor(&bad_ms, &group(), &member).expect("seals").0,
+                &group()
+            ),
+            Err(GuestbookError::Stream(StreamError::BadMs))
+        ));
+
+        let bad_verb = build_rumor_ms(KIND_JOIN_LEAVE, member.public_key(), "maybe", vec![], AT);
+        assert!(matches!(
+            open(
+                &seal_rumor(&bad_verb, &group(), &member).expect("seals").0,
+                &group()
+            ),
+            Err(GuestbookError::BadTag(TAG_CONTENT))
+        ));
+
+        let ambiguous = build_rumor_ms(
+            KIND_KICK,
+            moderator.public_key(),
+            "",
+            vec![
+                Tag::custom(TAG_TARGET, [target.public_key().to_hex()]),
+                citation_tag(&citation()),
+                citation_tag(&citation()),
+            ],
+            AT,
+        );
+        assert!(matches!(
+            open(
+                &seal_rumor(&ambiguous, &group(), &moderator)
+                    .expect("seals")
+                    .0,
+                &group()
+            ),
+            Err(GuestbookError::DuplicateTag(TAG_CITATION))
+        ));
+
+        for fields in [
+            vec![snapshot_id(), "0".to_owned(), "2".to_owned()],
+            vec![snapshot_id(), "3".to_owned(), "2".to_owned()],
+            vec![snapshot_id(), "1".to_owned()],
+        ] {
+            let rumor = build_rumor_ms(
+                KIND_SNAPSHOT,
+                moderator.public_key(),
+                "[]",
+                vec![Tag::custom(TAG_SNAP, fields)],
+                AT,
+            );
+            assert!(matches!(
+                open(
+                    &seal_rumor(&rumor, &group(), &moderator).expect("seals").0,
+                    &group()
+                ),
+                Err(GuestbookError::BadTag(TAG_SNAP))
+            ));
+        }
+    }
+
+    fn snapshot_id() -> String {
+        "ab".repeat(32)
+    }
+}

crates/concord/src/cords/cord02/list.rs

@@ -0,0 +1,476 @@
+use std::collections::BTreeMap;
+use std::collections::btree_map::Entry;
+use std::fmt;
+
+use nostr_sdk::prelude::*;
+use serde::{Deserialize, Serialize};
+
+use crate::cord01::{self, NIP44_MAX_PLAINTEXT};
+use crate::cord05::{ChannelGrant, CommunityInvite};
+use crate::{CommunityId, Epoch, Extra};
+
+pub const KIND_COMMUNITY_LIST: u16 = 13302;
+pub const MAX_MEMBERSHIPS: usize = 50;
+
+#[derive(Debug)]
+pub enum ListError {
+    Kind(u16),
+    Crypto(String),
+    Json(String),
+    TooManyMemberships(usize),
+    Oversize(usize),
+}
+
+impl fmt::Display for ListError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            ListError::Kind(kind) => write!(f, "not a community list kind: {kind}"),
+            ListError::Crypto(error) => write!(f, "crypto: {error}"),
+            ListError::Json(error) => write!(f, "json: {error}"),
+            ListError::TooManyMemberships(count) => {
+                write!(
+                    f,
+                    "list carries {count} memberships (cap {MAX_MEMBERSHIPS})"
+                )
+            }
+            ListError::Oversize(len) => {
+                write!(f, "list is {len} bytes (cap {NIP44_MAX_PLAINTEXT})")
+            }
+        }
+    }
+}
+
+impl std::error::Error for ListError {}
+
+impl From<cord01::StreamError> for ListError {
+    fn from(error: cord01::StreamError) -> Self {
+        ListError::Crypto(error.to_string())
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct JoinMaterial {
+    pub community_id: CommunityId,
+    pub owner: PublicKey,
+    pub owner_salt: String,
+    pub community_root: String,
+    pub root_epoch: Epoch,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub control_pk: Option<PublicKey>,
+    /// Present only when the holder is staff.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub control_root: Option<String>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub channels: Vec<ChannelGrant>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub relays: Vec<String>,
+    pub name: String,
+    #[serde(flatten)]
+    pub extra: Extra,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct CommunityListEntry {
+    pub community_id: CommunityId,
+    pub seed: JoinMaterial,
+    pub current: JoinMaterial,
+    pub added_at: u64,
+    #[serde(flatten)]
+    pub extra: Extra,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct Tombstone {
+    pub community_id: CommunityId,
+    pub removed_at: u64,
+    #[serde(flatten)]
+    pub extra: Extra,
+}
+
+#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
+pub struct CommunityList {
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub entries: Vec<CommunityListEntry>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub tombstones: Vec<Tombstone>,
+    #[serde(flatten)]
+    pub extra: Extra,
+}
+
+impl CommunityList {
+    pub fn is_live(&self, community_id: &CommunityId) -> bool {
+        let added = self
+            .entries
+            .iter()
+            .find(|entry| entry.community_id == *community_id)
+            .map(|entry| entry.added_at);
+
+        match added {
+            None => false,
+            Some(added) => self
+                .tombstones
+                .iter()
+                .find(|tombstone| tombstone.community_id == *community_id)
+                .is_none_or(|tombstone| added > tombstone.removed_at),
+        }
+    }
+
+    pub fn fits(&self) -> Result<(), ListError> {
+        if self.entries.len() > MAX_MEMBERSHIPS {
+            return Err(ListError::TooManyMemberships(self.entries.len()));
+        }
+
+        let json = serde_json::to_string(self).map_err(json_error)?;
+
+        if json.len() > NIP44_MAX_PLAINTEXT {
+            return Err(ListError::Oversize(json.len()));
+        }
+
+        Ok(())
+    }
+}
+
+pub fn join_material(invite: &CommunityInvite, control_root: Option<&[u8; 32]>) -> JoinMaterial {
+    JoinMaterial {
+        community_id: invite.community_id,
+        owner: invite.owner,
+        owner_salt: invite.owner_salt.clone(),
+        community_root: invite.community_root.clone(),
+        root_epoch: invite.root_epoch,
+        control_pk: invite.control_pk,
+        control_root: control_root.map(|key| data_encoding::HEXLOWER.encode(key)),
+        channels: invite.channels.clone(),
+        relays: invite.relays.clone(),
+        name: invite.name.clone(),
+        extra: Extra::default(),
+    }
+}
+
+pub fn merge(held: CommunityList, incoming: CommunityList) -> CommunityList {
+    let mut entries: BTreeMap<CommunityId, CommunityListEntry> = BTreeMap::new();
+
+    for entry in held.entries.into_iter().chain(incoming.entries) {
+        match entries.entry(entry.community_id) {
+            Entry::Vacant(slot) => {
+                slot.insert(entry);
+            }
+            Entry::Occupied(mut slot) => merge_entry(slot.get_mut(), entry),
+        }
+    }
+
+    let mut tombstones: BTreeMap<CommunityId, Tombstone> = BTreeMap::new();
+
+    for tombstone in held.tombstones.into_iter().chain(incoming.tombstones) {
+        match tombstones.entry(tombstone.community_id) {
+            Entry::Vacant(slot) => {
+                slot.insert(tombstone);
+            }
+            Entry::Occupied(mut slot) => {
+                let held = slot.get_mut();
+                held.removed_at = held.removed_at.max(tombstone.removed_at);
+                union(&mut held.extra, tombstone.extra);
+            }
+        }
+    }
+
+    let mut extra = held.extra;
+    union(&mut extra, incoming.extra);
+
+    CommunityList {
+        entries: entries.into_values().collect(),
+        tombstones: tombstones.into_values().collect(),
+        extra,
+    }
+}
+
+pub fn build_list_event(keys: &Keys, list: &CommunityList) -> Result<Event, ListError> {
+    list.fits()?;
+
+    let json = serde_json::to_string(list).map_err(json_error)?;
+    let content = cord01::seal_to_self(keys, json.as_bytes())?;
+
+    EventBuilder::new(Kind::Custom(KIND_COMMUNITY_LIST), content)
+        .finalize(keys)
+        .map_err(crypto_error)
+}
+
+pub fn parse_list_event(keys: &Keys, event: &Event) -> Result<CommunityList, ListError> {
+    if event.kind.as_u16() != KIND_COMMUNITY_LIST {
+        return Err(ListError::Kind(event.kind.as_u16()));
+    }
+
+    let json = cord01::open_to_self(keys, &event.content)?;
+
+    serde_json::from_slice(&json).map_err(json_error)
+}
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+enum Snapshot {
+    Seed,
+    Current,
+}
+
+fn merge_entry(held: &mut CommunityListEntry, incoming: CommunityListEntry) {
+    held.added_at = held.added_at.max(incoming.added_at);
+    held.seed = pick(&held.seed, &incoming.seed, Snapshot::Seed).clone();
+    held.current = pick(&held.current, &incoming.current, Snapshot::Current).clone();
+    union(&mut held.extra, incoming.extra);
+}
+
+fn pick<'a>(
+    held: &'a JoinMaterial,
+    incoming: &'a JoinMaterial,
+    which: Snapshot,
+) -> &'a JoinMaterial {
+    let preferred = match which {
+        Snapshot::Seed => incoming.root_epoch < held.root_epoch,
+        Snapshot::Current => incoming.root_epoch > held.root_epoch,
+    };
+
+    if preferred {
+        return incoming;
+    }
+
+    if incoming.root_epoch == held.root_epoch && canonical(incoming) < canonical(held) {
+        return incoming;
+    }
+
+    held
+}
+
+pub(crate) fn union(into: &mut Extra, other: Extra) {
+    for (key, value) in other {
+        let replace = match into.get(&key) {
+            Some(existing) => canonical(&value) < canonical(existing),
+            None => true,
+        };
+
+        if replace {
+            into.insert(key, value);
+        }
+    }
+}
+
+pub(crate) fn canonical<T: Serialize>(value: &T) -> String {
+    serde_json::to_string(value).unwrap_or_default()
+}
+
+fn json_error(error: serde_json::Error) -> ListError {
+    ListError::Json(error.to_string())
+}
+
+fn crypto_error(error: impl fmt::Display) -> ListError {
+    ListError::Crypto(error.to_string())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn id(byte: u8) -> CommunityId {
+        CommunityId::from_bytes([byte; 32])
+    }
+
+    fn material(
+        community_id: CommunityId,
+        owner: PublicKey,
+        name: &str,
+        epoch: u64,
+    ) -> JoinMaterial {
+        JoinMaterial {
+            community_id,
+            owner,
+            owner_salt: "33".repeat(32),
+            community_root: "44".repeat(32),
+            root_epoch: Epoch(epoch),
+            control_pk: None,
+            control_root: None,
+            channels: vec![],
+            relays: vec!["wss://relay.example".to_owned()],
+            name: name.to_owned(),
+            extra: Extra::default(),
+        }
+    }
+
+    fn entry(
+        community_id: CommunityId,
+        seed: JoinMaterial,
+        current: JoinMaterial,
+        added_at: u64,
+    ) -> CommunityListEntry {
+        CommunityListEntry {
+            community_id,
+            seed,
+            current,
+            added_at,
+            extra: Extra::default(),
+        }
+    }
+
+    fn list(entries: Vec<CommunityListEntry>) -> CommunityList {
+        CommunityList {
+            entries,
+            ..Default::default()
+        }
+    }
+
+    fn removal(community_id: CommunityId, removed_at: u64) -> CommunityList {
+        CommunityList {
+            tombstones: vec![Tombstone {
+                community_id,
+                removed_at,
+                extra: Extra::default(),
+            }],
+            ..Default::default()
+        }
+    }
+
+    #[test]
+    fn merge_keeps_the_earlier_seed_and_the_later_current_either_way_round() {
+        let owner = Keys::generate().public_key();
+        let older = material(id(0x11), owner, "Room", 1);
+        let newer = material(id(0x11), owner, "Room", 3);
+
+        let a = list(vec![entry(id(0x11), older.clone(), newer.clone(), 5_000)]);
+        let b = list(vec![entry(id(0x11), newer, older, 5_000)]);
+
+        for merged in [merge(a.clone(), b.clone()), merge(b, a)] {
+            let merged = merged.entries.first().expect("one membership");
+            assert_eq!(
+                merged.seed.root_epoch,
+                Epoch(1),
+                "seed anchors the earliest epoch held"
+            );
+            assert_eq!(merged.current.root_epoch, Epoch(3));
+            assert_eq!(merged.added_at, 5_000);
+        }
+
+        // An epoch tie breaks on the whole snapshot's bytes, and does so for both
+        // orders, so two devices never flap competing republishes.
+        let alpha = material(id(0x11), owner, "Alpha", 2);
+        let beta = material(id(0x11), owner, "Beta", 2);
+        let a = list(vec![entry(id(0x11), alpha.clone(), alpha, 1)]);
+        let b = list(vec![entry(id(0x11), beta.clone(), beta, 1)]);
+
+        let first = merge(a.clone(), b.clone());
+        assert_eq!(first, merge(b, a));
+        assert_eq!(first.entries[0].current.name, "Alpha");
+    }
+
+    #[test]
+    fn a_tombstone_is_terminal_until_a_newer_join_outruns_it() {
+        let owner = Keys::generate().public_key();
+        let joined = entry(
+            id(0x11),
+            material(id(0x11), owner, "Room", 0),
+            material(id(0x11), owner, "Room", 0),
+            5_000,
+        );
+
+        let left = merge(list(vec![joined.clone()]), removal(id(0x11), 6_000));
+        assert!(!left.is_live(&id(0x11)));
+        assert_eq!(
+            left.entries.len(),
+            1,
+            "a retired entry stays in the document"
+        );
+
+        // A stale device re-merging the entry cannot resurrect it.
+        assert!(!merge(left.clone(), list(vec![joined.clone()])).is_live(&id(0x11)));
+
+        // A re-join genuinely newer than the removal does.
+        let rejoined = list(vec![entry(
+            id(0x11),
+            material(id(0x11), owner, "Room", 0),
+            material(id(0x11), owner, "Room", 0),
+            7_000,
+        )]);
+        let live = merge(left, rejoined);
+        assert!(live.is_live(&id(0x11)));
+
+        // And the older removal is not re-applied on top of it.
+        assert!(merge(live, removal(id(0x11), 6_000)).is_live(&id(0x11)));
+    }
+
+    #[test]
+    fn a_second_device_reconstructs_membership_from_13302() {
+        let me = Keys::generate();
+        let owner = Keys::generate().public_key();
+        let mine = CommunityList {
+            entries: vec![
+                entry(
+                    id(0x11),
+                    material(id(0x11), owner, "Room", 1),
+                    material(id(0x11), owner, "Room", 4),
+                    AT,
+                ),
+                entry(
+                    id(0x22),
+                    material(id(0x22), owner, "Other", 0),
+                    material(id(0x22), owner, "Other", 0),
+                    AT + 1,
+                ),
+            ],
+            tombstones: vec![Tombstone {
+                community_id: id(0x33),
+                removed_at: AT,
+                extra: Extra::default(),
+            }],
+            extra: Extra::default(),
+        };
+
+        let event = build_list_event(&me, &mine).expect("builds");
+        assert_eq!(event.kind, Kind::Custom(KIND_COMMUNITY_LIST));
+        assert_eq!(parse_list_event(&me, &event).expect("parses"), mine);
+        assert!(
+            !parse_list_event(&me, &event)
+                .expect("parses")
+                .is_live(&id(0x33))
+        );
+
+        // Only the member's own keys open it, and an unreadable list is "no news".
+        let stranger = Keys::generate();
+        assert!(parse_list_event(&stranger, &event).is_err());
+
+        // Unknown fields survive the round trip, so a republish cannot wipe them.
+        let mut held = mine.clone();
+        held.extra
+            .insert("future".to_owned(), serde_json::json!({"deep": [1, 2]}));
+        held.entries[0]
+            .current
+            .extra
+            .insert("held_roots".to_owned(), serde_json::json!([{"epoch": 1}]));
+        let rebuilt =
+            parse_list_event(&me, &build_list_event(&me, &held).expect("builds")).expect("parses");
+        assert_eq!(rebuilt, held);
+
+        // The write gate refuses an over-cap or oversized List before publishing.
+        let crowded = list(
+            (0..=MAX_MEMBERSHIPS)
+                .map(|index| {
+                    let community_id = CommunityId::from_bytes([index as u8; 32]);
+                    entry(
+                        community_id,
+                        material(community_id, owner, "Room", 0),
+                        material(community_id, owner, "Room", 0),
+                        AT,
+                    )
+                })
+                .collect(),
+        );
+        assert!(matches!(
+            build_list_event(&me, &crowded),
+            Err(ListError::TooManyMemberships(n)) if n == MAX_MEMBERSHIPS + 1
+        ));
+
+        let oversized = list(vec![entry(
+            id(0x11),
+            material(id(0x11), owner, &"x".repeat(NIP44_MAX_PLAINTEXT), 0),
+            material(id(0x11), owner, "Room", 0),
+            AT,
+        )]);
+        assert!(matches!(oversized.fits(), Err(ListError::Oversize(_))));
+    }
+
+    const AT: u64 = 1_719_800_000_000;
+}

crates/concord/src/cords/cord04/mod.rs

@@ -0,0 +1,555 @@
+pub mod pins;
+pub mod roles;
+
+use std::cmp::Reverse;
+use std::collections::BTreeMap;
+use std::fmt;
+
+use data_encoding::HEXLOWER;
+use nostr_sdk::prelude::{EventId, PublicKey, Tag, UnsignedEvent};
+use serde::{Deserialize, Serialize};
+use sha2::{Digest, Sha256};
+
+use crate::cord01::build_rumor_secs;
+use crate::decode_hex_32;
+
+pub const KIND_CONTROL: u16 = 3308;
+
+const EDITION_LABEL: &[u8] = b"vector-community/v1/edition";
+
+/// Entity types an edition can address.
+pub mod vsk {
+    pub const COMMUNITY_METADATA: &str = "0";
+    pub const ROLE: &str = "1";
+    pub const CHANNEL_METADATA: &str = "2";
+    pub const GRANT: &str = "3";
+    pub const BANLIST: &str = "4";
+    pub const INVITE_LIVE: &str = "6";
+    pub const INVITE_LINKS: &str = "8";
+    pub const INVITE_REVOKED: &str = "9";
+    pub const DISSOLVED: &str = "10";
+    pub const PINS: &str = "11";
+}
+
+pub const TAG_SUBKIND: &str = "vsk";
+pub const TAG_CITATION: &str = "vac";
+
+const TAG_ENTITY: &str = "eid";
+const TAG_VERSION: &str = "ev";
+const TAG_PREV: &str = "ep";
+
+#[derive(Debug)]
+pub enum EditionError {
+    BadKind(u16),
+    BadField(&'static str),
+    Duplicate(&'static str),
+    Missing(&'static str),
+}
+
+impl fmt::Display for EditionError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            EditionError::BadKind(kind) => write!(f, "not an edition kind: {kind}"),
+            EditionError::BadField(name) => write!(f, "malformed edition field: {name}"),
+            EditionError::Duplicate(name) => write!(f, "duplicate edition field: {name}"),
+            EditionError::Missing(name) => write!(f, "missing edition field: {name}"),
+        }
+    }
+}
+
+impl std::error::Error for EditionError {}
+
+/// A `vac`: the Grant edition an actor claims rank under, pinned by coordinate, version and hash.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct AuthorityCitation {
+    pub entity: [u8; 32],
+    pub version: u64,
+    pub hash: [u8; 32],
+}
+
+#[derive(Debug, Clone)]
+pub struct ParsedEdition {
+    pub author: PublicKey,
+    pub subkind: String,
+    pub entity: [u8; 32],
+    pub version: u64,
+    pub prev: Option<[u8; 32]>,
+    pub citation: Option<AuthorityCitation>,
+    pub content: String,
+    pub self_hash: [u8; 32],
+    pub rumor_id: EventId,
+}
+
+pub struct EditionFields<'a> {
+    pub author: PublicKey,
+    pub subkind: &'a str,
+    pub entity: [u8; 32],
+    pub version: u64,
+    pub prev: Option<[u8; 32]>,
+    pub citation: Option<AuthorityCitation>,
+    pub content: &'a str,
+    pub at_secs: u64,
+}
+
+fn signing_bytes(
+    entity: &[u8; 32],
+    version: u64,
+    prev: Option<&[u8; 32]>,
+    content: &[u8],
+) -> Vec<u8> {
+    let mut bytes =
+        Vec::with_capacity(8 + EDITION_LABEL.len() + 32 + 8 + 1 + 32 + 8 + content.len());
+
+    bytes.extend_from_slice(&(EDITION_LABEL.len() as u64).to_be_bytes());
+    bytes.extend_from_slice(EDITION_LABEL);
+    bytes.extend_from_slice(entity);
+    bytes.extend_from_slice(&version.to_be_bytes());
+
+    match prev {
+        Some(prev) => {
+            bytes.push(1);
+            bytes.extend_from_slice(prev);
+        }
+        None => {
+            bytes.push(0);
+            bytes.extend_from_slice(&[0u8; 32]);
+        }
+    }
+
+    bytes.extend_from_slice(&(content.len() as u64).to_be_bytes());
+    bytes.extend_from_slice(content);
+    bytes
+}
+
+pub fn edition_hash(
+    entity: &[u8; 32],
+    version: u64,
+    prev: Option<&[u8; 32]>,
+    content: &[u8],
+) -> [u8; 32] {
+    Sha256::digest(signing_bytes(entity, version, prev, content)).into()
+}
+
+pub fn citation_tag(citation: &AuthorityCitation) -> Tag {
+    Tag::custom(
+        TAG_CITATION,
+        [
+            HEXLOWER.encode(&citation.entity),
+            citation.version.to_string(),
+            HEXLOWER.encode(&citation.hash),
+        ],
+    )
+}
+
+pub fn citation_from(fields: &[String]) -> Option<AuthorityCitation> {
+    if fields.len() != 4 {
+        return None;
+    }
+
+    Some(AuthorityCitation {
+        entity: hex32(&fields[1], TAG_CITATION).ok()?,
+        version: canonical_decimal(&fields[2])?,
+        hash: hex32(&fields[3], TAG_CITATION).ok()?,
+    })
+}
+
+pub fn build_edition(fields: EditionFields<'_>) -> UnsignedEvent {
+    let mut tags = vec![
+        Tag::custom(TAG_SUBKIND, [fields.subkind]),
+        Tag::custom(TAG_ENTITY, [HEXLOWER.encode(&fields.entity)]),
+        Tag::custom(TAG_VERSION, [fields.version.to_string()]),
+    ];
+
+    if let Some(prev) = fields.prev {
+        tags.push(Tag::custom(TAG_PREV, [HEXLOWER.encode(&prev)]));
+    }
+
+    if let Some(citation) = fields.citation {
+        tags.push(citation_tag(&citation));
+    }
+
+    build_rumor_secs(
+        KIND_CONTROL,
+        fields.author,
+        fields.content,
+        tags,
+        fields.at_secs,
+    )
+}
+
+pub fn parse_edition(rumor: &UnsignedEvent) -> Result<ParsedEdition, EditionError> {
+    let kind = rumor.kind.as_u16();
+
+    if kind != KIND_CONTROL {
+        return Err(EditionError::BadKind(kind));
+    }
+
+    let subkind = value(rumor, TAG_SUBKIND)?
+        .ok_or(EditionError::Missing(TAG_SUBKIND))?
+        .to_owned();
+
+    if canonical_decimal(&subkind).is_none() {
+        return Err(EditionError::BadField(TAG_SUBKIND));
+    }
+
+    let entity = hex32(
+        value(rumor, TAG_ENTITY)?.ok_or(EditionError::Missing(TAG_ENTITY))?,
+        TAG_ENTITY,
+    )?;
+
+    let version =
+        canonical_decimal(value(rumor, TAG_VERSION)?.ok_or(EditionError::Missing(TAG_VERSION))?)
+            .ok_or(EditionError::BadField(TAG_VERSION))?;
+
+    let prev = match value(rumor, TAG_PREV)? {
+        Some(raw) => Some(hex32(raw, TAG_PREV)?),
+        None => None,
+    };
+
+    let citation = match fields(rumor, TAG_CITATION)? {
+        Some(fields) => Some(citation_from(fields).ok_or(EditionError::BadField(TAG_CITATION))?),
+        None => None,
+    };
+
+    let self_hash = edition_hash(&entity, version, prev.as_ref(), rumor.content.as_bytes());
+
+    Ok(ParsedEdition {
+        author: rumor.pubkey,
+        subkind,
+        entity,
+        version,
+        prev,
+        citation,
+        content: rumor.content.clone(),
+        self_hash,
+        rumor_id: rumor.id.unwrap_or_else(|| rumor.compute_id()),
+    })
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct EditionMeta {
+    pub version: u64,
+    pub self_hash: [u8; 32],
+    pub prev: Option<[u8; 32]>,
+    pub tiebreak_id: EventId,
+}
+
+impl From<&ParsedEdition> for EditionMeta {
+    fn from(edition: &ParsedEdition) -> Self {
+        Self {
+            version: edition.version,
+            self_hash: edition.self_hash,
+            prev: edition.prev,
+            tiebreak_id: edition.rumor_id,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub struct FoldResult {
+    pub head: Option<usize>,
+    pub gap: bool,
+    pub anchored: bool,
+}
+
+/// The highest version whose chain is intact, given a held floor.
+pub fn fold(editions: &[EditionMeta], floor: u64, floor_hash: Option<&[u8; 32]>) -> FoldResult {
+    let mut by_version: BTreeMap<u64, usize> = BTreeMap::new();
+
+    for (index, edition) in editions.iter().enumerate() {
+        if edition.version < floor {
+            continue;
+        }
+
+        match by_version.get(&edition.version) {
+            Some(&current) if editions[current].tiebreak_id <= edition.tiebreak_id => {}
+            _ => {
+                by_version.insert(edition.version, index);
+            }
+        }
+    }
+
+    let Some((&lowest_version, &lowest_index)) = by_version.first_key_value() else {
+        return FoldResult::default();
+    };
+
+    let lowest = editions[lowest_index];
+
+    let anchored = if floor == 0 {
+        lowest_version == 1 && lowest.prev.is_none()
+    } else if lowest_version == floor {
+        floor_hash == Some(&lowest.self_hash)
+    } else if lowest_version == floor + 1 {
+        floor_hash.is_some() && lowest.prev.as_ref() == floor_hash
+    } else {
+        false
+    };
+
+    let mut head = Some(lowest_index);
+    let mut gap = !anchored;
+    let mut previous_version = lowest_version;
+    let mut previous_hash = lowest.self_hash;
+
+    for (&version, &index) in by_version.range(lowest_version + 1..) {
+        let edition = editions[index];
+
+        if version == previous_version + 1 && edition.prev == Some(previous_hash) {
+            head = Some(index);
+            previous_version = version;
+            previous_hash = edition.self_hash;
+        } else {
+            gap = true;
+            break;
+        }
+    }
+
+    FoldResult {
+        head,
+        gap,
+        anchored,
+    }
+}
+
+/// The highest version overall, ignoring contiguity.
+pub fn bootstrap_head(editions: &[EditionMeta]) -> Option<usize> {
+    editions
+        .iter()
+        .enumerate()
+        .min_by_key(|(_, edition)| (Reverse(edition.version), edition.tiebreak_id))
+        .map(|(index, _)| index)
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub struct HeadSelection {
+    pub head: Option<usize>,
+    pub gap: bool,
+}
+
+/// The head to prefer for one entity, given what this client already committed to.
+pub fn fold_head(editions: &[EditionMeta], floor: Option<&EntityHead>) -> HeadSelection {
+    let Some(floor) = floor else {
+        return HeadSelection {
+            head: bootstrap_head(editions),
+            gap: false,
+        };
+    };
+
+    let anchored = fold(editions, floor.version, Some(&floor.self_hash));
+
+    if anchored.anchored {
+        return HeadSelection {
+            head: anchored.head,
+            gap: anchored.gap,
+        };
+    }
+
+    if anchored.head.is_none() && !anchored.gap {
+        return HeadSelection::default();
+    }
+
+    let fork = editions
+        .iter()
+        .enumerate()
+        .filter(|(_, edition)| edition.version == floor.version)
+        .min_by_key(|(_, edition)| edition.tiebreak_id);
+
+    let winner = match fork {
+        Some((_, edition))
+            if edition.self_hash != floor.self_hash && edition.tiebreak_id < floor.rumor_id =>
+        {
+            edition.self_hash
+        }
+        _ => {
+            return HeadSelection {
+                head: None,
+                gap: true,
+            };
+        }
+    };
+
+    let refolded = fold(editions, floor.version, Some(&winner));
+
+    if refolded.anchored {
+        HeadSelection {
+            head: refolded.head,
+            gap: refolded.gap,
+        }
+    } else {
+        HeadSelection {
+            head: None,
+            gap: true,
+        }
+    }
+}
+
+/// A committed head, and the refuse-downgrade floor a later fold is judged against.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct EntityHead {
+    pub entity: [u8; 32],
+    pub version: u64,
+    pub self_hash: [u8; 32],
+    pub rumor_id: EventId,
+}
+
+impl From<&ParsedEdition> for EntityHead {
+    fn from(edition: &ParsedEdition) -> Self {
+        Self {
+            entity: edition.entity,
+            version: edition.version,
+            self_hash: edition.self_hash,
+            rumor_id: edition.rumor_id,
+        }
+    }
+}
+
+/// Every entity's committed head, keyed by coordinate.
+pub type Floors = BTreeMap<[u8; 32], EntityHead>;
+
+pub(crate) fn canonical_decimal(raw: &str) -> Option<u64> {
+    if raw.is_empty() || !raw.bytes().all(|byte| byte.is_ascii_digit()) {
+        return None;
+    }
+
+    if raw.len() > 1 && raw.starts_with('0') {
+        return None;
+    }
+
+    raw.parse().ok()
+}
+
+fn hex32(raw: &str, name: &'static str) -> Result<[u8; 32], EditionError> {
+    decode_hex_32(raw).map_err(|_| EditionError::BadField(name))
+}
+
+fn fields<'a>(
+    rumor: &'a UnsignedEvent,
+    name: &'static str,
+) -> Result<Option<&'a [String]>, EditionError> {
+    let mut found: Option<&[String]> = None;
+
+    for tag in rumor.tags.iter() {
+        let tag_fields = tag.as_slice();
+
+        if tag_fields.first().map(String::as_str) != Some(name) {
+            continue;
+        }
+
+        if found.is_some() {
+            return Err(EditionError::Duplicate(name));
+        }
+
+        found = Some(tag_fields);
+    }
+
+    Ok(found)
+}
+
+fn value<'a>(
+    rumor: &'a UnsignedEvent,
+    name: &'static str,
+) -> Result<Option<&'a str>, EditionError> {
+    match fields(rumor, name)? {
+        Some(fields) if fields.len() == 2 => Ok(Some(fields[1].as_str())),
+        Some(_) => Err(EditionError::BadField(name)),
+        None => Ok(None),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn meta(version: u64, prev: Option<[u8; 32]>, hash: u8, tiebreak: u8) -> EditionMeta {
+        EditionMeta {
+            version,
+            self_hash: [hash; 32],
+            prev,
+            tiebreak_id: EventId::from_byte_array([tiebreak; 32]),
+        }
+    }
+
+    fn head(version: u64, hash: u8, rumor: u8) -> EntityHead {
+        EntityHead {
+            entity: [0x11; 32],
+            version,
+            self_hash: [hash; 32],
+            rumor_id: EventId::from_byte_array([rumor; 32]),
+        }
+    }
+
+    #[test]
+    fn fold_picks_the_head_from_the_chain_and_the_floor() {
+        let chain = [
+            meta(1, None, 0xa1, 1),
+            meta(2, Some([0xa1; 32]), 0xa2, 2),
+            meta(3, Some([0xa2; 32]), 0xa3, 3),
+        ];
+
+        let folded = fold(&chain, 0, None);
+        assert_eq!(folded.head, Some(2));
+        assert!(!folded.gap && folded.anchored);
+
+        // A missing link stops the walk at the last contiguous edition.
+        let gapped = fold(&[chain[0], chain[2]], 0, None);
+        assert_eq!(gapped.head, Some(0));
+        assert!(gapped.gap && gapped.anchored);
+
+        // Everything below the held floor is a stale relay, not a gap.
+        let stale = fold(&chain[..2], 3, Some(&[0xa3; 32]));
+        assert_eq!(stale.head, None);
+        assert!(!stale.gap && !stale.anchored);
+
+        // A fork at a version breaks on the lower inner rumor id, and the chain resumes.
+        let fork = [meta(1, None, 0xb1, 9), meta(1, None, 0xa1, 1)];
+        assert_eq!(
+            fold(&fork, 0, None).head,
+            Some(1),
+            "the lower rumor id wins"
+        );
+        let forked = [fork[0], fork[1], chain[1], chain[2]];
+        assert_eq!(fold(&forked, 0, None).head, Some(3));
+
+        // A re-wrap onto the head we hold is the legitimate case; one whose `prev` no
+        // longer resolves is a withholding.
+        let rewrapped = meta(5, Some([0x99; 32]), 0xc5, 5);
+        assert_eq!(
+            fold_head(&[rewrapped], Some(&head(4, 0x99, 4))).head,
+            Some(0)
+        );
+        let dangling = meta(5, Some([0x88; 32]), 0xc5, 5);
+        let refused = fold_head(&[dangling], Some(&head(4, 0x99, 4)));
+        assert_eq!(refused.head, None);
+        assert!(refused.gap);
+
+        // A bootstrap takes it anyway: a compaction would leave a joiner with nothing.
+        assert_eq!(bootstrap_head(&[dangling]), Some(0));
+        assert_eq!(fold_head(&[dangling], None).head, Some(0));
+
+        // A fork at the floor's own version converges to the lower rumor id when that is
+        // genuinely earlier than what we hold, and the chain above it re-anchors.
+        let forked = [
+            meta(2, Some([0xa1; 32]), 0xb2, 3),
+            meta(3, Some([0xb2; 32]), 0xb3, 4),
+        ];
+        let converged = fold_head(&forked, Some(&head(2, 0xaa, 9)));
+        assert_eq!(converged.head, Some(1));
+        assert!(!converged.gap);
+
+        // A fork that is not earlier than the held head is refused.
+        assert_eq!(fold_head(&forked, Some(&head(2, 0xaa, 2))).head, None);
+    }
+
+    #[test]
+    fn edition_hash_matches_the_cross_client_vector() {
+        let entity = [0x11u8; 32];
+
+        assert_eq!(
+            HEXLOWER.encode(&edition_hash(&entity, 1, None, b"hello")),
+            "2daf42e65a6bc259a4c99fac6df754a5d3d92310607cf13e2a1e8c94d42f6303"
+        );
+
+        // The golden vector only exercises the absent-prev encoding, so pin the flag.
+        let bytes = signing_bytes(&entity, 1, Some(&entity), b"hello");
+        assert_eq!(bytes[8 + EDITION_LABEL.len() + 32 + 8], 1);
+    }
+}

