From 45daeba8a64410ca8a3e9daf3252151e5338d556 Mon Sep 17 00:00:00 2001
From: Ren Amamiya <reyakov@proton.me>
Date: Tue, 29 Sep 2026 14:31:43 +0700
Subject: [PATCH] add invite

---
 Cargo.lock                       |   1 +
 crates/community/Cargo.toml      |   1 +
 crates/community/src/discover.rs | 131 +++++++++++++++++++++++++++++++
 crates/community/src/lib.rs      |   1 +
 4 files changed, 134 insertions(+)
 create mode 100644 crates/community/src/discover.rs

diff --git a/Cargo.lock b/Cargo.lock
index fe98f57e..7a072b53 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1291,6 +1291,7 @@ dependencies = [
  "log",
  "nostr-memory",
  "nostr-sdk",
+ "regex",
  "serde_json",
  "smallvec",
  "smol",
diff --git a/crates/community/Cargo.toml b/crates/community/Cargo.toml
index bbc23794..cf001397 100644
--- a/crates/community/Cargo.toml
+++ b/crates/community/Cargo.toml
@@ -10,6 +10,7 @@ state = { path = "../state" }
 
 gpui.workspace = true
 nostr-sdk.workspace = true
+regex = "1"
 
 anyhow.workspace = true
 data-encoding.workspace = true
diff --git a/crates/community/src/discover.rs b/crates/community/src/discover.rs
new file mode 100644
index 00000000..2ea0391c
--- /dev/null
+++ b/crates/community/src/discover.rs
@@ -0,0 +1,131 @@
+use std::collections::{BTreeMap, BTreeSet};
+use std::sync::LazyLock;
+
+use concord::cord05;
+use nostr_sdk::prelude::*;
+use regex::Regex;
+
+pub const KIND_COMMUNITY_ANNOUNCEMENT: u16 = 3314;
+
+static INVITE_URL: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(
+        r"(?i)(?:https?://\S+?/invite/naddr1[0-9a-z]+#[A-Za-z0-9_-]+)|(?:naddr1[0-9a-z]+#[A-Za-z0-9_-]+)",
+    )
+    .unwrap()
+});
+
+#[derive(Debug, Clone)]
+pub struct Invite {
+    pub invite_url: String,
+    pub link_signer: PublicKey,
+    pub source: Event,
+}
+
+impl Invite {
+    pub fn from_event(event: &Event) -> Option<Invite> {
+        let invite_url = extract_invite_urls(&event.content).into_iter().next()?;
+        let link_signer = cord05::parse_link(&invite_url).ok()?.link_signer;
+
+        Some(Invite {
+            invite_url,
+            link_signer,
+            source: event.clone(),
+        })
+    }
+}
+
+pub fn extract_invite_urls(text: &str) -> Vec<String> {
+    let mut urls = Vec::new();
+    let mut seen = BTreeSet::new();
+
+    for found in INVITE_URL.find_iter(text) {
+        let candidate = found.as_str();
+
+        let Ok(link) = cord05::parse_link(candidate) else {
+            continue;
+        };
+
+        if seen.insert(link.link_signer) {
+            urls.push(candidate.to_string());
+        }
+    }
+
+    urls
+}
+
+pub fn build_community_announcement(invite_url: &str) -> Option<EventBuilder> {
+    if cord05::parse_link(invite_url).is_err() {
+        return None;
+    }
+
+    Some(EventBuilder::new(
+        Kind::Custom(KIND_COMMUNITY_ANNOUNCEMENT),
+        invite_url.trim(),
+    ))
+}
+
+pub fn build_announcement_deletion(ids: &[EventId]) -> EventBuilder {
+    let mut tags: Vec<Tag> = ids.iter().map(|id| Tag::event(*id)).collect();
+    tags.push(Tag::custom("k", [KIND_COMMUNITY_ANNOUNCEMENT.to_string()]));
+
+    EventBuilder::new(Kind::EventDeletion, "").tags(tags)
+}
+
+pub fn fold_announcements(announcements: &[Event], deletes: &[Event]) -> Vec<Invite> {
+    let authors: BTreeMap<EventId, PublicKey> = announcements
+        .iter()
+        .filter(|event| event.kind == Kind::Custom(KIND_COMMUNITY_ANNOUNCEMENT))
+        .map(|event| (event.id, event.pubkey))
+        .collect();
+
+    let deleted = deleted_ids(&authors, deletes);
+
+    let mut ordered: Vec<&Event> = announcements.iter().collect();
+    ordered.sort_by_key(|event| std::cmp::Reverse(event.created_at));
+
+    let mut seen = BTreeSet::new();
+    let mut folded = Vec::new();
+
+    for event in ordered {
+        if deleted.contains(&event.id) {
+            continue;
+        }
+
+        let Some(invite) = Invite::from_event(event) else {
+            continue;
+        };
+
+        if seen.insert(invite.link_signer) {
+            folded.push(invite);
+        }
+    }
+
+    folded
+}
+
+fn deleted_ids(authors: &BTreeMap<EventId, PublicKey>, deletes: &[Event]) -> BTreeSet<EventId> {
+    let mut deleted = BTreeSet::new();
+
+    for event in deletes
+        .iter()
+        .filter(|event| event.kind == Kind::EventDeletion)
+    {
+        for tag in event.tags.iter() {
+            let fields = tag.as_slice();
+
+            if fields.len() < 2 || fields[0] != "e" {
+                continue;
+            }
+
+            let Ok(id) = EventId::from_hex(&fields[1]) else {
+                continue;
+            };
+
+            if authors.get(&id) == Some(&event.pubkey) {
+                deleted.insert(id);
+            }
+        }
+    }
+
+    deleted
+}
diff --git a/crates/community/src/lib.rs b/crates/community/src/lib.rs
index 67fbae2e..7e4feb89 100644
--- a/crates/community/src/lib.rs
+++ b/crates/community/src/lib.rs
@@ -17,6 +17,7 @@ use crate::rekey::WatchRegistry;
 
 pub mod cache;
 mod community;
+pub mod discover;
 pub mod history;
 mod rekey;
 mod sync;