crates/concord/src/cords/cord04/pins.rs

@@ -0,0 +1,817 @@
+use std::fmt;
+
+use chacha20::ChaCha20;
+use chacha20::cipher::{KeyIvInit, StreamCipher};
+use data_encoding::{BASE64, HEXLOWER};
+use hkdf::Hkdf;
+use hmac::{Hmac, Mac};
+use nostr_sdk::prelude::*;
+use serde::{Deserialize, Serialize};
+use sha2::Sha256;
+
+use crate::cord01::{self, OpenedStream, SealForm, resolve_ms_strict};
+use crate::cord03::{ChatAction, ChatRumor, KIND_COMMENT, KIND_EDIT, KIND_MESSAGE};
+use crate::cord04::canonical_decimal;
+use crate::{ChannelId, Epoch, Extra, GroupKey, decode_hex_lower};
+
+pub const PIN_MAX_ENTRIES: usize = 25;
+pub const PIN_MAX_CONTENT_BYTES: usize = 32_768;
+
+/// The serialized disclosure: `chacha_key[32] || chacha_nonce[12] || hmac_key[32]`.
+pub const MESSAGE_KEYS_BYTES: usize = 76;
+
+const TAG_CHANNEL: &str = "channel";
+const TAG_EPOCH: &str = "epoch";
+const TAG_TARGET: &str = "e";
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum PinError {
+    NotEncryptedSeal,
+    BadPayload,
+    Unverifiable,
+    Unreadable,
+    TooManyEntries,
+    Oversize(usize),
+    Seal(String),
+    Encode(String),
+}
+
+impl fmt::Display for PinError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            PinError::NotEncryptedSeal => write!(f, "pin requires an encrypted seal"),
+            PinError::BadPayload => write!(f, "the seal payload does not open"),
+            PinError::Unverifiable => write!(f, "the entry would not verify"),
+            PinError::Unreadable => {
+                write!(f, "refusing to publish a pin list this client cannot read")
+            }
+            PinError::TooManyEntries => write!(f, "pin list exceeds {PIN_MAX_ENTRIES} entries"),
+            PinError::Oversize(len) => {
+                write!(
+                    f,
+                    "pin list content is {len} bytes (cap {PIN_MAX_CONTENT_BYTES})"
+                )
+            }
+            PinError::Seal(error) => write!(f, "seal: {error}"),
+            PinError::Encode(error) => write!(f, "encode: {error}"),
+        }
+    }
+}
+
+impl std::error::Error for PinError {}
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct MessageKeys {
+    chacha_key: [u8; 32],
+    chacha_nonce: [u8; 12],
+    hmac_key: [u8; 32],
+}
+
+impl MessageKeys {
+    pub fn to_hex(&self) -> String {
+        let mut packed = [0u8; MESSAGE_KEYS_BYTES];
+        packed[0..32].copy_from_slice(&self.chacha_key);
+        packed[32..44].copy_from_slice(&self.chacha_nonce);
+        packed[44..76].copy_from_slice(&self.hmac_key);
+        HEXLOWER.encode(&packed)
+    }
+
+    pub fn from_hex(value: &str) -> Option<Self> {
+        let bytes = decode_hex_lower::<MESSAGE_KEYS_BYTES>(value).ok()?;
+
+        Some(Self {
+            chacha_key: bytes[0..32].try_into().ok()?,
+            chacha_nonce: bytes[32..44].try_into().ok()?,
+            hmac_key: bytes[44..76].try_into().ok()?,
+        })
+    }
+
+    fn derive(conversation_key: &[u8; 32], nonce: &[u8]) -> Option<Self> {
+        let hkdf = Hkdf::<Sha256>::from_prk(conversation_key).ok()?;
+        let mut key_material = [0u8; MESSAGE_KEYS_BYTES];
+        hkdf.expand(nonce, &mut key_material).ok()?;
+
+        Some(Self {
+            chacha_key: key_material[0..32].try_into().ok()?,
+            chacha_nonce: key_material[32..44].try_into().ok()?,
+            hmac_key: key_material[44..76].try_into().ok()?,
+        })
+    }
+}
+
+struct Payload {
+    nonce: [u8; 32],
+    ciphertext: Vec<u8>,
+    mac: [u8; 32],
+}
+
+fn decode_payload(payload: &str) -> Option<Payload> {
+    let data = BASE64.decode(payload.as_bytes()).ok()?;
+
+    if data.len() < 99 || data[0] != 2 {
+        return None;
+    }
+
+    let mac_at = data.len() - 32;
+
+    Some(Payload {
+        nonce: data[1..33].try_into().ok()?,
+        ciphertext: data[33..mac_at].to_vec(),
+        mac: data[mac_at..].try_into().ok()?,
+    })
+}
+
+fn disclose_keys(payload: &str, conversation_key: &[u8; 32]) -> Option<MessageKeys> {
+    let decoded = decode_payload(payload)?;
+    MessageKeys::derive(conversation_key, &decoded.nonce)
+}
+
+fn open_payload(payload: &str, keys: &MessageKeys) -> Option<String> {
+    let decoded = decode_payload(payload)?;
+
+    let mut mac = Hmac::<Sha256>::new_from_slice(&keys.hmac_key).ok()?;
+    mac.update(&decoded.nonce);
+    mac.update(&decoded.ciphertext);
+    mac.verify_slice(&decoded.mac).ok()?;
+
+    let mut padded = decoded.ciphertext;
+    let mut cipher = ChaCha20::new((&keys.chacha_key).into(), (&keys.chacha_nonce).into());
+    cipher.apply_keystream(&mut padded);
+
+    unpad(&padded)
+}
+
+fn unpad(padded: &[u8]) -> Option<String> {
+    let (len, prefix) = plaintext_length(padded)?;
+    let unpadded = padded.get(prefix..prefix.checked_add(len)?)?;
+
+    if len < 1 || padded.len() != prefix.checked_add(padded_len(len)?)? {
+        return None;
+    }
+
+    String::from_utf8(unpadded.to_vec()).ok()
+}
+
+fn plaintext_length(padded: &[u8]) -> Option<(usize, usize)> {
+    let short = u16::from_be_bytes(padded.get(..2)?.try_into().ok()?);
+
+    if short != 0 {
+        return Some((short as usize, 2));
+    }
+
+    let long = u32::from_be_bytes(padded.get(2..6)?.try_into().ok()?);
+
+    if long < 65_536 {
+        return None;
+    }
+
+    Some((long as usize, 6))
+}
+
+fn padded_len(len: usize) -> Option<usize> {
+    if len < 1 {
+        return None;
+    }
+
+    if len <= 32 {
+        return Some(32);
+    }
+
+    let next_power = 1usize.checked_shl(usize::BITS - (len - 1).leading_zeros())?;
+    let chunk = if next_power <= 256 {
+        32
+    } else {
+        next_power / 8
+    };
+
+    Some(chunk * ((len - 1) / chunk + 1))
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct PinEditBundle {
+    pub seal: Event,
+    pub keys: String,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct PinEntry {
+    pub seal: Event,
+    pub keys: String,
+    /// An unverifiable locator hint; a mismatch is expected and never fatal.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub wrap: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub edit: Option<PinEditBundle>,
+    #[serde(flatten)]
+    pub extra: Extra,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct EditedContent {
+    pub content: String,
+    pub at_ms: u64,
+}
+
+#[derive(Debug, Clone)]
+pub struct VerifiedPin {
+    pub rumor_id: EventId,
+    pub author: PublicKey,
+    pub kind: u16,
+    pub content: String,
+    pub tags: Tags,
+    pub epoch: Epoch,
+    pub at_ms: u64,
+    pub created_at: u64,
+    pub wrap: Option<String>,
+    pub edited: Option<EditedContent>,
+    pub entry: PinEntry,
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct ReadPinList {
+    pub entries: Vec<PinEntry>,
+    pub sealed: bool,
+}
+
+pub fn build_entry(
+    opened: &OpenedStream,
+    group: &GroupKey,
+    channel: &ChannelId,
+) -> Result<PinEntry, PinError> {
+    let keys = disclosed_keys(opened, group)?;
+
+    let entry = PinEntry {
+        seal: opened.seal.clone(),
+        keys: keys.to_hex(),
+        wrap: Some(opened.wrapper_id.to_hex()),
+        edit: None,
+        extra: Extra::default(),
+    };
+
+    if verify_entry(&entry, channel).is_none() {
+        return Err(PinError::Unverifiable);
+    }
+
+    Ok(entry)
+}
+
+pub fn build_edit_bundle(
+    edit: &OpenedStream,
+    group: &GroupKey,
+    original: &VerifiedPin,
+    channel: &ChannelId,
+) -> Result<PinEditBundle, PinError> {
+    let bundle = PinEditBundle {
+        seal: edit.seal.clone(),
+        keys: disclosed_keys(edit, group)?.to_hex(),
+    };
+
+    if verify_edit_bundle(&bundle, &original.author, &original.rumor_id, channel).is_none() {
+        return Err(PinError::Unverifiable);
+    }
+
+    Ok(bundle)
+}
+
+pub fn with_proven_edit(
+    entry: &PinEntry,
+    edit: &OpenedStream,
+    group: &GroupKey,
+    channel: &ChannelId,
+) -> PinEntry {
+    let Some(original) = verify_entry(entry, channel) else {
+        return entry.clone();
+    };
+
+    let Ok(bundle) = build_edit_bundle(edit, group, &original, channel) else {
+        return entry.clone();
+    };
+
+    let mut refreshed = entry.clone();
+    refreshed.edit = Some(bundle);
+    refreshed
+}
+
+fn disclosed_keys(opened: &OpenedStream, group: &GroupKey) -> Result<MessageKeys, PinError> {
+    if opened.seal_form != SealForm::Encrypted {
+        return Err(PinError::NotEncryptedSeal);
+    }
+
+    let conversation: [u8; 32] = group
+        .conversation()
+        .as_bytes()
+        .try_into()
+        .map_err(|_| PinError::BadPayload)?;
+
+    let keys = disclose_keys(&opened.seal.content, &conversation).ok_or(PinError::BadPayload)?;
+
+    if open_payload(&opened.seal.content, &keys).is_none() {
+        return Err(PinError::BadPayload);
+    }
+
+    Ok(keys)
+}
+
+pub fn verify_entry(entry: &PinEntry, channel: &ChannelId) -> Option<VerifiedPin> {
+    let seal = &entry.seal;
+
+    if seal.kind.as_u16() != cord01::KIND_SEAL_ENCRYPTED || seal.verify().is_err() {
+        return None;
+    }
+
+    let keys = MessageKeys::from_hex(&entry.keys)?;
+    let plaintext = open_payload(&seal.content, &keys)?;
+    let rumor = UnsignedEvent::from_json(&plaintext).ok()?;
+
+    // NIP-59's impersonation check: the renderer shows the rumor's fields.
+    if rumor.pubkey != seal.pubkey {
+        return None;
+    }
+
+    let kind = rumor.kind.as_u16();
+
+    if kind != KIND_MESSAGE && kind != KIND_COMMENT {
+        return None;
+    }
+
+    // CORD-01's binding, restated: a keyholder must not pin a message into another Channel's list.
+    if tag_value(&rumor, TAG_CHANNEL)? != channel.to_hex() {
+        return None;
+    }
+
+    let epoch = Epoch(canonical_decimal(tag_value(&rumor, TAG_EPOCH)?)?);
+
+    // Recomputed from the decrypted bytes; a claimed `id` is never trusted.
+    rumor.verify_id().ok()?;
+    let rumor_id = rumor.compute_id();
+
+    let edited = entry
+        .edit
+        .as_ref()
+        .and_then(|bundle| verify_edit_bundle(bundle, &rumor.pubkey, &rumor_id, channel));
+
+    Some(VerifiedPin {
+        author: rumor.pubkey,
+        content: edited
+            .as_ref()
+            .map_or_else(|| rumor.content.clone(), |edited| edited.content.clone()),
+        epoch,
+        at_ms: resolve_ms_strict(&rumor).ok()?,
+        created_at: rumor.created_at.as_secs(),
+        tags: rumor.tags.clone(),
+        wrap: entry.wrap.clone(),
+        edited,
+        entry: entry.clone(),
+        kind,
+        rumor_id,
+    })
+}
+
+fn verify_edit_bundle(
+    bundle: &PinEditBundle,
+    original_author: &PublicKey,
+    original_id: &EventId,
+    channel: &ChannelId,
+) -> Option<EditedContent> {
+    let seal = &bundle.seal;
+
+    // Checkable before any crypto: nobody else may revise another member's words.
+    if seal.kind.as_u16() != cord01::KIND_SEAL_ENCRYPTED || seal.pubkey != *original_author {
+        return None;
+    }
+
+    if seal.verify().is_err() {
+        return None;
+    }
+
+    let keys = MessageKeys::from_hex(&bundle.keys)?;
+    let plaintext = open_payload(&seal.content, &keys)?;
+    let rumor = UnsignedEvent::from_json(&plaintext).ok()?;
+
+    if rumor.pubkey != seal.pubkey || rumor.kind.as_u16() != KIND_EDIT {
+        return None;
+    }
+
+    if tag_value(&rumor, TAG_CHANNEL)? != channel.to_hex() {
+        return None;
+    }
+
+    if tag_value(&rumor, TAG_TARGET)? != original_id.to_hex() {
+        return None;
+    }
+
+    rumor.verify_id().ok()?;
+
+    Some(EditedContent {
+        content: rumor.content.clone(),
+        at_ms: resolve_ms_strict(&rumor).ok()?,
+    })
+}
+
+fn tag_value<'a>(rumor: &'a UnsignedEvent, name: &str) -> Option<&'a str> {
+    rumor
+        .tags
+        .iter()
+        .find(|tag| tag.as_slice().first().map(String::as_str) == Some(name))
+        .and_then(|tag| tag.as_slice().get(1))
+        .map(String::as_str)
+}
+
+#[derive(Serialize, Deserialize)]
+struct PlainForm {
+    entries: Vec<PinEntry>,
+}
+
+pub fn publishable(
+    read: &ReadPinList,
+    private: bool,
+    group: &GroupKey,
+    epoch: Epoch,
+) -> Result<String, PinError> {
+    if read.sealed {
+        return Err(PinError::Unreadable);
+    }
+
+    if private {
+        serialize_sealed(&read.entries, group, epoch)
+    } else {
+        serialize_public(&read.entries)
+    }
+}
+
+fn serialize_public(entries: &[PinEntry]) -> Result<String, PinError> {
+    let content = encode_form(entries)?;
+    check_caps(entries.len(), &content)?;
+
+    Ok(content)
+}
+
+fn serialize_sealed(
+    entries: &[PinEntry],
+    group: &GroupKey,
+    epoch: Epoch,
+) -> Result<String, PinError> {
+    if entries.len() > PIN_MAX_ENTRIES {
+        return Err(PinError::TooManyEntries);
+    }
+
+    let inner = encode_form(entries)?;
+    let sealed = cord01::seal_bytes(group.conversation(), inner.as_bytes())
+        .map_err(|error| PinError::Seal(error.to_string()))?;
+    let content = serde_json::json!({ "epoch": epoch.to_string(), "sealed": sealed }).to_string();
+
+    check_caps(entries.len(), &content)?;
+
+    Ok(content)
+}
+
+fn encode_form(entries: &[PinEntry]) -> Result<String, PinError> {
+    serde_json::to_string(&PlainForm {
+        entries: entries.to_vec(),
+    })
+    .map_err(|error| PinError::Encode(error.to_string()))
+}
+
+fn check_caps(count: usize, content: &str) -> Result<(), PinError> {
+    if count > PIN_MAX_ENTRIES {
+        return Err(PinError::TooManyEntries);
+    }
+
+    if content.len() > PIN_MAX_CONTENT_BYTES {
+        return Err(PinError::Oversize(content.len()));
+    }
+
+    Ok(())
+}
+
+pub fn read_list(content: &str, unseal: impl Fn(Epoch) -> Option<GroupKey>) -> ReadPinList {
+    const EMPTY: ReadPinList = ReadPinList {
+        entries: Vec::new(),
+        sealed: false,
+    };
+
+    if content.len() > PIN_MAX_CONTENT_BYTES {
+        return EMPTY;
+    }
+
+    let Ok(value) = serde_json::from_str::<serde_json::Value>(content) else {
+        return EMPTY;
+    };
+
+    if value.get("entries").is_some() {
+        return match serde_json::from_value::<PlainForm>(value) {
+            Ok(form) if form.entries.len() <= PIN_MAX_ENTRIES => ReadPinList {
+                entries: form.entries,
+                sealed: false,
+            },
+            _ => EMPTY,
+        };
+    }
+
+    let (Some(epoch), Some(sealed)) = (
+        value.get("epoch").and_then(serde_json::Value::as_str),
+        value.get("sealed").and_then(serde_json::Value::as_str),
+    ) else {
+        return EMPTY;
+    };
+
+    let Some(epoch) = canonical_decimal(epoch) else {
+        return EMPTY;
+    };
+
+    let Some(group) = unseal(Epoch(epoch)) else {
+        return ReadPinList {
+            sealed: true,
+            ..EMPTY
+        };
+    };
+
+    let Ok(inner) = cord01::open_bytes(group.conversation(), sealed) else {
+        return EMPTY;
+    };
+
+    let Ok(form) = serde_json::from_slice::<PlainForm>(&inner) else {
+        return EMPTY;
+    };
+
+    if form.entries.len() > PIN_MAX_ENTRIES {
+        return EMPTY;
+    }
+
+    ReadPinList {
+        entries: form.entries,
+        sealed: false,
+    }
+}
+
+pub fn killed_by(pin: &VerifiedPin, delete: &ChatRumor) -> bool {
+    delete.author == pin.author
+        && matches!(&delete.action, ChatAction::Delete { target, .. } if *target == pin.rumor_id)
+}
+
+#[cfg(test)]
+mod tests {
+    use nostr::nips::nip44::v2::{self, ConversationKey};
+
+    use super::*;
+    use crate::cord03::{ChatRumor, build_delete, build_edit, build_message, open, seal_rumor};
+    use crate::derive::channel_group_key;
+
+    const AT_MS: u64 = 1_700_000_000_000;
+    const SECRET: [u8; 32] = [0x21u8; 32];
+
+    fn channel() -> ChannelId {
+        ChannelId::from_bytes([0xabu8; 32])
+    }
+
+    fn group() -> GroupKey {
+        channel_group_key(&SECRET, &channel(), Epoch(0)).expect("derives")
+    }
+
+    fn conversation() -> ConversationKey {
+        *group().conversation()
+    }
+
+    /// A real message through the production seal/open pipeline, as a pinner sees it.
+    fn sealed_message(author: &Keys, text: &str, at_ms: u64) -> (OpenedStream, ChatRumor) {
+        let rumor = build_message(
+            author.public_key(),
+            &channel(),
+            Epoch(0),
+            text,
+            None,
+            at_ms,
+            None,
+        );
+        let (wrap, _) = seal_rumor(&rumor, &group(), author, false).expect("seals");
+
+        open(&wrap, &group(), &channel(), Epoch(0)).expect("opens")
+    }
+
+    fn entry_for(author: &Keys, text: &str) -> (PinEntry, OpenedStream) {
+        let (opened, _) = sealed_message(author, text, AT_MS);
+        let entry = build_entry(&opened, &group(), &channel()).expect("builds");
+        (entry, opened)
+    }
+
+    fn some(entries: Vec<PinEntry>) -> ReadPinList {
+        ReadPinList {
+            entries,
+            sealed: false,
+        }
+    }
+
+    /// The load-bearing primitive: the reproduction must open what nostr's own
+    /// encryption produced, through the disclosure alone.
+    #[test]
+    fn a_disclosure_opens_its_message_and_nothing_else() {
+        let nonce = [0x5au8; 32];
+        let disclosure =
+            MessageKeys::derive(conversation().as_bytes().try_into().expect("32"), &nonce)
+                .expect("derives");
+
+        for text in ["a", "hello world", &"padding boundary ".repeat(40)] {
+            let raw = v2::encrypt_to_bytes_with_nonce(&conversation(), text.as_bytes(), nonce)
+                .expect("encrypts");
+            let payload = BASE64.encode(&raw);
+
+            assert_eq!(open_payload(&payload, &disclosure).as_deref(), Some(text));
+        }
+
+        // Another nonce discloses different keys, which open nothing else.
+        let other = v2::encrypt_to_bytes_with_nonce(&conversation(), b"second", [0x99u8; 32])
+            .expect("encrypts");
+        assert!(open_payload(&BASE64.encode(&other), &disclosure).is_none());
+
+        let hex = disclosure.to_hex();
+        assert_eq!(
+            MessageKeys::from_hex(&hex).map(|keys| keys.to_hex()),
+            Some(hex.clone())
+        );
+        assert!(MessageKeys::from_hex(&hex.to_uppercase()).is_none());
+    }
+
+    #[test]
+    fn a_built_entry_proves_its_author_and_cannot_cross_channels() {
+        let author = Keys::generate();
+        let (entry, opened) = entry_for(&author, "pin me");
+        let verified = verify_entry(&entry, &channel()).expect("verifies");
+
+        assert_eq!(verified.author, author.public_key());
+        assert_eq!(verified.content, "pin me");
+        assert_eq!(verified.rumor_id, opened.rumor_id);
+        assert_eq!(verified.at_ms, AT_MS);
+        assert_eq!(verified.epoch, Epoch(0));
+
+        // A keyholder must not be able to pin channel X's message into Y's list.
+        let foreign = ChannelId::from_bytes([0xcdu8; 32]);
+        assert!(verify_entry(&entry, &foreign).is_none());
+
+        // Tampered keys and a re-signed seal both fail.
+        let mut bad_keys = entry.clone();
+        bad_keys.keys = format!("00{}", &entry.keys[2..]);
+        assert!(verify_entry(&bad_keys, &channel()).is_none());
+
+        let mut forged = entry.clone();
+        forged.seal.pubkey = Keys::generate().public_key();
+        assert!(verify_entry(&forged, &channel()).is_none());
+
+        // A rumor carrying a claimed id that is not its own is refused.
+        let plaintext = cord01::open_bytes(&conversation(), &opened.seal.content).expect("opens");
+        let mut value: serde_json::Value = serde_json::from_slice(&plaintext).expect("json");
+        value["id"] = serde_json::Value::String("00".repeat(32));
+
+        let raw = v2::encrypt_to_bytes_with_nonce(
+            &conversation(),
+            value.to_string().as_bytes(),
+            [0x11u8; 32],
+        )
+        .expect("encrypts");
+        let content = BASE64.encode(&raw);
+        let seal = EventBuilder::new(Kind::Custom(cord01::KIND_SEAL_ENCRYPTED), &content)
+            .custom_created_at(opened.seal.created_at)
+            .finalize(&author)
+            .expect("signs");
+
+        let lying = PinEntry {
+            keys: disclose_keys(&content, conversation().as_bytes().try_into().expect("32"))
+                .expect("discloses")
+                .to_hex(),
+            seal,
+            wrap: None,
+            edit: None,
+            extra: Extra::default(),
+        };
+        assert!(verify_entry(&lying, &channel()).is_none());
+    }
+
+    #[test]
+    fn a_proven_edit_replaces_the_words_and_a_stranger_cannot_revise() {
+        let author = Keys::generate();
+        let (entry, original) = entry_for(&author, "teh typo");
+
+        let edit = build_edit(
+            author.public_key(),
+            &channel(),
+            Epoch(0),
+            original.rumor_id,
+            "the typo, fixed",
+            AT_MS + 5_000,
+            None,
+        );
+        let (wrap, _) = seal_rumor(&edit, &group(), &author, false).expect("seals");
+        let (edit_opened, _) = open(&wrap, &group(), &channel(), Epoch(0)).expect("opens");
+
+        let refreshed = with_proven_edit(&entry, &edit_opened, &group(), &channel());
+        let verified = verify_entry(&refreshed, &channel()).expect("verifies");
+        assert_eq!(verified.content, "the typo, fixed");
+        assert_eq!(verified.edited.expect("edited").at_ms, AT_MS + 5_000);
+
+        // A stranger's edit of the same message never attaches.
+        let stranger = Keys::generate();
+        let hijack = build_edit(
+            stranger.public_key(),
+            &channel(),
+            Epoch(0),
+            original.rumor_id,
+            "hijacked",
+            AT_MS + 6_000,
+            None,
+        );
+        let (wrap, _) = seal_rumor(&hijack, &group(), &stranger, false).expect("seals");
+        let (hijack_opened, _) = open(&wrap, &group(), &channel(), Epoch(0)).expect("opens");
+
+        let unchanged = with_proven_edit(&entry, &hijack_opened, &group(), &channel());
+        assert!(unchanged.edit.is_none());
+    }
+
+    #[test]
+    fn both_list_forms_round_trip_and_obey_their_caps() {
+        let author = Keys::generate();
+        let (entry, _) = entry_for(&author, "hello");
+
+        let public =
+            publishable(&some(vec![entry.clone()]), false, &group(), Epoch(0)).expect("publishes");
+        let read = read_list(&public, |_| None);
+        assert!(!read.sealed);
+        assert_eq!(read.entries.len(), 1);
+        assert!(verify_entry(&read.entries[0], &channel()).is_some());
+
+        // A sealed list stays dark without its key, lights with it, and a wrong
+        // key reads empty rather than panicking.
+        let at_epoch_4 = channel_group_key(&SECRET, &channel(), Epoch(4)).expect("derives");
+        let sealed = publishable(&some(vec![entry.clone()]), true, &at_epoch_4, Epoch(4))
+            .expect("publishes");
+
+        let dark = read_list(&sealed, |_| None);
+        assert!(dark.sealed && dark.entries.is_empty());
+
+        let lit = read_list(&sealed, |epoch| {
+            (epoch == Epoch(4))
+                .then(|| channel_group_key(&SECRET, &channel(), Epoch(4)).expect("derives"))
+        });
+        assert!(!lit.sealed);
+        assert!(verify_entry(&lit.entries[0], &channel()).is_some());
+
+        assert!(read_list(&sealed, |_| Some(group())).entries.is_empty());
+
+        // 26 entries: the writer refuses, and a hand-built violating edition
+        // reads as empty rather than forking the chain.
+        let many = vec![entry; PIN_MAX_ENTRIES + 1];
+        assert_eq!(
+            publishable(&some(many.clone()), false, &group(), Epoch(0)),
+            Err(PinError::TooManyEntries)
+        );
+        let violating = serde_json::json!({ "entries": many }).to_string();
+        assert!(read_list(&violating, |_| None).entries.is_empty());
+
+        // Garbage never panics and never reads as a list.
+        for bad in [
+            "",
+            "not json",
+            "[]",
+            "42",
+            r#"{"entries": 7}"#,
+            r#"{"epoch":"04","sealed":"y"}"#,
+        ] {
+            let read = read_list(bad, |_| None);
+            assert!(read.entries.is_empty() && !read.sealed, "{bad}");
+        }
+    }
+
+    #[test]
+    fn a_dark_list_is_never_reformed_and_only_the_author_kills_a_pin() {
+        let author = Keys::generate();
+        let (entry, _) = entry_for(&author, "delete me later");
+
+        let dark = ReadPinList {
+            entries: vec![entry.clone()],
+            sealed: true,
+        };
+        assert_eq!(
+            publishable(&dark, false, &group(), Epoch(0)),
+            Err(PinError::Unreadable)
+        );
+
+        let verified = verify_entry(&entry, &channel()).expect("verifies");
+
+        for author_keys in [&author, &Keys::generate()] {
+            let delete = build_delete(
+                author_keys.public_key(),
+                &channel(),
+                Epoch(0),
+                verified.rumor_id,
+                Some(KIND_MESSAGE),
+                None,
+                AT_MS + 1_000,
+            );
+            let (wrap, _) = seal_rumor(&delete, &group(), author_keys, false).expect("seals");
+            let (_, rumor) = open(&wrap, &group(), &channel(), Epoch(0)).expect("opens");
+
+            assert_eq!(
+                killed_by(&verified, &rumor),
+                author_keys.public_key() == author.public_key()
+            );
+        }
+    }
+}

crates/concord/src/cords/cord05.rs

@@ -0,0 +1,954 @@
+use std::collections::BTreeMap;
+use std::collections::btree_map::Entry;
+use std::fmt;
+
+use data_encoding::BASE64URL_NOPAD;
+use nostr::nips::nip01::Coordinate;
+use nostr::nips::nip19::{Nip19, Nip19Coordinate};
+use nostr::nips::nip44::v2::ConversationKey;
+use nostr::nips::nip59::{GiftWrapBuilder, UnwrappedGift};
+use nostr_sdk::prelude::*;
+use serde::{Deserialize, Serialize};
+
+use crate::cord01::{self, NIP44_MAX_PLAINTEXT, StreamError};
+use crate::cord02::list::{canonical, union};
+use crate::cord02::{ImageRef, MAX_RELAYS};
+use crate::cord04::{TAG_SUBKIND, vsk};
+use crate::derive::{TOKEN_LEN, verify_community_id};
+use crate::{ChannelId, CommunityId, Epoch, Extra, decode_hex_32};
+
+pub const KIND_BUNDLE: u16 = 33301;
+pub const KIND_INVITE_LIST: u16 = 13303;
+pub const KIND_DIRECT_INVITE: u16 = 3313;
+pub const FRAGMENT_VERSION: u8 = 4;
+pub const MAX_BUNDLE_CHANNELS: usize = 256;
+pub const MAX_BOOTSTRAP_RELAYS: usize = 3;
+pub const MAX_BUNDLE_EPOCH: u64 = 1 << 40;
+pub const MAX_INVITE_ENTRIES: usize = 64;
+
+const FLAG_STOCK_SET: u8 = 0x01;
+const INVITE_PATH: &str = "/invite/";
+const TAG_IDENTIFIER: &str = "d";
+const TAG_EXPIRATION: &str = "expiration";
+
+const RELAY_DICT: [&str; 4] = [
+    "wss://jskitty.com/nostr",
+    "wss://asia.vectorapp.io/nostr",
+    "wss://relay.ditto.pub",
+    "wss://relay.dreamith.to",
+];
+
+#[derive(Debug)]
+pub enum InviteError {
+    Stream(StreamError),
+    Json(String),
+    BadHex(&'static str),
+    TooManyChannels(usize),
+    TooManyInvites(usize),
+    Oversize(usize),
+    Kind(u16),
+    EpochTooLarge(u64),
+    OwnerMismatch,
+    BadFragment(&'static str),
+    BadVersion(u8),
+    BadLink(&'static str),
+    BadEvent(&'static str),
+    Crypto(String),
+}
+
+impl fmt::Display for InviteError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            InviteError::Stream(error) => write!(f, "stream: {error}"),
+            InviteError::Json(error) => write!(f, "json: {error}"),
+            InviteError::BadHex(field) => write!(f, "{field} is not 32-byte lowercase hex"),
+            InviteError::TooManyChannels(count) => {
+                write!(
+                    f,
+                    "bundle carries {count} channels (cap {MAX_BUNDLE_CHANNELS})"
+                )
+            }
+            InviteError::TooManyInvites(count) => {
+                write!(
+                    f,
+                    "invite list carries {count} entries (cap {MAX_INVITE_ENTRIES})"
+                )
+            }
+            InviteError::Oversize(len) => {
+                write!(f, "invite list is {len} bytes (cap {NIP44_MAX_PLAINTEXT})")
+            }
+            InviteError::Kind(kind) => write!(f, "not an invite list kind: {kind}"),
+            InviteError::EpochTooLarge(epoch) => write!(f, "epoch {epoch} out of range"),
+            InviteError::OwnerMismatch => {
+                write!(f, "bundle owner does not reproduce its community_id")
+            }
+            InviteError::BadFragment(why) => write!(f, "bad invite fragment: {why}"),
+            InviteError::BadVersion(version) => {
+                write!(f, "unsupported invite fragment version {version}")
+            }
+            InviteError::BadLink(why) => write!(f, "bad invite link: {why}"),
+            InviteError::BadEvent(why) => write!(f, "bad invite bundle event: {why}"),
+            InviteError::Crypto(error) => write!(f, "crypto: {error}"),
+        }
+    }
+}
+
+impl std::error::Error for InviteError {}
+
+impl From<StreamError> for InviteError {
+    fn from(error: StreamError) -> Self {
+        InviteError::Stream(error)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct ChannelGrant {
+    pub id: ChannelId,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub key: Option<String>,
+    pub epoch: Epoch,
+    #[serde(default)]
+    pub name: String,
+    #[serde(flatten)]
+    pub extra: Extra,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct CommunityInvite {
+    pub community_id: CommunityId,
+    pub owner: PublicKey,
+    pub owner_salt: String,
+    pub community_root: String,
+    pub root_epoch: Epoch,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub control_pk: Option<PublicKey>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub channels: Vec<ChannelGrant>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub relays: Vec<String>,
+    pub name: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub icon: Option<ImageRef>,
+    /// Unix **ms**: past it the preview still renders, joining refuses.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub expires_at: Option<u64>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub creator_npub: Option<PublicKey>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub label: Option<String>,
+    #[serde(flatten)]
+    pub extra: Extra,
+}
+
+impl CommunityInvite {
+    pub fn from_bundle_json(json: &str) -> Result<Self, InviteError> {
+        let mut invite: Self =
+            serde_json::from_str(json).map_err(|error| InviteError::Json(error.to_string()))?;
+
+        if invite.channels.len() > MAX_BUNDLE_CHANNELS {
+            return Err(InviteError::TooManyChannels(invite.channels.len()));
+        }
+
+        invite.relays.truncate(MAX_RELAYS);
+        invite.validate()?;
+
+        Ok(invite)
+    }
+
+    pub fn validate(&self) -> Result<(), InviteError> {
+        if self.channels.len() > MAX_BUNDLE_CHANNELS {
+            return Err(InviteError::TooManyChannels(self.channels.len()));
+        }
+
+        for epoch in std::iter::once(self.root_epoch).chain(self.channels.iter().map(|c| c.epoch)) {
+            if epoch.0 > MAX_BUNDLE_EPOCH {
+                return Err(InviteError::EpochTooLarge(epoch.0));
+            }
+        }
+
+        let owner_salt = hex32(&self.owner_salt, "owner_salt")?;
+        hex32(&self.community_root, "community_root")?;
+
+        for channel in &self.channels {
+            if let Some(key) = &channel.key {
+                hex32(key, "channel key")?;
+            }
+        }
+
+        if !verify_community_id(&self.community_id, &self.owner.to_bytes(), &owner_salt) {
+            return Err(InviteError::OwnerMismatch);
+        }
+
+        Ok(())
+    }
+
+    pub fn expired(&self, now_ms: u64) -> bool {
+        self.expires_at.is_some_and(|expires| now_ms > expires)
+    }
+}
+
+#[derive(Debug, Clone)]
+pub enum BundleState {
+    Live(Box<CommunityInvite>),
+    Revoked,
+}
+
+pub fn build_bundle_event(
+    link_signer: &Keys,
+    invite: &CommunityInvite,
+    bundle_key: &[u8; 32],
+) -> Result<Event, InviteError> {
+    invite.validate()?;
+
+    let json = serde_json::to_string(invite).map_err(json_error)?;
+    let content = seal_bundle(bundle_key, &json)?;
+
+    EventBuilder::new(Kind::Custom(KIND_BUNDLE), content)
+        .tags([empty_identifier(), subkind_tag(vsk::INVITE_LIVE)])
+        .finalize(link_signer)
+        .map_err(crypto_error)
+}
+
+pub fn build_revocation(link_signer: &Keys) -> Result<Event, InviteError> {
+    EventBuilder::new(Kind::Custom(KIND_BUNDLE), "")
+        .tags([empty_identifier(), subkind_tag(vsk::INVITE_REVOKED)])
+        .finalize(link_signer)
+        .map_err(crypto_error)
+}
+
+pub fn parse_bundle_event(
+    event: &Event,
+    expected_signer: &PublicKey,
+    bundle_key: &[u8; 32],
+) -> Result<BundleState, InviteError> {
+    if event.kind.as_u16() != KIND_BUNDLE {
+        return Err(InviteError::BadEvent("wrong kind"));
+    }
+
+    if event.pubkey != *expected_signer {
+        return Err(InviteError::BadEvent("author is not the link signer"));
+    }
+
+    if first_tag(event, TAG_IDENTIFIER).is_some_and(|identifier| !identifier.is_empty()) {
+        return Err(InviteError::BadEvent(
+            "bundle is not at the link's coordinate",
+        ));
+    }
+
+    event
+        .verify()
+        .map_err(|_| InviteError::BadEvent("signature invalid"))?;
+
+    match first_tag(event, TAG_SUBKIND).as_deref() {
+        Some(vsk::INVITE_REVOKED) => return Ok(BundleState::Revoked),
+        Some(vsk::INVITE_LIVE) => {}
+        _ => return Err(InviteError::BadEvent("unknown or missing bundle marker")),
+    }
+
+    let json = open_bundle(bundle_key, &event.content)?;
+
+    Ok(BundleState::Live(Box::new(
+        CommunityInvite::from_bundle_json(&json)?,
+    )))
+}
+
+pub fn stock_relays() -> Vec<String> {
+    RELAY_DICT.iter().map(|relay| relay.to_string()).collect()
+}
+
+pub fn encode_fragment(token: &[u8; TOKEN_LEN], relays: &[String]) -> Result<String, InviteError> {
+    let stock = relays == RELAY_DICT;
+
+    let mut bytes = Vec::with_capacity(2 + TOKEN_LEN + relays.len() * 8);
+    bytes.push(FRAGMENT_VERSION);
+
+    if stock {
+        bytes.push(FLAG_STOCK_SET);
+    } else {
+        bytes.push(0x00);
+
+        let bounded = &relays[..relays.len().min(MAX_BOOTSTRAP_RELAYS)];
+        bytes.push(bounded.len() as u8);
+
+        for relay in bounded {
+            match dict_id(relay) {
+                Some(id) => bytes.push(id),
+                None => {
+                    let (lead, literal) = match relay.strip_prefix("wss://") {
+                        Some(host) => (0x00, host),
+                        None => (0xff, relay.as_str()),
+                    };
+
+                    if literal.len() > u8::MAX as usize {
+                        return Err(InviteError::BadFragment("relay too long"));
+                    }
+
+                    bytes.extend_from_slice(&[lead, literal.len() as u8]);
+                    bytes.extend_from_slice(literal.as_bytes());
+                }
+            }
+        }
+    }
+
+    bytes.extend_from_slice(token);
+
+    Ok(BASE64URL_NOPAD.encode(&bytes))
+}
+
+pub fn decode_fragment(fragment: &str) -> Result<([u8; TOKEN_LEN], Vec<String>), InviteError> {
+    let bytes = BASE64URL_NOPAD
+        .decode(fragment.trim().as_bytes())
+        .map_err(|_| InviteError::BadFragment("not base64url"))?;
+
+    let version = *bytes.first().ok_or(InviteError::BadFragment("truncated"))?;
+
+    if version != FRAGMENT_VERSION {
+        return Err(InviteError::BadVersion(version));
+    }
+
+    let flags = *bytes.get(1).ok_or(InviteError::BadFragment("truncated"))?;
+
+    let mut offset = 2;
+    let mut relays = Vec::new();
+
+    if flags & FLAG_STOCK_SET != 0 {
+        relays = stock_relays();
+    } else {
+        let count = *bytes
+            .get(offset)
+            .ok_or(InviteError::BadFragment("truncated"))? as usize;
+        offset += 1;
+
+        if count > MAX_BOOTSTRAP_RELAYS {
+            return Err(InviteError::BadFragment("too many bootstrap relays"));
+        }
+
+        for _ in 0..count {
+            let lead = *bytes
+                .get(offset)
+                .ok_or(InviteError::BadFragment("truncated"))?;
+            offset += 1;
+
+            if (1..=254).contains(&lead) {
+                if let Some(url) = dict_url(lead) {
+                    relays.push(url.to_string());
+                }
+
+                continue;
+            }
+
+            let len = *bytes
+                .get(offset)
+                .ok_or(InviteError::BadFragment("truncated"))? as usize;
+            offset += 1;
+
+            let end = offset
+                .checked_add(len)
+                .ok_or(InviteError::BadFragment("truncated"))?;
+
+            let raw = bytes
+                .get(offset..end)
+                .ok_or(InviteError::BadFragment("truncated"))?;
+
+            let text = std::str::from_utf8(raw)
+                .map_err(|_| InviteError::BadFragment("relay is not utf8"))?;
+
+            relays.push(match lead {
+                0x00 => format!("wss://{text}"),
+                0xff => text.to_string(),
+                _ => return Err(InviteError::BadFragment("unknown relay lead byte")),
+            });
+
+            offset = end;
+        }
+    }
+
+    let end = offset
+        .checked_add(TOKEN_LEN)
+        .ok_or(InviteError::BadFragment("truncated"))?;
+
+    let raw = bytes
+        .get(offset..end)
+        .ok_or(InviteError::BadFragment("truncated"))?;
+
+    if end != bytes.len() {
+        return Err(InviteError::BadFragment("trailing bytes"));
+    }
+
+    let mut token = [0u8; TOKEN_LEN];
+    token.copy_from_slice(raw);
+
+    Ok((token, relays))
+}
+
+pub fn bundle_naddr(link_signer: &PublicKey) -> Result<String, InviteError> {
+    let coordinate = Coordinate {
+        kind: Kind::Custom(KIND_BUNDLE),
+        public_key: *link_signer,
+        identifier: String::new(),
+    };
+
+    Nip19::Coordinate(Nip19Coordinate {
+        coordinate,
+        relays: Vec::new(),
+    })
+    .to_bech32()
+    .map_err(|_| InviteError::BadLink("invalid naddr"))
+}
+
+pub fn build_invite_url(
+    base: &str,
+    link_signer: &PublicKey,
+    token: &[u8; TOKEN_LEN],
+    relays: &[String],
+) -> Result<String, InviteError> {
+    let naddr = bundle_naddr(link_signer)?;
+    let fragment = encode_fragment(token, relays)?;
+
+    Ok(format!(
+        "{}{INVITE_PATH}{naddr}#{fragment}",
+        base.trim_end_matches('/')
+    ))
+}
+
+#[derive(Debug, Clone)]
+pub struct ParsedInviteLink {
+    /// The bundle coordinate's author.
+    pub link_signer: PublicKey,
+    pub token: [u8; TOKEN_LEN],
+    pub bootstrap_relays: Vec<String>,
+    /// The bare naddr as it appeared in the link, for the fetch.
+    pub naddr: String,
+}
+
+pub fn parse_link(input: &str) -> Result<ParsedInviteLink, InviteError> {
+    let (locator, fragment) = input
+        .trim()
+        .split_once('#')
+        .ok_or(InviteError::BadLink("no fragment"))?;
+
+    if fragment.is_empty() {
+        return Err(InviteError::BadLink("empty fragment"));
+    }
+
+    let naddr = match locator.find(INVITE_PATH) {
+        Some(index) => locator[index + INVITE_PATH.len()..].trim_end_matches('/'),
+        None => locator.trim_start_matches("nostr:"),
+    };
+
+    let link_signer = signer_from_naddr(naddr)?;
+    let (token, bootstrap_relays) = decode_fragment(fragment)?;
+
+    Ok(ParsedInviteLink {
+        link_signer,
+        token,
+        bootstrap_relays,
+        naddr: naddr.to_string(),
+    })
+}
+
+pub fn build_direct_invite(
+    inviter: &Keys,
+    recipient: &PublicKey,
+    invite: &CommunityInvite,
+) -> Result<Event, InviteError> {
+    invite.validate()?;
+
+    let json = serde_json::to_string(invite).map_err(json_error)?;
+    let rumor = EventBuilder::new(Kind::Custom(KIND_DIRECT_INVITE), json)
+        .finalize_unsigned(inviter.public_key());
+
+    let mut tags = vec![Tag::custom("k", [KIND_DIRECT_INVITE.to_string()])];
+
+    if let Some(expires_at) = invite.expires_at {
+        tags.push(Tag::custom(
+            TAG_EXPIRATION,
+            [(expires_at / 1000).to_string()],
+        ));
+    }
+
+    GiftWrapBuilder::new(*recipient, rumor)
+        .extra_tags(tags)
+        .finalize(inviter)
+        .map_err(crypto_error)
+}
+
+pub fn unwrap_direct_invite(
+    wrap: &Event,
+    recipient: &Keys,
+) -> Result<(PublicKey, CommunityInvite), InviteError> {
+    let unwrapped = UnwrappedGift::from_gift_wrap(recipient, wrap).map_err(crypto_error)?;
+
+    if unwrapped.rumor.kind.as_u16() != KIND_DIRECT_INVITE {
+        return Err(InviteError::BadEvent("rumor is not a direct invite"));
+    }
+
+    Ok((
+        unwrapped.sender,
+        CommunityInvite::from_bundle_json(&unwrapped.rumor.content)?,
+    ))
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct InviteEntry {
+    /// The link's unlock secret, and its merge key.
+    pub token: String,
+    /// The `link_signer` secret: refreshing or retiring the bundle needs it.
+    pub signer_sk: String,
+    pub community_id: CommunityId,
+    pub url: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub label: Option<String>,
+    pub created_at: u64,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub expires_at: Option<u64>,
+    #[serde(flatten)]
+    pub extra: Extra,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct InviteTombstone {
+    pub token: String,
+    pub community_id: CommunityId,
+    #[serde(flatten)]
+    pub extra: Extra,
+}
+
+/// A creator's own link bookkeeping.
+#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
+pub struct InviteList {
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub entries: Vec<InviteEntry>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub tombstones: Vec<InviteTombstone>,
+    #[serde(flatten)]
+    pub extra: Extra,
+}
+
+impl InviteList {
+    /// A tombstone beats an entry terminally, so a stale device can never resurrect a revoked link.
+    pub fn is_live(&self, token: &str) -> bool {
+        self.entries.iter().any(|entry| entry.token == token)
+            && !self
+                .tombstones
+                .iter()
+                .any(|tombstone| tombstone.token == token)
+    }
+
+    pub fn fits(&self) -> Result<(), InviteError> {
+        if self.entries.len() > MAX_INVITE_ENTRIES {
+            return Err(InviteError::TooManyInvites(self.entries.len()));
+        }
+
+        let json = serde_json::to_string(self).map_err(json_error)?;
+
+        if json.len() > NIP44_MAX_PLAINTEXT {
+            return Err(InviteError::Oversize(json.len()));
+        }
+
+        Ok(())
+    }
+}
+
+pub fn merge_invite_lists(held: InviteList, incoming: InviteList) -> InviteList {
+    let mut entries: BTreeMap<String, InviteEntry> = BTreeMap::new();
+
+    for entry in held.entries.into_iter().chain(incoming.entries) {
+        match entries.entry(entry.token.clone()) {
+            Entry::Vacant(slot) => {
+                slot.insert(entry);
+            }
+            Entry::Occupied(mut slot) => {
+                let merged = merge_entry(slot.get(), &entry);
+                *slot.get_mut() = merged;
+            }
+        }
+    }
+
+    let mut tombstones: BTreeMap<String, InviteTombstone> = BTreeMap::new();
+
+    for tombstone in held.tombstones.into_iter().chain(incoming.tombstones) {
+        match tombstones.entry(tombstone.token.clone()) {
+            Entry::Vacant(slot) => {
+                slot.insert(tombstone);
+            }
+            Entry::Occupied(mut slot) => {
+                if canonical(&tombstone) < canonical(slot.get()) {
+                    *slot.get_mut() = tombstone;
+                }
+            }
+        }
+    }
+
+    let mut extra = held.extra;
+    union(&mut extra, incoming.extra);
+
+    InviteList {
+        entries: entries.into_values().collect(),
+        tombstones: tombstones.into_values().collect(),
+        extra,
+    }
+}
+
+pub fn build_invite_list(keys: &Keys, list: &InviteList) -> Result<Event, InviteError> {
+    list.fits()?;
+
+    let json = serde_json::to_string(list).map_err(json_error)?;
+    let content = cord01::seal_to_self(keys, json.as_bytes())?;
+
+    EventBuilder::new(Kind::Custom(KIND_INVITE_LIST), content)
+        .finalize(keys)
+        .map_err(crypto_error)
+}
+
+pub fn parse_invite_list(keys: &Keys, event: &Event) -> Result<InviteList, InviteError> {
+    if event.kind.as_u16() != KIND_INVITE_LIST {
+        return Err(InviteError::Kind(event.kind.as_u16()));
+    }
+
+    let json = cord01::open_to_self(keys, &event.content)?;
+
+    serde_json::from_slice(&json).map_err(json_error)
+}
+
+/// An entry is immutable once minted, so two copies should agree.
+fn merge_entry(held: &InviteEntry, incoming: &InviteEntry) -> InviteEntry {
+    let (winner, loser) = if canonical(incoming) < canonical(held) {
+        (incoming, held)
+    } else {
+        (held, incoming)
+    };
+
+    let mut merged = winner.clone();
+    union(&mut merged.extra, loser.extra.clone());
+
+    merged
+}
+
+fn seal_bundle(bundle_key: &[u8; 32], json: &str) -> Result<String, InviteError> {
+    Ok(cord01::seal_bytes(
+        &ConversationKey::new(*bundle_key),
+        json.as_bytes(),
+    )?)
+}
+
+fn open_bundle(bundle_key: &[u8; 32], content: &str) -> Result<String, InviteError> {
+    let plaintext = cord01::open_bytes(&ConversationKey::new(*bundle_key), content)?;
+
+    String::from_utf8(plaintext).map_err(|_| InviteError::BadFragment("bundle is not utf8"))
+}
+
+fn signer_from_naddr(naddr: &str) -> Result<PublicKey, InviteError> {
+    match Nip19::from_bech32(naddr.trim_start_matches("nostr:")) {
+        Ok(Nip19::Coordinate(coordinate))
+            if coordinate.coordinate.kind.as_u16() == KIND_BUNDLE
+                && coordinate.coordinate.identifier.is_empty() =>
+        {
+            Ok(coordinate.coordinate.public_key)
+        }
+        _ => Err(InviteError::BadLink(
+            "naddr is not an invite-bundle coordinate",
+        )),
+    }
+}
+
+fn hex32(value: &str, field: &'static str) -> Result<[u8; 32], InviteError> {
+    decode_hex_32(value).map_err(|_| InviteError::BadHex(field))
+}
+
+fn dict_id(relay: &str) -> Option<u8> {
+    RELAY_DICT
+        .iter()
+        .position(|known| *known == relay)
+        .map(|index| index as u8 + 1)
+}
+
+fn dict_url(id: u8) -> Option<&'static str> {
+    RELAY_DICT.get(id.checked_sub(1)? as usize).copied()
+}
+
+fn empty_identifier() -> Tag {
+    Tag::identifier("")
+}
+
+fn subkind_tag(value: &str) -> Tag {
+    Tag::custom(TAG_SUBKIND, [value])
+}
+
+fn first_tag(event: &Event, name: &str) -> Option<String> {
+    event.tags.iter().find_map(|tag| {
+        let fields = tag.as_slice();
+
+        (fields.len() >= 2 && fields[0] == name).then(|| fields[1].clone())
+    })
+}
+
+fn json_error(error: serde_json::Error) -> InviteError {
+    InviteError::Json(error.to_string())
+}
+
+fn crypto_error(error: impl fmt::Display) -> InviteError {
+    InviteError::Crypto(error.to_string())
+}
+
+#[cfg(test)]
+mod tests {
+    use data_encoding::HEXLOWER;
+
+    use super::*;
+    use crate::derive::{community_id_of, invite_bundle_key};
+
+    const SALT: [u8; 32] = [0x33u8; 32];
+
+    fn bundle() -> CommunityInvite {
+        let owner = Keys::generate();
+
+        CommunityInvite {
+            community_id: community_id_of(&owner.public_key().to_bytes(), &SALT),
+            owner: owner.public_key(),
+            owner_salt: HEXLOWER.encode(&SALT),
+            community_root: "44".repeat(32),
+            root_epoch: Epoch(0),
+            control_pk: None,
+            channels: vec![ChannelGrant {
+                id: ChannelId::from_bytes([0x9cu8; 32]),
+                key: Some("55".repeat(32)),
+                epoch: Epoch(1),
+                name: "lounge".to_owned(),
+                extra: Extra::default(),
+            }],
+            relays: vec!["wss://relay.example".to_owned()],
+            name: "Test community".to_owned(),
+            icon: None,
+            expires_at: None,
+            creator_npub: None,
+            label: None,
+            extra: Extra::default(),
+        }
+    }
+
+    fn token16() -> [u8; TOKEN_LEN] {
+        std::array::from_fn(|i| i as u8)
+    }
+
+    #[test]
+    fn fragment_goldens_pin_the_wire_layout() {
+        let token = token16();
+
+        // [04 version][01 stock flag][token 00..0f]
+        let stock = encode_fragment(&token, &stock_relays()).expect("encodes");
+        assert_eq!(stock, "BAEAAQIDBAUGBwgJCgsMDQ4P");
+        assert_eq!(
+            decode_fragment(&stock).expect("decodes"),
+            (token, stock_relays())
+        );
+
+        // [04][00 flags][02 count][02 dict-id][04 dict-id][token 00..0f]
+        let mixed = vec![RELAY_DICT[1].to_owned(), RELAY_DICT[3].to_owned()];
+        let encoded = encode_fragment(&token, &mixed).expect("encodes");
+        assert_eq!(encoded, "BAACAgQAAQIDBAUGBwgJCgsMDQ4P");
+        assert_eq!(decode_fragment(&encoded).expect("decodes"), (token, mixed));
+
+        // [04][00][01 count][ff verbatim lead][06 len]["ws://h"][token 00..0f]
+        let verbatim = vec!["ws://h".to_owned()];
+        let encoded = encode_fragment(&token, &verbatim).expect("encodes");
+        assert_eq!(encoded, "BAAB_wZ3czovL2gAAQIDBAUGBwgJCgsMDQ4P");
+        assert_eq!(
+            decode_fragment(&encoded).expect("decodes"),
+            (token, verbatim)
+        );
+    }
+
+    #[test]
+    fn a_fragment_is_strict_about_framing_and_counts() {
+        let token = token16();
+
+        for version in [3u8, 5] {
+            let mut bytes = vec![version, FLAG_STOCK_SET];
+            bytes.extend_from_slice(&token);
+            let encoded = BASE64URL_NOPAD.encode(&bytes);
+            assert!(
+                matches!(decode_fragment(&encoded), Err(InviteError::BadVersion(v)) if v == version),
+                "a legacy and a future version are both refused"
+            );
+        }
+
+        let mut trailing = vec![FRAGMENT_VERSION, FLAG_STOCK_SET];
+        trailing.extend_from_slice(&token);
+        trailing.push(0xff);
+        assert!(matches!(
+            decode_fragment(&BASE64URL_NOPAD.encode(&trailing)),
+            Err(InviteError::BadFragment(_))
+        ));
+
+        let mut over = vec![FRAGMENT_VERSION, 0x00, 0x04, 1, 2, 3, 4];
+        over.extend_from_slice(&token);
+        assert!(matches!(
+            decode_fragment(&BASE64URL_NOPAD.encode(&over)),
+            Err(InviteError::BadFragment(_))
+        ));
+
+        // An unknown dictionary id is skipped, not fatal, so the dictionary can grow.
+        let mut unknown = vec![FRAGMENT_VERSION, 0x00, 0x01, 200];
+        unknown.extend_from_slice(&token);
+        let (decoded, relays) =
+            decode_fragment(&BASE64URL_NOPAD.encode(&unknown)).expect("decodes");
+        assert_eq!(decoded, token);
+        assert!(relays.is_empty());
+    }
+
+    #[test]
+    fn a_link_round_trips_and_refuses_a_non_invite() {
+        let link_signer = Keys::generate();
+        let token = token16();
+        let relays = vec!["wss://a.example".to_owned()];
+
+        let url = build_invite_url(
+            "https://vectorapp.io/",
+            &link_signer.public_key(),
+            &token,
+            &relays,
+        )
+        .expect("builds");
+
+        let parsed = parse_link(&url).expect("parses");
+        assert_eq!(parsed.link_signer, link_signer.public_key());
+        assert_eq!(parsed.token, token);
+        assert_eq!(parsed.bootstrap_relays, relays);
+
+        let fragment = url.split('#').nth(1).expect("carries a fragment");
+        let bare = format!("{}#{fragment}", parsed.naddr);
+        let reparsed = parse_link(&bare).expect("parses the domain-agnostic form");
+        assert_eq!(reparsed.link_signer, link_signer.public_key());
+        assert_eq!(reparsed.token, token);
+
+        assert!(
+            parse_link("https://x/invite/#frag").is_err(),
+            "the naddr is not optional"
+        );
+    }
+
+    #[test]
+    fn a_bundle_round_trips_while_a_revocation_reads_as_revoked() {
+        let invite = bundle();
+        let link_signer = Keys::generate();
+        let key = invite_bundle_key(&[7u8; TOKEN_LEN]);
+
+        let event = build_bundle_event(&link_signer, &invite, &key).expect("builds");
+        assert_eq!(event.pubkey, link_signer.public_key());
+
+        match parse_bundle_event(&event, &link_signer.public_key(), &key).expect("parses") {
+            BundleState::Live(opened) => {
+                assert_eq!(opened.community_id, invite.community_id);
+                assert_eq!(opened.channels.len(), 1);
+            }
+            BundleState::Revoked => panic!("expected a live bundle"),
+        }
+
+        let revocation = build_revocation(&link_signer).expect("builds");
+        assert!(matches!(
+            parse_bundle_event(&revocation, &link_signer.public_key(), &key),
+            Ok(BundleState::Revoked)
+        ));
+
+        // The token is the only way in, and a squatter is a different coordinate.
+        assert!(
+            parse_bundle_event(
+                &event,
+                &link_signer.public_key(),
+                &invite_bundle_key(&[8u8; TOKEN_LEN])
+            )
+            .is_err()
+        );
+        let squatter = Keys::generate();
+        assert!(matches!(
+            parse_bundle_event(&event, &squatter.public_key(), &key),
+            Err(InviteError::BadEvent(_))
+        ));
+    }
+
+    #[test]
+    fn a_bundle_off_its_coordinate_or_off_its_owner_is_refused() {
+        let invite = bundle();
+        let link_signer = Keys::generate();
+        let key = invite_bundle_key(&[9u8; TOKEN_LEN]);
+        let json = serde_json::to_string(&invite).expect("serializes");
+        let content = seal_bundle(&key, &json).expect("seals");
+
+        // The fetch filters on the author, so the empty `d` is pinned here: a
+        // signature-valid event of the same author at another `d` is not the bundle.
+        let elsewhere = EventBuilder::new(Kind::Custom(KIND_BUNDLE), content)
+            .tags([Tag::identifier("elsewhere"), subkind_tag(vsk::INVITE_LIVE)])
+            .finalize(&link_signer)
+            .expect("signs");
+        assert!(matches!(
+            parse_bundle_event(&elsewhere, &link_signer.public_key(), &key),
+            Err(InviteError::BadEvent(_))
+        ));
+
+        let mut forged = bundle();
+        forged.owner = Keys::generate().public_key();
+        assert!(matches!(forged.validate(), Err(InviteError::OwnerMismatch)));
+        assert!(matches!(
+            build_bundle_event(&link_signer, &forged, &key),
+            Err(InviteError::OwnerMismatch)
+        ));
+
+        let mut malformed = bundle();
+        malformed.community_root = "not hex".to_owned();
+        assert!(matches!(malformed.validate(), Err(InviteError::BadHex(_))));
+
+        let mut crowded = bundle();
+        crowded.channels = (0..=MAX_BUNDLE_CHANNELS)
+            .map(|_| ChannelGrant {
+                id: ChannelId::from_bytes([0x01; 32]),
+                key: None,
+                epoch: Epoch(0),
+                name: String::new(),
+                extra: Extra::default(),
+            })
+            .collect();
+        assert!(matches!(
+            crowded.validate(),
+            Err(InviteError::TooManyChannels(n)) if n == MAX_BUNDLE_CHANNELS + 1
+        ));
+    }
+
+    #[test]
+    fn a_direct_invite_round_trips_and_refuses_a_foreign_rumor() {
+        let inviter = Keys::generate();
+        let recipient = Keys::generate();
+        let invite = bundle();
+
+        let wrap = build_direct_invite(&inviter, &recipient.public_key(), &invite).expect("builds");
+        assert_eq!(wrap.kind, Kind::GiftWrap);
+        assert_ne!(
+            wrap.pubkey,
+            inviter.public_key(),
+            "the wrap author is ephemeral"
+        );
+        assert!(
+            wrap.tags.iter().any(|tag| tag.as_slice() == ["k", "3313"]),
+            "the k tag is what makes an invite indexable"
+        );
+
+        let (sender, opened) = unwrap_direct_invite(&wrap, &recipient).expect("unwraps");
+        assert_eq!(sender, inviter.public_key());
+        assert_eq!(opened.community_id, invite.community_id);
+
+        // Somebody else's wrap is not ours to open...
+        let stranger = Keys::generate();
+        assert!(unwrap_direct_invite(&wrap, &stranger).is_err());
+
+        // ...and a wrap that opens to some other kind is not an invite.
+        let rumor = EventBuilder::new(Kind::Custom(crate::cord03::KIND_MESSAGE), "hello")
+            .finalize_unsigned(recipient.public_key());
+        let wrap = GiftWrapBuilder::new(recipient.public_key(), rumor)
+            .finalize(&recipient)
+            .expect("wraps");
+        assert!(matches!(
+            unwrap_direct_invite(&wrap, &recipient),
+            Err(InviteError::BadEvent(_))
+        ));
+    }
+}

crates/concord/src/cords/mod.rs

@@ -0,0 +1,9 @@
+//! One module per CORD document. CORD-07 (audio/video) is unimplemented, and
+//! CORD-08's timer rides the Chat and Control planes it edits rather than owning a file.
+
+pub mod cord01;
+pub mod cord02;
+pub mod cord03;
+pub mod cord04;
+pub mod cord05;
+pub mod cord06;

crates/concord/src/lib.rs

@@ -0,0 +1,12 @@
+mod cords;
+mod types;
+mod utils;
+
+pub mod store;
+
+pub use cords::{cord01, cord02, cord03, cord04, cord05, cord06};
+pub use types::{ChannelId, CommunityId, Epoch, RoleId};
+pub use utils::derive::{self, GroupKey};
+
+pub(crate) use types::Extra;
+pub(crate) use utils::{decode_hex_32, decode_hex_lower, fill_random, random_32};

crates/concord/src/store.rs

@@ -0,0 +1,491 @@
+use std::cmp::Reverse;
+use std::collections::{BTreeMap, BTreeSet};
+use std::sync::LazyLock;
+
+use anyhow::{Result, anyhow};
+use nostr_sdk::prelude::*;
+use serde::{Deserialize, Serialize};
+
+use crate::cord01::{KIND_WRAP_EPHEMERAL, OpenedStream};
+use crate::cord02::{
+    ChannelMetadata, CommunityGenesis, CommunityMetadata, ControlFold, ROOT_EPOCH,
+};
+use crate::cord03::{self, ChatRumor, plane_keys};
+use crate::cord04::{EntityHead, Floors, ParsedEdition, vsk};
+use crate::derive::control_signer_group_key;
+use crate::{ChannelId, CommunityId, Epoch, GroupKey};
+
+static LOCAL_KEYS: LazyLock<Keys> = LazyLock::new(Keys::generate);
+
+const MAX_PAGES: usize = 8;
+const CHANNEL_TAG: SingleLetterTag = SingleLetterTag::LOWERCASE_C;
+const MARK_TAG: SingleLetterTag = SingleLetterTag::LOWERCASE_T;
+const MARK_VALUE: &str = "concord";
+const WRAP_TAG: &str = "e";
+const KIND_TAG: &str = "k";
+const STATE_PREFIX: &str = "concord/";
+
+/// An already-expired rumor is refused at ingest. Returns whether it was kept.
+pub async fn cache_rumor(
+    client: &Client,
+    channel: &ChannelId,
+    opened: &OpenedStream,
+) -> Result<bool> {
+    let at = Timestamp::from_secs(opened.at_ms / 1000);
+
+    if cord03::expiration_of(&opened.rumor)?
+        .is_some_and(|expiration| expiration <= Timestamp::now())
+    {
+        return Ok(false);
+    }
+
+    let tags = vec![
+        Tag::identifier(opened.rumor_id),
+        Tag::custom(KIND_TAG, [opened.rumor.kind.to_string()]),
+        Tag::custom(WRAP_TAG, [opened.wrapper_id.to_string()]),
+        Tag::custom(MARK_TAG.as_str(), [MARK_VALUE]),
+        Tag::custom(CHANNEL_TAG.as_str(), [channel.to_hex()]),
+        Tag::public_key(opened.author),
+    ];
+
+    let event = EventBuilder::new(Kind::ApplicationSpecificData, opened.rumor.as_json())
+        .tags(tags)
+        .custom_created_at(at)
+        .finalize_async(&*LOCAL_KEYS)
+        .await?;
+
+    client.database().save_event(&event).await?;
+
+    Ok(true)
+}
+
+pub async fn purge_expired(client: &Client, channel: &ChannelId, now: Timestamp) -> Result<usize> {
+    let filter = Filter::new()
+        .kind(Kind::ApplicationSpecificData)
+        .custom_tag(MARK_TAG, MARK_VALUE)
+        .custom_tag(CHANNEL_TAG, channel.to_hex());
+
+    let mut expired = Vec::new();
+
+    for event in client.database().query(filter).await? {
+        let Ok(rumor) = UnsignedEvent::from_json(&event.content) else {
+            continue;
+        };
+
+        let Ok(Some(expiration)) = cord03::expiration_of(&rumor) else {
+            continue;
+        };
+
+        if expiration <= now {
+            expired.push(event.id);
+        }
+    }
+
+    let purged = expired.len();
+
+    if purged > 0 {
+        client.database().delete(Filter::new().ids(expired)).await?;
+    }
+
+    Ok(purged)
+}
+
+pub async fn query_rumors(
+    database: &dyn NostrDatabase,
+    channel: &ChannelId,
+    until: Option<Timestamp>,
+    limit: usize,
+) -> Result<Vec<UnsignedEvent>> {
+    let mut filter = Filter::new()
+        .kind(Kind::ApplicationSpecificData)
+        .custom_tag(MARK_TAG, MARK_VALUE)
+        .custom_tag(CHANNEL_TAG, channel.to_hex());
+
+    if let Some(until) = until {
+        filter = filter.until(until);
+    }
+
+    let mut newest: BTreeMap<String, Event> = BTreeMap::new();
+    for event in database.query(filter).await? {
+        let Some(rumor_id) = event.tags.identifier() else {
+            continue;
+        };
+
+        match newest.get(&rumor_id) {
+            Some(existing) if existing.created_at >= event.created_at => {}
+            _ => {
+                newest.insert(rumor_id, event);
+            }
+        }
+    }
+
+    let mut events: Vec<Event> = newest.into_values().collect();
+    events.sort_by_key(|event| std::cmp::Reverse(event.created_at));
+    events.truncate(limit);
+
+    let mut rumors = Vec::with_capacity(events.len());
+    for event in events {
+        let rumor = UnsignedEvent::from_json(event.content)
+            .map_err(|error| anyhow!("cached rumor is not a valid event: {error}"))?;
+        rumors.push(rumor);
+    }
+
+    Ok(rumors)
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct ChannelKeyRef {
+    pub id: ChannelId,
+    pub name: String,
+    pub private: bool,
+    pub epoch: Epoch,
+}
+
+/// One local document per community, keyed by `concord/<community_id>`.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct CommunityState {
+    pub id: CommunityId,
+    pub owner: PublicKey,
+    pub owner_salt: [u8; 32],
+    pub community_root: [u8; 32],
+    pub root_epoch: Epoch,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub control_root: Option<[u8; 32]>,
+    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+    pub control_pks: BTreeMap<u64, PublicKey>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub channels: Vec<ChannelKeyRef>,
+    pub relays: Vec<RelayUrl>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub heads: Vec<EntityHead>,
+    #[serde(default, skip_serializing_if = "BTreeSet::is_empty")]
+    pub banned: BTreeSet<PublicKey>,
+    #[serde(default)]
+    pub dissolved: bool,
+    pub added_at_ms: u64,
+}
+
+impl CommunityState {
+    pub fn from_genesis(
+        genesis: &CommunityGenesis,
+        editions: &[ParsedEdition],
+        added_at_ms: u64,
+    ) -> Result<Self> {
+        let mut channels = Vec::new();
+        let mut heads = Vec::with_capacity(editions.len());
+        let mut relays = Vec::new();
+
+        for edition in editions {
+            heads.push(EntityHead {
+                entity: edition.entity,
+                version: edition.version,
+                self_hash: edition.self_hash,
+                rumor_id: edition.rumor_id,
+            });
+
+            match edition.subkind.as_str() {
+                vsk::COMMUNITY_METADATA => {
+                    let metadata: CommunityMetadata = serde_json::from_str(&edition.content)?;
+                    relays.extend(
+                        metadata
+                            .relays
+                            .iter()
+                            .filter_map(|relay| RelayUrl::parse(relay).ok()),
+                    );
+                }
+                vsk::CHANNEL_METADATA => {
+                    let metadata: ChannelMetadata = serde_json::from_str(&edition.content)?;
+                    channels.push(ChannelKeyRef {
+                        id: ChannelId::from_bytes(edition.entity),
+                        name: metadata.name,
+                        private: metadata.private,
+                        epoch: ROOT_EPOCH,
+                    });
+                }
+                _ => {}
+            }
+        }
+
+        let control_pks = BTreeMap::from([(
+            ROOT_EPOCH.0,
+            control_signer_group_key(
+                &genesis.control_root,
+                &genesis.identity.community_id,
+                ROOT_EPOCH,
+            )?
+            .pk(),
+        )]);
+
+        Ok(Self {
+            id: genesis.identity.community_id,
+            owner: genesis.identity.owner,
+            owner_salt: genesis.identity.owner_salt,
+            community_root: genesis.community_root,
+            root_epoch: ROOT_EPOCH,
+            control_root: Some(genesis.control_root),
+            control_pks,
+            channels,
+            relays,
+            heads,
+            banned: BTreeSet::new(),
+            dissolved: false,
+            added_at_ms,
+        })
+    }
+
+    pub fn identifier(&self) -> String {
+        state_identifier(&self.id)
+    }
+
+    pub fn floors(&self) -> Floors {
+        self.heads
+            .iter()
+            .map(|head| (head.entity, head.clone()))
+            .collect()
+    }
+
+    pub fn apply_fold(&mut self, fold: &ControlFold) {
+        self.heads = fold.floors.values().cloned().collect();
+        self.banned = fold.banned.clone();
+
+        if let Some(community) = &fold.community {
+            self.relays = community
+                .relays
+                .iter()
+                .filter_map(|relay| RelayUrl::parse(relay).ok())
+                .collect();
+        }
+
+        for (id, metadata) in &fold.channels {
+            if metadata.deleted.unwrap_or(false) {
+                self.channels.retain(|channel| channel.id != *id);
+                continue;
+            }
+
+            match self.channels.iter_mut().find(|channel| channel.id == *id) {
+                Some(channel) => {
+                    channel.name = metadata.name.clone();
+
+                    if !metadata.private {
+                        channel.private = false;
+                    }
+                }
+                None if !metadata.private => self.channels.push(ChannelKeyRef {
+                    id: *id,
+                    name: metadata.name.clone(),
+                    private: false,
+                    epoch: self.root_epoch,
+                }),
+                None => {}
+            }
+        }
+    }
+}
+
+fn state_identifier(id: &CommunityId) -> String {
+    format!("{STATE_PREFIX}{}", id.to_hex())
+}
+
+pub async fn save_state(client: &Client, state: &CommunityState) -> Result<()> {
+    let event = EventBuilder::new(Kind::ApplicationSpecificData, serde_json::to_string(state)?)
+        .tags([Tag::identifier(state.identifier())])
+        .finalize_async(&*LOCAL_KEYS)
+        .await?;
+
+    client.database().save_event(&event).await?;
+
+    Ok(())
+}
+
+pub async fn load_state<D>(database: &D, id: &CommunityId) -> Result<Option<CommunityState>>
+where
+    D: NostrDatabase + ?Sized,
+{
+    let filter = Filter::new()
+        .kind(Kind::ApplicationSpecificData)
+        .identifier(state_identifier(id))
+        .limit(1);
+
+    match database.query(filter).await?.into_iter().next() {
+        Some(event) => Ok(Some(serde_json::from_str(&event.content)?)),
+        None => Ok(None),
+    }
+}
+
+pub async fn backfill(
+    client: &Client,
+    channel: &ChannelId,
+    held: &[(Epoch, [u8; 32])],
+    until: Option<Timestamp>,
+    limit: usize,
+) -> Result<Vec<ChatRumor>> {
+    let planes = plane_keys(held, channel)?;
+    let authors: Vec<PublicKey> = planes.iter().map(|(_, group)| group.pk()).collect();
+
+    let mut cursor = until;
+    let mut seen: BTreeSet<EventId> = BTreeSet::new();
+    let mut found: Vec<ChatRumor> = Vec::new();
+
+    for _ in 0..MAX_PAGES {
+        let page = fetch_page(client, &authors, cursor, limit).await?;
+
+        if page.is_empty() {
+            break;
+        }
+
+        let (fresh, next) = advance(&page, &planes, channel, cursor, limit, &mut seen);
+
+        for (opened, rumor) in fresh {
+            if cache_rumor(client, channel, &opened).await? {
+                found.push(rumor);
+            }
+        }
+
+        match next {
+            Some(next) => cursor = Some(next),
+            None => break,
+        }
+    }
+
+    found.sort_by_key(|rumor| (Reverse(rumor.at_ms), rumor.id));
+    found.truncate(limit);
+
+    Ok(found)
+}
+
+fn advance(
+    page: &BTreeSet<Event>,
+    planes: &[(Epoch, GroupKey)],
+    channel: &ChannelId,
+    cursor: Option<Timestamp>,
+    limit: usize,
+    seen: &mut BTreeSet<EventId>,
+) -> (Vec<(OpenedStream, ChatRumor)>, Option<Timestamp>) {
+    let mut fresh = Vec::new();
+
+    for wrap in page {
+        let Some((epoch, group)) = planes.iter().find(|(_, group)| group.pk() == wrap.pubkey)
+        else {
+            continue;
+        };
+
+        let Ok((opened, rumor)) = cord03::open(wrap, group, channel, *epoch) else {
+            continue;
+        };
+
+        if seen.insert(rumor.id) {
+            fresh.push((opened, rumor));
+        }
+    }
+
+    if fresh.is_empty() || page.len() < limit {
+        return (fresh, None);
+    }
+
+    let oldest = page.iter().map(|event| event.created_at).min();
+
+    match oldest {
+        Some(oldest) if cursor != Some(oldest) => (fresh, Some(oldest)),
+        _ => (fresh, None),
+    }
+}
+
+async fn fetch_page(
+    client: &Client,
+    authors: &[PublicKey],
+    until: Option<Timestamp>,
+    limit: usize,
+) -> Result<BTreeSet<Event>> {
+    let mut filter = Filter::new()
+        .kinds([Kind::GiftWrap, Kind::Custom(KIND_WRAP_EPHEMERAL)])
+        .authors(authors.iter().copied())
+        .limit(limit);
+
+    if let Some(until) = until {
+        filter = filter.until(until);
+    }
+
+    Ok(client.fetch_events(filter).await?)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::Epoch;
+    use crate::cord03::{build_message, seal_rumor};
+    use crate::derive::channel_group_key;
+
+    const SECRET: [u8; 32] = [0x07u8; 32];
+    const NEXT_SECRET: [u8; 32] = [0x11u8; 32];
+
+    /// What a relay does with an inclusive `until` and a `limit`.
+    fn serve_page(
+        relay: &BTreeSet<Event>,
+        cursor: Option<Timestamp>,
+        limit: usize,
+    ) -> BTreeSet<Event> {
+        let mut events: Vec<Event> = relay
+            .iter()
+            .filter(|event| cursor.is_none_or(|cursor| event.created_at <= cursor))
+            .cloned()
+            .collect();
+
+        events.sort_by_key(|event| Reverse(event.created_at));
+        events.truncate(limit);
+        events.into_iter().collect()
+    }
+
+    #[test]
+    fn history_pages_back_across_a_rekey() {
+        let channel = ChannelId::from_bytes([0x9cu8; 32]);
+        let author = Keys::generate();
+        let held = [(Epoch(0), SECRET), (Epoch(1), NEXT_SECRET)];
+        let planes = plane_keys(&held, &channel).expect("derives");
+
+        // Three messages a second apart: a page boundary falls between each.
+        let base = 1_700_000_000_000;
+        let mut relay: BTreeSet<Event> = BTreeSet::new();
+
+        for (content, secret, epoch, at_ms) in [
+            ("before the rekey", &SECRET, Epoch(0), base),
+            ("still before", &SECRET, Epoch(0), base + 1_000),
+            ("after the rekey", &NEXT_SECRET, Epoch(1), base + 2_000),
+        ] {
+            let group = channel_group_key(secret, &channel, epoch).expect("derives");
+            let rumor = build_message(
+                author.public_key(),
+                &channel,
+                epoch,
+                content,
+                None,
+                at_ms,
+                None,
+            );
+            relay.insert(seal_rumor(&rumor, &group, &author, false).expect("seals").0);
+        }
+
+        let mut seen = BTreeSet::new();
+        let mut found = Vec::new();
+        let mut cursor = None;
+
+        for _ in 0..3 {
+            let page = serve_page(&relay, cursor, 2);
+            let (fresh, next) = advance(&page, &planes, &channel, cursor, 2, &mut seen);
+
+            found.extend(fresh.into_iter().map(|(_, rumor)| rumor));
+
+            match next {
+                Some(next) => cursor = Some(next),
+                None => break,
+            }
+        }
+
+        found.sort_by_key(|rumor| (Reverse(rumor.at_ms), rumor.id));
+
+        let contents: Vec<&str> = found.iter().map(|rumor| rumor.content.as_str()).collect();
+        assert_eq!(
+            contents,
+            ["after the rekey", "still before", "before the rekey"]
+        );
+    }
+}

crates/concord/src/types/mod.rs

@@ -0,0 +1,98 @@
+use std::fmt;
+use std::str::FromStr;
+
+use anyhow::Result;
+use data_encoding::HEXLOWER;
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+use crate::decode_hex_32;
+
+/// Unknown fields a content struct does not model, so a republish cannot wipe them.
+pub(crate) type Extra = serde_json::Map<String, serde_json::Value>;
+
+macro_rules! hex_id {
+    ($(#[$meta:meta])* $name:ident) => {
+        $(#[$meta])*
+        #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+        pub struct $name([u8; 32]);
+
+        impl $name {
+            pub fn from_bytes(bytes: [u8; 32]) -> Self {
+                Self(bytes)
+            }
+
+            pub fn as_bytes(&self) -> &[u8; 32] {
+                &self.0
+            }
+
+            pub fn to_hex(&self) -> String {
+                HEXLOWER.encode(&self.0)
+            }
+        }
+
+        impl From<[u8; 32]> for $name {
+            fn from(bytes: [u8; 32]) -> Self {
+                Self(bytes)
+            }
+        }
+
+        impl fmt::Display for $name {
+            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+                f.write_str(&self.to_hex())
+            }
+        }
+
+        impl fmt::Debug for $name {
+            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+                write!(f, "{}({})", stringify!($name), self.to_hex())
+            }
+        }
+
+        impl FromStr for $name {
+            type Err = anyhow::Error;
+
+            fn from_str(value: &str) -> Result<Self> {
+                Ok(Self(decode_hex_32(value)?))
+            }
+        }
+
+        impl Serialize for $name {
+            fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+                serializer.serialize_str(&self.to_hex())
+            }
+        }
+
+        impl<'de> Deserialize<'de> for $name {
+            fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+                let value = String::deserialize(deserializer)?;
+                value.parse().map_err(serde::de::Error::custom)
+            }
+        }
+    };
+}
+
+hex_id! {
+    /// A self-certifying commitment to the owner's key, never on the wire.
+    CommunityId
+}
+
+hex_id! {
+    ChannelId
+}
+
+hex_id! {
+    /// Both a Role's entity coordinate and the field it repeats in its own content.
+    RoleId
+}
+
+/// A key-rotation counter; it bumps only on a Rekey that removes somebody.
+#[derive(
+    Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Default, Serialize, Deserialize,
+)]
+pub struct Epoch(pub u64);
+
+impl fmt::Display for Epoch {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}

crates/concord/src/utils/derive.rs

@@ -0,0 +1,407 @@
+use anyhow::{Result, bail};
+use hkdf::Hkdf;
+use nostr::nips::nip44::v2::ConversationKey;
+use nostr_sdk::prelude::{Keys, PublicKey, SecretKey};
+use sha2::{Digest, Sha256};
+
+use crate::{ChannelId, CommunityId, Epoch};
+
+pub const TOKEN_LEN: usize = 16;
+
+const LABEL_CHANNEL: &str = "concord/channel";
+const LABEL_CONTROL: &str = "concord/control";
+const LABEL_CONTROL_SIGNER: &str = "concord/control-signer";
+const LABEL_REKEY_PSEUDONYM: &str = "concord/rekey-pseudonym";
+const LABEL_BASE_REKEY_PSEUDONYM: &str = "concord/base-rekey-pseudonym";
+const LABEL_RECIPIENT_PSEUDONYM: &str = "concord/recipient-pseudonym";
+const LABEL_GUESTBOOK: &str = "concord/guestbook";
+const LABEL_DISSOLVED: &str = "concord/dissolved";
+const LABEL_GRANT: &str = "concord/grant";
+const LABEL_BANLIST: &str = "concord/banlist";
+const LABEL_PINS: &str = "concord/pins";
+const LABEL_INVITE_LINKS: &str = "concord/invite-links";
+const LABEL_INVITE_KEY: &str = "concord/invite-key";
+
+const LABEL_COMMUNITY: &str = "concord/community";
+const LABEL_EPOCH_COMMITMENT: &str = "concord/epoch-key-commitment";
+
+const ZERO32: [u8; 32] = [0u8; 32];
+
+fn build_info(label: &str, id32: &[u8; 32], epoch: Option<u64>) -> Vec<u8> {
+    let mut info = Vec::with_capacity(label.len() + 1 + 32 + 8);
+    info.extend_from_slice(label.as_bytes());
+    info.push(0x00);
+    info.extend_from_slice(id32);
+
+    if let Some(epoch) = epoch {
+        info.extend_from_slice(&epoch.to_be_bytes());
+    }
+
+    info
+}
+
+fn hkdf32(ikm: &[u8], info: &[u8]) -> [u8; 32] {
+    let mut okm = [0u8; 32];
+    Hkdf::<Sha256>::new(None, ikm)
+        .expand(info, &mut okm)
+        .expect("expanding HKDF to 32 bytes is below the 255*32 ceiling");
+    okm
+}
+
+fn hkdf_to_secret_key(ikm: &[u8], base_info: &[u8]) -> Result<SecretKey> {
+    if let Ok(secret_key) = SecretKey::from_slice(&hkdf32(ikm, base_info)) {
+        return Ok(secret_key);
+    }
+
+    for counter in 0u8..=u8::MAX {
+        let mut info = Vec::with_capacity(base_info.len() + 1);
+        info.extend_from_slice(base_info);
+        info.push(counter);
+
+        if let Ok(secret_key) = SecretKey::from_slice(&hkdf32(ikm, &info)) {
+            return Ok(secret_key);
+        }
+    }
+
+    bail!("seed stayed out of the secp256k1 scalar range across all 256 counters")
+}
+
+#[derive(Clone)]
+pub struct GroupKey {
+    keys: Keys,
+    conversation: ConversationKey,
+}
+
+impl GroupKey {
+    fn derive(label: &str, secret: &[u8], id32: &[u8; 32], epoch: Option<u64>) -> Result<Self> {
+        let secret_key = hkdf_to_secret_key(secret, &build_info(label, id32, epoch))?;
+        let keys = Keys::new(secret_key);
+        let conversation = ConversationKey::derive(keys.secret_key(), &keys.public_key())?;
+
+        Ok(Self { keys, conversation })
+    }
+
+    pub fn pk(&self) -> PublicKey {
+        self.keys.public_key()
+    }
+
+    pub fn pk_hex(&self) -> String {
+        self.keys.public_key().to_hex()
+    }
+
+    pub fn keys(&self) -> &Keys {
+        &self.keys
+    }
+
+    pub fn conversation(&self) -> &ConversationKey {
+        &self.conversation
+    }
+}
+
+impl std::fmt::Debug for GroupKey {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("GroupKey")
+            .field("pk", &self.pk_hex())
+            .finish()
+    }
+}
+
+/// `secret` is the `community_root` for a public channel.
+pub fn channel_group_key(secret: &[u8; 32], channel: &ChannelId, epoch: Epoch) -> Result<GroupKey> {
+    GroupKey::derive(LABEL_CHANNEL, secret, channel.as_bytes(), Some(epoch.0))
+}
+
+/// The plane's read key: its conversation key encrypts the wraps for every member.
+pub fn control_group_key(
+    community_root: &[u8; 32],
+    community_id: &CommunityId,
+    epoch: Epoch,
+) -> Result<GroupKey> {
+    GroupKey::derive(
+        LABEL_CONTROL,
+        community_root,
+        community_id.as_bytes(),
+        Some(epoch.0),
+    )
+}
+
+/// The plane's address and wrap signer, held only by staff; wraps still read under [`control_group_key`].
+pub fn control_signer_group_key(
+    control_root: &[u8; 32],
+    community_id: &CommunityId,
+    epoch: Epoch,
+) -> Result<GroupKey> {
+    GroupKey::derive(
+        LABEL_CONTROL_SIGNER,
+        control_root,
+        community_id.as_bytes(),
+        Some(epoch.0),
+    )
+}
+
+/// Member-writable, unlike the Control Plane: a join or a leave is each member's own word.
+pub fn guestbook_group_key(
+    community_root: &[u8; 32],
+    community_id: &CommunityId,
+    epoch: Epoch,
+) -> Result<GroupKey> {
+    GroupKey::derive(
+        LABEL_GUESTBOOK,
+        community_root,
+        community_id.as_bytes(),
+        Some(epoch.0),
+    )
+}
+
+/// Keyed by the prior `community_root`, so any retained member recovers any epoch's rekey.
+pub fn channel_rekey_group_key(
+    prior_root: &[u8; 32],
+    channel: &ChannelId,
+    new_epoch: Epoch,
+) -> Result<GroupKey> {
+    GroupKey::derive(
+        LABEL_REKEY_PSEUDONYM,
+        prior_root,
+        channel.as_bytes(),
+        Some(new_epoch.0),
+    )
+}
+
+pub fn base_rekey_group_key(
+    prior_root: &[u8; 32],
+    community_id: &CommunityId,
+    new_epoch: Epoch,
+) -> Result<GroupKey> {
+    GroupKey::derive(
+        LABEL_BASE_REKEY_PSEUDONYM,
+        prior_root,
+        community_id.as_bytes(),
+        Some(new_epoch.0),
+    )
+}
+
+pub fn dissolved_group_key(community_id: &CommunityId) -> Result<GroupKey> {
+    GroupKey::derive(LABEL_DISSOLVED, community_id.as_bytes(), &ZERO32, None)
+}
+
+pub fn community_id_of(owner_xonly: &[u8; 32], owner_salt: &[u8; 32]) -> CommunityId {
+    let mut hasher = Sha256::new();
+    hasher.update(LABEL_COMMUNITY.as_bytes());
+    hasher.update(owner_xonly);
+    hasher.update(owner_salt);
+    CommunityId::from_bytes(hasher.finalize().into())
+}
+
+pub fn verify_community_id(
+    community_id: &CommunityId,
+    owner_xonly: &[u8; 32],
+    owner_salt: &[u8; 32],
+) -> bool {
+    community_id_of(owner_xonly, owner_salt) == *community_id
+}
+
+/// The continuity a rekey blob must satisfy against the key currently held.
+pub fn epoch_key_commitment(previous_epoch: Epoch, previous_key: &[u8; 32]) -> [u8; 32] {
+    let mut hasher = Sha256::new();
+    hasher.update(LABEL_EPOCH_COMMITMENT.as_bytes());
+    hasher.update(previous_epoch.0.to_be_bytes());
+    hasher.update(previous_key);
+    hasher.finalize().into()
+}
+
+/// Bound to the `community_id`, so a member's Grant coordinate survives every refounding.
+pub fn grant_locator(community_id: &CommunityId, member_xonly: &[u8; 32]) -> [u8; 32] {
+    hkdf32(
+        community_id.as_bytes(),
+        &build_info(LABEL_GRANT, member_xonly, None),
+    )
+}
+
+pub fn banlist_locator(community_id: &CommunityId) -> [u8; 32] {
+    hkdf32(
+        community_id.as_bytes(),
+        &build_info(LABEL_BANLIST, &ZERO32, None),
+    )
+}
+
+pub fn pins_locator(community_id: &CommunityId, channel: &ChannelId) -> [u8; 32] {
+    hkdf32(
+        community_id.as_bytes(),
+        &build_info(LABEL_PINS, channel.as_bytes(), None),
+    )
+}
+
+/// Bound to the creator, so each creator owns exactly their own registry.
+pub fn invite_links_locator(community_id: &CommunityId, creator_xonly: &[u8; 32]) -> [u8; 32] {
+    hkdf32(
+        community_id.as_bytes(),
+        &build_info(LABEL_INVITE_LINKS, creator_xonly, None),
+    )
+}
+
+/// Built from public inputs only, so a locator match proves nothing about authenticity
+pub fn recipient_locator(
+    rotator_xonly: &[u8; 32],
+    recipient_xonly: &[u8; 32],
+    scope_id: &[u8; 32],
+    new_epoch: Epoch,
+) -> [u8; 32] {
+    let mut ikm = [0u8; 64];
+    ikm[..32].copy_from_slice(rotator_xonly);
+    ikm[32..].copy_from_slice(recipient_xonly);
+    hkdf32(
+        &ikm,
+        &build_info(LABEL_RECIPIENT_PSEUDONYM, scope_id, Some(new_epoch.0)),
+    )
+}
+
+/// The raw output is the NIP-44 conversation key (CORD-05 §2).
+pub fn invite_bundle_key(token: &[u8; TOKEN_LEN]) -> [u8; 32] {
+    hkdf32(token, &build_info(LABEL_INVITE_KEY, &ZERO32, None))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const CHANNEL_E0_SEED: &str =
+        "1a99a5958bf9fcc5336e6e19db42aabf36ffbfa12f38a1d5fbde2ae383ed751b";
+    const CHANNEL_E0_PK: &str = "7a5c5dff759a63f1fc2779864487432bae3d1ea72c4ffabd39f4c1fdaf62097a";
+    const CHANNEL_EMULTI_PK: &str =
+        "f20c7d192cc87615d7341e86f38f85303f4708b40232d4fea521ab8217767391";
+    const CONTROL_E0_PK: &str = "c43df20bf4d6eeaea5149619662ffe9b211f31e11bb4a59f56b6e906f702d46f";
+    const CONTROL_SIGNER_E0_SEED: &str =
+        "c4a3e8354d95137132087356412b67b53e025d127d45de45cff9ecf45b0c24f6";
+    const CONTROL_SIGNER_E0_PK: &str =
+        "718aef388257f3fd9f1bfae5cf2cbd0594a2ffc31adb5c1fe22c502c046acaee";
+    const CONTROL_SIGNER_EMULTI_PK: &str =
+        "e27235cc13be2f9ad65648e01ff2b63402846469c8638b5386c625688194ec7d";
+    const GUESTBOOK_E0_PK: &str =
+        "ad09de582026fa7a052db18bb5827fa24c15e929d59aadcc91efb8508f5368ad";
+    const CHANNEL_REKEY_E1_PK: &str =
+        "7c55cdb957e9db2b4800d687b2a07d3f7066b1a35824a1e86ba871f55e87e8b5";
+    const BASE_REKEY_E1_PK: &str =
+        "fb2fa44fba66ba15595f784255a1cb569531db8784432ac0e4fe838498dd9dea";
+    const DISSOLVED_PK: &str = "4d3d55d88fdf9d9c2089651e5cbb0dfa93b6b9b10cdcb2319b0dce1a1398096a";
+    const GRANT_LOCATOR: &str = "fd2f88cc7f1eb8d7d862c91dc22afe700c358d1845158b3f353b769ce4898e35";
+    const BANLIST_LOCATOR: &str =
+        "88089214afae6d3c412fd817ada44d6df4d485a53565646471e74476397693c9";
+    const INVITE_LINKS_LOCATOR: &str =
+        "f4ae29994165767bac23e8dce630f81b926d2c8aa150e5cbf0bdf75865e8379a";
+    const RECIPIENT_LOCATOR: &str =
+        "342deb400e191f0f52c81f27600934552550beb85aa9bf169f02d0e7f826cf74";
+    const INVITE_KEY: &str = "94bf8b0d89e579ddaeccf8d9db3f5de5c86a1259c597f2560ff0120173bc5e1f";
+    const COMMUNITY_ID: &str = "2b790bd59df98bdc52092b74ebd6933a89ef8eaeecc9030861cbdeae7c814c46";
+    const EPOCH_COMMITMENT: &str =
+        "3e6d6a3c9973c16d1ca7c5602d36979927c55c21a7e2c840f883af3f047e80a4";
+    const PINS_LOCATOR: &str = "3b4529395a35c981ed409b588af3c4cd3081992958a485347356a173c3146c52";
+    const EPOCH_MULTI: u64 = 0x0102030405060708;
+
+    /// `0x00..0x1f` / `0xff..0xe0` / `0x11` x32 — the inputs every vector uses.
+    fn secret() -> [u8; 32] {
+        let mut key = [0u8; 32];
+        for (index, byte) in key.iter_mut().enumerate() {
+            *byte = index as u8;
+        }
+        key
+    }
+
+    fn id32() -> [u8; 32] {
+        let mut id = [0u8; 32];
+        for (index, byte) in id.iter_mut().enumerate() {
+            *byte = 255 - index as u8;
+        }
+        id
+    }
+
+    fn hex(bytes: &[u8]) -> String {
+        data_encoding::HEXLOWER.encode(bytes)
+    }
+
+    #[test]
+    fn golden_vectors() {
+        let secret = secret();
+        let id = id32();
+        let alt = [0x11u8; 32];
+        let community_id = CommunityId::from_bytes(id);
+        let channel = ChannelId::from_bytes(id);
+
+        let channel_e0 = channel_group_key(&secret, &channel, Epoch(0)).expect("derives");
+        assert_eq!(
+            hex(channel_e0.keys().secret_key().as_secret_bytes()),
+            CHANNEL_E0_SEED
+        );
+        assert_eq!(channel_e0.pk_hex(), CHANNEL_E0_PK);
+        assert_eq!(
+            channel_group_key(&secret, &channel, Epoch(EPOCH_MULTI))
+                .expect("derives")
+                .pk_hex(),
+            CHANNEL_EMULTI_PK
+        );
+
+        assert_eq!(
+            control_group_key(&secret, &community_id, Epoch(0))
+                .expect("derives")
+                .pk_hex(),
+            CONTROL_E0_PK
+        );
+
+        let signer = control_signer_group_key(&secret, &community_id, Epoch(0)).expect("derives");
+        assert_eq!(
+            hex(signer.keys().secret_key().as_secret_bytes()),
+            CONTROL_SIGNER_E0_SEED
+        );
+        assert_eq!(signer.pk_hex(), CONTROL_SIGNER_E0_PK);
+        assert_eq!(
+            control_signer_group_key(&secret, &community_id, Epoch(EPOCH_MULTI))
+                .expect("derives")
+                .pk_hex(),
+            CONTROL_SIGNER_EMULTI_PK
+        );
+
+        assert_eq!(
+            guestbook_group_key(&secret, &community_id, Epoch(0))
+                .expect("derives")
+                .pk_hex(),
+            GUESTBOOK_E0_PK
+        );
+
+        assert_eq!(
+            channel_rekey_group_key(&secret, &channel, Epoch(1))
+                .expect("derives")
+                .pk_hex(),
+            CHANNEL_REKEY_E1_PK
+        );
+        assert_eq!(
+            base_rekey_group_key(&secret, &community_id, Epoch(1))
+                .expect("derives")
+                .pk_hex(),
+            BASE_REKEY_E1_PK
+        );
+        assert_eq!(
+            dissolved_group_key(&community_id)
+                .expect("derives")
+                .pk_hex(),
+            DISSOLVED_PK
+        );
+
+        assert_eq!(hex(&grant_locator(&community_id, &alt)), GRANT_LOCATOR);
+        assert_eq!(hex(&banlist_locator(&community_id)), BANLIST_LOCATOR);
+        assert_eq!(
+            hex(&invite_links_locator(&community_id, &alt)),
+            INVITE_LINKS_LOCATOR
+        );
+        assert_eq!(hex(&pins_locator(&community_id, &channel)), PINS_LOCATOR);
+        assert_eq!(
+            hex(&recipient_locator(&secret, &alt, &id, Epoch(3))),
+            RECIPIENT_LOCATOR
+        );
+        assert_eq!(hex(&invite_bundle_key(&[0x07u8; TOKEN_LEN])), INVITE_KEY);
+
+        assert_eq!(hex(community_id_of(&secret, &alt).as_bytes()), COMMUNITY_ID);
+        assert_eq!(
+            hex(&epoch_key_commitment(Epoch(2), &secret)),
+            EPOCH_COMMITMENT
+        );
+    }
+}

crates/concord/src/utils/mod.rs

@@ -0,0 +1,40 @@
+pub mod derive;
+
+use anyhow::{Result, anyhow, bail};
+use data_encoding::HEXLOWER;
+use rand::TryRng as _;
+use rand::rngs::SysRng;
+
+/// Uppercase and other non-canonical spellings are rejected.
+pub(crate) fn decode_hex_32(value: &str) -> Result<[u8; 32]> {
+    decode_hex_lower::<32>(value)
+}
+
+pub(crate) fn decode_hex_lower<const N: usize>(value: &str) -> Result<[u8; N]> {
+    let bytes = HEXLOWER
+        .decode(value.as_bytes())
+        .map_err(|error| anyhow!("invalid hex: {error}"))?;
+
+    let decoded: [u8; N] = bytes
+        .as_slice()
+        .try_into()
+        .map_err(|_| anyhow!("expected {N} bytes, got {}", bytes.len()))?;
+
+    if HEXLOWER.encode(&decoded) != value {
+        bail!("hex must be lowercase and canonical");
+    }
+
+    Ok(decoded)
+}
+
+pub(crate) fn fill_random(bytes: &mut [u8]) -> Result<()> {
+    SysRng
+        .try_fill_bytes(bytes)
+        .map_err(|error| anyhow!("os rng: {error}"))
+}
+
+pub(crate) fn random_32() -> Result<[u8; 32]> {
+    let mut bytes = [0u8; 32];
+    fill_random(&mut bytes)?;
+    Ok(bytes)
+}

crates/device/Cargo.toml

@@ -14,12 +14,11 @@ settings = { path = "../settings" }
 
 gpui.workspace = true
 nostr-sdk.workspace = true
-
+instant.workspace = true
 anyhow.workspace = true
-itertools.workspace = true
 smallvec.workspace = true
-smol.workspace = true
 log.workspace = true
 flume.workspace = true
-serde.workspace = true
-serde_json.workspace = true
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+smol.workspace = true

crates/device/src/lib.rs

@@ -4,18 +4,18 @@ use std::path::PathBuf;
 use std::rc::Rc;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, Ordering};
-use std::time::Duration;
 
 use anyhow::{Context as AnyhowContext, Error, anyhow};
 use gpui::{
     App, AppContext, Context, Entity, EventEmitter, Global, IntoElement, ParentElement,
     SharedString, Styled, Subscription, Task, Window, div, relative,
 };
+use instant::Duration;
 use nostr_sdk::prelude::*;
 use person::PersonRegistry;
 use settings::AppSettings;
 use smallvec::{SmallVec, smallvec};
-use state::{Announcement, CLIENT_NAME, NostrRegistry};
+use state::{Announcement, CLIENT_NAME, NostrRegistry, UniversalSigner};
 use theme::ActiveTheme;
 use ui::avatar::Avatar;
 use ui::button::Button;
@@ -66,7 +66,7 @@ pub struct DeviceRegistry {
     pub announcement_existed: Arc<AtomicBool>,
 
     /// Signer
-    signer: Entity<Option<Keys>>,
+    signer: Entity<Option<UniversalSigner>>,
 
     /// Async tasks
     tasks: Vec<Task<Result<(), Error>>>,
@@ -90,14 +90,10 @@ impl DeviceRegistry {
 
     /// Create a new device registry instance
     fn new(window: &mut Window, cx: &mut Context<Self>) -> Self {
-        let signer = cx.new(|_| None);
-
         let nostr = NostrRegistry::global(cx);
-        let user_signer = nostr.read(cx).signer.clone();
-
         let settings = AppSettings::global(cx);
-        let is_nip4e_enabled = settings.read(cx).is_nip4e_enabled(cx);
 
+        let signer = cx.new(|_| None);
         let mut subscriptions = smallvec![];
 
         subscriptions.push(
@@ -111,10 +107,10 @@ impl DeviceRegistry {
 
         subscriptions.push(
             // Observe the user signer
-            cx.observe(&user_signer, move |this, signer, cx| {
-                if signer.read(cx).is_some() && is_nip4e_enabled {
+            cx.subscribe(&nostr, move |this, _nostr, event, cx| {
+                if event.signer_changed() && settings.read(cx).is_nip4e_enabled(cx) {
                     this.get_announcement(cx);
-                };
+                }
             }),
         );
 
@@ -134,7 +130,7 @@ impl DeviceRegistry {
     fn handle_notifications(&mut self, window: &mut Window, cx: &mut Context<Self>) {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
-        let current_user = nostr.read(cx).signer_pubkey(cx);
+        let signer = nostr.read(cx).signer();
 
         let announcement_existed = self.announcement_existed.clone();
         let (tx, rx) = flume::bounded::<Event>(100);
@@ -142,6 +138,7 @@ impl DeviceRegistry {
         self.tasks.push(cx.background_spawn(async move {
             let mut notifications = client.notifications();
             let mut processed_events = HashSet::new();
+            let current_user = signer.get_public_key_async().await.ok();
 
             while let Some(notification) = notifications.next().await {
                 if let ClientNotification::Message { message, .. } = notification
@@ -205,14 +202,14 @@ impl DeviceRegistry {
     }
 
     /// Get the signer
-    pub fn signer(&self, cx: &App) -> Option<Keys> {
+    pub fn signer(&self, cx: &App) -> Option<UniversalSigner> {
         self.signer.read(cx).clone()
     }
 
     /// Set the decoupled encryption key for the current user
-    fn set_signer(&mut self, new: Keys, cx: &mut Context<Self>) {
+    fn set_signer(&mut self, new_signer: Keys, cx: &mut Context<Self>) {
         self.signer.update(cx, |this, cx| {
-            *this = Some(new);
+            *this = Some(UniversalSigner::new(new_signer));
             cx.notify();
         });
         cx.emit(DeviceEvent::Set);
@@ -222,15 +219,17 @@ impl DeviceRegistry {
     pub fn backup(&self, path: PathBuf, cx: &App) -> Task<Result<(), Error>> {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
-
-        let Some(signer) = nostr.read(cx).signer(cx) else {
-            return Task::ready(Err(anyhow!("Signer is required")));
-        };
+        let signer = nostr.read(cx).signer();
 
         cx.background_spawn(async move {
             let keys = get_keys(&client, &signer).await?;
             let content = keys.secret_key().to_bech32()?;
 
+            if cfg!(target_arch = "wasm32") {
+                return Err(anyhow!("Not supported"));
+            }
+
+            #[cfg(not(target_arch = "wasm32"))]
             smol::fs::write(path, &content).await?;
 
             Ok(())
@@ -241,13 +240,11 @@ impl DeviceRegistry {
     pub fn get_announcement(&mut self, cx: &mut Context<Self>) {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
-
-        let Some(current_user) = nostr.read(cx).signer_pubkey(cx) else {
-            return;
-        };
+        let signer = nostr.read(cx).signer();
 
         self.tasks.push(cx.background_spawn(async move {
             let opts = SubscribeAutoCloseOptions::default().exit_policy(ReqExitPolicy::ExitOnEOSE);
+            let current_user = signer.get_public_key_async().await?;
 
             // Construct the filter for the device announcement event
             let filter = Filter::new()
@@ -267,25 +264,18 @@ impl DeviceRegistry {
         let announcement_existed = self.announcement_existed.clone();
 
         self.tasks.push(cx.spawn(async move |this, cx| {
-            if !cx
-                .background_spawn(async move {
-                    // Wait for 5 seconds
-                    smol::Timer::after(Duration::from_secs(5)).await;
+            // Wait for 5 seconds
+            cx.background_executor().timer(Duration::from_secs(5)).await;
 
-                    // Then check if the msg relays have been found
-                    if !announcement_existed.load(Ordering::Acquire) {
-                        return true;
-                    }
-
-                    false
-                })
-                .await
-            {
-                this.update(cx, |_this, cx| {
-                    cx.emit(DeviceEvent::NotSet);
-                })?;
+            // Then check if the msg relays have been found
+            if announcement_existed.load(Ordering::Acquire) {
+                return Ok(());
             }
 
+            this.update(cx, |_this, cx| {
+                cx.emit(DeviceEvent::NotSet);
+            })?;
+
             Ok(())
         }));
     }
@@ -316,14 +306,11 @@ impl DeviceRegistry {
     fn create_encryption(&self, keys: Keys, cx: &App) -> Task<Result<Keys, Error>> {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
+        let signer = nostr.read(cx).signer();
 
         let secret = keys.secret_key().to_secret_hex();
         let n = keys.public_key();
 
-        let Some(signer) = nostr.read(cx).signer(cx) else {
-            return Task::ready(Err(anyhow!("Signer is required")));
-        };
-
         cx.background_spawn(async move {
             // Construct an announcement event
             let event = EventBuilder::new(Kind::Custom(10044), "")
@@ -352,10 +339,7 @@ impl DeviceRegistry {
     fn set_encryption(&mut self, event: &Event, cx: &mut Context<Self>) {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
-
-        let Some(signer) = nostr.read(cx).signer(cx) else {
-            return;
-        };
+        let signer = nostr.read(cx).signer();
 
         let announcement = Announcement::from(event);
         let device_pubkey = announcement.public_key();
@@ -391,10 +375,7 @@ impl DeviceRegistry {
     fn wait_for_request(&mut self, cx: &mut Context<Self>) {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
-
-        let Some(signer) = nostr.read(cx).signer(cx) else {
-            return;
-        };
+        let signer = nostr.read(cx).signer();
 
         self.tasks.push(cx.background_spawn(async move {
             let public_key = signer.get_public_key_async().await?;
@@ -417,16 +398,12 @@ impl DeviceRegistry {
     pub fn request(&mut self, cx: &mut Context<Self>) {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
+        let signer = nostr.read(cx).signer();
 
-        let Some(signer) = nostr.read(cx).signer(cx) else {
-            return;
-        };
-
-        let Ok(app_keys) = get_or_init_app_keys(cx) else {
-            return;
-        };
+        let app_keys_task = get_or_init_app_keys(cx);
 
         let task: Task<Result<Option<Event>, Error>> = cx.background_spawn(async move {
+            let app_keys = app_keys_task.await?;
             let app_pubkey = app_keys.public_key();
             let public_key = signer.get_public_key_async().await?;
 
@@ -437,7 +414,7 @@ impl DeviceRegistry {
                 .pubkey(app_pubkey)
                 .limit(1);
 
-            match client.database().query(filter).await?.first_owned() {
+            match client.database().query(filter).await?.into_iter().next() {
                 // Found an approval event
                 Some(event) => Ok(Some(event)),
                 // No approval event found, construct a request event
@@ -485,10 +462,7 @@ impl DeviceRegistry {
     fn wait_for_approval(&mut self, cx: &mut Context<Self>) {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
-
-        let Some(signer) = nostr.read(cx).signer(cx) else {
-            return;
-        };
+        let signer = nostr.read(cx).signer();
 
         cx.emit(DeviceEvent::Requesting);
 
@@ -510,11 +484,10 @@ impl DeviceRegistry {
 
     /// Parse the approval event to get encryption key then set it
     fn extract_encryption(&mut self, event: Event, cx: &mut Context<Self>) {
-        let Ok(app_keys) = get_or_init_app_keys(cx) else {
-            return;
-        };
+        let app_keys_task = get_or_init_app_keys(cx);
 
         let task: Task<Result<Keys, Error>> = cx.background_spawn(async move {
+            let app_keys = app_keys_task.await?;
             let master = event
                 .tags
                 .iter()
@@ -553,10 +526,7 @@ impl DeviceRegistry {
     fn approve(&mut self, event: &Event, window: &mut Window, cx: &mut Context<Self>) {
         let nostr = NostrRegistry::global(cx);
         let client = nostr.read(cx).client();
-
-        let Some(signer) = nostr.read(cx).signer(cx) else {
-            return;
-        };
+        let signer = nostr.read(cx).signer();
 
         // Get user's write relays
         let event = event.clone();
@@ -597,7 +567,7 @@ impl DeviceRegistry {
             Ok(())
         });
 
-        cx.spawn_in(window, async move |_this, cx| {
+        self.tasks.push(cx.spawn_in(window, async move |_this, cx| {
             match task.await {
                 Ok(_) => {
                     cx.update(|window, cx| {
@@ -615,8 +585,9 @@ impl DeviceRegistry {
                     .ok();
                 }
             };
-        })
-        .detach();
+
+            Ok(())
+        }));
     }
 
     /// Handle encryption request
@@ -684,7 +655,11 @@ impl DeviceRegistry {
                                             .child(
                                                 h_flex()
                                                     .gap_2()
-                                                    .child(Avatar::new(profile.avatar()).xsmall())
+                                                    .child(
+                                                        Avatar::new(profile.avatar())
+                                                            .seed(profile.avatar_seed())
+                                                            .xsmall(),
+                                                    )
                                                     .child(profile.name()),
                                             ),
                                     ),
@@ -739,37 +714,38 @@ impl DeviceRegistry {
 
 struct DeviceNotification;
 
-/// Get or create new app keys
-fn get_or_init_app_keys(cx: &App) -> Result<Keys, Error> {
+/// Get or create new app keys (async, returns a task)
+fn get_or_init_app_keys(cx: &App) -> Task<Result<Keys, Error>> {
     let read = cx.read_credentials(CLIENT_NAME);
-    let stored_keys: Option<Keys> = cx.foreground_executor().block_on(async move {
-        if let Ok(Some((_, secret))) = read.await {
-            SecretKey::from_slice(&secret).map(Keys::new).ok()
-        } else {
-            None
-        }
-    });
 
-    if let Some(keys) = stored_keys {
-        Ok(keys)
-    } else {
+    cx.spawn(async move |cx| {
+        if let Ok(Some((_, secret))) = read.await
+            && let Ok(keys) = SecretKey::from_slice(&secret).map(Keys::new)
+        {
+            return Ok(keys);
+        }
+
+        // No stored keys found or invalid — generate new ones
         let keys = Keys::generate();
         let user = keys.public_key().to_hex();
         let secret = keys.secret_key().to_secret_bytes();
-        let write = cx.write_credentials(CLIENT_NAME, &user, &secret);
 
-        cx.foreground_executor().block_on(async move {
-            if let Err(e) = write.await {
-                log::error!("Keyring not available or panic: {e}")
-            }
+        cx.update(|cx| {
+            let write = cx.write_credentials(CLIENT_NAME, &user, &secret);
+            cx.background_spawn(async move {
+                if let Err(e) = write.await {
+                    log::error!("Keyring not available or panic: {e}")
+                }
+            })
+            .detach();
         });
 
         Ok(keys)
-    }
+    })
 }
 
 /// Encrypt and store device keys in the local database.
-async fn set_keys(client: &Client, signer: &Keys, secret: &str) -> Result<(), Error> {
+async fn set_keys(client: &Client, signer: &UniversalSigner, secret: &str) -> Result<(), Error> {
     let public_key = signer.get_public_key_async().await?;
     let content = signer.nip44_encrypt_async(&public_key, secret).await?;
 
@@ -786,7 +762,7 @@ async fn set_keys(client: &Client, signer: &Keys, secret: &str) -> Result<(), Er
 }
 
 /// Get device keys from the local database.
-async fn get_keys(client: &Client, signer: &Keys) -> Result<Keys, Error> {
+async fn get_keys(client: &Client, signer: &UniversalSigner) -> Result<Keys, Error> {
     let public_key = signer.get_public_key_async().await?;
 
     let filter = Filter::new()

crates/gpui_tokio/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "gpui_tokio"
+version = "0.1.0"
+edition.workspace = true
+publish.workspace = true
+
+[dependencies]
+anyhow.workspace = true
+gpui.workspace = true
+gpui_util.workspace = true
+tokio = { version = "1", features = ["rt", "rt-multi-thread"] }

crates/gpui_tokio/src/lib.rs

@@ -0,0 +1,102 @@
+//! Vendored from zed's `crates/gpui_tokio` (Apache-2.0) because the `gpui-pre` family
+//! does not republish it, and `nostr-sdk`'s reqwest client needs a Tokio runtime.
+
+use std::future::Future;
+
+use gpui::{App, AppContext, Global, ReadGlobal, Task};
+use gpui_util::defer;
+pub use tokio::task::JoinError;
+
+/// Initializes the Tokio wrapper using a new Tokio runtime with 2 worker threads.
+///
+/// If you need more threads (or access to the runtime outside of GPUI), you can create the runtime
+/// yourself and pass a Handle to `init_from_handle`.
+pub fn init(cx: &mut App) {
+    let runtime = tokio::runtime::Builder::new_multi_thread()
+        // Since we now have two executors, let's try to keep our footprint small
+        .worker_threads(2)
+        .enable_all()
+        .build()
+        .expect("Failed to initialize Tokio");
+
+    let handle = runtime.handle().clone();
+    cx.set_global(GlobalTokio {
+        owned_runtime: Some(runtime),
+        handle,
+    });
+}
+
+/// Initializes the Tokio wrapper using a Tokio runtime handle.
+pub fn init_from_handle(cx: &mut App, handle: tokio::runtime::Handle) {
+    cx.set_global(GlobalTokio {
+        owned_runtime: None,
+        handle,
+    });
+}
+
+struct GlobalTokio {
+    owned_runtime: Option<tokio::runtime::Runtime>,
+    handle: tokio::runtime::Handle,
+}
+
+impl Global for GlobalTokio {}
+
+impl Drop for GlobalTokio {
+    fn drop(&mut self) {
+        if let Some(runtime) = self.owned_runtime.take() {
+            runtime.shutdown_background();
+        }
+    }
+}
+
+pub struct Tokio {}
+
+impl Tokio {
+    /// Spawns the given future on Tokio's thread pool, and returns it via a GPUI task
+    /// Note that the Tokio task will be cancelled if the GPUI task is dropped
+    pub fn spawn<C, Fut, R>(cx: &C, f: Fut) -> Task<Result<R, JoinError>>
+    where
+        C: AppContext,
+        Fut: Future<Output = R> + Send + 'static,
+        R: Send + 'static,
+    {
+        cx.read_global(|tokio: &GlobalTokio, cx| {
+            let join_handle = tokio.handle.spawn(f);
+            let abort_handle = join_handle.abort_handle();
+            let cancel = defer(move || {
+                abort_handle.abort();
+            });
+            cx.background_spawn(async move {
+                let result = join_handle.await;
+                drop(cancel);
+                result
+            })
+        })
+    }
+
+    /// Spawns the given future on Tokio's thread pool, and returns it via a GPUI task
+    /// Note that the Tokio task will be cancelled if the GPUI task is dropped
+    pub fn spawn_result<C, Fut, R>(cx: &C, f: Fut) -> Task<anyhow::Result<R>>
+    where
+        C: AppContext,
+        Fut: Future<Output = anyhow::Result<R>> + Send + 'static,
+        R: Send + 'static,
+    {
+        cx.read_global(|tokio: &GlobalTokio, cx| {
+            let join_handle = tokio.handle.spawn(f);
+            let abort_handle = join_handle.abort_handle();
+            let cancel = defer(move || {
+                abort_handle.abort();
+            });
+            cx.background_spawn(async move {
+                let result = join_handle.await?;
+                drop(cancel);
+                result
+            })
+        })
+    }
+
+    pub fn handle(cx: &App) -> tokio::runtime::Handle {
+        GlobalTokio::global(cx).handle.clone()
+    }
+}

crates/person/Cargo.toml

@@ -10,9 +10,8 @@ state = { path = "../state" }
 
 gpui.workspace = true
 nostr-sdk.workspace = true
+instant.workspace = true
 anyhow.workspace = true
 smallvec.workspace = true
-smol.workspace = true
 flume.workspace = true
 log.workspace = true
-urlencoding = "2.1.3"

crates/person/src/lib.rs

@@ -1,11 +1,10 @@
-use std::cell::RefCell;
 use std::collections::{HashMap, HashSet};
-use std::rc::Rc;
-use std::time::Duration;
+use std::sync::RwLock;
 
 use anyhow::{Error, anyhow};
 use common::EventExt;
 use gpui::{App, AppContext, Context, Entity, Global, Task, Window};
+use instant::Duration;
 use nostr_sdk::prelude::*;
 use smallvec::{SmallVec, smallvec};
 use state::{Announcement, BOOTSTRAP_RELAYS, NostrRegistry, TIMEOUT};
@@ -24,9 +23,9 @@ impl Global for GlobalPersonRegistry {}
 
 #[derive(Debug, Clone)]
 enum Dispatch {
-    Person(Box<Person>),
-    Announcement(Box<Event>),
-    Relays(Box<Event>),
+    Person(Person),
+    Announcement(Event),
+    Relays(Event),
 }
 
 /// Person Registry
@@ -36,7 +35,7 @@ pub struct PersonRegistry {
     persons: HashMap<PublicKey, Entity<Person>>,
 
     /// Set of public keys that have been seen
-    seens: Rc<RefCell<HashSet<PublicKey>>>,
+    seen: RwLock<HashSet<PublicKey>>,
 
     /// Sender for requesting metadata
     sender: flume::Sender<PublicKey>,
@@ -63,53 +62,38 @@ impl PersonRegistry {
 
         // Channel for communication between nostr and gpui
         let (tx, rx) = flume::bounded::<Dispatch>(100);
-        let (mta_tx, mta_rx) = flume::unbounded::<PublicKey>();
+        let (metadata_tx, metadata_rx) = flume::unbounded::<PublicKey>();
 
         let mut tasks = smallvec![];
 
-        tasks.push(
-            // Handle nostr notifications
-            cx.background_spawn({
-                let client = client.clone();
+        let client2 = client.clone();
+        tasks.push(cx.background_spawn(async move {
+            Self::handle_notifications(&client2, &tx).await;
+        }));
 
-                async move {
-                    Self::handle_notifications(&client, &tx).await;
-                }
-            }),
-        );
+        let client3 = client.clone();
+        tasks.push(cx.background_spawn(async move {
+            Self::handle_requests(&client3, &metadata_rx).await;
+        }));
 
-        tasks.push(
-            // Handle metadata requests
-            cx.background_spawn({
-                let client = client.clone();
-
-                async move {
-                    Self::handle_requests(&client, &mta_rx).await;
-                }
-            }),
-        );
-
-        tasks.push(
-            // Update GPUI state
-            cx.spawn(async move |this, cx| {
-                while let Ok(event) = rx.recv_async().await {
-                    this.update(cx, |this, cx| {
-                        match event {
-                            Dispatch::Person(person) => {
-                                this.insert(*person, cx);
-                            }
-                            Dispatch::Announcement(event) => {
-                                this.set_announcement(&event, cx);
-                            }
-                            Dispatch::Relays(event) => {
-                                this.set_messaging_relays(&event, cx);
-                            }
-                        };
-                    })
-                    .ok();
-                }
-            }),
-        );
+        tasks.push(cx.spawn(async move |this, cx| {
+            while let Ok(event) = rx.recv_async().await {
+                this.update(cx, |this, cx| {
+                    match event {
+                        Dispatch::Person(person) => {
+                            this.insert(person, cx);
+                        }
+                        Dispatch::Announcement(event) => {
+                            this.set_announcement(&event, cx);
+                        }
+                        Dispatch::Relays(event) => {
+                            this.set_messaging_relays(&event, cx);
+                        }
+                    };
+                })
+                .ok();
+            }
+        }));
 
         // Load all user profiles from the database
         cx.defer_in(window, |this, _window, cx| {
@@ -118,8 +102,8 @@ impl PersonRegistry {
 
         Self {
             persons: HashMap::new(),
-            seens: Rc::new(RefCell::new(HashSet::new())),
-            sender: mta_tx,
+            seen: RwLock::new(HashSet::new()),
+            sender: metadata_tx,
             tasks,
         }
     }
@@ -145,24 +129,25 @@ impl PersonRegistry {
                     Kind::Metadata => {
                         let metadata = Metadata::from_json(&event.content).unwrap_or_default();
                         let person = Person::new(event.pubkey, metadata);
-                        let val = Box::new(person);
-                        // Send
-                        tx.send_async(Dispatch::Person(val)).await.ok();
+                        if tx.send_async(Dispatch::Person(person)).await.is_err() {
+                            log::warn!("PersonRegistry channel closed, dropping metadata event");
+                        }
                     }
                     Kind::ContactList => {
                         let public_keys = event.extract_public_keys();
-                        // Get metadata for all public keys
-                        get_metadata(client, public_keys).await.ok();
+                        if let Err(e) = get_metadata(client, public_keys).await {
+                            log::warn!("Failed to get metadata for contact list: {e}");
+                        }
                     }
                     Kind::InboxRelays => {
-                        let val = Box::new(event.into_owned());
-                        // Send
-                        tx.send_async(Dispatch::Relays(val)).await.ok();
+                        tx.send_async(Dispatch::Relays(event.into_owned()))
+                            .await
+                            .ok();
                     }
                     Kind::Custom(10044) => {
-                        let val = Box::new(event.into_owned());
-                        // Send
-                        tx.send_async(Dispatch::Announcement(val)).await.ok();
+                        tx.send_async(Dispatch::Announcement(event.into_owned()))
+                            .await
+                            .ok();
                     }
                     _ => {}
                 }
@@ -182,13 +167,17 @@ impl PersonRegistry {
                 Ok(Some(public_key)) => {
                     batch.insert(public_key);
                     // Process the batch if it's full
-                    if batch.len() >= 20 {
-                        get_metadata(client, std::mem::take(&mut batch)).await.ok();
+                    if batch.len() >= 20
+                        && let Err(e) = get_metadata(client, std::mem::take(&mut batch)).await
+                    {
+                        log::warn!("Failed to get metadata batch: {e}");
                     }
                 }
                 _ => {
-                    if !batch.is_empty() {
-                        get_metadata(client, std::mem::take(&mut batch)).await.ok();
+                    if !batch.is_empty()
+                        && let Err(e) = get_metadata(client, std::mem::take(&mut batch)).await
+                    {
+                        log::warn!("Failed to get metadata batch: {e}");
                     }
                 }
             }
@@ -217,7 +206,7 @@ impl PersonRegistry {
         self.tasks.push(cx.spawn(async move |this, cx| {
             if let Ok(persons) = task.await {
                 this.update(cx, |this, cx| {
-                    this.bulk_inserts(persons, cx);
+                    this.bulk_insert(persons, cx);
                 })
                 .ok();
             }
@@ -256,7 +245,7 @@ impl PersonRegistry {
     }
 
     /// Insert batch of persons
-    fn bulk_inserts(&mut self, persons: Vec<Person>, cx: &mut Context<Self>) {
+    fn bulk_insert(&mut self, persons: Vec<Person>, cx: &mut Context<Self>) {
         for person in persons.into_iter() {
             let public_key = person.public_key();
             self.persons
@@ -290,15 +279,14 @@ impl PersonRegistry {
         }
 
         let public_key = *public_key;
-        let mut seen = self.seens.borrow_mut();
 
-        if seen.insert(public_key) {
+        if self.seen.write().unwrap().insert(public_key) {
             let sender = self.sender.clone();
 
             // Spawn background task to request metadata
             cx.background_spawn(async move {
                 if let Err(e) = sender.send_async(public_key).await {
-                    log::warn!("Failed to send public key for metadata request: {}", e);
+                    log::warn!("Failed to send public key for metadata request: {e}");
                 }
             })
             .detach();

crates/person/src/person.rs

@@ -5,8 +5,6 @@ use gpui::SharedString;
 use nostr_sdk::prelude::*;
 use state::Announcement;
 
-const IMAGE_RESIZER: &str = "https://wsrv.nl";
-
 /// Person
 #[derive(Debug, Clone)]
 pub struct Person {
@@ -105,20 +103,18 @@ impl Person {
         self.messaging_relays.first().cloned()
     }
 
-    /// Get profile avatar
-    pub fn avatar(&self) -> SharedString {
+    /// Get profile picture, if the profile has one
+    pub fn avatar(&self) -> Option<SharedString> {
         self.metadata()
             .picture
             .as_ref()
             .filter(|picture| !picture.is_empty())
-            .map(|picture| {
-                let encoded_picture = urlencoding::encode(picture);
-                let url = format!(
-                    "{IMAGE_RESIZER}/?url={encoded_picture}&w=100&h=100&fit=cover&mask=circle&n=-1"
-                );
-                url.into()
-            })
-            .unwrap_or_else(|| "brand/avatar.png".into())
+            .map(SharedString::from)
+    }
+
+    /// A stable seed for this profile's generated avatar
+    pub fn avatar_seed(&self) -> SharedString {
+        SharedString::from(self.public_key().to_hex())
     }
 
     /// Get profile name
@@ -126,13 +122,13 @@ impl Person {
         if let Some(display_name) = self.metadata().display_name.as_ref()
             && !display_name.is_empty()
         {
-            return SharedString::from(display_name);
+            return SharedString::from(display_name.trim());
         }
 
         if let Some(name) = self.metadata().name.as_ref()
             && !name.is_empty()
         {
-            return SharedString::from(name);
+            return SharedString::from(name.trim());
         }
 
         SharedString::from(shorten_pubkey(self.public_key(), 4))

crates/relay_auth/src/lib.rs

@@ -1,372 +0,0 @@
-use std::borrow::Cow;
-use std::cell::Cell;
-use std::collections::HashSet;
-use std::hash::Hash;
-use std::rc::Rc;
-use std::sync::Arc;
-
-use anyhow::{Context as AnyhowContext, Error, anyhow};
-use gpui::{
-    App, AppContext, Context, Entity, Global, IntoElement, ParentElement, SharedString, Styled,
-    Task, Window, div, relative,
-};
-use nostr_sdk::prelude::*;
-use settings::{AppSettings, AuthMode};
-use smallvec::{SmallVec, smallvec};
-use state::NostrRegistry;
-use theme::ActiveTheme;
-use ui::button::Button;
-use ui::notification::{Notification, NotificationKind};
-use ui::{Disableable, WindowExtension, v_flex};
-
-const AUTH_MESSAGE: &str =
-    "Approve the authentication request to allow Coop to continue sending or receiving events.";
-
-pub fn init(window: &mut Window, cx: &mut App) {
-    RelayAuth::set_global(cx.new(|cx| RelayAuth::new(window, cx)), cx);
-}
-
-/// Authentication request
-#[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
-struct AuthRequest {
-    url: RelayUrl,
-    challenge: String,
-}
-
-impl AuthRequest {
-    pub fn new<S>(challenge: S, url: RelayUrl) -> Self
-    where
-        S: Into<String>,
-    {
-        Self {
-            challenge: challenge.into(),
-            url,
-        }
-    }
-
-    pub fn url(&self) -> &RelayUrl {
-        &self.url
-    }
-
-    pub fn challenge(&self) -> &str {
-        &self.challenge
-    }
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
-enum Signal {
-    Auth(Arc<AuthRequest>),
-    Pending((EventId, RelayUrl)),
-}
-
-struct GlobalRelayAuth(Entity<RelayAuth>);
-
-impl Global for GlobalRelayAuth {}
-
-// Relay authentication
-#[derive(Debug)]
-pub struct RelayAuth {
-    /// Pending events waiting for resend after authentication
-    pending_events: HashSet<(EventId, RelayUrl)>,
-
-    /// Tasks for asynchronous operations
-    _tasks: SmallVec<[Task<()>; 2]>,
-}
-
-impl RelayAuth {
-    /// Retrieve the global relay auth state
-    pub fn global(cx: &App) -> Entity<Self> {
-        cx.global::<GlobalRelayAuth>().0.clone()
-    }
-
-    /// Set the global relay auth instance
-    fn set_global(state: Entity<Self>, cx: &mut App) {
-        cx.set_global(GlobalRelayAuth(state));
-    }
-
-    /// Create a new relay auth instance
-    fn new(window: &mut Window, cx: &mut Context<Self>) -> Self {
-        let nostr = NostrRegistry::global(cx);
-        let client = nostr.read(cx).client();
-
-        let mut tasks = smallvec![];
-
-        // Channel for communication between nostr and gpui
-        let (tx, rx) = flume::bounded::<Signal>(256);
-
-        tasks.push(cx.background_spawn(async move {
-            let mut notifications = client.notifications();
-            let mut challenges: HashSet<Cow<'_, str>> = HashSet::default();
-
-            while let Some(notification) = notifications.next().await {
-                if let ClientNotification::Message { relay_url, message } = notification {
-                    match *message {
-                        RelayMessage::Auth { challenge } => {
-                            if challenges.insert(challenge.clone()) {
-                                let request = Arc::new(AuthRequest::new(challenge, relay_url));
-                                let signal = Signal::Auth(request);
-
-                                tx.send_async(signal).await.ok();
-                            }
-                        }
-                        RelayMessage::Ok {
-                            event_id, message, ..
-                        } => {
-                            let msg = MachineReadablePrefix::parse(&message);
-
-                            // Handle authentication messages
-                            if let Some(MachineReadablePrefix::AuthRequired) = msg {
-                                let signal = Signal::Pending((event_id, relay_url));
-                                tx.send_async(signal).await.ok();
-                            }
-                        }
-                        _ => {}
-                    }
-                }
-            }
-        }));
-
-        tasks.push(cx.spawn_in(window, async move |this, cx| {
-            while let Ok(signal) = rx.recv_async().await {
-                match signal {
-                    Signal::Auth(req) => {
-                        this.update_in(cx, |this, window, cx| {
-                            this.handle_auth(&req, window, cx);
-                        })
-                        .ok();
-                    }
-                    Signal::Pending((event_id, relay_url)) => {
-                        this.update_in(cx, |this, _window, cx| {
-                            this.insert_pending_event(event_id, relay_url, cx);
-                        })
-                        .ok();
-                    }
-                }
-            }
-        }));
-
-        Self {
-            pending_events: HashSet::default(),
-            _tasks: tasks,
-        }
-    }
-
-    /// Insert a pending event waiting for resend after authentication
-    fn insert_pending_event(&mut self, id: EventId, relay: RelayUrl, cx: &mut Context<Self>) {
-        self.pending_events.insert((id, relay));
-        cx.notify();
-    }
-
-    /// Get all pending events for a specific relay,
-    fn get_pending_events(&self, relay: &RelayUrl, _cx: &App) -> Vec<EventId> {
-        self.pending_events
-            .iter()
-            .filter(|(_, pending_relay)| pending_relay == relay)
-            .map(|(id, _relay)| id)
-            .cloned()
-            .collect()
-    }
-
-    /// Clear all pending events for a specific relay,
-    fn clear_pending_events(&mut self, relay: &RelayUrl, cx: &mut Context<Self>) {
-        self.pending_events
-            .retain(|(_, pending_relay)| pending_relay != relay);
-        cx.notify();
-    }
-
-    /// Handle authentication request
-    fn handle_auth(&mut self, req: &Arc<AuthRequest>, window: &mut Window, cx: &mut Context<Self>) {
-        let settings = AppSettings::global(cx);
-        let trusted_relay = settings.read(cx).trusted_relay(req.url(), cx);
-        let mode = AppSettings::get_auth_mode(cx);
-
-        if trusted_relay && mode == AuthMode::Auto {
-            // Automatically authenticate if the relay is authenticated before
-            self.response(req, window, cx);
-        } else {
-            // Otherwise open the auth request popup
-            self.ask_for_approval(req, window, cx);
-        }
-    }
-
-    /// Send auth response and wait for confirmation
-    fn auth(&self, req: &Arc<AuthRequest>, cx: &App) -> Task<Result<(), Error>> {
-        let nostr = NostrRegistry::global(cx);
-        let client = nostr.read(cx).client();
-
-        let Some(signer) = nostr.read(cx).signer(cx) else {
-            return Task::ready(Err(anyhow!("Signer is required")));
-        };
-
-        // Get all pending events for the relay
-        let req = req.clone();
-        let pending_events = self.get_pending_events(req.url(), cx);
-
-        cx.background_spawn(async move {
-            // Construct event
-            let event = EventBuilder::auth(req.challenge(), req.url().clone())
-                .finalize_async(&signer)
-                .await?;
-
-            // Get the event ID
-            let id = event.id;
-
-            // Get the relay
-            let relay = client.relay(req.url()).await?.context("Relay not found")?;
-
-            // Subscribe to notifications
-            let mut notifications = relay.notifications();
-
-            // Send the AUTH message
-            relay
-                .send_msg(ClientMessage::Auth(Cow::Borrowed(&event)))
-                .await?;
-
-            while let Some(notification) = notifications.next().await {
-                match notification {
-                    RelayNotification::Message { message } => {
-                        if let RelayMessage::Ok { event_id, .. } = *message {
-                            if id != event_id {
-                                continue;
-                            }
-
-                            // Get all subscriptions
-                            let subscriptions = relay.subscriptions().await;
-
-                            // Re-subscribe to previous subscriptions
-                            for (id, filters) in subscriptions.into_iter() {
-                                if !filters.is_empty() {
-                                    relay.send_msg(ClientMessage::req(id, filters)).await?;
-                                }
-                            }
-
-                            // Re-send pending events
-                            for id in pending_events {
-                                if let Some(event) = client.database().event_by_id(&id).await? {
-                                    relay.send_event(&event).await?;
-                                }
-                            }
-
-                            return Ok(());
-                        }
-                    }
-                    RelayNotification::AuthenticationFailed => break,
-                    _ => {}
-                }
-            }
-
-            Err(anyhow!("Authentication failed"))
-        })
-    }
-
-    /// Respond to an authentication request.
-    fn response(&self, req: &Arc<AuthRequest>, window: &Window, cx: &Context<Self>) {
-        let settings = AppSettings::global(cx);
-        let req = req.clone();
-        let challenge = SharedString::from(req.challenge().to_string());
-
-        // Create a task for authentication
-        let task = self.auth(&req, cx);
-
-        cx.spawn_in(window, async move |this, cx| {
-            let result = task.await;
-            let url = req.url();
-
-            this.update_in(cx, |this, window, cx| {
-                window.clear_notification_by_id::<AuthNotification>(challenge, cx);
-
-                if let Err(e) = result {
-                    window
-                        .push_notification(Notification::error(e.to_string()).autohide(false), cx);
-                } else {
-                    // Clear pending events for the authenticated relay
-                    this.clear_pending_events(url, cx);
-
-                    let domain = url.domain().unwrap_or_default();
-                    let msg = format!("Relay {} has been authenticated", domain);
-
-                    window.push_notification(Notification::success(msg), cx);
-
-                    // Save the authenticated relay to automatically authenticate future requests
-                    settings.update(cx, |this, cx| {
-                        this.add_trusted_relay(url, cx);
-                    });
-                }
-            })
-            .ok();
-        })
-        .detach();
-    }
-
-    /// Push a popup to approve the authentication request.
-    fn ask_for_approval(&self, req: &Arc<AuthRequest>, window: &Window, cx: &Context<Self>) {
-        let notification = self.notification(req, cx);
-
-        cx.spawn_in(window, async move |_this, cx| {
-            cx.update(|window, cx| {
-                window.push_notification(notification, cx);
-            })
-            .ok();
-        })
-        .detach();
-    }
-
-    /// Build a notification for the authentication request.
-    fn notification(&self, req: &Arc<AuthRequest>, cx: &Context<Self>) -> Notification {
-        let req = req.clone();
-        let challenge = SharedString::from(req.challenge.clone());
-        let url = SharedString::from(req.url().to_string());
-        let entity = cx.entity().downgrade();
-        let loading = Rc::new(Cell::new(false));
-
-        Notification::new()
-            .type_id::<AuthNotification>(challenge)
-            .autohide(false)
-            .with_kind(NotificationKind::Info)
-            .title("Authentication Required")
-            .content(move |_this, _window, cx| {
-                v_flex()
-                    .gap_2()
-                    .child(
-                        div()
-                            .text_sm()
-                            .line_height(relative(1.25))
-                            .child(SharedString::from(AUTH_MESSAGE)),
-                    )
-                    .child(
-                        v_flex()
-                            .py_1()
-                            .px_1p5()
-                            .rounded_sm()
-                            .text_xs()
-                            .bg(cx.theme().elevated_surface_background)
-                            .text_color(cx.theme().text)
-                            .child(url.clone()),
-                    )
-                    .into_any_element()
-            })
-            .action(move |_this, _window, _cx| {
-                let view = entity.clone();
-                let req = req.clone();
-
-                Button::new("approve")
-                    .label("Approve")
-                    .loading(loading.get())
-                    .disabled(loading.get())
-                    .on_click({
-                        let loading = Rc::clone(&loading);
-                        move |_ev, window, cx| {
-                            // Set loading state to true
-                            loading.set(true);
-                            // Process to approve the request
-                            view.update(cx, |this, cx| {
-                                this.response(&req, window, cx);
-                            })
-                            .ok();
-                        }
-                    })
-            })
-    }
-}
-
-struct AuthNotification;

crates/settings/Cargo.toml

@@ -10,7 +10,6 @@ common = { path = "../common" }
 
 nostr-sdk.workspace = true
 gpui.workspace = true
-smol.workspace = true
 anyhow.workspace = true
 log.workspace = true
 smallvec.workspace = true
@@ -18,3 +17,6 @@ serde.workspace = true
 serde_json.workspace = true
 
 paste = "1.0.15"
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+smol.workspace = true

crates/settings/src/lib.rs

@@ -1,4 +1,3 @@
-use std::fmt::Display;
 use std::rc::Rc;
 
 use anyhow::{Error, anyhow};
@@ -13,6 +12,9 @@ pub fn init(window: &mut Window, cx: &mut App) {
     AppSettings::set_global(cx.new(|cx| AppSettings::new(window, cx)), cx)
 }
 
+const DEFAULT_FILE_SERVER: &str = "https://nostr.download/";
+const LEGACY_FILE_SERVER: &str = "blossom.band";
+
 macro_rules! setting_accessors {
     ($(pub $field:ident: $type:ty),* $(,)?) => {
         impl AppSettings {
@@ -42,26 +44,10 @@ setting_accessors! {
     pub hide_avatar: bool,
     pub screening: bool,
     pub nip4e: bool,
-    pub auth_mode: AuthMode,
     pub trusted_relays: Vec<String>,
     pub file_server: Url,
-}
-
-/// Authentication mode
-#[derive(Debug, Clone, Default, Serialize, Deserialize, PartialEq, Eq, PartialOrd, Ord)]
-pub enum AuthMode {
-    #[default]
-    Auto,
-    Manual,
-}
-
-impl Display for AuthMode {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            AuthMode::Auto => write!(f, "Auto"),
-            AuthMode::Manual => write!(f, "Ask every time"),
-        }
-    }
+    pub pinned_rooms: Vec<u64>,
+    pub expanded_sections: Option<Vec<String>>,
 }
 
 /// Signer kind
@@ -141,14 +127,19 @@ pub struct Settings {
     /// Enable decoupling encryption key
     pub nip4e: bool,
 
-    /// Authentication mode
-    pub auth_mode: AuthMode,
-
     /// Trusted relays; Coop will automatically authenticate with these relays
     pub trusted_relays: Vec<String>,
 
     /// Server for blossom media attachments
     pub file_server: Url,
+
+    /// Pinned sidebar room ids, in pin order
+    #[serde(default)]
+    pub pinned_rooms: Vec<u64>,
+
+    /// Expanded sidebar tree sections; `None` means the default sections
+    #[serde(default)]
+    pub expanded_sections: Option<Vec<String>>,
 }
 
 impl Default for Settings {
@@ -159,9 +150,10 @@ impl Default for Settings {
             hide_avatar: false,
             screening: true,
             nip4e: false,
-            auth_mode: AuthMode::default(),
             trusted_relays: vec![],
-            file_server: Url::parse("https://blossom.band/").unwrap(),
+            file_server: Url::parse(DEFAULT_FILE_SERVER).unwrap(),
+            pinned_rooms: vec![],
+            expanded_sections: None,
         }
     }
 }
@@ -191,6 +183,13 @@ impl AppSettings {
         cx.global::<GlobalAppSettings>().0.clone()
     }
 
+    /// The underlying settings entity, which notifies whenever any field changes.
+    /// Settings load asynchronously, so observers can watch it to pick up values
+    /// that arrive after construction.
+    pub fn entity(&self) -> &Entity<Settings> {
+        &self.inner
+    }
+
     /// Set the global settings instance
     fn set_global(state: Entity<Self>, cx: &mut App) {
         cx.set_global(GlobalAppSettings(state));
@@ -229,17 +228,23 @@ impl AppSettings {
     /// Load settings
     fn load(&mut self, window: &mut Window, cx: &mut Context<Self>) {
         let task: Task<Result<Settings, Error>> = cx.background_spawn(async move {
-            let path = config_dir().join(".settings");
-
-            if let Ok(content) = smol::fs::read_to_string(&path).await {
-                Ok(serde_json::from_str(&content)?)
-            } else {
-                Err(anyhow!("Not found"))
+            #[cfg(not(target_arch = "wasm32"))]
+            {
+                let path = config_dir().join(".settings");
+                if let Ok(content) = smol::fs::read_to_string(&path).await {
+                    return Ok(serde_json::from_str(&content)?);
+                }
             }
+            Err(anyhow!("Not found"))
         });
 
         cx.spawn_in(window, async move |this, cx| {
-            let settings = task.await.unwrap_or(Settings::default());
+            let mut settings = task.await.unwrap_or(Settings::default());
+
+            // Move settings still pointed at the old default file server over to the new one
+            if settings.file_server.host_str() == Some(LEGACY_FILE_SERVER) {
+                settings.file_server = Url::parse(DEFAULT_FILE_SERVER).unwrap();
+            }
 
             // Update settings
             this.update_in(cx, |this, window, cx| {
@@ -254,11 +259,10 @@ impl AppSettings {
     /// Save settings
     pub fn save(&mut self, cx: &mut Context<Self>) {
         let settings = self.inner.read(cx);
-
         if let Ok(content) = serde_json::to_string(&settings) {
+            #[cfg(not(target_arch = "wasm32"))]
             cx.background_spawn(async move {
                 let path = config_dir().join(".settings");
-                // Write settings to file
                 smol::fs::write(&path, content).await.ok();
             })
             .detach();

crates/state/Cargo.toml

@@ -9,22 +9,31 @@ common = { path = "../common" }
 
 nostr.workspace = true
 nostr-sdk.workspace = true
-nostr-lmdb.workspace = true
 nostr-gossip-memory.workspace = true
-nostr-connect.workspace = true
 nostr-blossom.workspace = true
+nostr-connect.workspace = true
 
 gpui.workspace = true
-gpui_tokio.workspace = true
-smol.workspace = true
+instant.workspace = true
 flume.workspace = true
+futures.workspace = true
 log.workspace = true
 anyhow.workspace = true
 webbrowser.workspace = true
-serde.workspace = true
 serde_json.workspace = true
 
-rustls = "0.23"
-petname = "2.0.2"
-whoami = "1.6.1"
 mime_guess = "2.0.4"
+
+aes-gcm.workspace = true
+sha2.workspace = true
+data-encoding.workspace = true
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+nostr-memory.workspace = true
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+browser-signer-proxy = { path = "../browser-signer-proxy" }
+nostr-lmdb.workspace = true
+smol.workspace = true
+gpui_tokio.workspace = true
+rustls = "0.23"

crates/state/src/blossom.rs

@@ -1,27 +1,56 @@
 use std::path::PathBuf;
 
-use anyhow::{anyhow, Error};
+use anyhow::{Error, anyhow};
 use gpui::AsyncApp;
+#[cfg(not(target_arch = "wasm32"))]
 use gpui_tokio::Tokio;
+#[cfg(not(target_arch = "wasm32"))]
 use mime_guess::from_path;
 use nostr_blossom::prelude::*;
 use nostr_sdk::prelude::*;
 
-pub async fn upload(server: Url, path: PathBuf, cx: &AsyncApp) -> Result<Url, Error> {
-    let content_type = from_path(&path).first_or_octet_stream().to_string();
-    let data = smol::fs::read(path).await?;
-    let keys = Keys::generate();
+#[cfg(not(target_arch = "wasm32"))]
+use crate::file::sha256_hex;
 
-    // Construct the blossom client
-    let client = BlossomClient::new(server);
+/// Upload a blob to a blossom server and return its URL
+#[cfg(not(target_arch = "wasm32"))]
+pub(crate) async fn upload_blob(
+    server: &Url,
+    data: Vec<u8>,
+    content_type: &str,
+    sha256: &str,
+    cx: &AsyncApp,
+) -> Result<Url, Error> {
+    let client = BlossomClient::new(server.clone());
+    let keys = Keys::generate();
+    let content_type = content_type.to_string();
+    let base = server.clone();
+    let hash = sha256.to_string();
 
     Tokio::spawn(cx, async move {
-        let blob = client
+        match client
             .upload_blob(data, Some(content_type), None, Some(&keys))
-            .await?;
-
-        Ok(blob.url)
+            .await
+        {
+            Ok(blob) => Ok(blob.url),
+            Err(e) if e.to_string().contains("201 Created") => Ok::<Url, Error>(base.join(&hash)?),
+            Err(e) => Err(anyhow!(e.to_string())),
+        }
     })
     .await
     .map_err(|e| anyhow!("Upload error: {e}"))?
 }
+
+#[cfg(not(target_arch = "wasm32"))]
+pub async fn upload(server: Url, path: PathBuf, cx: &AsyncApp) -> Result<Url, Error> {
+    let content_type = from_path(&path).first_or_octet_stream().to_string();
+    let data = smol::fs::read(&path).await?;
+    let sha256 = sha256_hex(&data);
+
+    upload_blob(&server, data, &content_type, &sha256, cx).await
+}
+
+#[cfg(target_arch = "wasm32")]
+pub async fn upload(_server: Url, _path: PathBuf, _cx: &AsyncApp) -> Result<Url, Error> {
+    Err(anyhow!("File upload not supported on web"))
+}

crates/state/src/constants.rs

@@ -8,14 +8,12 @@ pub const COOP_PUBKEY: &str = "npub1j3rz3ndl902lya6ywxvy5c983lxs8mpukqnx4pa4lt5w
 pub const APP_ID: &str = "su.reya.coop";
 
 /// Keyring name
-pub const KEYRING: &str = "Coop Safe Storage";
+pub const MASTER_KEYRING: &str = "Coop Master Key";
+pub const USER_KEYRING: &str = "Coop User Credential";
 
 /// Default timeout for subscription
 pub const TIMEOUT: u64 = 2;
 
-/// Default image cache size
-pub const IMAGE_CACHE_SIZE: usize = 20;
-
 /// Default delay for searching
 pub const FIND_DELAY: u64 = 600;
 
@@ -38,14 +36,15 @@ pub const NOSTR_CONNECT_RELAY: &str = "wss://relay.nip46.com";
 pub const WOT_RELAYS: [&str; 1] = ["wss://relay.vertexlab.io"];
 
 /// Default search relays
-pub const INDEXER_RELAYS: [&str; 1] = ["wss://indexer.coracle.social"];
+pub const INDEXER_RELAYS: [&str; 2] = ["wss://indexer.coracle.social", "wss://user.kindpag.es"];
 
 /// Default search relays
 pub const SEARCH_RELAYS: [&str; 2] = ["wss://antiprimal.net", "wss://search.nos.today"];
 
 /// Default bootstrap relays
-pub const BOOTSTRAP_RELAYS: [&str; 3] = [
-    "wss://relay.damus.io",
+pub const BOOTSTRAP_RELAYS: [&str; 4] = [
+    "wss://relay.ditto.pub",
     "wss://relay.primal.net",
-    "wss://user.kindpag.es",
+    "wss://relay.nostr.net",
+    "wss://profiles.nostr1.com",
 ];

crates/state/src/file.rs

@@ -0,0 +1,337 @@
+use std::path::PathBuf;
+
+use aes_gcm::aead::consts::{U12, U16, U32};
+use aes_gcm::aead::{Aead, AeadCore, KeyInit, OsRng};
+use aes_gcm::aes::Aes256;
+use aes_gcm::{Aes256Gcm, AesGcm, Nonce};
+use anyhow::{Error, anyhow, bail};
+use data_encoding::HEXLOWER;
+use futures::AsyncReadExt;
+use gpui::http_client::AsyncBody;
+use gpui::{AsyncApp, SharedString};
+#[cfg(not(target_arch = "wasm32"))]
+use mime_guess::from_path;
+use nostr::nips::nip94::Sha256Hash;
+use nostr_sdk::prelude::*;
+use sha2::{Digest, Sha256};
+
+pub const ALGORITHM: &str = "aes-gcm";
+
+pub const MAX_FILE_SIZE: usize = 25 * 1024 * 1024;
+
+const TAG_SHA256: &str = "x";
+const TAG_ORIGINAL_SHA256: &str = "ox";
+const TAG_FILE_TYPE: &str = "file-type";
+const TAG_ALGORITHM: &str = "encryption-algorithm";
+const TAG_KEY: &str = "decryption-key";
+const TAG_NONCE: &str = "decryption-nonce";
+const TAG_SIZE: &str = "size";
+const TAG_DIM: &str = "dim";
+const TAG_ALT: &str = "alt";
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct EncryptedFile {
+    pub data: Vec<u8>,
+    pub key: String,
+    pub nonce: String,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct FileAttachment {
+    pub url: Url,
+    pub mime: String,
+    pub key: String,
+    pub nonce: String,
+    pub sha256: Option<String>,
+    pub original_sha256: Option<String>,
+    pub size: Option<u64>,
+    pub dim: Option<(u32, u32)>,
+    pub name: Option<String>,
+}
+
+impl FileAttachment {
+    pub fn tags(&self) -> Vec<Tag> {
+        let mut tags = vec![
+            Tag::custom(TAG_FILE_TYPE, [self.mime.clone()]),
+            Tag::custom(TAG_ALGORITHM, [ALGORITHM]),
+            Tag::custom(TAG_KEY, [self.key.clone()]),
+            Tag::custom(TAG_NONCE, [self.nonce.clone()]),
+        ];
+
+        if let Some(sha256) = &self.sha256 {
+            tags.push(Tag::custom(TAG_SHA256, [sha256.clone()]));
+        }
+
+        if let Some(original_sha256) = &self.original_sha256 {
+            tags.push(Tag::custom(TAG_ORIGINAL_SHA256, [original_sha256.clone()]));
+        }
+
+        if let Some(size) = self.size {
+            tags.push(Tag::custom(TAG_SIZE, [size.to_string()]));
+        }
+
+        if let Some((width, height)) = self.dim {
+            tags.push(Tag::custom(TAG_DIM, [format!("{width}x{height}")]));
+        }
+
+        if let Some(name) = &self.name {
+            tags.push(Tag::custom(TAG_ALT, [name.clone()]));
+        }
+
+        tags
+    }
+
+    pub fn from_tags(content: &str, tags: &Tags) -> Option<Self> {
+        if tag_value(tags, TAG_ALGORITHM)? != ALGORITHM {
+            return None;
+        }
+
+        Some(Self {
+            url: Url::parse(content).ok()?,
+            mime: tag_value(tags, TAG_FILE_TYPE)?.to_string(),
+            key: tag_value(tags, TAG_KEY)?.to_string(),
+            nonce: tag_value(tags, TAG_NONCE)?.to_string(),
+            sha256: tag_value(tags, TAG_SHA256).map(str::to_string),
+            original_sha256: tag_value(tags, TAG_ORIGINAL_SHA256).map(str::to_string),
+            size: tag_value(tags, TAG_SIZE).and_then(|size| size.parse().ok()),
+            dim: tag_value(tags, TAG_DIM).and_then(parse_dim),
+            name: tag_value(tags, TAG_ALT).map(str::to_string),
+        })
+    }
+
+    pub fn is_image(&self) -> bool {
+        self.mime.starts_with("image/")
+    }
+
+    pub fn display_name(&self) -> SharedString {
+        if let Some(name) = &self.name {
+            return name.clone().into();
+        }
+
+        match self.size {
+            Some(size) => format!("{} ({size} bytes)", self.mime).into(),
+            None => self.mime.clone().into(),
+        }
+    }
+}
+
+pub fn encrypt(data: &[u8]) -> Result<EncryptedFile, Error> {
+    let key = Aes256Gcm::generate_key(OsRng);
+    let nonce = AesGcm::<Aes256, U16>::generate_nonce(OsRng);
+    let cipher = AesGcm::<Aes256, U16>::new(&key);
+
+    let data = cipher
+        .encrypt(&nonce, data)
+        .map_err(|_| anyhow!("Failed to encrypt file"))?;
+
+    Ok(EncryptedFile {
+        data,
+        key: HEXLOWER.encode(key.as_slice()),
+        nonce: HEXLOWER.encode(nonce.as_slice()),
+    })
+}
+
+pub fn decrypt(data: &[u8], key: &str, nonce: &str) -> Result<Vec<u8>, Error> {
+    let key = decode(key, "decryption key")?;
+    let nonce = decode(nonce, "decryption nonce")?;
+
+    if key.len() != 32 {
+        bail!(
+            "Invalid decryption key length: expected 32 bytes, got {}",
+            key.len()
+        );
+    }
+
+    match nonce.len() {
+        12 => Aes256Gcm::new_from_slice(&key)
+            .map_err(|_| anyhow!("Invalid decryption key"))?
+            .decrypt(Nonce::<U12>::from_slice(&nonce), data)
+            .map_err(|_| anyhow!("Failed to decrypt file")),
+        16 => AesGcm::<Aes256, U16>::new_from_slice(&key)
+            .map_err(|_| anyhow!("Invalid decryption key"))?
+            .decrypt(Nonce::<U16>::from_slice(&nonce), data)
+            .map_err(|_| anyhow!("Failed to decrypt file")),
+        32 => AesGcm::<Aes256, U32>::new_from_slice(&key)
+            .map_err(|_| anyhow!("Invalid decryption key"))?
+            .decrypt(Nonce::<U32>::from_slice(&nonce), data)
+            .map_err(|_| anyhow!("Failed to decrypt file")),
+        len => bail!("Unsupported decryption nonce length: {len} bytes"),
+    }
+}
+
+pub fn sha256_hex(data: &[u8]) -> String {
+    let hash: [u8; 32] = Sha256::digest(data).into();
+
+    Sha256Hash::from_byte_array(hash).to_hex()
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+pub async fn upload_encrypted(
+    server: Url,
+    path: PathBuf,
+    cx: &AsyncApp,
+) -> Result<FileAttachment, Error> {
+    let mime = from_path(&path).first_or_octet_stream().to_string();
+    let name = path
+        .file_name()
+        .map(|name| name.to_string_lossy().into_owned());
+    let data = smol::fs::read(&path).await?;
+
+    let encrypted = encrypt(&data)?;
+    let sha256 = sha256_hex(&encrypted.data);
+    let original_sha256 = sha256_hex(&data);
+    let size = encrypted.data.len() as u64;
+    let base_url = server.to_string();
+
+    let url = crate::blossom::upload_blob(
+        &server,
+        encrypted.data,
+        "application/octet-stream",
+        &sha256,
+        cx,
+    )
+    .await
+    .map_err(|e| {
+        let message = e.to_string();
+
+        if !message.contains("415") {
+            return anyhow!(message);
+        }
+
+        anyhow!(
+            "{base_url} rejected the encrypted file. Encrypted attachments are uploaded as
+             opaque data, which this file server does not accept. Choose a different file
+             server in the settings."
+        )
+    })?;
+
+    Ok(FileAttachment {
+        url,
+        mime,
+        key: encrypted.key,
+        nonce: encrypted.nonce,
+        sha256: Some(sha256),
+        original_sha256: Some(original_sha256),
+        size: Some(size),
+        dim: None,
+        name,
+    })
+}
+
+#[cfg(target_arch = "wasm32")]
+pub async fn upload_encrypted(
+    _server: Url,
+    _path: PathBuf,
+    _cx: &AsyncApp,
+) -> Result<FileAttachment, Error> {
+    Err(anyhow!("File upload not supported on web"))
+}
+
+pub async fn download_and_decrypt(
+    url: &Url,
+    key: &str,
+    nonce: &str,
+    expected_sha256: Option<&str>,
+    cx: &AsyncApp,
+) -> Result<Vec<u8>, Error> {
+    let client = cx.update(|app| app.http_client());
+    let response = client.get(url.as_str(), AsyncBody::default(), true).await?;
+
+    if !response.status().is_success() {
+        bail!("Failed to download file: HTTP {}", response.status());
+    }
+
+    let mut data = Vec::new();
+    response
+        .into_body()
+        .take(MAX_FILE_SIZE as u64 + 1)
+        .read_to_end(&mut data)
+        .await?;
+
+    if data.len() > MAX_FILE_SIZE {
+        bail!("File is too large (max {MAX_FILE_SIZE} bytes)");
+    }
+
+    if let Some(expected) = expected_sha256
+        && !sha256_hex(&data).eq_ignore_ascii_case(expected)
+    {
+        bail!("File hash mismatch");
+    }
+
+    decrypt(&data, key, nonce)
+}
+
+/// Download and decrypt a file attachment into a temporary file.
+///
+/// The same attachment always maps to the same path, so callers can render the
+/// result directly (e.g. with `img`) without downloading it more than once.
+#[cfg(not(target_arch = "wasm32"))]
+pub async fn download_and_decrypt_to_file(
+    file: &FileAttachment,
+    cx: &AsyncApp,
+) -> Result<PathBuf, Error> {
+    let name = file
+        .sha256
+        .clone()
+        .unwrap_or_else(|| sha256_hex(file.url.as_str().as_bytes()));
+
+    let extension = mime_guess::get_mime_extensions_str(&file.mime)
+        .and_then(|extensions| extensions.first())
+        .copied()
+        .unwrap_or("bin");
+
+    let path = std::env::temp_dir()
+        .join("coop-files")
+        .join(format!("{name}.{extension}"));
+
+    if smol::fs::metadata(&path).await.is_ok() {
+        return Ok(path);
+    }
+
+    let data = download_and_decrypt(
+        &file.url,
+        &file.key,
+        &file.nonce,
+        file.sha256.as_deref(),
+        cx,
+    )
+    .await?;
+
+    let Some(parent) = path.parent() else {
+        bail!("Invalid file path");
+    };
+    smol::fs::create_dir_all(parent).await?;
+
+    // Write under a temporary name first, so an interrupted download is never reused
+    let partial = path.with_extension("download");
+    smol::fs::write(&partial, data).await?;
+    smol::fs::rename(&partial, &path).await?;
+
+    Ok(path)
+}
+
+#[cfg(target_arch = "wasm32")]
+pub async fn download_and_decrypt_to_file(
+    _file: &FileAttachment,
+    _cx: &AsyncApp,
+) -> Result<PathBuf, Error> {
+    Err(anyhow!("File download not supported on web"))
+}
+
+fn tag_value<'a>(tags: &'a Tags, name: &str) -> Option<&'a str> {
+    tags.iter()
+        .find(|tag| tag.kind() == name)
+        .and_then(|tag| tag.content())
+}
+
+fn parse_dim(value: &str) -> Option<(u32, u32)> {
+    let (width, height) = value.split_once('x')?;
+
+    Some((width.parse().ok()?, height.parse().ok()?))
+}
+
+fn decode(value: &str, label: &str) -> Result<Vec<u8>, Error> {
+    HEXLOWER
+        .decode(value.to_ascii_lowercase().as_bytes())
+        .map_err(|_| anyhow!("Invalid {label} encoding"))
+}

crates/state/src/lib.rs

@@ -1,36 +1,48 @@
 use std::collections::HashMap;
-use std::time::Duration;
 
 use anyhow::{Error, anyhow};
+#[cfg(not(target_arch = "wasm32"))]
+use browser_signer_proxy::prelude::*;
 use common::config_dir;
-use gpui::{App, AppContext, Context, Entity, EventEmitter, Global, SharedString, Task, Window};
+use gpui::{App, AppContext, Context, Entity, EventEmitter, Global, Task, Window};
+use gpui_tokio::Tokio;
+use instant::Duration;
 use nostr_connect::prelude::*;
 use nostr_gossip_memory::prelude::*;
+#[cfg(not(target_arch = "wasm32"))]
 use nostr_lmdb::prelude::*;
+#[cfg(target_arch = "wasm32")]
+use nostr_memory::prelude::*;
 use nostr_sdk::prelude::*;
 
 mod blossom;
 mod constants;
+mod file;
 mod nip05;
 mod nip4e;
+mod signer;
 
 pub use blossom::*;
 pub use constants::*;
+pub use file::*;
 pub use nip4e::*;
 pub use nip05::*;
+pub use signer::{CoopAuthUrlHandler, UniversalSigner};
 
-pub fn init(window: &mut Window, cx: &mut App) {
+pub fn init(window: &mut Window, cx: &mut App, cli_key: Option<SecretKey>) {
     // rustls uses the `aws_lc_rs` provider by default
     // This only errors if the default provider has already
     // been installed. We can ignore this `Result`.
+    #[cfg(not(target_arch = "wasm32"))]
     rustls::crypto::aws_lc_rs::default_provider()
         .install_default()
         .ok();
 
     // Initialize the tokio runtime
+    #[cfg(not(target_arch = "wasm32"))]
     gpui_tokio::init(cx);
 
-    NostrRegistry::set_global(cx.new(|cx| NostrRegistry::new(window, cx)), cx);
+    NostrRegistry::set_global(cx.new(|cx| NostrRegistry::new(window, cx, cli_key)), cx);
 }
 
 struct GlobalNostrRegistry(Entity<NostrRegistry>);
@@ -40,18 +52,24 @@ impl Global for GlobalNostrRegistry {}
 /// Signer event.
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub enum StateEvent {
-    /// Connecting to the bootstrapping relay
-    Connecting,
-    /// Connected to the bootstrapping relay
-    Connected,
+    /// The state is busy
+    Busy,
+    /// User has no signer
+    NoSigner,
+    /// The signer has changed
+    SignerChanged,
     /// An error occurred
-    Error(SharedString),
+    Error(String),
 }
 
 impl StateEvent {
+    pub fn signer_changed(&self) -> bool {
+        matches!(self, StateEvent::SignerChanged)
+    }
+
     pub fn error<T>(error: T) -> Self
     where
-        T: Into<SharedString>,
+        T: Into<String>,
     {
         Self::Error(error.into())
     }
@@ -63,8 +81,11 @@ pub struct NostrRegistry {
     /// Nostr client
     client: Client,
 
-    /// Currently active signer
-    pub signer: Entity<Option<Keys>>,
+    /// Universal signer
+    signer: UniversalSigner,
+
+    /// Current user's public key
+    current_user: Option<PublicKey>,
 
     /// Tasks for asynchronous operations
     tasks: Vec<Task<Result<(), Error>>>,
@@ -84,19 +105,25 @@ impl NostrRegistry {
     }
 
     /// Create a new nostr instance
-    fn new(window: &mut Window, cx: &mut Context<Self>) -> Self {
-        let signer = cx.new(|_| None);
+    fn new(window: &mut Window, cx: &mut Context<Self>, cli_key: Option<SecretKey>) -> Self {
+        let signer = UniversalSigner::new(Keys::generate());
+        let authenticator = SignerAuthenticator::new(signer.clone());
 
         // Construct the nostr lmdb instance
-        let lmdb = cx.foreground_executor().block_on(async move {
+        #[cfg(not(target_arch = "wasm32"))]
+        let database = cx.foreground_executor().block_on(async move {
             NostrLmdb::open(config_dir().join("nostr"))
                 .await
                 .expect("Failed to initialize database")
         });
 
+        #[cfg(target_arch = "wasm32")]
+        let database = MemoryDatabase::unbounded();
+
         // Construct the nostr client
         let client = ClientBuilder::default()
-            .database(lmdb)
+            .database(database)
+            .authenticator(authenticator)
             .gossip(NostrGossipMemory::unbounded())
             .gossip_config(GossipConfig::default().no_background_refresh())
             .connect_timeout(Duration::from_secs(10))
@@ -105,14 +132,25 @@ impl NostrRegistry {
             })
             .build();
 
-        // Run at the end of current cycle
+        // Connect to bootstrap relays after the window is ready
         cx.defer_in(window, |this, _window, cx| {
-            this.connect(cx);
+            this.connect_bootstrap_relays(cx);
+
+            if cfg!(target_arch = "wasm32") {
+                cx.emit(StateEvent::NoSigner);
+            } else if let Some(secret) = cli_key {
+                // Use CLI-provided key -- same path as get_user_credential
+                let keys = Keys::new(secret);
+                this.set_signer(keys, cx);
+            } else {
+                this.get_user_credential(cx);
+            }
         });
 
         Self {
             client,
             signer,
+            current_user: None,
             tasks: vec![],
         }
     }
@@ -122,26 +160,48 @@ impl NostrRegistry {
         self.client.clone()
     }
 
-    /// Get the signer
-    pub fn signer(&self, cx: &App) -> Option<Keys> {
-        self.signer.read(cx).clone()
+    /// Get the current signer
+    pub fn signer(&self) -> UniversalSigner {
+        self.signer.clone()
     }
 
-    /// Get the public key of the signer
-    pub fn signer_pubkey(&self, cx: &App) -> Option<PublicKey> {
-        self.signer.read(cx).as_ref().map(|s| s.public_key())
+    /// Get the current user's public key
+    pub fn current_user(&self) -> Option<PublicKey> {
+        self.current_user
     }
 
-    /// Set the signer to the given keys
-    pub fn set_signer(&mut self, new_keys: Keys, cx: &mut Context<Self>) {
-        self.signer.update(cx, |this, cx| {
-            *this = Some(new_keys);
-            cx.notify();
+    /// Update the signer
+    pub fn set_signer<T>(&mut self, new_signer: T, cx: &mut Context<Self>)
+    where
+        T: AsyncGetPublicKey + AsyncSignEvent + AsyncNip44 + 'static,
+        <T as AsyncGetPublicKey>::Error: std::error::Error + Send + Sync + 'static,
+        <T as AsyncSignEvent>::Error: std::error::Error + Send + Sync + 'static,
+        <T as AsyncNip44>::Error: std::error::Error + Send + Sync + 'static,
+    {
+        let task = cx.spawn(async move |this, cx| {
+            match new_signer.get_public_key_async().await {
+                Ok(public_key) => {
+                    this.update(cx, |this, cx| {
+                        this.signer.swap_inner(new_signer);
+                        this.current_user = Some(public_key);
+                        cx.emit(StateEvent::SignerChanged);
+                        cx.notify();
+                    })?;
+                }
+                Err(e) => {
+                    this.update(cx, |_this, cx| {
+                        cx.emit(StateEvent::error(e.to_string()));
+                    })?;
+                }
+            };
+
+            Ok(())
         });
+        self.tasks.push(task);
     }
 
     /// Connect to the bootstrapping relays
-    fn connect(&mut self, cx: &mut Context<Self>) {
+    fn connect_bootstrap_relays(&mut self, cx: &mut Context<Self>) {
         let client = self.client();
 
         let task: Task<Result<(), Error>> = cx.background_spawn(async move {
@@ -164,24 +224,174 @@ impl NostrRegistry {
             Ok(())
         });
 
-        // Emit connecting event
-        cx.emit(StateEvent::Connecting);
-
         self.tasks.push(cx.spawn(async move |this, cx| {
             if let Err(e) = task.await {
                 this.update(cx, |_this, cx| {
                     cx.emit(StateEvent::error(e.to_string()));
                 })?;
-            } else {
-                this.update(cx, |_this, cx| {
-                    cx.emit(StateEvent::Connected);
-                })?;
+            }
+            Ok(())
+        }));
+    }
+
+    /// Check the user's credential and set the signer if valid
+    fn get_user_credential(&mut self, cx: &mut Context<Self>) {
+        let user_keyring = cx.read_credentials(USER_KEYRING);
+        let master_keyring = self.get_master_key(cx);
+
+        self.tasks.push(cx.spawn(async move |this, cx| {
+            match user_keyring.await {
+                Ok(Some((_username, secret))) => {
+                    let content = String::from_utf8(secret)?;
+
+                    if content.starts_with("nsec1") {
+                        let secret_key = SecretKey::parse(&content)?;
+                        let keys = Keys::new(secret_key);
+
+                        this.update(cx, |this, cx| {
+                            this.set_signer(keys, cx);
+                            cx.notify();
+                        })?;
+                    } else if content.starts_with("bunker://") {
+                        let keys = master_keyring.await;
+                        let timeout = Duration::from_secs(30);
+                        let uri = NostrConnectUri::parse(content)?;
+
+                        // Construct the nostr connect signer
+                        let mut signer = NostrConnect::new(uri, keys, timeout, None)?;
+
+                        // Handle auth url with the default browser
+                        signer.auth_url_handler(CoopAuthUrlHandler);
+
+                        this.update(cx, |this, cx| {
+                            this.set_signer(signer, cx);
+                            cx.notify();
+                        })?;
+                    } else if content == "proxy" {
+                        #[cfg(not(target_arch = "wasm32"))]
+                        this.update(cx, |this, cx| {
+                            this.connect_proxy(cx);
+                        })?;
+                    }
+                }
+                _ => {
+                    this.update(cx, |_, cx| {
+                        cx.emit(StateEvent::NoSigner);
+                    })?;
+                }
             }
 
             Ok(())
         }));
     }
 
+    /// Get the master key that used for Nostr Connect
+    pub fn get_master_key(&self, cx: &App) -> Task<Keys> {
+        if cfg!(target_arch = "wasm32") {
+            return cx.background_spawn(async move { Keys::generate() });
+        }
+
+        let task = cx.read_credentials(MASTER_KEYRING);
+
+        cx.spawn(async move |cx| {
+            let (keys, new_key) = match task.await {
+                Ok(Some((_user, secret))) => match SecretKey::from_slice(&secret) {
+                    Ok(secret_key) => (Keys::new(secret_key), false),
+                    _ => (Keys::generate(), true),
+                },
+                _ => (Keys::generate(), true),
+            };
+
+            if new_key {
+                let keys_clone = keys.clone();
+                let username = keys_clone.public_key().to_hex();
+                let password = keys_clone.secret_key().to_secret_bytes();
+
+                cx.update(|cx| {
+                    let task = cx.write_credentials(MASTER_KEYRING, &username, &password);
+                    cx.background_spawn(async move { task.await.ok() }).detach();
+                });
+            }
+
+            keys
+        })
+    }
+
+    /// Start the browser proxy
+    #[cfg(not(target_arch = "wasm32"))]
+    pub fn connect_proxy(&mut self, cx: &mut Context<Self>) {
+        let proxy = BrowserSignerProxy::new(BrowserSignerProxyOptions::default());
+        let (tx, rx) = flume::bounded::<String>(1);
+
+        self.tasks.push(Tokio::spawn_result(cx, {
+            let proxy = proxy.clone();
+            async move {
+                // Start the proxy and get the web url
+                proxy.start().await?;
+                // Notify GPUI
+                let url = proxy.url();
+                tx.send(url).ok();
+                Ok(())
+            }
+        }));
+
+        self.tasks.push(Tokio::spawn_result(cx, {
+            let proxy = proxy.clone();
+            async move {
+                loop {
+                    if proxy.is_session_active() {
+                        break;
+                    }
+                    smol::Timer::after(Duration::from_secs(1)).await;
+                }
+                Ok(())
+            }
+        }));
+
+        self.tasks.push(cx.spawn({
+            let proxy = proxy.clone();
+            async move |this, cx| {
+                while let Ok(url) = rx.recv_async().await {
+                    this.update(cx, |this, cx| {
+                        let save = cx.write_credentials(USER_KEYRING, "proxy", b"proxy");
+                        cx.background_spawn(async move { save.await.ok() }).detach();
+                        cx.open_url(&url);
+                        this.set_signer(proxy.clone(), cx);
+                    })?;
+                }
+                Ok(())
+            }
+        }));
+
+        // Monitor the session, if the browser disconnects, notify user to reconnect
+        self.tasks.push(cx.spawn({
+            let proxy = proxy.clone();
+            let executor = cx.background_executor().clone();
+            async move |this, cx| {
+                // Wait for the signer to be confirmed (timeout is 30s)
+                executor.timer(Duration::from_secs(30)).await;
+
+                loop {
+                    executor.timer(Duration::from_secs(5)).await;
+                    if !proxy.is_session_active() {
+                        _ = this.update(cx, |this, cx| {
+                            // Only notify if this proxy is still the active signer
+                            if this.current_user.is_some() {
+                                this.signer.swap_inner(Keys::generate());
+                                this.current_user = None;
+                                cx.emit(StateEvent::NoSigner);
+                                cx.notify();
+                            }
+                        });
+                        break;
+                    }
+                }
+
+                Ok(())
+            }
+        }));
+    }
+
     /// Get the public key of a NIP-05 address
     pub fn query_address(&self, addr: Nip05Address, cx: &App) -> Task<Result<PublicKey, Error>> {
         let client = self.client();
@@ -291,10 +501,7 @@ impl NostrRegistry {
     pub fn wot_search(&self, query: &str, cx: &App) -> Task<Result<Vec<PublicKey>, Error>> {
         let client = self.client();
         let query = query.to_string();
-
-        let Some(signer) = self.signer.read(cx).clone() else {
-            return Task::ready(Err(anyhow!("Signer is required")));
-        };
+        let signer = self.signer.clone();
 
         cx.background_spawn(async move {
             // Construct a vertex request event

crates/state/src/nip05.rs

@@ -1,9 +1,10 @@
 use std::sync::Arc;
 
 use anyhow::Error;
+use futures::io::AsyncReadExt;
 use gpui::http_client::{AsyncBody, HttpClient};
 use nostr_sdk::prelude::*;
-use smol::io::AsyncReadExt;
+use serde_json::Value;
 
 #[allow(async_fn_in_trait)]
 pub trait NostrAddress {

crates/state/src/signer.rs

@@ -0,0 +1,206 @@
+use std::error::Error;
+use std::fmt;
+use std::future::Future;
+use std::pin::Pin;
+use std::sync::{Arc, RwLock};
+
+use nostr_connect::client::AuthUrlHandler;
+use nostr_sdk::prelude::*;
+
+#[derive(Debug)]
+pub struct UniversalSignerError(Box<dyn Error + Send + Sync + 'static>);
+
+impl fmt::Display for UniversalSignerError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+impl Error for UniversalSignerError {
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        Some(&*self.0)
+    }
+}
+
+impl UniversalSignerError {
+    pub fn new<E>(err: E) -> Self
+    where
+        E: Error + Send + Sync + 'static,
+    {
+        UniversalSignerError(Box::new(err))
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct UniversalSigner {
+    inner: Arc<RwLock<Arc<dyn InnerSigner>>>,
+}
+
+impl UniversalSigner {
+    pub fn new<T>(signer: T) -> Self
+    where
+        T: AsyncGetPublicKey + AsyncSignEvent + AsyncNip44 + 'static,
+        <T as AsyncGetPublicKey>::Error: Error + Send + Sync + 'static,
+        <T as AsyncSignEvent>::Error: Error + Send + Sync + 'static,
+        <T as AsyncNip44>::Error: Error + Send + Sync + 'static,
+    {
+        Self {
+            inner: Arc::new(RwLock::new(Arc::new(InnerSignerImpl(signer)))),
+        }
+    }
+
+    /// Swap the inner signer in-place. All clones see the new signer.
+    pub fn swap_inner<T>(&self, new_signer: T)
+    where
+        T: AsyncGetPublicKey + AsyncSignEvent + AsyncNip44 + 'static,
+        <T as AsyncGetPublicKey>::Error: Error + Send + Sync + 'static,
+        <T as AsyncSignEvent>::Error: Error + Send + Sync + 'static,
+        <T as AsyncNip44>::Error: Error + Send + Sync + 'static,
+    {
+        *self.inner.write().expect("RwLock poisoned") = Arc::new(InnerSignerImpl(new_signer));
+    }
+}
+
+trait InnerSigner: fmt::Debug + Send + Sync + 'static {
+    fn get_public_key_async(
+        &self,
+    ) -> Pin<Box<dyn Future<Output = Result<PublicKey, UniversalSignerError>> + Send + '_>>;
+    fn sign_event_async(
+        &self,
+        unsigned: UnsignedEvent,
+    ) -> Pin<Box<dyn Future<Output = Result<Event, UniversalSignerError>> + Send + '_>>;
+    fn nip44_encrypt_async<'a>(
+        &'a self,
+        public_key: &'a PublicKey,
+        content: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, UniversalSignerError>> + Send + 'a>>;
+    fn nip44_decrypt_async<'a>(
+        &'a self,
+        public_key: &'a PublicKey,
+        payload: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, UniversalSignerError>> + Send + 'a>>;
+}
+
+#[derive(Debug)]
+struct InnerSignerImpl<T>(T);
+
+impl<T> InnerSigner for InnerSignerImpl<T>
+where
+    T: AsyncGetPublicKey + AsyncSignEvent + AsyncNip44 + Send + Sync + 'static,
+    <T as AsyncGetPublicKey>::Error: Error + Send + Sync + 'static,
+    <T as AsyncSignEvent>::Error: Error + Send + Sync + 'static,
+    <T as AsyncNip44>::Error: Error + Send + Sync + 'static,
+{
+    fn get_public_key_async(
+        &self,
+    ) -> Pin<Box<dyn Future<Output = Result<PublicKey, UniversalSignerError>> + Send + '_>> {
+        Box::pin(async move {
+            AsyncGetPublicKey::get_public_key_async(&self.0)
+                .await
+                .map_err(UniversalSignerError::new)
+        })
+    }
+
+    fn sign_event_async(
+        &self,
+        unsigned: UnsignedEvent,
+    ) -> Pin<Box<dyn Future<Output = Result<Event, UniversalSignerError>> + Send + '_>> {
+        Box::pin(async move {
+            AsyncSignEvent::sign_event_async(&self.0, unsigned)
+                .await
+                .map_err(UniversalSignerError::new)
+        })
+    }
+
+    fn nip44_encrypt_async<'a>(
+        &'a self,
+        public_key: &'a PublicKey,
+        content: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, UniversalSignerError>> + Send + 'a>> {
+        Box::pin(async move {
+            AsyncNip44::nip44_encrypt_async(&self.0, public_key, content)
+                .await
+                .map_err(UniversalSignerError::new)
+        })
+    }
+
+    fn nip44_decrypt_async<'a>(
+        &'a self,
+        public_key: &'a PublicKey,
+        payload: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, UniversalSignerError>> + Send + 'a>> {
+        Box::pin(async move {
+            AsyncNip44::nip44_decrypt_async(&self.0, public_key, payload)
+                .await
+                .map_err(UniversalSignerError::new)
+        })
+    }
+}
+
+impl UniversalSigner {
+    #[allow(dead_code)]
+    fn with_inner<R>(&self, f: impl FnOnce(&dyn InnerSigner) -> R) -> R {
+        let guard = self.inner.read().expect("RwLock poisoned");
+        f(&**guard)
+    }
+}
+
+impl AsyncGetPublicKey for UniversalSigner {
+    type Error = UniversalSignerError;
+
+    fn get_public_key_async(
+        &self,
+    ) -> Pin<Box<dyn Future<Output = Result<PublicKey, Self::Error>> + Send + '_>> {
+        let inner = self.inner.read().expect("RwLock poisoned").clone();
+        Box::pin(async move { inner.get_public_key_async().await })
+    }
+}
+
+impl AsyncSignEvent for UniversalSigner {
+    type Error = UniversalSignerError;
+
+    fn sign_event_async(
+        &self,
+        unsigned: UnsignedEvent,
+    ) -> Pin<Box<dyn Future<Output = Result<Event, Self::Error>> + Send + '_>> {
+        let inner = self.inner.read().expect("RwLock poisoned").clone();
+        Box::pin(async move { inner.sign_event_async(unsigned).await })
+    }
+}
+
+impl AsyncNip44 for UniversalSigner {
+    type Error = UniversalSignerError;
+
+    fn nip44_encrypt_async<'a>(
+        &'a self,
+        public_key: &'a PublicKey,
+        content: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, Self::Error>> + Send + 'a>> {
+        let inner = self.inner.read().expect("RwLock poisoned").clone();
+        Box::pin(async move { inner.nip44_encrypt_async(public_key, content).await })
+    }
+
+    fn nip44_decrypt_async<'a>(
+        &'a self,
+        public_key: &'a PublicKey,
+        payload: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, Self::Error>> + Send + 'a>> {
+        let inner = self.inner.read().expect("RwLock poisoned").clone();
+        Box::pin(async move { inner.nip44_decrypt_async(public_key, payload).await })
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct CoopAuthUrlHandler;
+
+impl AuthUrlHandler for CoopAuthUrlHandler {
+    fn on_auth_url(
+        &self,
+        auth_url: Url,
+    ) -> Pin<Box<dyn Future<Output = Result<(), nostr_connect::error::Error>> + Send + '_>> {
+        Box::pin(async move {
+            webbrowser::open(auth_url.as_str()).unwrap();
+            Ok(())
+        })
+    }
+}

crates/theme/Cargo.toml

@@ -6,6 +6,7 @@ publish.workspace = true
 
 [dependencies]
 gpui.workspace = true
+gpui-base.workspace = true
 anyhow.workspace = true
 log.workspace = true
 serde.workspace = true

crates/theme/src/colors.rs

@@ -112,7 +112,7 @@ impl ThemeColors {
             elevated_surface_background: neutral().light().step_3(),
             panel_background: neutral().light().step_1(),
             overlay: neutral().light_alpha().step_3(),
-            title_bar: neutral().light().step_3(),
+            title_bar: neutral().light().step_2(),
             title_bar_inactive: neutral().light().step_1(),
             window_border: hsl(240.0, 5.9, 78.0),
 
@@ -198,7 +198,7 @@ impl ThemeColors {
             elevated_surface_background: neutral().dark().step_3(),
             panel_background: neutral().dark().step_1(),
             overlay: neutral().dark_alpha().step_3(),
-            title_bar: neutral().dark().step_3(),
+            title_bar: neutral().dark().step_2(),
             title_bar_inactive: neutral().dark().step_1(),
             window_border: hsl(240.0, 3.7, 28.0),
 

crates/theme/src/lib.rs

@@ -34,7 +34,7 @@ pub const CLIENT_SIDE_DECORATION_BORDER: Pixels = px(1.0);
 pub const TITLEBAR_HEIGHT: Pixels = px(36.0);
 
 /// Defines workspace tabbar height
-pub const TABBAR_HEIGHT: Pixels = px(28.0);
+pub const TABBAR_HEIGHT: Pixels = px(44.0);
 
 /// Defines default sidebar width
 pub const SIDEBAR_WIDTH: Pixels = px(240.);
@@ -46,6 +46,63 @@ pub fn init(cx: &mut App) {
     Theme::sync_scrollbar_appearance(cx);
 }
 
+/// Mirror the active coop theme into the `gpui-base` global theme.
+///
+/// Base paints a few things from its own tokens -- the focus ring, the wash
+/// behind selected text, scrollbars, and overlay backdrops -- so the two
+/// globals have to agree or those details drift away from the palette.
+///
+/// Only roles base can act on are projected. Radius, spacing, typography sizes,
+/// shadows, and scrollbar geometry keep their base defaults: coop has a single
+/// `radius`/`radius_lg`/`font_size` where base has six-point scales, so any
+/// mapping would be invented rather than derived.
+///
+/// This is a no-op before the coop theme global exists; [`Theme::change`] is the
+/// authoritative hook that keeps the projection current.
+pub fn sync_base(cx: &mut App) {
+    let Some(theme) = cx.try_global::<Theme>() else {
+        return;
+    };
+
+    let appearance = if theme.mode.is_dark() {
+        gpui_base::ThemeAppearance::Dark
+    } else {
+        gpui_base::ThemeAppearance::Light
+    };
+    let scrollbar_mode = match theme.scrollbar_mode {
+        ScrollbarMode::Scrolling => gpui_base::ScrollbarMode::Scrolling,
+        ScrollbarMode::Hover => gpui_base::ScrollbarMode::Hover,
+        ScrollbarMode::Always => gpui_base::ScrollbarMode::Always,
+    };
+    let colors = theme.colors;
+    let font_family = theme.font_family.clone();
+
+    let base = gpui_base::Theme::global_mut(cx);
+    base.appearance = appearance;
+    base.scrollbar = base.scrollbar.clone().with_mode(scrollbar_mode);
+    base.tokens.typography.sans = font_family;
+
+    let tokens = &mut base.tokens.colors;
+    tokens.background = colors.background;
+    tokens.foreground = colors.text;
+    tokens.surface = colors.surface_background;
+    tokens.surface_foreground = colors.text;
+    tokens.primary = colors.element_background;
+    tokens.primary_foreground = colors.element_foreground;
+    tokens.secondary = colors.secondary_background;
+    tokens.secondary_foreground = colors.secondary_foreground;
+    tokens.muted = colors.ghost_element_background_alt;
+    tokens.muted_foreground = colors.text_muted;
+    tokens.accent = colors.ghost_element_hover;
+    tokens.accent_foreground = colors.text;
+    tokens.destructive = colors.danger_background;
+    tokens.destructive_foreground = colors.danger_foreground;
+    tokens.border = colors.border;
+    tokens.input = colors.border;
+    tokens.ring = colors.ring;
+    tokens.selection = colors.selection;
+}
+
 pub trait ActiveTheme {
     fn theme(&self) -> &Theme;
 }
@@ -183,6 +240,9 @@ impl Theme {
         if let Some(window) = window {
             window.refresh();
         }
+
+        // Keep the base-layer projection in step with the coop palette
+        sync_base(cx);
     }
 }
 
@@ -192,7 +252,6 @@ impl From<ThemeFamily> for Theme {
         let mode = ThemeMode::default();
 
         // Define the font family based on the platform.
-        // TODO: Use native fonts on Linux too.
         let font_family = match platform {
             PlatformKind::Linux => "Inter",
             _ => ".SystemUIFont",

crates/theme/src/platform_kind.rs

@@ -3,6 +3,7 @@ pub enum PlatformKind {
     Mac,
     Linux,
     Windows,
+    Web,
 }
 
 impl PlatformKind {
@@ -11,22 +12,21 @@ impl PlatformKind {
             Self::Linux
         } else if cfg!(target_os = "windows") {
             Self::Windows
-        } else {
+        } else if cfg!(target_os = "macos") {
             Self::Mac
+        } else {
+            Self::Web
         }
     }
 
-    #[allow(dead_code)]
     pub fn is_linux(&self) -> bool {
         matches!(self, Self::Linux)
     }
 
-    #[allow(dead_code)]
     pub fn is_windows(&self) -> bool {
         matches!(self, Self::Windows)
     }
 
-    #[allow(dead_code)]
     pub fn is_mac(&self) -> bool {
         matches!(self, Self::Mac)
     }

crates/theme/src/theme.rs

@@ -64,7 +64,7 @@ impl Default for ThemeFamily {
             id: "coop".into(),
             name: "Coop Default Theme".into(),
             author: "Coop".into(),
-            url: "https://github.com/lumehq/coop".into(),
+            url: "https://github.com/reyakov/coop".into(),
             light: ThemeColors::light(),
             dark: ThemeColors::dark(),
         }
@@ -186,7 +186,7 @@ mod tests {
             "id": "test-theme",
             "name": "Test Theme",
             "author": "Coop",
-            "url": "https://github.com/lumehq/coop",
+            "url": "https://github.com/reyakov/coop",
             "light": {
                 "background": "#ffffff",
                 "surface_background": "#fafafa",

crates/ui/Cargo.toml

@@ -9,19 +9,15 @@ common = { path = "../common" }
 theme = { path = "../theme" }
 
 gpui.workspace = true
-smol.workspace = true
+gpui-base.workspace = true
+instant.workspace = true
 serde.workspace = true
-serde_json.workspace = true
 smallvec.workspace = true
 anyhow.workspace = true
 itertools.workspace = true
 log.workspace = true
 
-unicode-segmentation = "1.12.0"
 uuid = "1.10"
-regex = "1"
-image = "0.25.1"
-lsp-types = "0.97.0"
-ropey = { version = "=2.0.0-beta.1", features = ["metric_lines_lf", "metric_utf16"] }
-sum_tree = { git = "https://github.com/zed-industries/zed" }
-tree-sitter = "0.26"
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+smol.workspace = true

crates/ui/src/actions.rs

@@ -1,12 +0,0 @@
-use gpui::{actions, Action};
-use serde::Deserialize;
-
-/// Define a custom confirm action
-#[derive(Clone, Action, PartialEq, Eq, Deserialize)]
-#[action(namespace = list, no_json)]
-pub struct Confirm {
-    /// Is confirm with secondary.
-    pub secondary: bool,
-}
-
-actions!(ui, [Cancel, SelectUp, SelectDown, SelectLeft, SelectRight]);

crates/ui/src/avatar.rs

@@ -1,12 +1,25 @@
 use gpui::prelude::FluentBuilder;
 use gpui::{
-    AbsoluteLength, App, Div, Hsla, ImageSource, Img, InteractiveElement, Interactivity,
-    IntoElement, ParentElement, RenderOnce, StyleRefinement, Styled, StyledImage, Window, div, img,
-    px,
+    AbsoluteLength, AnyElement, App, Bounds, Div, Hsla, InteractiveElement, Interactivity,
+    IntoElement, ObjectFit, ParentElement, PathBuilder, Pixels, Point, RenderOnce, SharedString,
+    StyleRefinement, Styled, StyledImage, Window, canvas, div, img, point, px,
 };
 use theme::ActiveTheme;
 
-use crate::{Selectable, Sizable, Size};
+use crate::{Selectable, Sizable, Size, StyledExt};
+
+/// Number of rows and columns in the generated pixel grid.
+const PIXEL_GRID: usize = 8;
+/// Probability that a cell in the left half of the grid is filled.
+const FILL_PROBABILITY: f32 = 0.42;
+/// Probability that a filled cell uses the accent shade instead of the main color.
+const ACCENT_PROBABILITY: f32 = 0.25;
+/// Minimum number of filled left-half cells, so a pattern never reads as empty.
+const MIN_FILLED: usize = 5;
+/// Fallback seed for an avatar that has neither a picture nor a seed of its own.
+const FALLBACK_SEED: &str = "coop";
+/// Number of segments used to approximate the avatar circle.
+const CIRCLE_SEGMENTS: usize = 32;
 
 /// Returns the size of the avatar based on the given [`Size`].
 pub(super) fn avatar_size(size: Size) -> AbsoluteLength {
@@ -19,21 +32,350 @@ pub(super) fn avatar_size(size: Size) -> AbsoluteLength {
     }
 }
 
-/// An element that renders a user avatar with customizable appearance options.
+/// A deterministic, offline pixel-art avatar derived from a seed.
+///
+/// Use it for entities that have no profile picture: the same seed always
+/// renders the same pattern, so identities stay recognizable without a
+/// network round trip. The pattern is painted as geometry and cropped to a
+/// circle, at the same sizes as [`Avatar`].
 ///
 /// # Examples
 ///
 /// ```
-/// use ui::{Avatar};
+/// use ui::avatar::PixelAvatar;
 ///
-/// Avatar::new("path/to/image.png")
-///     .grayscale(true)
-///     .border_color(gpui::red());
+/// PixelAvatar::new("alice");
+/// ```
+#[derive(IntoElement)]
+pub struct PixelAvatar {
+    seed: u64,
+    size: Size,
+    style: StyleRefinement,
+}
+
+impl PixelAvatar {
+    /// Creates a pixel avatar from `seed`.
+    pub fn new(seed: impl AsRef<str>) -> Self {
+        Self {
+            seed: fnv1a(seed.as_ref().as_bytes()),
+            size: Size::Medium,
+            style: StyleRefinement::default(),
+        }
+    }
+}
+
+impl Sizable for PixelAvatar {
+    fn with_size(mut self, size: impl Into<Size>) -> Self {
+        self.size = size.into();
+        self
+    }
+}
+
+impl Styled for PixelAvatar {
+    fn style(&mut self) -> &mut StyleRefinement {
+        &mut self.style
+    }
+}
+
+impl RenderOnce for PixelAvatar {
+    fn render(self, window: &mut Window, _cx: &mut App) -> impl IntoElement {
+        let side = avatar_size(self.size).to_pixels(window.rem_size());
+        let seed = self.seed;
+
+        canvas(
+            move |_bounds, _window, _cx| seed,
+            move |bounds, seed, window, cx| {
+                let theme = cx.theme();
+                let main = Hsla {
+                    h: (theme.icon_accent.h + seed as f32 / u64::MAX as f32) % 1.,
+                    s: 0.6,
+                    l: if theme.is_dark() { 0.6 } else { 0.45 },
+                    a: 1.,
+                };
+                let shade = if theme.is_dark() {
+                    Hsla {
+                        l: (main.l * 1.6).min(0.95),
+                        ..main
+                    }
+                } else {
+                    Hsla {
+                        l: (main.l * 0.45).max(0.18),
+                        ..main
+                    }
+                };
+
+                let circle = circle_polygon(bounds.center(), bounds.size.width.as_f32() / 2.);
+                paint_polygons(window, std::iter::once(&circle), main.opacity(0.16));
+
+                let pattern = pixel_pattern(seed);
+                let mut cells = Vec::new();
+
+                for (value, color) in [(1u8, main), (2u8, shade)] {
+                    cells.clear();
+
+                    for row in 0..PIXEL_GRID {
+                        for col in 0..PIXEL_GRID {
+                            if pattern[row * PIXEL_GRID + col] != value {
+                                continue;
+                            }
+
+                            let cell = clip_polygon(&cell_polygon(&bounds, row, col), &circle);
+                            if cell.len() >= 3 {
+                                cells.push(cell);
+                            }
+                        }
+                    }
+
+                    paint_polygons(window, cells.iter(), color);
+                }
+            },
+        )
+        .refine_style(&self.style)
+        .size(side)
+        .flex_shrink_0()
+    }
+}
+
+/// Builds the mirrored fill pattern for `seed`.
+fn pixel_pattern(seed: u64) -> [u8; PIXEL_GRID * PIXEL_GRID] {
+    let mut rng = PixelRng::new(seed);
+    let mut pattern = [0u8; PIXEL_GRID * PIXEL_GRID];
+    let mut filled = 0usize;
+
+    for row in 0..PIXEL_GRID {
+        for col in 0..PIXEL_GRID / 2 {
+            if rng.chance(FILL_PROBABILITY) {
+                let accent = rng.chance(ACCENT_PROBABILITY);
+                set_cell(&mut pattern, row, col, if accent { 2 } else { 1 });
+                filled += 1;
+            }
+        }
+    }
+
+    if filled < MIN_FILLED {
+        let half = PIXEL_GRID * PIXEL_GRID / 2;
+        let start = (rng.next() % half as u64) as usize;
+
+        for offset in 0..half {
+            if filled >= MIN_FILLED {
+                break;
+            }
+
+            let ix = (start + offset) % half;
+            let row = ix / (PIXEL_GRID / 2);
+            let col = ix % (PIXEL_GRID / 2);
+
+            if pattern[row * PIXEL_GRID + col] == 0 {
+                set_cell(&mut pattern, row, col, 1);
+                filled += 1;
+            }
+        }
+    }
+
+    pattern
+}
+
+/// Paints `polygons` as a single anti-aliased filled path in `color`.
+fn paint_polygons<'a>(
+    window: &mut Window,
+    polygons: impl IntoIterator<Item = &'a Vec<Point<Pixels>>>,
+    color: Hsla,
+) {
+    let mut builder = PathBuilder::fill();
+    let mut painted = false;
+
+    for polygon in polygons {
+        if polygon.len() >= 3 {
+            builder.add_polygon(polygon, true);
+            painted = true;
+        }
+    }
+
+    if painted && let Ok(path) = builder.build() {
+        window.paint_path(path, color);
+    }
+}
+
+/// Approximates the circle of `radius` around `center` as a convex polygon,
+/// wound so that its interior is on the left of every directed edge.
+fn circle_polygon(center: Point<Pixels>, radius: f32) -> Vec<Point<Pixels>> {
+    let center_x = center.x.as_f32();
+    let center_y = center.y.as_f32();
+
+    (0..CIRCLE_SEGMENTS)
+        .map(|index| {
+            let angle = std::f32::consts::TAU * index as f32 / CIRCLE_SEGMENTS as f32;
+            point(
+                px(center_x + radius * angle.cos()),
+                px(center_y + radius * angle.sin()),
+            )
+        })
+        .collect()
+}
+
+/// The four corners of cell `(row, col)` of the grid laid out in `bounds`.
+fn cell_polygon(bounds: &Bounds<Pixels>, row: usize, col: usize) -> [Point<Pixels>; 4] {
+    let cell = bounds.size.width.as_f32() / PIXEL_GRID as f32;
+    let left = bounds.origin.x.as_f32() + col as f32 * cell;
+    let top = bounds.origin.y.as_f32() + row as f32 * cell;
+
+    [
+        point(px(left), px(top)),
+        point(px(left + cell), px(top)),
+        point(px(left + cell), px(top + cell)),
+        point(px(left), px(top + cell)),
+    ]
+}
+
+/// Clips `subject` to the convex `clip` polygon, keeping the part inside it.
+fn clip_polygon(subject: &[Point<Pixels>], clip: &[Point<Pixels>]) -> Vec<Point<Pixels>> {
+    let mut current = subject.to_vec();
+    let mut next = Vec::with_capacity(subject.len() + 4);
+
+    for (&start, &end) in clip.iter().zip(clip.iter().cycle().skip(1)) {
+        if current.is_empty() {
+            break;
+        }
+
+        next.clear();
+        let mut previous = match current.last() {
+            Some(&vertex) => vertex,
+            None => break,
+        };
+
+        for &vertex in current.iter() {
+            let previous_inside = is_inside(start, end, previous);
+            let vertex_inside = is_inside(start, end, vertex);
+
+            if vertex_inside {
+                if !previous_inside
+                    && let Some(crossing) = line_intersection(start, end, previous, vertex)
+                {
+                    next.push(crossing);
+                }
+                next.push(vertex);
+            } else if previous_inside
+                && let Some(crossing) = line_intersection(start, end, previous, vertex)
+            {
+                next.push(crossing);
+            }
+
+            previous = vertex;
+        }
+
+        std::mem::swap(&mut current, &mut next);
+    }
+
+    current
+}
+
+/// Whether `vertex` lies on the interior side of the directed edge `start -> end`.
+fn is_inside(start: Point<Pixels>, end: Point<Pixels>, vertex: Point<Pixels>) -> bool {
+    let start_x = start.x.as_f32();
+    let start_y = start.y.as_f32();
+    let edge_x = end.x.as_f32() - start_x;
+    let edge_y = end.y.as_f32() - start_y;
+    let to_vertex_x = vertex.x.as_f32() - start_x;
+    let to_vertex_y = vertex.y.as_f32() - start_y;
+
+    edge_x * to_vertex_y - edge_y * to_vertex_x >= 0.
+}
+
+/// The intersection of segment `from -> to` with the infinite line `start -> end`.
+fn line_intersection(
+    start: Point<Pixels>,
+    end: Point<Pixels>,
+    from: Point<Pixels>,
+    to: Point<Pixels>,
+) -> Option<Point<Pixels>> {
+    let start_x = start.x.as_f32();
+    let start_y = start.y.as_f32();
+    let edge_x = end.x.as_f32() - start_x;
+    let edge_y = end.y.as_f32() - start_y;
+    let from_x = from.x.as_f32();
+    let from_y = from.y.as_f32();
+    let segment_x = to.x.as_f32() - from_x;
+    let segment_y = to.y.as_f32() - from_y;
+    let denominator = edge_x * segment_y - edge_y * segment_x;
+
+    if denominator.abs() < f32::EPSILON {
+        return None;
+    }
+
+    let offset_x = from_x - start_x;
+    let offset_y = from_y - start_y;
+    let t = (edge_y * offset_x - edge_x * offset_y) / denominator;
+
+    Some(point(
+        px(from_x + segment_x * t),
+        px(from_y + segment_y * t),
+    ))
+}
+
+/// Fills `cell (row, col)` and its horizontal mirror.
+fn set_cell(pattern: &mut [u8; PIXEL_GRID * PIXEL_GRID], row: usize, col: usize, value: u8) {
+    pattern[row * PIXEL_GRID + col] = value;
+    pattern[row * PIXEL_GRID + (PIXEL_GRID - 1 - col)] = value;
+}
+
+/// FNV-1a 64-bit hash, stable across platforms and runs.
+fn fnv1a(bytes: &[u8]) -> u64 {
+    let mut hash = 0xcbf2_9ce4_8422_2325u64;
+    for &byte in bytes {
+        hash ^= byte as u64;
+        hash = hash.wrapping_mul(0x0000_0100_0000_01b3);
+    }
+    hash
+}
+
+/// Tiny xorshift64* PRNG for deriving the pattern from the seed.
+struct PixelRng(u64);
+
+impl PixelRng {
+    fn new(seed: u64) -> Self {
+        Self(seed.max(1))
+    }
+
+    fn next(&mut self) -> u64 {
+        let mut x = self.0;
+        x ^= x >> 12;
+        x ^= x << 25;
+        x ^= x >> 27;
+        self.0 = x;
+        x.wrapping_mul(0x2545_f491_4f6c_dd1d)
+    }
+
+    fn chance(&mut self, probability: f32) -> bool {
+        self.next() as f32 / (u64::MAX as f32) < probability
+    }
+}
+
+/// Renders the generated pixel avatar shown in place of a missing picture.
+fn generated_avatar(seed: Option<&str>, size: Pixels) -> AnyElement {
+    PixelAvatar::new(seed.unwrap_or(FALLBACK_SEED))
+        .with_size(size)
+        .into_any_element()
+}
+
+/// An element that renders a user avatar with customizable appearance options.
+///
+/// Entities without a picture still get a stable identity: the avatar falls
+/// back to a [`PixelAvatar`] seeded through [`Avatar::seed`], both when there
+/// is no picture and when the picture fails to load.
+///
+/// # Examples
+///
+/// ```
+/// use ui::avatar::Avatar;
+///
+/// Avatar::new(None).seed("alice");
 /// ```
 #[derive(IntoElement)]
 pub struct Avatar {
     base: Div,
-    image: Img,
+    picture: Option<SharedString>,
+    grayscale: bool,
+    seed: Option<SharedString>,
     style: StyleRefinement,
     size: Size,
     border_color: Option<Hsla>,
@@ -41,11 +383,16 @@ pub struct Avatar {
 }
 
 impl Avatar {
-    /// Creates a new avatar element with the specified image source.
-    pub fn new(src: impl Into<ImageSource>) -> Self {
+    /// Creates an avatar for an entity whose profile picture may be missing.
+    ///
+    /// Use [`Avatar::seed`] to choose the generated pixel avatar rendered when
+    /// `picture` is `None`.
+    pub fn new(picture: Option<SharedString>) -> Self {
         Avatar {
             base: div(),
-            image: img(src),
+            picture,
+            grayscale: false,
+            seed: None,
             style: StyleRefinement::default(),
             size: Size::Medium,
             border_color: None,
@@ -53,17 +400,26 @@ impl Avatar {
         }
     }
 
+    /// Sets the seed for the generated pixel avatar.
+    ///
+    /// The seed should be a stable identifier of the entity the avatar
+    /// represents, such as a public key.
+    pub fn seed(mut self, seed: impl Into<SharedString>) -> Self {
+        self.seed = Some(seed.into());
+        self
+    }
+
     /// Applies a grayscale filter to the avatar image.
     ///
     /// # Examples
     ///
     /// ```
-    /// use ui::{Avatar, AvatarShape};
+    /// use ui::avatar::Avatar;
     ///
-    /// let avatar = Avatar::new("path/to/image.png").grayscale(true);
+    /// Avatar::new(None).grayscale(true);
     /// ```
     pub fn grayscale(mut self, grayscale: bool) -> Self {
-        self.image = self.image.grayscale(grayscale);
+        self.grayscale = grayscale;
         self
     }
 
@@ -115,8 +471,24 @@ impl RenderOnce for Avatar {
         } else {
             px(0.)
         };
-        let image_size = avatar_size(self.size);
-        let container_size = image_size.to_pixels(window.rem_size()) + border_width * 2.;
+        let image_size = avatar_size(self.size).to_pixels(window.rem_size());
+        let container_size = image_size + border_width * 2.;
+
+        let content = match self.picture {
+            Some(picture) => {
+                let seed = self.seed;
+                let grayscale = self.grayscale;
+                img(picture)
+                    .size(image_size)
+                    .rounded_full()
+                    .object_fit(ObjectFit::Cover)
+                    .grayscale(grayscale)
+                    .bg(cx.theme().ghost_element_background)
+                    .with_fallback(move || generated_avatar(seed.as_deref(), image_size))
+                    .into_any_element()
+            }
+            None => generated_avatar(self.seed.as_deref(), image_size),
+        };
 
         div()
             .flex_shrink_0()
@@ -126,18 +498,79 @@ impl RenderOnce for Avatar {
             .when_some(self.border_color, |this, color| {
                 this.border(border_width).border_color(color)
             })
-            .child(
-                self.image
-                    .size(image_size)
-                    .rounded_full()
-                    .object_fit(gpui::ObjectFit::Fill)
-                    .bg(cx.theme().ghost_element_background)
-                    .with_fallback(move || {
-                        img("brand/avatar.png")
-                            .size(image_size)
-                            .rounded_full()
-                            .into_any_element()
-                    }),
-            )
+            .child(content)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn pixel_patterns_are_symmetric_and_stable() {
+        for seed in 0..50 {
+            let pattern = pixel_pattern(seed);
+            let filled = pattern.iter().filter(|&&cell| cell != 0).count();
+
+            assert!(
+                filled >= MIN_FILLED * 2,
+                "pattern too sparse for seed {seed}"
+            );
+
+            for row in 0..PIXEL_GRID {
+                for col in 0..PIXEL_GRID {
+                    assert_eq!(
+                        pattern[row * PIXEL_GRID + col],
+                        pattern[row * PIXEL_GRID + (PIXEL_GRID - 1 - col)],
+                        "asymmetric pattern for seed {seed} at ({row}, {col})"
+                    );
+                }
+            }
+        }
+
+        for seed in [0, 1, 42, u64::MAX] {
+            assert_eq!(pixel_pattern(seed), pixel_pattern(seed));
+        }
+
+        assert_ne!(pixel_pattern(42), pixel_pattern(43));
+    }
+
+    fn area(polygon: &[Point<Pixels>]) -> f32 {
+        let mut sum: f32 = 0.;
+        for (&a, &b) in polygon.iter().zip(polygon.iter().cycle().skip(1)) {
+            sum += a.x.as_f32() * b.y.as_f32() - b.x.as_f32() * a.y.as_f32();
+        }
+        (sum / 2.).abs()
+    }
+
+    #[test]
+    fn clipping_keeps_only_the_part_inside_the_circle() {
+        let circle = circle_polygon(point(px(10.), px(10.)), 10.);
+        let square = |left: f32, top: f32| {
+            [
+                point(px(left), px(top)),
+                point(px(left + 4.), px(top)),
+                point(px(left + 4.), px(top + 4.)),
+                point(px(left), px(top + 4.)),
+            ]
+        };
+
+        let inside = clip_polygon(&square(8., 8.), &circle);
+        assert!((area(&inside) - 16.).abs() < 0.05, "area {}", area(&inside));
+
+        assert!(clip_polygon(&square(20., 20.), &circle).is_empty());
+
+        let straddling = clip_polygon(&square(0., 0.), &circle);
+        for vertex in &straddling {
+            let delta_x = vertex.x.as_f32() - 10.;
+            let delta_y = vertex.y.as_f32() - 10.;
+            assert!(
+                delta_x.hypot(delta_y) <= 10. + 0.1,
+                "clipped vertex outside the circle"
+            );
+        }
+
+        let area = area(&straddling);
+        assert!(area > 0. && area < 16., "area {area}");
     }
 }

crates/ui/src/button.rs

@@ -2,15 +2,16 @@ use std::rc::Rc;
 
 use gpui::prelude::FluentBuilder as _;
 use gpui::{
-    div, relative, AnyElement, App, ClickEvent, Div, ElementId, Hsla, InteractiveElement,
-    IntoElement, ParentElement, RenderOnce, SharedString, Stateful,
-    StatefulInteractiveElement as _, StyleRefinement, Styled, Window,
+    AnyElement, App, ClickEvent, ElementId, Hsla, InteractiveElement, IntoElement, MouseButton,
+    ParentElement, RenderOnce, SharedString, StatefulInteractiveElement as _, StyleRefinement,
+    Styled, Window, div, relative,
 };
+use gpui_base::Button as BaseButton;
 use theme::ActiveTheme;
 
 use crate::indicator::Indicator;
 use crate::tooltip::Tooltip;
-use crate::{h_flex, Disableable, Icon, IconName, Selectable, Sizable, Size, StyledExt};
+use crate::{Disableable, Icon, IconName, Selectable, Sizable, Size, h_flex};
 
 #[derive(Clone, Copy, PartialEq, Eq)]
 pub struct ButtonCustomVariant {
@@ -114,9 +115,7 @@ pub trait ButtonVariants: Sized {
 #[derive(IntoElement)]
 #[allow(clippy::type_complexity)]
 pub struct Button {
-    id: ElementId,
-    base: Stateful<Div>,
-    style: StyleRefinement,
+    base: BaseButton,
 
     icon: Option<Icon>,
     label: Option<SharedString>,
@@ -151,12 +150,8 @@ impl From<Button> for AnyElement {
 
 impl Button {
     pub fn new(id: impl Into<ElementId>) -> Self {
-        let id = id.into();
-
         Self {
-            id: id.clone(),
-            base: div().flex_shrink_0().id(id),
-            style: StyleRefinement::default(),
+            base: BaseButton::new(id),
             icon: None,
             label: None,
             variant: ButtonVariant::default(),
@@ -301,7 +296,7 @@ impl ButtonVariants for Button {
 
 impl Styled for Button {
     fn style(&mut self) -> &mut StyleRefinement {
-        &mut self.style
+        self.base.style()
     }
 }
 
@@ -318,7 +313,7 @@ impl InteractiveElement for Button {
 }
 
 impl RenderOnce for Button {
-    fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement {
+    fn render(self, _window: &mut Window, cx: &mut App) -> impl IntoElement {
         let style: ButtonVariant = self.variant;
         let clickable = self.clickable();
         let hoverable = self.hoverable();
@@ -329,18 +324,21 @@ impl RenderOnce for Button {
             _ => self.size,
         };
 
-        let focus_handle = window
-            .use_keyed_state(self.id.clone(), cx, |_window, cx| cx.focus_handle())
-            .read(cx)
-            .clone();
-
         self.base
-            .when(!self.disabled, |this| {
-                this.track_focus(
-                    &focus_handle
-                        .tab_index(self.tab_index)
-                        .tab_stop(self.tab_stop),
-                )
+            .tab_index(self.tab_index)
+            .tab_stop(self.tab_stop)
+            .disabled(self.disabled)
+            .when_some(self.on_click.clone(), |this, on_click| {
+                this.on_click(move |event, window, cx| {
+                    // Stop handle any click event when disabled.
+                    // To avoid handle dropdown menu open when button is disabled.
+                    if !clickable {
+                        cx.stop_propagation();
+                        return;
+                    }
+
+                    on_click(event, window, cx);
+                })
             })
             .relative()
             .flex_shrink_0()
@@ -349,7 +347,6 @@ impl RenderOnce for Button {
             .justify_center()
             .cursor_default()
             .overflow_hidden()
-            .refine_style(&self.style)
             .map(|this| match self.rounded {
                 false => this.rounded(cx.theme().radius),
                 true => this.rounded_full(),
@@ -399,8 +396,7 @@ impl RenderOnce for Button {
                     }
                 }
             })
-            .refine_style(&self.style)
-            .on_mouse_down(gpui::MouseButton::Left, move |_, window, cx| {
+            .on_mouse_down(MouseButton::Left, move |_, window, cx| {
                 // Stop handle any click event when disabled.
                 // To avoid handle dropdown menu open when button is disabled.
                 if self.disabled {
@@ -410,18 +406,6 @@ impl RenderOnce for Button {
                 // Avoid focus on mouse down.
                 window.prevent_default();
             })
-            .when_some(self.on_click, |this, on_click| {
-                this.on_click(move |event, window, cx| {
-                    // Stop handle any click event when disabled.
-                    // To avoid handle dropdown menu open when button is disabled.
-                    if !clickable {
-                        cx.stop_propagation();
-                        return;
-                    }
-
-                    on_click(event, window, cx);
-                })
-            })
             .when_some(self.on_hover.filter(|_| hoverable), |this, on_hover| {
                 this.on_hover(move |hovered, window, cx| {
                     (on_hover)(hovered, window, cx);
@@ -617,7 +601,7 @@ impl ButtonVariant {
         };
 
         let fg = match self {
-            ButtonVariant::Primary => cx.theme().text_muted, // TODO: use a different color?
+            ButtonVariant::Primary => cx.theme().text_muted,
             _ => cx.theme().text_muted,
         };
 

crates/ui/src/checkbox.rs

@@ -1,312 +0,0 @@
-use std::rc::Rc;
-use std::time::Duration;
-
-use gpui::prelude::FluentBuilder as _;
-use gpui::{
-    div, px, relative, rems, svg, Animation, AnimationExt, AnyElement, App, Div, ElementId,
-    InteractiveElement, IntoElement, ParentElement, RenderOnce, SharedString,
-    StatefulInteractiveElement, StyleRefinement, Styled, Window,
-};
-use theme::ActiveTheme;
-
-use crate::icon::IconNamed;
-use crate::{v_flex, Disableable, IconName, Selectable, Sizable, Size, StyledExt as _};
-
-/// A Checkbox element.
-#[allow(clippy::type_complexity)]
-#[derive(IntoElement)]
-pub struct Checkbox {
-    id: ElementId,
-    base: Div,
-    style: StyleRefinement,
-    label: Option<SharedString>,
-    children: Vec<AnyElement>,
-    checked: bool,
-    disabled: bool,
-    size: Size,
-    tab_stop: bool,
-    tab_index: isize,
-    on_click: Option<Rc<dyn Fn(&bool, &mut Window, &mut App) + 'static>>,
-}
-
-impl Checkbox {
-    /// Create a new Checkbox with the given id.
-    pub fn new(id: impl Into<ElementId>) -> Self {
-        Self {
-            id: id.into(),
-            base: div(),
-            style: StyleRefinement::default(),
-            label: None,
-            children: Vec::new(),
-            checked: false,
-            disabled: false,
-            size: Size::default(),
-            on_click: None,
-            tab_stop: true,
-            tab_index: 0,
-        }
-    }
-
-    /// Set the label for the checkbox.
-    pub fn label(mut self, label: impl Into<SharedString>) -> Self {
-        self.label = Some(label.into());
-        self
-    }
-
-    /// Set the checked state for the checkbox.
-    pub fn checked(mut self, checked: bool) -> Self {
-        self.checked = checked;
-        self
-    }
-
-    /// Set the click handler for the checkbox.
-    ///
-    /// The `&bool` parameter indicates the new checked state after the click.
-    pub fn on_click(mut self, handler: impl Fn(&bool, &mut Window, &mut App) + 'static) -> Self {
-        self.on_click = Some(Rc::new(handler));
-        self
-    }
-
-    /// Set the tab stop for the checkbox, default is true.
-    pub fn tab_stop(mut self, tab_stop: bool) -> Self {
-        self.tab_stop = tab_stop;
-        self
-    }
-
-    /// Set the tab index for the checkbox, default is 0.
-    pub fn tab_index(mut self, tab_index: isize) -> Self {
-        self.tab_index = tab_index;
-        self
-    }
-
-    #[allow(clippy::type_complexity)]
-    fn handle_click(
-        on_click: &Option<Rc<dyn Fn(&bool, &mut Window, &mut App) + 'static>>,
-        checked: bool,
-        window: &mut Window,
-        cx: &mut App,
-    ) {
-        let new_checked = !checked;
-        if let Some(f) = on_click {
-            (f)(&new_checked, window, cx);
-        }
-    }
-}
-
-impl InteractiveElement for Checkbox {
-    fn interactivity(&mut self) -> &mut gpui::Interactivity {
-        self.base.interactivity()
-    }
-}
-impl StatefulInteractiveElement for Checkbox {}
-
-impl Styled for Checkbox {
-    fn style(&mut self) -> &mut gpui::StyleRefinement {
-        &mut self.style
-    }
-}
-
-impl Disableable for Checkbox {
-    fn disabled(mut self, disabled: bool) -> Self {
-        self.disabled = disabled;
-        self
-    }
-}
-
-impl Selectable for Checkbox {
-    fn selected(self, selected: bool) -> Self {
-        self.checked(selected)
-    }
-
-    fn is_selected(&self) -> bool {
-        self.checked
-    }
-}
-
-impl ParentElement for Checkbox {
-    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
-        self.children.extend(elements);
-    }
-}
-
-impl Sizable for Checkbox {
-    fn with_size(mut self, size: impl Into<Size>) -> Self {
-        self.size = size.into();
-        self
-    }
-}
-
-pub(crate) fn checkbox_check_icon(
-    id: ElementId,
-    size: Size,
-    checked: bool,
-    disabled: bool,
-    window: &mut Window,
-    cx: &mut App,
-) -> impl IntoElement {
-    let toggle_state = window.use_keyed_state(id, cx, |_, _| checked);
-
-    let color = if disabled {
-        cx.theme().text.opacity(0.5)
-    } else {
-        cx.theme().text
-    };
-
-    svg()
-        .absolute()
-        .top_px()
-        .left_px()
-        .map(|this| match size {
-            Size::XSmall => this.size_2(),
-            Size::Small => this.size_2p5(),
-            Size::Medium => this.size_3(),
-            Size::Large => this.size_3p5(),
-            _ => this.size_3(),
-        })
-        .text_color(color)
-        .map(|this| match checked {
-            true => this.path(IconName::Check.path()),
-            _ => this,
-        })
-        .map(|this| {
-            if !disabled && checked != *toggle_state.read(cx) {
-                let duration = Duration::from_secs_f64(0.25);
-                cx.spawn({
-                    let toggle_state = toggle_state.clone();
-                    async move |cx| {
-                        cx.background_executor().timer(duration).await;
-                        toggle_state.update(cx, |this, _| *this = checked);
-                    }
-                })
-                .detach();
-
-                this.with_animation(
-                    ElementId::NamedInteger("toggle".into(), checked as u64),
-                    Animation::new(Duration::from_secs_f64(0.25)),
-                    move |this, delta| {
-                        this.opacity(if checked { 1.0 * delta } else { 1.0 - delta })
-                    },
-                )
-                .into_any_element()
-            } else {
-                this.into_any_element()
-            }
-        })
-}
-
-impl RenderOnce for Checkbox {
-    fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement {
-        let focus_handle = window
-            .use_keyed_state(self.id.clone(), cx, |_, cx| cx.focus_handle())
-            .read(cx)
-            .clone();
-
-        let checked = self.checked;
-        let radius = cx.theme().radius.min(px(4.));
-
-        let border_color = if checked {
-            cx.theme().border_focused
-        } else {
-            cx.theme().border
-        };
-
-        let color = if self.disabled {
-            border_color.opacity(0.5)
-        } else {
-            border_color
-        };
-
-        div().child(
-            self.base
-                .id(self.id.clone())
-                .when(!self.disabled, |this| {
-                    this.track_focus(
-                        &focus_handle
-                            .tab_stop(self.tab_stop)
-                            .tab_index(self.tab_index),
-                    )
-                })
-                .h_flex()
-                .gap_2()
-                .items_start()
-                .line_height(relative(1.))
-                .text_color(cx.theme().text)
-                .map(|this| match self.size {
-                    Size::XSmall => this.text_xs(),
-                    Size::Small => this.text_sm(),
-                    Size::Medium => this.text_base(),
-                    Size::Large => this.text_lg(),
-                    _ => this,
-                })
-                .when(self.disabled, |this| this.text_color(cx.theme().text_muted))
-                .rounded(cx.theme().radius * 0.5)
-                .refine_style(&self.style)
-                .child(
-                    div()
-                        .relative()
-                        .map(|this| match self.size {
-                            Size::XSmall => this.size_3(),
-                            Size::Small => this.size_3p5(),
-                            Size::Medium => this.size_4(),
-                            Size::Large => this.size(rems(1.125)),
-                            _ => this.size_4(),
-                        })
-                        .flex_shrink_0()
-                        .border_1()
-                        .border_color(color)
-                        .rounded(radius)
-                        .when(cx.theme().shadow && !self.disabled, |this| this.shadow_xs())
-                        .map(|this| match checked {
-                            false => this.bg(cx.theme().background),
-                            _ => this.bg(color),
-                        })
-                        .child(checkbox_check_icon(
-                            self.id,
-                            self.size,
-                            checked,
-                            self.disabled,
-                            window,
-                            cx,
-                        )),
-                )
-                .when(self.label.is_some() || !self.children.is_empty(), |this| {
-                    this.child(
-                        v_flex()
-                            .w_full()
-                            .line_height(relative(1.2))
-                            .gap_1()
-                            .map(|this| {
-                                if let Some(label) = self.label {
-                                    this.child(
-                                        div()
-                                            .size_full()
-                                            .text_color(cx.theme().text)
-                                            .when(self.disabled, |this| {
-                                                this.text_color(cx.theme().text_muted)
-                                            })
-                                            .line_height(relative(1.))
-                                            .child(label),
-                                    )
-                                } else {
-                                    this
-                                }
-                            })
-                            .children(self.children),
-                    )
-                })
-                .on_mouse_down(gpui::MouseButton::Left, |_, window, _| {
-                    // Avoid focus on mouse down.
-                    window.prevent_default();
-                })
-                .when(!self.disabled, |this| {
-                    this.on_click({
-                        let on_click = self.on_click.clone();
-                        move |_, window, cx| {
-                            window.prevent_default();
-                            Self::handle_click(&on_click, checked, window, cx);
-                        }
-                    })
-                }),
-        )
-    }
-}

crates/ui/src/dock/dock.rs

@@ -1,436 +0,0 @@
-use std::ops::Deref;
-use std::sync::Arc;
-
-use gpui::prelude::FluentBuilder as _;
-use gpui::{
-    App, AppContext, Axis, Context, Element, Empty, Entity, IntoElement, MouseMoveEvent,
-    MouseUpEvent, ParentElement as _, Pixels, Point, Render, Style, StyleRefinement, Styled as _,
-    WeakEntity, Window, div, px,
-};
-
-use super::{DockArea, DockItem};
-use crate::StyledExt;
-use crate::dock::panel::PanelView;
-use crate::dock::tab_panel::TabPanel;
-use crate::resizable::{PANEL_MIN_SIZE, resize_handle};
-
-#[derive(Clone)]
-struct ResizePanel;
-
-impl Render for ResizePanel {
-    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
-        Empty
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum DockPlacement {
-    Center,
-    Left,
-    Bottom,
-    Right,
-}
-
-impl DockPlacement {
-    fn axis(&self) -> Axis {
-        match self {
-            Self::Left | Self::Right => Axis::Horizontal,
-            Self::Bottom => Axis::Vertical,
-            Self::Center => unreachable!(),
-        }
-    }
-
-    pub fn is_left(&self) -> bool {
-        matches!(self, Self::Left)
-    }
-
-    pub fn is_bottom(&self) -> bool {
-        matches!(self, Self::Bottom)
-    }
-
-    pub fn is_right(&self) -> bool {
-        matches!(self, Self::Right)
-    }
-}
-
-/// The Dock is a fixed container that places at left, bottom, right of the Windows.
-///
-/// This is unlike Panel, it can't be move or add any other panel.
-pub struct Dock {
-    pub(super) placement: DockPlacement,
-    dock_area: WeakEntity<DockArea>,
-
-    /// Dock layout
-    pub(crate) panel: DockItem,
-
-    /// The size is means the width or height of the Dock, if the placement is left or right, the size is width, otherwise the size is height.
-    pub(super) size: Pixels,
-
-    /// Whether the Dock is open
-    pub(super) open: bool,
-
-    /// Whether the Dock is collapsible, default: true
-    pub(super) collapsible: bool,
-
-    /// Whether the Dock is resizing
-    resizing: bool,
-}
-
-impl Dock {
-    pub(crate) fn new(
-        dock_area: WeakEntity<DockArea>,
-        placement: DockPlacement,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) -> Self {
-        let panel = cx.new(|cx| {
-            let mut tab = TabPanel::new(None, dock_area.clone(), window, cx);
-            tab.closable = true;
-            tab
-        });
-
-        let panel = DockItem::Tabs {
-            items: Vec::new(),
-            active_ix: 0,
-            view: panel.clone(),
-        };
-
-        Self::subscribe_panel_events(dock_area.clone(), &panel, window, cx);
-
-        Self {
-            placement,
-            dock_area,
-            panel,
-            open: true,
-            collapsible: true,
-            size: px(200.0),
-            resizing: false,
-        }
-    }
-
-    pub fn left(
-        dock_area: WeakEntity<DockArea>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) -> Self {
-        Self::new(dock_area, DockPlacement::Left, window, cx)
-    }
-
-    pub fn bottom(
-        dock_area: WeakEntity<DockArea>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) -> Self {
-        Self::new(dock_area, DockPlacement::Bottom, window, cx)
-    }
-
-    pub fn right(
-        dock_area: WeakEntity<DockArea>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) -> Self {
-        Self::new(dock_area, DockPlacement::Right, window, cx)
-    }
-
-    /// Update the Dock to be collapsible or not.
-    ///
-    /// And if the Dock is not collapsible, it will be open.
-    pub fn set_collapsible(
-        &mut self,
-        collapsible: bool,
-        _window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        self.collapsible = collapsible;
-        if !collapsible {
-            self.open = true
-        }
-        cx.notify();
-    }
-
-    fn subscribe_panel_events(
-        dock_area: WeakEntity<DockArea>,
-        panel: &DockItem,
-        window: &mut Window,
-        cx: &mut App,
-    ) {
-        match panel {
-            DockItem::Tabs { view, .. } => {
-                window.defer(cx, {
-                    let view = view.clone();
-                    move |window, cx| {
-                        _ = dock_area.update(cx, |this, cx| {
-                            this.subscribe_panel(&view, window, cx);
-                        });
-                    }
-                });
-            }
-            DockItem::Split { items, view, .. } => {
-                for item in items {
-                    Self::subscribe_panel_events(dock_area.clone(), item, window, cx);
-                }
-                window.defer(cx, {
-                    let view = view.clone();
-                    move |window, cx| {
-                        _ = dock_area.update(cx, |this, cx| {
-                            this.subscribe_panel(&view, window, cx);
-                        });
-                    }
-                });
-            }
-            DockItem::Panel { .. } => {
-                // Not supported
-            }
-        }
-    }
-
-    pub fn set_panel(&mut self, panel: DockItem, _window: &mut Window, cx: &mut Context<Self>) {
-        self.panel = panel;
-        cx.notify();
-    }
-
-    pub fn is_open(&self) -> bool {
-        self.open
-    }
-
-    pub fn toggle_open(&mut self, window: &mut Window, cx: &mut Context<Self>) {
-        self.set_open(!self.open, window, cx);
-    }
-
-    /// Returns the size of the Dock, the size is means the width or height of
-    /// the Dock, if the placement is left or right, the size is width,
-    /// otherwise the size is height.
-    pub fn size(&self) -> Pixels {
-        self.size
-    }
-
-    /// Set the size of the Dock.
-    pub fn set_size(&mut self, size: Pixels, _window: &mut Window, cx: &mut Context<Self>) {
-        self.size = size.max(PANEL_MIN_SIZE);
-        cx.notify();
-    }
-
-    /// Set the open state of the Dock.
-    pub fn set_open(&mut self, open: bool, window: &mut Window, cx: &mut Context<Self>) {
-        self.open = open;
-        let item = self.panel.clone();
-        cx.defer_in(window, move |_, window, cx| {
-            item.set_collapsed(!open, window, cx);
-        });
-        cx.notify();
-    }
-
-    /// Add item to the Dock.
-    pub fn add_panel(
-        &mut self,
-        panel: Arc<dyn PanelView>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        self.panel.add_panel(panel, &self.dock_area, window, cx);
-        cx.notify();
-    }
-
-    fn render_resize_handle(
-        &mut self,
-        _window: &mut Window,
-        cx: &mut Context<Self>,
-    ) -> impl IntoElement {
-        let axis = self.placement.axis();
-        let view = cx.entity().clone();
-
-        resize_handle("resize-handle", axis)
-            .placement(self.placement)
-            .on_drag(ResizePanel {}, move |info, _, _, cx| {
-                cx.stop_propagation();
-                view.update(cx, |view, _cx| {
-                    view.resizing = true;
-                });
-                cx.new(|_| info.deref().clone())
-            })
-    }
-
-    fn resize(
-        &mut self,
-        mouse_position: Point<Pixels>,
-        _window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        if !self.resizing {
-            return;
-        }
-
-        let dock_area = self
-            .dock_area
-            .upgrade()
-            .expect("DockArea is missing")
-            .read(cx);
-
-        let area_bounds = dock_area.bounds;
-        let mut left_dock_size = px(0.0);
-        let mut right_dock_size = px(0.0);
-
-        // Get the size of the left dock if it's open and not the current dock
-        if let Some(left_dock) = &dock_area.left_dock
-            && left_dock.entity_id() != cx.entity().entity_id()
-        {
-            let left_dock_read = left_dock.read(cx);
-            if left_dock_read.is_open() {
-                left_dock_size = left_dock_read.size;
-            }
-        }
-
-        // Get the size of the right dock if it's open and not the current dock
-        if let Some(right_dock) = &dock_area.right_dock
-            && right_dock.entity_id() != cx.entity().entity_id()
-        {
-            let right_dock_read = right_dock.read(cx);
-            if right_dock_read.is_open() {
-                right_dock_size = right_dock_read.size;
-            }
-        }
-
-        let size = match self.placement {
-            DockPlacement::Left => mouse_position.x - area_bounds.left(),
-            DockPlacement::Right => area_bounds.right() - mouse_position.x,
-            DockPlacement::Bottom => area_bounds.bottom() - mouse_position.y,
-            DockPlacement::Center => unreachable!(),
-        };
-
-        match self.placement {
-            DockPlacement::Left => {
-                let max_size = area_bounds.size.width - PANEL_MIN_SIZE - right_dock_size;
-                self.size = size.clamp(PANEL_MIN_SIZE, max_size);
-            }
-            DockPlacement::Right => {
-                let max_size = area_bounds.size.width - PANEL_MIN_SIZE - left_dock_size;
-                self.size = size.clamp(PANEL_MIN_SIZE, max_size);
-            }
-            DockPlacement::Bottom => {
-                let max_size = area_bounds.size.height - PANEL_MIN_SIZE;
-                self.size = size.clamp(PANEL_MIN_SIZE, max_size);
-            }
-            DockPlacement::Center => unreachable!(),
-        }
-
-        cx.notify();
-    }
-
-    fn done_resizing(&mut self, _window: &mut Window, _cx: &mut Context<Self>) {
-        self.resizing = false;
-    }
-}
-
-impl Render for Dock {
-    fn render(&mut self, window: &mut Window, cx: &mut Context<Self>) -> impl gpui::IntoElement {
-        if !self.open && !self.placement.is_bottom() {
-            return div();
-        }
-
-        let cache_style = StyleRefinement::default().absolute().size_full();
-
-        div()
-            .relative()
-            .overflow_hidden()
-            .map(|this| match self.placement {
-                DockPlacement::Left | DockPlacement::Right => this.h_flex().h_full().w(self.size),
-                DockPlacement::Bottom => this.w_full().h(self.size),
-                DockPlacement::Center => unreachable!(),
-            })
-            // Bottom Dock should keep the title bar, then user can click the Toggle button
-            .when(!self.open && self.placement.is_bottom(), |this| {
-                this.h(px(29.))
-            })
-            .map(|this| match &self.panel {
-                DockItem::Split { view, .. } => this.child(view.clone()),
-                DockItem::Tabs { view, .. } => this.child(view.clone()),
-                DockItem::Panel { view, .. } => this.child(view.clone().view().cached(cache_style)),
-            })
-            .child(self.render_resize_handle(window, cx))
-            .child(DockElement {
-                view: cx.entity().clone(),
-            })
-    }
-}
-
-struct DockElement {
-    view: Entity<Dock>,
-}
-
-impl IntoElement for DockElement {
-    type Element = Self;
-
-    fn into_element(self) -> Self::Element {
-        self
-    }
-}
-
-impl Element for DockElement {
-    type PrepaintState = ();
-    type RequestLayoutState = ();
-
-    fn id(&self) -> Option<gpui::ElementId> {
-        None
-    }
-
-    fn source_location(&self) -> Option<&'static std::panic::Location<'static>> {
-        None
-    }
-
-    fn request_layout(
-        &mut self,
-        _: Option<&gpui::GlobalElementId>,
-        _: Option<&gpui::InspectorElementId>,
-        window: &mut gpui::Window,
-        cx: &mut App,
-    ) -> (gpui::LayoutId, Self::RequestLayoutState) {
-        (window.request_layout(Style::default(), None, cx), ())
-    }
-
-    fn prepaint(
-        &mut self,
-        _: Option<&gpui::GlobalElementId>,
-        _: Option<&gpui::InspectorElementId>,
-        _: gpui::Bounds<Pixels>,
-        _: &mut Self::RequestLayoutState,
-        _window: &mut Window,
-        _cx: &mut App,
-    ) -> Self::PrepaintState {
-    }
-
-    fn paint(
-        &mut self,
-        _: Option<&gpui::GlobalElementId>,
-        _: Option<&gpui::InspectorElementId>,
-        _: gpui::Bounds<Pixels>,
-        _: &mut Self::RequestLayoutState,
-        _: &mut Self::PrepaintState,
-        window: &mut gpui::Window,
-        cx: &mut App,
-    ) {
-        window.on_mouse_event({
-            let view = self.view.clone();
-            let is_resizing = view.read(cx).resizing;
-            move |e: &MouseMoveEvent, phase, window, cx| {
-                if !is_resizing {
-                    return;
-                }
-                if !phase.bubble() {
-                    return;
-                }
-
-                view.update(cx, |view, cx| view.resize(e.position, window, cx))
-            }
-        });
-
-        // When any mouse up, stop dragging
-        window.on_mouse_event({
-            let view = self.view.clone();
-            move |_: &MouseUpEvent, phase, window, cx| {
-                if phase.bubble() {
-                    view.update(cx, |view, cx| view.done_resizing(window, cx));
-                }
-            }
-        })
-    }
-}

crates/ui/src/dock/panel.rs

@@ -1,7 +1,11 @@
+use std::any::Any;
+use std::sync::Arc;
+
 use gpui::{
     AnyElement, AnyView, App, Element, Entity, EventEmitter, FocusHandle, Focusable, Render,
     SharedString, Window,
 };
+use gpui_base::dock::{PanelId, PanelState};
 
 use crate::button::Button;
 use crate::menu::PopupMenu;
@@ -13,14 +17,6 @@ pub enum PanelEvent {
     LayoutChanged,
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum PanelStyle {
-    /// Display the TabBar when there are multiple tabs, otherwise display the simple title.
-    Default,
-    /// Always display the tab bar.
-    TabBar,
-}
-
 pub trait Panel: EventEmitter<PanelEvent> + Render + Focusable {
     /// The name of the panel used to serialize, deserialize and identify the panel.
     ///
@@ -156,3 +152,84 @@ impl PartialEq for dyn PanelView {
         self.view() == other.view()
     }
 }
+
+#[derive(Clone)]
+pub struct PanelHandle {
+    id: PanelId,
+    panel: Arc<dyn PanelView>,
+}
+
+impl PanelHandle {
+    pub fn new<P: Panel>(panel: Entity<P>) -> Self {
+        Self {
+            id: PanelId::from(panel.entity_id()),
+            panel: Arc::new(panel),
+        }
+    }
+
+    /// Recover the coop handle behind one of base's.
+    pub fn of(panel: &Arc<dyn gpui_base::dock::PanelView>) -> Option<&Self> {
+        panel.as_any().downcast_ref::<Self>()
+    }
+
+    /// The coop panel behind this handle.
+    pub fn panel(&self) -> &Arc<dyn PanelView> {
+        &self.panel
+    }
+}
+
+impl gpui_base::dock::PanelView for PanelHandle {
+    fn panel_name(&self, _: &App) -> &'static str {
+        "CoopPanel"
+    }
+
+    fn panel_id(&self, _: &App) -> PanelId {
+        self.id
+    }
+
+    fn closable(&self, cx: &App) -> bool {
+        self.panel.closable(cx)
+    }
+
+    fn zoomable(&self, cx: &App) -> bool {
+        self.panel.zoomable(cx)
+    }
+
+    fn visible(&self, cx: &App) -> bool {
+        self.panel.visible(cx)
+    }
+
+    fn set_active(&self, active: bool, _: &mut Window, cx: &mut App) {
+        self.panel.set_active(active, cx);
+    }
+
+    fn set_zoomed(&self, zoomed: bool, _: &mut Window, cx: &mut App) {
+        self.panel.set_zoomed(zoomed, cx);
+    }
+
+    fn on_added_to(
+        &self,
+        _group: gpui::WeakEntity<gpui_base::dock::TabGroup>,
+        _: &mut Window,
+        _: &mut App,
+    ) {
+    }
+
+    fn on_removed(&self, _: &mut Window, _: &mut App) {}
+
+    fn view(&self) -> AnyView {
+        self.panel.view()
+    }
+
+    fn focus_handle(&self, cx: &App) -> FocusHandle {
+        self.panel.focus_handle(cx)
+    }
+
+    fn dump(&self, cx: &App) -> PanelState {
+        PanelState::new(self.panel_name(cx))
+    }
+
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+}

crates/ui/src/dock/stack_panel.rs

@@ -1,394 +0,0 @@
-use std::sync::Arc;
-
-use gpui::prelude::FluentBuilder;
-use gpui::{
-    App, AppContext, Axis, Context, DismissEvent, Entity, EventEmitter, FocusHandle, Focusable,
-    IntoElement, ParentElement, Pixels, Render, SharedString, Styled, Subscription, WeakEntity,
-    Window,
-};
-use smallvec::SmallVec;
-use theme::{ActiveTheme, AxisExt as _, CLIENT_SIDE_DECORATION_ROUNDING, Placement};
-
-use super::{DockArea, PanelEvent};
-use crate::dock::panel::{Panel, PanelView};
-use crate::dock::tab_panel::TabPanel;
-use crate::h_flex;
-use crate::resizable::{
-    PANEL_MIN_SIZE, ResizablePanelEvent, ResizablePanelGroup, ResizablePanelState, ResizableState,
-    resizable_panel,
-};
-
-pub struct StackPanel {
-    pub(super) parent: Option<WeakEntity<StackPanel>>,
-    pub(super) axis: Axis,
-    focus_handle: FocusHandle,
-    pub(crate) panels: SmallVec<[Arc<dyn PanelView>; 2]>,
-    state: Entity<ResizableState>,
-    _subscriptions: Vec<Subscription>,
-}
-
-impl Panel for StackPanel {
-    fn panel_id(&self) -> SharedString {
-        "StackPanel".into()
-    }
-
-    fn title(&self, _cx: &App) -> gpui::AnyElement {
-        "StackPanel".into_any_element()
-    }
-}
-
-impl StackPanel {
-    pub fn new(axis: Axis, window: &mut Window, cx: &mut Context<Self>) -> Self {
-        let state = cx.new(|_| ResizableState::default());
-
-        // Bubble up the resize event.
-        let subscriptions =
-            vec![
-                cx.subscribe_in(&state, window, |_, _, _: &ResizablePanelEvent, _, cx| {
-                    cx.emit(PanelEvent::LayoutChanged)
-                }),
-            ];
-
-        Self {
-            axis,
-            parent: None,
-            focus_handle: cx.focus_handle(),
-            panels: SmallVec::new(),
-            state,
-            _subscriptions: subscriptions,
-        }
-    }
-
-    /// The first level of the stack panel is root, will not have a parent.
-    fn is_root(&self) -> bool {
-        self.parent.is_none()
-    }
-
-    /// Return true if self or parent only have last panel.
-    pub fn is_last_panel(&self, cx: &App) -> bool {
-        if self.panels.len() > 1 {
-            return false;
-        }
-
-        if let Some(parent) = &self.parent
-            && let Some(parent) = parent.upgrade()
-        {
-            return parent.read(cx).is_last_panel(cx);
-        }
-
-        true
-    }
-
-    pub fn panels_len(&self) -> usize {
-        self.panels.len()
-    }
-
-    /// Return the index of the panel.
-    pub fn index_of_panel(&self, panel: Arc<dyn PanelView>) -> Option<usize> {
-        self.panels.iter().position(|p| p == &panel)
-    }
-
-    /// Add a panel at the end of the stack.
-    pub fn add_panel(
-        &mut self,
-        panel: Arc<dyn PanelView>,
-        size: Option<Pixels>,
-        dock_area: WeakEntity<DockArea>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        self.insert_panel(panel, self.panels.len(), size, dock_area, window, cx);
-    }
-
-    pub fn add_panel_at(
-        &mut self,
-        panel: Arc<dyn PanelView>,
-        placement: Placement,
-        size: Option<Pixels>,
-        dock_area: WeakEntity<DockArea>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        self.insert_panel_at(
-            panel,
-            self.panels_len(),
-            placement,
-            size,
-            dock_area,
-            window,
-            cx,
-        );
-    }
-
-    #[allow(clippy::too_many_arguments)]
-    pub fn insert_panel_at(
-        &mut self,
-        panel: Arc<dyn PanelView>,
-        ix: usize,
-        placement: Placement,
-        size: Option<Pixels>,
-        dock_area: WeakEntity<DockArea>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        match placement {
-            Placement::Top | Placement::Left => {
-                self.insert_panel_before(panel, ix, size, dock_area, window, cx)
-            }
-            Placement::Right | Placement::Bottom => {
-                self.insert_panel_after(panel, ix, size, dock_area, window, cx)
-            }
-        }
-    }
-
-    /// Insert a panel at the index.
-    pub fn insert_panel_before(
-        &mut self,
-        panel: Arc<dyn PanelView>,
-        ix: usize,
-        size: Option<Pixels>,
-        dock_area: WeakEntity<DockArea>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        self.insert_panel(panel, ix, size, dock_area, window, cx);
-    }
-
-    /// Insert a panel after the index.
-    pub fn insert_panel_after(
-        &mut self,
-        panel: Arc<dyn PanelView>,
-        ix: usize,
-        size: Option<Pixels>,
-        dock_area: WeakEntity<DockArea>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        self.insert_panel(panel, ix + 1, size, dock_area, window, cx);
-    }
-
-    fn insert_panel(
-        &mut self,
-        panel: Arc<dyn PanelView>,
-        ix: usize,
-        size: Option<Pixels>,
-        dock_area: WeakEntity<DockArea>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        // If the panel is already in the stack, return.
-        if self.index_of_panel(panel.clone()).is_some() {
-            return;
-        }
-
-        let view = cx.entity().clone();
-
-        window.defer(cx, {
-            let panel = panel.clone();
-
-            move |window, cx| {
-                // If the panel is a TabPanel, set its parent to this.
-                if let Ok(tab_panel) = panel.view().downcast::<TabPanel>() {
-                    tab_panel.update(cx, |tab_panel, _| tab_panel.set_parent(view.downgrade()));
-                } else if let Ok(stack_panel) = panel.view().downcast::<Self>() {
-                    stack_panel.update(cx, |stack_panel, _| {
-                        stack_panel.parent = Some(view.downgrade())
-                    });
-                }
-
-                // Subscribe to the panel's layout change event.
-                _ = dock_area.update(cx, |this, cx| {
-                    if let Ok(tab_panel) = panel.view().downcast::<TabPanel>() {
-                        this.subscribe_panel(&tab_panel, window, cx);
-                    } else if let Ok(stack_panel) = panel.view().downcast::<Self>() {
-                        this.subscribe_panel(&stack_panel, window, cx);
-                    }
-                });
-            }
-        });
-
-        let ix = if ix > self.panels.len() {
-            self.panels.len()
-        } else {
-            ix
-        };
-
-        // Get avg size of all panels to insert new panel, if size is None.
-        let size = match size {
-            Some(size) => size,
-            None => {
-                let state = self.state.read(cx);
-                (state.container_size() / (state.sizes().len() + 1) as f32).max(PANEL_MIN_SIZE)
-            }
-        };
-
-        // Insert panel
-        self.panels.insert(ix, panel.clone());
-
-        // Update resizable state
-        self.state.update(cx, |state, cx| {
-            state.insert_panel(Some(size), Some(ix), cx);
-        });
-
-        cx.emit(PanelEvent::LayoutChanged);
-        cx.notify();
-    }
-
-    /// Remove panel from the stack.
-    ///
-    /// If `ix` is not found, do nothing.
-    pub fn remove_panel(
-        &mut self,
-        panel: Arc<dyn PanelView>,
-        window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        let Some(ix) = self.index_of_panel(panel.clone()) else {
-            return;
-        };
-
-        self.panels.remove(ix);
-        self.state.update(cx, |state, cx| {
-            state.remove_panel(ix, cx);
-        });
-
-        cx.emit(PanelEvent::LayoutChanged);
-
-        self.remove_self_if_empty(window, cx);
-    }
-
-    /// Replace the old panel with the new panel at same index.
-    pub fn replace_panel(
-        &mut self,
-        old_panel: Arc<dyn PanelView>,
-        new_panel: Entity<StackPanel>,
-        _window: &mut Window,
-        cx: &mut Context<Self>,
-    ) {
-        if let Some(ix) = self.index_of_panel(old_panel.clone()) {
-            self.panels[ix] = Arc::new(new_panel.clone());
-            self.state.update(cx, |state, cx| {
-                state.replace_panel(ix, ResizablePanelState::default(), cx);
-            });
-            cx.emit(PanelEvent::LayoutChanged);
-        }
-    }
-
-    /// If children is empty, remove self from parent view.
-    pub fn remove_self_if_empty(&mut self, window: &mut Window, cx: &mut Context<Self>) {
-        if self.is_root() {
-            return;
-        }
-
-        if !self.panels.is_empty() {
-            return;
-        }
-
-        let view = cx.entity().clone();
-        if let Some(parent) = self.parent.as_ref() {
-            _ = parent.update(cx, |parent, cx| {
-                parent.remove_panel(Arc::new(view.clone()), window, cx);
-            });
-        }
-
-        cx.emit(PanelEvent::LayoutChanged);
-        cx.notify();
-    }
-
-    /// Find the first top left in the stack.
-    pub fn left_top_tab_panel(&self, check_parent: bool, cx: &App) -> Option<Entity<TabPanel>> {
-        if check_parent
-            && let Some(parent) = self.parent.as_ref().and_then(|parent| parent.upgrade())
-            && let Some(panel) = parent.read(cx).left_top_tab_panel(true, cx)
-        {
-            return Some(panel);
-        }
-
-        let first_panel = self.panels.first();
-        if let Some(view) = first_panel {
-            if let Ok(tab_panel) = view.view().downcast::<TabPanel>() {
-                Some(tab_panel)
-            } else if let Ok(stack_panel) = view.view().downcast::<StackPanel>() {
-                stack_panel.read(cx).left_top_tab_panel(false, cx)
-            } else {
-                None
-            }
-        } else {
-            None
-        }
-    }
-
-    /// Find the first top right in the stack.
-    pub fn right_top_tab_panel(&self, check_parent: bool, cx: &App) -> Option<Entity<TabPanel>> {
-        if check_parent
-            && let Some(parent) = self.parent.as_ref().and_then(|parent| parent.upgrade())
-            && let Some(panel) = parent.read(cx).right_top_tab_panel(true, cx)
-        {
-            return Some(panel);
-        }
-
-        let panel = if self.axis.is_vertical() {
-            self.panels.first()
-        } else {
-            self.panels.last()
-        };
-
-        if let Some(view) = panel {
-            if let Ok(tab_panel) = view.view().downcast::<TabPanel>() {
-                Some(tab_panel)
-            } else if let Ok(stack_panel) = view.view().downcast::<StackPanel>() {
-                stack_panel.read(cx).right_top_tab_panel(false, cx)
-            } else {
-                None
-            }
-        } else {
-            None
-        }
-    }
-
-    /// Remove all panels from the stack.
-    pub fn remove_all_panels(&mut self, _: &mut Window, cx: &mut Context<Self>) {
-        self.panels.clear();
-        self.state.update(cx, |state, cx| {
-            state.clear();
-            cx.notify();
-        });
-    }
-
-    /// Change the axis of the stack panel.
-    pub fn set_axis(&mut self, axis: Axis, _: &mut Window, cx: &mut Context<Self>) {
-        self.axis = axis;
-        cx.notify();
-    }
-}
-
-impl Focusable for StackPanel {
-    fn focus_handle(&self, _cx: &App) -> FocusHandle {
-        self.focus_handle.clone()
-    }
-}
-
-impl EventEmitter<PanelEvent> for StackPanel {}
-impl EventEmitter<DismissEvent> for StackPanel {}
-
-impl Render for StackPanel {
-    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
-        h_flex()
-            .size_full()
-            .overflow_hidden()
-            .bg(cx.theme().panel_background)
-            .when(cx.theme().platform.is_linux(), |this| {
-                this.rounded_br(CLIENT_SIDE_DECORATION_ROUNDING)
-            })
-            .child(
-                ResizablePanelGroup::new("stack-panel-group")
-                    .with_state(&self.state)
-                    .axis(self.axis)
-                    .children(self.panels.clone().into_iter().map(|panel| {
-                        resizable_panel()
-                            .child(panel.view())
-                            .visible(panel.visible(cx))
-                    })),
-            )
-    }
-}

crates/ui/src/element_ext.rs

@@ -1,27 +0,0 @@
-use gpui::{canvas, App, Bounds, ParentElement, Pixels, Styled as _, Window};
-
-/// A trait to extend [`gpui::Element`] with additional functionality.
-pub trait ElementExt: ParentElement + Sized {
-    /// Add a prepaint callback to the element.
-    ///
-    /// This is a helper method to get the bounds of the element after paint.
-    ///
-    /// The first argument is the bounds of the element in pixels.
-    ///
-    /// See also [`gpui::canvas`].
-    fn on_prepaint<F>(self, f: F) -> Self
-    where
-        F: FnOnce(Bounds<Pixels>, &mut Window, &mut App) + 'static,
-    {
-        self.child(
-            canvas(
-                move |bounds, window, cx| f(bounds, window, cx),
-                |_, _, _, _| {},
-            )
-            .absolute()
-            .size_full(),
-        )
-    }
-}
-
-impl<T: ParentElement> ElementExt for T {}

crates/ui/src/event.rs

@@ -1,21 +0,0 @@
-use gpui::{App, ClickEvent, InteractiveElement, Stateful, Window};
-
-pub trait InteractiveElementExt: InteractiveElement {
-    /// Set the listener for a double click event.
-    fn on_double_click(
-        mut self,
-        listener: impl Fn(&ClickEvent, &mut Window, &mut App) + 'static,
-    ) -> Self
-    where
-        Self: Sized,
-    {
-        self.interactivity().on_click(move |event, window, cx| {
-            if event.click_count() == 2 {
-                listener(event, window, cx);
-            }
-        });
-        self
-    }
-}
-
-impl<E: InteractiveElement> InteractiveElementExt for Stateful<E> {}

crates/ui/src/focusable.rs

@@ -1,39 +0,0 @@
-use gpui::{Context, FocusHandle, Window};
-
-/// A trait for views that can cycle focus between its children.
-///
-/// This will provide a default implementation for the `cycle_focus` method that will cycle focus.
-///
-/// You should implement the `cycle_focus_handles` method to return a list of focus handles that
-/// should be cycled, and the cycle will follow the order of the list.
-pub trait FocusableCycle {
-    /// Returns a list of focus handles that should be cycled.
-    fn cycle_focus_handles(&self, window: &mut Window, cx: &mut Context<Self>) -> Vec<FocusHandle>
-    where
-        Self: Sized;
-
-    /// Cycles focus between the focus handles returned by `cycle_focus_handles`.
-    /// If `is_next` is `true`, it will cycle to the next focus handle, otherwise it will cycle to prev.
-    fn cycle_focus(&self, is_next: bool, window: &mut Window, cx: &mut Context<Self>)
-    where
-        Self: Sized,
-    {
-        let focused_handle = window.focused(cx);
-        let handles = self.cycle_focus_handles(window, cx);
-        let handles = if is_next {
-            handles
-        } else {
-            handles.into_iter().rev().collect()
-        };
-
-        let fallback_handle = handles[0].clone();
-        let target_focus_handle = handles
-            .into_iter()
-            .skip_while(|handle| Some(handle) != focused_handle.as_ref())
-            .nth(1)
-            .unwrap_or(fallback_handle);
-
-        target_focus_handle.focus(window, cx);
-        cx.stop_propagation();
-    }
-}

crates/ui/src/history.rs

@@ -1,184 +0,0 @@
-use std::fmt::Debug;
-use std::time::{Duration, Instant};
-
-/// A HistoryItem represents a single change in the history.
-/// It must implement Clone and PartialEq to be used in the History.
-pub trait HistoryItem: Clone + PartialEq {
-    fn version(&self) -> usize;
-    fn set_version(&mut self, version: usize);
-}
-
-/// The History is used to keep track of changes to a model and to allow undo and redo operations.
-///
-/// This is now used in Input for undo/redo operations. You can also use this in
-/// your own models to keep track of changes, for example to track the tab
-/// history for prev/next features.
-///
-/// ## Use cases
-///
-/// - Undo/redo operations in Input
-/// - Tracking tab history for prev/next features
-#[derive(Debug)]
-pub struct History<I: HistoryItem> {
-    undos: Vec<I>,
-    redos: Vec<I>,
-    last_changed_at: Instant,
-    version: usize,
-    pub(crate) ignore: bool,
-    max_undos: usize,
-    group_interval: Option<Duration>,
-    grouping: bool,
-    unique: bool,
-}
-
-impl<I> History<I>
-where
-    I: HistoryItem,
-{
-    pub fn new() -> Self {
-        Self {
-            undos: Default::default(),
-            redos: Default::default(),
-            ignore: false,
-            last_changed_at: Instant::now(),
-            version: 0,
-            max_undos: 1000,
-            group_interval: None,
-            grouping: false,
-            unique: false,
-        }
-    }
-
-    /// Set the maximum number of undo steps to keep, defaults to 1000.
-    pub fn max_undos(mut self, max_undos: usize) -> Self {
-        self.max_undos = max_undos;
-        self
-    }
-
-    /// Set the history to be unique, defaults to false.
-    /// If set to true, the history will only keep unique changes.
-    pub fn unique(mut self) -> Self {
-        self.unique = true;
-        self
-    }
-
-    /// Set the interval in milliseconds to group changes, defaults to None.
-    pub fn group_interval(mut self, group_interval: Duration) -> Self {
-        self.group_interval = Some(group_interval);
-        self
-    }
-
-    /// Start grouping changes, this will prevent the version from being incremented until `end_grouping` is called.
-    pub fn start_grouping(&mut self) {
-        self.grouping = true;
-    }
-
-    /// End grouping changes, this will allow the version to be incremented again.
-    pub fn end_grouping(&mut self) {
-        self.grouping = false;
-    }
-
-    /// Increment the version number if the last change was made more than `GROUP_INTERVAL` milliseconds ago.
-    fn inc_version(&mut self) -> usize {
-        let t = Instant::now();
-        if !self.grouping && Some(self.last_changed_at.elapsed()) > self.group_interval {
-            self.version += 1;
-        }
-
-        self.last_changed_at = t;
-        self.version
-    }
-
-    /// Get the current version number.
-    pub fn version(&self) -> usize {
-        self.version
-    }
-
-    /// Push a new change to the history.
-    pub fn push(&mut self, item: I) {
-        let version = self.inc_version();
-
-        if self.undos.len() >= self.max_undos {
-            self.undos.remove(0);
-        }
-
-        if self.unique {
-            self.undos.retain(|c| *c != item);
-            self.redos.retain(|c| *c != item);
-        }
-
-        let mut item = item;
-        item.set_version(version);
-        self.undos.push(item);
-    }
-
-    /// Get the undo stack.
-    pub fn undos(&self) -> &Vec<I> {
-        &self.undos
-    }
-
-    /// Get the redo stack.
-    pub fn redos(&self) -> &Vec<I> {
-        &self.redos
-    }
-
-    /// Clear the undo and redo stacks.
-    pub fn clear(&mut self) {
-        self.undos.clear();
-        self.redos.clear();
-    }
-
-    /// Undo the last change and return the changes that were undone.
-    pub fn undo(&mut self) -> Option<Vec<I>> {
-        if let Some(first_change) = self.undos.pop() {
-            let mut changes = vec![first_change.clone()];
-            // pick the next all changes with the same version
-            while self
-                .undos
-                .iter()
-                .filter(|c| c.version() == first_change.version())
-                .count()
-                > 0
-            {
-                let change = self.undos.pop().unwrap();
-                changes.push(change);
-            }
-
-            self.redos.extend(changes.clone());
-            Some(changes)
-        } else {
-            None
-        }
-    }
-
-    /// Redo the last undone change and return the changes that were redone.
-    pub fn redo(&mut self) -> Option<Vec<I>> {
-        if let Some(first_change) = self.redos.pop() {
-            let mut changes = vec![first_change.clone()];
-            // pick the next all changes with the same version
-            while self
-                .redos
-                .iter()
-                .filter(|c| c.version() == first_change.version())
-                .count()
-                > 0
-            {
-                let change = self.redos.pop().unwrap();
-                changes.push(change);
-            }
-            self.undos.extend(changes.clone());
-            Some(changes)
-        } else {
-            None
-        }
-    }
-}
-
-impl<I> Default for History<I>
-where
-    I: HistoryItem,
-{
-    fn default() -> Self {
-        Self::new()
-    }
-}

crates/ui/src/icon.rs

@@ -33,12 +33,14 @@ pub enum IconName {
     Close,
     CloseCircle,
     CloseCircleFill,
+    Compass,
     Copy,
     Device,
     Door,
     Ellipsis,
     Emoji,
     Eye,
+    Folder,
     Input,
     Info,
     Invite,
@@ -46,6 +48,8 @@ pub enum IconName {
     InboxFill,
     Link,
     Loader,
+    Lock,
+    Message,
     Moon,
     Plus,
     PlusCircle,
@@ -105,12 +109,14 @@ impl IconNamed for IconName {
             Self::Close => "icons/close.svg",
             Self::CloseCircle => "icons/close-circle.svg",
             Self::CloseCircleFill => "icons/close-circle-fill.svg",
+            Self::Compass => "icons/compass.svg",
             Self::Copy => "icons/copy.svg",
             Self::Device => "icons/device.svg",
             Self::Door => "icons/door.svg",
             Self::Ellipsis => "icons/ellipsis.svg",
             Self::Emoji => "icons/emoji.svg",
             Self::Eye => "icons/eye.svg",
+            Self::Folder => "icons/folder.svg",
             Self::Input => "icons/input.svg",
             Self::Info => "icons/info.svg",
             Self::Invite => "icons/invite.svg",
@@ -118,6 +124,8 @@ impl IconNamed for IconName {
             Self::InboxFill => "icons/inbox-fill.svg",
             Self::Link => "icons/link.svg",
             Self::Loader => "icons/loader.svg",
+            Self::Lock => "icons/lock.svg",
+            Self::Message => "icons/message.svg",
             Self::Moon => "icons/moon.svg",
             Self::Plus => "icons/plus.svg",
             Self::PlusCircle => "icons/plus-circle.svg",

crates/ui/src/index_path.rs

@@ -1,69 +0,0 @@
-use std::fmt::{Debug, Display};
-
-use gpui::ElementId;
-
-/// Represents an index path in a list, which consists of a section index,
-///
-/// The default values for section, row, and column are all set to 0.
-#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
-pub struct IndexPath {
-    /// The section index.
-    pub section: usize,
-    /// The item index in the section.
-    pub row: usize,
-    /// The column index.
-    pub column: usize,
-}
-
-impl From<IndexPath> for ElementId {
-    fn from(path: IndexPath) -> Self {
-        ElementId::Name(format!("index-path({},{},{})", path.section, path.row, path.column).into())
-    }
-}
-
-impl Display for IndexPath {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(
-            f,
-            "IndexPath(section: {}, row: {}, column: {})",
-            self.section, self.row, self.column
-        )
-    }
-}
-
-impl IndexPath {
-    /// Create a new index path with the specified section and row.
-    ///
-    /// The `section` is set to 0 by default.
-    /// The `column` is set to 0 by default.
-    pub fn new(row: usize) -> Self {
-        IndexPath {
-            section: 0,
-            row,
-            ..Default::default()
-        }
-    }
-
-    /// Set the section for the index path.
-    pub fn section(mut self, section: usize) -> Self {
-        self.section = section;
-        self
-    }
-
-    /// Set the row for the index path.
-    pub fn row(mut self, row: usize) -> Self {
-        self.row = row;
-        self
-    }
-
-    /// Set the column for the index path.
-    pub fn column(mut self, column: usize) -> Self {
-        self.column = column;
-        self
-    }
-
-    /// Check if the self is equal to the given index path (Same section and row).
-    pub fn eq_row(&self, index: IndexPath) -> bool {
-        self.section == index.section && self.row == index.row
-    }
-}

crates/ui/src/indicator.rs

@@ -1,4 +1,4 @@
-use std::time::Duration;
+use instant::Duration;
 
 use gpui::prelude::FluentBuilder as _;
 use gpui::{

crates/ui/src/input/blink_cursor.rs

@@ -1,96 +0,0 @@
-use std::time::Duration;
-
-use gpui::{Context, Pixels, Task, px};
-
-static INTERVAL: Duration = Duration::from_millis(500);
-static PAUSE_DELAY: Duration = Duration::from_millis(300);
-
-// On Windows, Linux, we should use integer to avoid blurry cursor.
-#[cfg(not(target_os = "macos"))]
-pub(super) const CURSOR_WIDTH: Pixels = px(2.);
-#[cfg(target_os = "macos")]
-pub(super) const CURSOR_WIDTH: Pixels = px(1.5);
-
-/// To manage the Input cursor blinking.
-///
-/// It will start blinking with a interval of 500ms.
-/// Every loop will notify the view to update the `visible`, and Input will observe this update to touch repaint.
-///
-/// The input painter will check if this in visible state, then it will draw the cursor.
-pub(crate) struct BlinkCursor {
-    visible: bool,
-    paused: bool,
-    epoch: usize,
-
-    _task: Task<()>,
-}
-
-impl BlinkCursor {
-    pub fn new() -> Self {
-        Self {
-            visible: false,
-            paused: false,
-            epoch: 0,
-            _task: Task::ready(()),
-        }
-    }
-
-    /// Start the blinking
-    pub fn start(&mut self, cx: &mut Context<Self>) {
-        self.blink(self.epoch, cx);
-    }
-
-    pub fn stop(&mut self, cx: &mut Context<Self>) {
-        self.epoch = 0;
-        cx.notify();
-    }
-
-    fn next_epoch(&mut self) -> usize {
-        self.epoch += 1;
-        self.epoch
-    }
-
-    fn blink(&mut self, epoch: usize, cx: &mut Context<Self>) {
-        if self.paused || epoch != self.epoch {
-            self.visible = true;
-            return;
-        }
-
-        self.visible = !self.visible;
-        cx.notify();
-
-        // Schedule the next blink
-        let epoch = self.next_epoch();
-        self._task = cx.spawn(async move |this, cx| {
-            cx.background_executor().timer(INTERVAL).await;
-            if let Some(this) = this.upgrade() {
-                this.update(cx, |this, cx| this.blink(epoch, cx));
-            }
-        });
-    }
-
-    pub fn visible(&self) -> bool {
-        // Keep showing the cursor if paused
-        self.paused || self.visible
-    }
-
-    /// Pause the blinking, and delay 500ms to resume the blinking.
-    pub fn pause(&mut self, cx: &mut Context<Self>) {
-        self.paused = true;
-        self.visible = true;
-        cx.notify();
-
-        // delay 500ms to start the blinking
-        let epoch = self.next_epoch();
-        self._task = cx.spawn(async move |this, cx| {
-            cx.background_executor().timer(PAUSE_DELAY).await;
-
-            if let Some(this) = this.upgrade() {
-                this.update(cx, |this, cx| {
-                    this.paused = false;
-                    this.blink(epoch, cx);
-                });
-            }
-        });
-    }
-}

crates/ui/src/input/change.rs

@@ -1,39 +0,0 @@
-use std::fmt::Debug;
-
-use crate::{history::HistoryItem, input::Selection};
-
-#[derive(Debug, PartialEq, Clone)]
-pub struct Change {
-    pub(crate) old_range: Selection,
-    pub(crate) old_text: String,
-    pub(crate) new_range: Selection,
-    pub(crate) new_text: String,
-    version: usize,
-}
-
-impl Change {
-    pub fn new(
-        old_range: impl Into<Selection>,
-        old_text: &str,
-        new_range: impl Into<Selection>,
-        new_text: &str,
-    ) -> Self {
-        Self {
-            old_range: old_range.into(),
-            old_text: old_text.to_string(),
-            new_range: new_range.into(),
-            new_text: new_text.to_string(),
-            version: 0,
-        }
-    }
-}
-
-impl HistoryItem for Change {
-    fn version(&self) -> usize {
-        self.version
-    }
-
-    fn set_version(&mut self, version: usize) {
-        self.version = version;
-    }
-}

crates/ui/src/input/cursor.rs

@@ -1,53 +0,0 @@
-use std::ops::{Range, RangeBounds};
-
-/// A selection in the text, represented by start and end byte indices.
-#[derive(Debug, Copy, Clone, PartialEq, Eq, Default)]
-pub struct Selection {
-    pub start: usize,
-    pub end: usize,
-}
-
-impl Selection {
-    pub fn new(start: usize, end: usize) -> Self {
-        Self { start, end }
-    }
-
-    pub fn len(&self) -> usize {
-        self.end.saturating_sub(self.start)
-    }
-
-    pub fn is_empty(&self) -> bool {
-        self.start == self.end
-    }
-
-    /// Clears the selection, setting start and end to 0.
-    pub fn clear(&mut self) {
-        self.start = 0;
-        self.end = 0;
-    }
-
-    /// Checks if the given offset is within the selection range.
-    pub fn contains(&self, offset: usize) -> bool {
-        offset >= self.start && offset < self.end
-    }
-}
-
-impl From<Range<usize>> for Selection {
-    fn from(value: Range<usize>) -> Self {
-        Self::new(value.start, value.end)
-    }
-}
-impl From<Selection> for Range<usize> {
-    fn from(value: Selection) -> Self {
-        value.start..value.end
-    }
-}
-impl RangeBounds<usize> for Selection {
-    fn start_bound(&self) -> std::ops::Bound<&usize> {
-        std::ops::Bound::Included(&self.start)
-    }
-
-    fn end_bound(&self) -> std::ops::Bound<&usize> {
-        std::ops::Bound::Excluded(&self.end)
-    }
-}

crates/ui/src/input/display_map/display_map.rs

@@ -1,336 +0,0 @@
-/// DisplayMap: Public facade for Editor/Input display mapping.
-///
-/// This combines WrapMap and FoldMap to provide a unified API:
-/// - BufferPoint ↔ DisplayPoint conversion
-/// - Fold management (candidates, toggle, query)
-/// - Automatic projection updates on text/layout changes
-use std::ops::Range;
-
-use gpui::{App, Font, Pixels};
-use ropey::Rope;
-
-use super::fold_map::FoldMap;
-use super::folding::FoldRange;
-use super::text_wrapper::{LineItem, WrapDisplayPoint};
-use super::wrap_map::WrapMap;
-use super::{BufferPoint, DisplayPoint};
-use crate::input::display_map::WrapPoint;
-use crate::input::rope_ext::RopeExt as _;
-use crate::input::Point as TreeSitterPoint;
-
-/// DisplayMap is the main interface for Editor/Input coordinate mapping.
-///
-/// It manages the two-layer projection:
-/// 1. Buffer → Wrap (soft-wrapping)
-/// 2. Wrap → Display (folding)
-///
-/// Editor/Input only needs to work with BufferPoint and DisplayPoint.
-pub struct DisplayMap {
-    wrap_map: WrapMap,
-    fold_map: FoldMap,
-}
-
-impl DisplayMap {
-    pub fn new(font: Font, font_size: Pixels, wrap_width: Option<Pixels>) -> Self {
-        Self {
-            wrap_map: WrapMap::new(font, font_size, wrap_width),
-            fold_map: FoldMap::new(),
-        }
-    }
-
-    // ==================== Core Coordinate Mapping ====================
-
-    /// Convert buffer position to display position
-    pub fn buffer_pos_to_display_pos(&self, pos: BufferPoint) -> DisplayPoint {
-        // Buffer → Wrap
-        let wrap_pos = self.wrap_map.buffer_pos_to_wrap_pos(pos);
-
-        // Wrap → Display
-        if let Some(display_row) = self.fold_map.wrap_row_to_display_row(wrap_pos.row) {
-            DisplayPoint::new(display_row, wrap_pos.col)
-        } else {
-            // Cursor is in a folded region, find nearest visible row
-            let display_row = self.fold_map.nearest_visible_display_row(wrap_pos.row);
-            DisplayPoint::new(display_row, 0) // Column 0 at fold boundary
-        }
-    }
-
-    /// Convert display position to buffer position
-    pub fn display_pos_to_buffer_pos(&self, pos: DisplayPoint) -> BufferPoint {
-        // Display → Wrap
-        let wrap_row = self.fold_map.display_row_to_wrap_row(pos.row).unwrap_or(0);
-
-        // Wrap → Buffer
-        let wrap_pos = WrapPoint::new(wrap_row, pos.col);
-        self.wrap_map.wrap_pos_to_buffer_pos(wrap_pos)
-    }
-
-    /// Get total number of visible display rows
-    #[inline]
-    pub fn display_row_count(&self) -> usize {
-        self.fold_map.display_row_count()
-    }
-
-    /// Get the buffer line for a given display row
-    pub fn display_row_to_buffer_line(&self, display_row: usize) -> usize {
-        // Display → Wrap
-        let wrap_row = self
-            .fold_map
-            .display_row_to_wrap_row(display_row)
-            .unwrap_or(0);
-
-        // Wrap → Buffer line
-        self.wrap_map.wrap_row_to_buffer_line(wrap_row)
-    }
-
-    /// Get the display row range for a buffer line: [start, end)
-    /// Returns None if the buffer line is completely hidden
-    pub fn buffer_line_to_display_row_range(&self, line: usize) -> Option<Range<usize>> {
-        // Buffer line → Wrap row range
-        let wrap_row_range = self.wrap_map.buffer_line_to_wrap_row_range(line);
-
-        // Find first and last visible display rows in this range
-        let mut first_display_row = None;
-        let mut last_display_row = None;
-
-        for wrap_row in wrap_row_range {
-            if let Some(display_row) = self.fold_map.wrap_row_to_display_row(wrap_row) {
-                if first_display_row.is_none() {
-                    first_display_row = Some(display_row);
-                }
-                last_display_row = Some(display_row);
-            }
-        }
-
-        if let (Some(start), Some(end)) = (first_display_row, last_display_row) {
-            Some(start..end + 1)
-        } else {
-            None // Completely folded
-        }
-    }
-
-    /// Check if a buffer line is completely hidden
-    #[inline]
-    pub fn is_buffer_line_hidden(&self, line: usize) -> bool {
-        self.buffer_line_to_display_row_range(line).is_none()
-    }
-
-    /// Set fold candidates (from tree-sitter/LSP)
-    pub fn set_fold_candidates(&mut self, candidates: Vec<FoldRange>) {
-        self.fold_map.set_candidates(candidates);
-        self.rebuild_fold_projection();
-    }
-
-    /// Set a fold at the given start_line (must be in candidates)
-    pub fn set_folded(&mut self, start_line: usize, folded: bool) {
-        self.fold_map.set_folded(start_line, folded);
-        self.rebuild_fold_projection();
-    }
-
-    /// Toggle fold at the given start_line
-    pub fn toggle_fold(&mut self, start_line: usize) {
-        self.fold_map.toggle_fold(start_line);
-        self.rebuild_fold_projection();
-    }
-
-    /// Check if a line is currently folded
-    #[inline]
-    pub fn is_folded_at(&self, start_line: usize) -> bool {
-        self.fold_map.is_folded_at(start_line)
-    }
-
-    /// Check if a line is a fold candidate
-    #[inline]
-    pub fn is_fold_candidate(&self, start_line: usize) -> bool {
-        self.fold_map.is_fold_candidate(start_line)
-    }
-
-    /// Get all currently folded ranges
-    #[inline]
-    pub fn folded_ranges(&self) -> &[FoldRange] {
-        self.fold_map.folded_ranges()
-    }
-
-    /// Clear all folds
-    pub fn clear_folds(&mut self) {
-        self.fold_map.clear_folds();
-        self.rebuild_fold_projection();
-    }
-
-    // ==================== Text and Layout Updates ====================
-
-    /// Adjust folds and candidates for a text edit before updating the wrap map.
-    ///
-    /// Must be called with the OLD text (before replacement) and the edit range/new_text
-    /// so we can compute which old lines were affected.
-    pub fn adjust_folds_for_edit(&mut self, old_text: &Rope, range: &Range<usize>, new_text: &str) {
-        if self.fold_map.folded_ranges().is_empty() && self.fold_map.fold_candidates().is_empty() {
-            return;
-        }
-
-        let edit_start_line = old_text.offset_to_point(range.start).row;
-        let edit_end_line = old_text.offset_to_point(range.end.min(old_text.len())).row;
-
-        let old_lines_in_range = edit_end_line.saturating_sub(edit_start_line);
-        let new_lines_in_range = new_text.chars().filter(|c| *c == '\n').count();
-        let line_delta = new_lines_in_range as isize - old_lines_in_range as isize;
-
-        self.fold_map
-            .adjust_folds_for_edit(edit_start_line, edit_end_line, line_delta);
-    }
-
-    /// Incrementally update fold candidates after a text edit.
-    ///
-    /// Extracts new fold candidates only within the edited byte range
-    /// and merges them with existing (already adjusted) candidates.
-    pub fn update_fold_candidates_for_edit(
-        &mut self,
-        tree: &super::folding::Tree,
-        edit_byte_range: Range<usize>,
-        new_text: &Rope,
-    ) {
-        let new_start_line = new_text.offset_to_point(edit_byte_range.start).row;
-        let new_end_line = new_text
-            .offset_to_point(edit_byte_range.end.min(new_text.len()))
-            .row;
-
-        let new_candidates = super::folding::extract_fold_ranges_in_range(tree, edit_byte_range);
-        self.fold_map
-            .merge_candidates_for_edit(new_start_line, new_end_line, new_candidates);
-    }
-
-    /// Update text (incremental or full)
-    pub fn on_text_changed(
-        &mut self,
-        changed_text: &Rope,
-        range: &Range<usize>,
-        new_text: &Rope,
-        cx: &mut App,
-    ) {
-        self.wrap_map
-            .on_text_changed(changed_text, range, new_text, cx);
-        self.rebuild_fold_projection();
-    }
-
-    /// Update layout parameters (wrap width or font)
-    pub fn on_layout_changed(&mut self, wrap_width: Option<Pixels>, cx: &mut App) {
-        self.wrap_map.on_layout_changed(wrap_width, cx);
-        self.rebuild_fold_projection();
-    }
-
-    /// Set font parameters
-    pub fn set_font(&mut self, font: Font, font_size: Pixels, cx: &mut App) {
-        self.wrap_map.set_font(font, font_size, cx);
-        self.rebuild_fold_projection();
-    }
-
-    /// Ensure text is prepared (initializes wrapper if needed)
-    pub fn ensure_text_prepared(&mut self, text: &Rope, cx: &mut App) {
-        let did_initialize = self.wrap_map.ensure_text_prepared(text, cx);
-        if did_initialize {
-            self.rebuild_fold_projection();
-        }
-    }
-
-    /// Initialize with text
-    pub fn set_text(&mut self, text: &Rope, cx: &mut App) {
-        self.wrap_map.set_text(text, cx);
-        self.rebuild_fold_projection();
-    }
-
-    // ==================== Internal Helpers ====================
-
-    /// Rebuild fold projection after wrap_map or fold state changes
-    /// Only rebuilds if there are actually folded ranges
-    fn rebuild_fold_projection(&mut self) {
-        if !self.fold_map.folded_ranges().is_empty() {
-            self.fold_map.rebuild(&self.wrap_map);
-        } else {
-            // No active folds: identity mapping (wrap_row == display_row).
-            // Just update cached count so query methods work without Vec allocation.
-            self.fold_map
-                .mark_dirty_with_wrap_count(self.wrap_map.wrap_row_count());
-        }
-    }
-
-    // ==================== Wrap Display Point Operations ====================
-
-    /// Convert byte offset to wrap display point (with soft wrap info).
-    #[inline]
-    pub(crate) fn offset_to_wrap_display_point(&self, offset: usize) -> WrapDisplayPoint {
-        self.wrap_map.wrapper().offset_to_display_point(offset)
-    }
-
-    /// Convert wrap display point to byte offset.
-    #[inline]
-    pub(crate) fn wrap_display_point_to_offset(&self, point: WrapDisplayPoint) -> usize {
-        self.wrap_map.wrapper().display_point_to_offset(point)
-    }
-
-    /// Convert wrap display point to TreeSitterPoint (buffer line/col).
-    #[inline]
-    pub(crate) fn wrap_display_point_to_point(
-        &self,
-        point: WrapDisplayPoint,
-    ) -> TreeSitterPoint {
-        self.wrap_map.wrapper().display_point_to_point(point)
-    }
-
-    /// Convert a wrap row to a display row (skipping folded rows).
-    /// Returns None if the wrap row is folded.
-    #[inline]
-    pub fn wrap_row_to_display_row(&self, wrap_row: usize) -> Option<usize> {
-        self.fold_map.wrap_row_to_display_row(wrap_row)
-    }
-
-    /// Find the nearest visible display row for a given wrap row.
-    #[inline]
-    pub fn nearest_visible_display_row(&self, wrap_row: usize) -> usize {
-        self.fold_map.nearest_visible_display_row(wrap_row)
-    }
-
-    /// Convert a display row to a wrap row.
-    #[inline]
-    pub fn display_row_to_wrap_row(&self, display_row: usize) -> Option<usize> {
-        self.fold_map.display_row_to_wrap_row(display_row)
-    }
-
-    /// Get the longest row index (by byte length).
-    #[inline]
-    pub(crate) fn longest_row(&self) -> usize {
-        self.wrap_map.wrapper().longest_row.row
-    }
-
-    // ==================== Access Methods ====================
-
-    /// Get access to line items (for rendering)
-    #[inline]
-    pub(crate) fn lines(&self) -> &[LineItem] {
-        self.wrap_map.lines()
-    }
-
-    /// Get the rope text
-    #[inline]
-    pub fn text(&self) -> &Rope {
-        self.wrap_map.text()
-    }
-
-    /// Calculate how many wrap rows of a buffer line are visible (not folded)
-    #[inline]
-    pub fn visible_wrap_row_count_for_buffer_line(&self, line: usize) -> usize {
-        self.wrap_map
-            .visible_wrap_row_count_for_line(line, &self.fold_map)
-    }
-
-    /// Get the wrap row count (before folding)
-    #[inline]
-    pub fn wrap_row_count(&self) -> usize {
-        self.wrap_map.wrap_row_count()
-    }
-
-    /// Get the buffer line count (logical lines)
-    #[inline]
-    pub fn buffer_line_count(&self) -> usize {
-        self.wrap_map.buffer_line_count()
-    }
-}

crates/ui/src/input/display_map/fold_map.rs

@@ -1,343 +0,0 @@
-/// FoldMap: Folding projection layer (Wrap rows → Display rows).
-///
-/// This module manages code folding by:
-/// - Filtering out wrap rows that belong to folded regions
-/// - Maintaining bidirectional mapping: wrap_row ↔ display_row
-/// - Handling fold state changes and rebuilding the projection
-use super::folding::FoldRange;
-use super::wrap_map::WrapMap;
-
-/// FoldMap projects wrap rows to display rows by hiding folded regions.
-pub struct FoldMap {
-    /// Mapping: display_row → wrap_row
-    /// index = display_row, value = actual wrap_row
-    visible_wrap_rows: Vec<usize>,
-
-    /// Reverse mapping: wrap_row → display_row
-    /// index = wrap_row, value = Some(display_row) if visible, None if folded
-    wrap_row_to_display_row: Vec<Option<usize>>,
-
-    /// Candidate fold ranges (from tree-sitter/LSP)
-    /// Sorted by start_line, unique start_line
-    candidates: Vec<FoldRange>,
-
-    /// Currently folded ranges
-    /// Subset of candidates, sorted by start_line
-    folded: Vec<FoldRange>,
-
-    /// Flag indicating if the fold projection needs rebuilding
-    /// Used for lazy evaluation to avoid expensive rebuilds on every text change
-    needs_rebuild: bool,
-
-    /// Cached wrap_row_count from last rebuild
-    /// Used to detect if WrapMap changed and rebuild is needed
-    cached_wrap_row_count: usize,
-}
-
-impl FoldMap {
-    pub fn new() -> Self {
-        Self {
-            visible_wrap_rows: Vec::new(),
-            wrap_row_to_display_row: Vec::new(),
-            candidates: Vec::new(),
-            folded: Vec::new(),
-            needs_rebuild: true,
-            cached_wrap_row_count: 0,
-        }
-    }
-
-    /// Update cached wrap_row_count without full rebuild.
-    /// Used when no folds are active (identity mapping assumed).
-    pub(super) fn mark_dirty_with_wrap_count(&mut self, wrap_row_count: usize) {
-        self.needs_rebuild = true;
-        self.cached_wrap_row_count = wrap_row_count;
-    }
-
-    /// Get total number of visible display rows
-    pub fn display_row_count(&self) -> usize {
-        if self.folded.is_empty() {
-            return self.cached_wrap_row_count;
-        }
-        self.visible_wrap_rows.len()
-    }
-
-    /// Convert wrap_row to display_row
-    /// Returns None if the wrap_row is hidden by folding
-    pub fn wrap_row_to_display_row(&self, wrap_row: usize) -> Option<usize> {
-        if self.folded.is_empty() {
-            return if wrap_row < self.cached_wrap_row_count {
-                Some(wrap_row)
-            } else {
-                None
-            };
-        }
-        self.wrap_row_to_display_row
-            .get(wrap_row)
-            .copied()
-            .flatten()
-    }
-
-    /// Convert display_row to wrap_row
-    pub fn display_row_to_wrap_row(&self, display_row: usize) -> Option<usize> {
-        if self.folded.is_empty() {
-            return if display_row < self.cached_wrap_row_count {
-                Some(display_row)
-            } else {
-                None
-            };
-        }
-        self.visible_wrap_rows.get(display_row).copied()
-    }
-
-    /// Find the nearest visible display_row for a given wrap_row
-    pub fn nearest_visible_display_row(&self, wrap_row: usize) -> usize {
-        if self.folded.is_empty() {
-            return wrap_row.min(self.cached_wrap_row_count.saturating_sub(1));
-        }
-
-        if let Some(dr) = self.wrap_row_to_display_row(wrap_row) {
-            return dr;
-        }
-
-        match self.visible_wrap_rows.binary_search(&wrap_row) {
-            Ok(idx) => idx,
-            Err(insert_pos) => insert_pos.saturating_sub(1),
-        }
-    }
-
-    /// Set fold candidates (from tree-sitter/LSP), full replacement.
-    pub fn set_candidates(&mut self, mut candidates: Vec<FoldRange>) {
-        // Sort and deduplicate by start_line
-        candidates.sort_by_key(|r| r.start_line);
-        candidates.dedup_by_key(|r| r.start_line);
-        self.candidates = candidates;
-
-        // Remove any folded ranges that are no longer in candidates
-        self.folded.retain(|fold| {
-            self.candidates
-                .iter()
-                .any(|c| c.start_line == fold.start_line)
-        });
-    }
-
-    /// Merge new candidates extracted from an edited region into existing candidates.
-    ///
-    /// Replaces candidates within [edit_start_line, edit_end_line] with `new_candidates`,
-    /// keeping candidates outside the edit range intact.
-    pub fn merge_candidates_for_edit(
-        &mut self,
-        edit_start_line: usize,
-        edit_end_line: usize,
-        new_candidates: Vec<FoldRange>,
-    ) {
-        // Remove old candidates within the edit range (already done by adjust_folds_for_edit)
-        // But do it again in case adjust wasn't called or range differs
-        self.candidates
-            .retain(|c| c.start_line < edit_start_line || c.start_line > edit_end_line);
-
-        // Add new candidates
-        self.candidates.extend(new_candidates);
-        self.candidates.sort_by_key(|r| r.start_line);
-        self.candidates.dedup_by_key(|r| r.start_line);
-    }
-
-    /// Set a fold at the given start_line (must be in candidates)
-    pub fn set_folded(&mut self, start_line: usize, folded: bool) {
-        if folded {
-            // Find the candidate range for this start_line
-            if let Some(candidate) = self.candidates.iter().find(|c| c.start_line == start_line) {
-                // Add to folded if not already present
-                if !self.folded.iter().any(|f| f.start_line == start_line) {
-                    self.folded.push(*candidate);
-                    self.folded.sort_by_key(|r| r.start_line);
-                    self.needs_rebuild = true;
-                }
-            }
-        } else {
-            // Remove from folded
-            self.folded.retain(|f| f.start_line != start_line);
-            self.needs_rebuild = true;
-        }
-    }
-
-    /// Toggle fold at the given start_line
-    pub fn toggle_fold(&mut self, start_line: usize) {
-        let is_folded = self.is_folded_at(start_line);
-        self.set_folded(start_line, !is_folded);
-    }
-
-    /// Check if a line is currently folded
-    pub fn is_folded_at(&self, start_line: usize) -> bool {
-        self.folded.iter().any(|f| f.start_line == start_line)
-    }
-
-    /// Check if a line is a fold candidate
-    pub fn is_fold_candidate(&self, start_line: usize) -> bool {
-        self.candidates.iter().any(|c| c.start_line == start_line)
-    }
-
-    /// Get all fold candidates
-    #[inline]
-    pub fn fold_candidates(&self) -> &[FoldRange] {
-        &self.candidates
-    }
-
-    /// Get all currently folded ranges
-    #[inline]
-    pub fn folded_ranges(&self) -> &[FoldRange] {
-        &self.folded
-    }
-
-    /// Clear all folds
-    #[inline]
-    pub fn clear_folds(&mut self) {
-        self.folded.clear();
-    }
-
-    /// Adjust folds and candidates after a text edit.
-    ///
-    /// - Folds/candidates overlapping the edited line range are removed
-    /// - Folds/candidates after the edit are shifted by line_delta
-    ///
-    /// This avoids expensive full tree traversal on every keystroke.
-    pub fn adjust_folds_for_edit(
-        &mut self,
-        edit_start_line: usize,
-        edit_end_line: usize,
-        line_delta: isize,
-    ) {
-        // Adjust folded ranges
-        if !self.folded.is_empty() {
-            self.folded.retain(|fold| {
-                !(fold.start_line <= edit_end_line && fold.end_line >= edit_start_line)
-            });
-
-            if line_delta != 0 {
-                for fold in &mut self.folded {
-                    if fold.start_line > edit_end_line {
-                        fold.start_line = (fold.start_line as isize + line_delta).max(0) as usize;
-                        fold.end_line = (fold.end_line as isize + line_delta).max(0) as usize;
-                    }
-                }
-            }
-        }
-
-        // Adjust candidates the same way
-        if !self.candidates.is_empty() {
-            self.candidates
-                .retain(|c| !(c.start_line <= edit_end_line && c.end_line >= edit_start_line));
-
-            if line_delta != 0 {
-                for c in &mut self.candidates {
-                    if c.start_line > edit_end_line {
-                        c.start_line = (c.start_line as isize + line_delta).max(0) as usize;
-                        c.end_line = (c.end_line as isize + line_delta).max(0) as usize;
-                    }
-                }
-            }
-        }
-
-        self.needs_rebuild = true;
-    }
-
-    /// Rebuild the fold mapping after wrap_map or fold state changes
-    ///
-    /// This is the core algorithm that projects wrap rows to display rows.
-    pub fn rebuild(&mut self, wrap_map: &WrapMap) {
-        let wrap_row_count = wrap_map.wrap_row_count();
-
-        // Performance optimization: skip rebuild if nothing changed
-        if !self.needs_rebuild && wrap_row_count == self.cached_wrap_row_count {
-            return;
-        }
-
-        self.cached_wrap_row_count = wrap_row_count;
-
-        self.visible_wrap_rows.clear();
-        self.wrap_row_to_display_row = vec![None; wrap_row_count];
-
-        if self.folded.is_empty() {
-            // Fast path: no folds, all wrap rows are visible
-            self.visible_wrap_rows = (0..wrap_row_count).collect();
-            for (display_row, &wrap_row) in self.visible_wrap_rows.iter().enumerate() {
-                self.wrap_row_to_display_row[wrap_row] = Some(display_row);
-            }
-            self.needs_rebuild = false;
-            return;
-        }
-
-        // Build set of hidden wrap_row ranges from folded buffer lines
-        let mut hidden_ranges = Vec::new();
-        for fold in &self.folded {
-            // Hide wrap rows from (start_line + 1) to (end_line - 1) (inclusive)
-            // Both the first line and last line of the fold remain visible
-            let hide_start_line = fold.start_line + 1;
-            let hide_end_line = fold.end_line.saturating_sub(1);
-
-            if hide_start_line > hide_end_line {
-                continue; // No middle lines to hide (0 or 1 lines between start and end)
-            }
-
-            // Get wrap_row ranges for the hidden buffer lines
-            let start_wrap_row = wrap_map.buffer_line_to_first_wrap_row(hide_start_line);
-            let end_wrap_row = if hide_end_line + 1 < wrap_map.buffer_line_count() {
-                wrap_map.buffer_line_to_first_wrap_row(hide_end_line + 1)
-            } else {
-                wrap_row_count
-            };
-
-            if start_wrap_row < end_wrap_row {
-                hidden_ranges.push(start_wrap_row..end_wrap_row);
-            }
-        }
-
-        // Merge overlapping hidden ranges
-        hidden_ranges.sort_by_key(|r| r.start);
-        let mut merged_hidden = Vec::new();
-        for range in hidden_ranges {
-            if let Some(last) = merged_hidden.last_mut() {
-                if range.start <= *last {
-                    // Overlapping or adjacent, merge
-                    *last = (*last).max(range.end);
-                } else {
-                    merged_hidden.push(range.start);
-                    merged_hidden.push(range.end);
-                }
-            } else {
-                merged_hidden.push(range.start);
-                merged_hidden.push(range.end);
-            }
-        }
-
-        // Scan all wrap rows and filter out hidden ones
-        let mut display_row = 0;
-        let mut hidden_iter = merged_hidden.chunks_exact(2);
-        let mut current_hidden = hidden_iter.next();
-
-        for wrap_row in 0..wrap_row_count {
-            // Check if wrap_row is in current hidden range
-            let is_hidden = if let Some(&[start, end]) = current_hidden {
-                if wrap_row >= end {
-                    current_hidden = hidden_iter.next();
-                    if let Some(&[new_start, new_end]) = current_hidden {
-                        wrap_row >= new_start && wrap_row < new_end
-                    } else {
-                        false
-                    }
-                } else {
-                    wrap_row >= start && wrap_row < end
-                }
-            } else {
-                false
-            };
-
-            if !is_hidden {
-                self.visible_wrap_rows.push(wrap_row);
-                self.wrap_row_to_display_row[wrap_row] = Some(display_row);
-                display_row += 1;
-            }
-        }
-
-        self.needs_rebuild = false;
-    }
-}