chore: bind user metadata to per-view directories (#31)

Reviewed-on: #31

crates/metadata/src/lib.rs

@@ -0,0 +1,9 @@
+mod profile;
+
+use gpui::{App, AppContext};
+pub use profile::{Profile, ProfileDirectory, ProfileEvent, ProfileStore};
+
+/// Initialize the global profile store.
+pub fn init(cx: &mut App) {
+    ProfileStore::set_global(cx.new(ProfileStore::new), cx);
+}

crates/metadata/src/profile.rs

@@ -0,0 +1,374 @@
+use std::cell::RefCell;
+use std::collections::{HashMap, HashSet};
+use std::time::{Duration, Instant};
+
+use flume::Sender;
+use gpui::{
+    App, AppContext, Context, Entity, EventEmitter, Global, SharedString, Subscription, Task,
+};
+use nostr_sdk::prelude::*;
+use signed_state::{Backend, BackendEvent, sync_bootstrap_only};
+use utils::shorten_pubkey;
+
+const BATCH_TIMEOUT: Duration = Duration::from_millis(500);
+const REQUEST_CHUNK: usize = 100;
+
+#[derive(Debug, Clone)]
+pub struct Profile {
+    public_key: PublicKey,
+    metadata: Metadata,
+}
+
+impl Profile {
+    pub fn new(public_key: PublicKey, metadata: Metadata) -> Self {
+        Self {
+            public_key,
+            metadata,
+        }
+    }
+
+    pub fn public_key(&self) -> PublicKey {
+        self.public_key
+    }
+
+    pub fn metadata(&self) -> &Metadata {
+        &self.metadata
+    }
+
+    // Falls back to `name`, then a shortened npub.
+    pub fn name(&self) -> SharedString {
+        if let Some(display_name) = self.metadata.display_name.as_ref()
+            && !display_name.is_empty()
+        {
+            return SharedString::from(display_name.trim().to_owned());
+        }
+
+        if let Some(name) = self.metadata.name.as_ref()
+            && !name.is_empty()
+        {
+            return SharedString::from(name.trim().to_owned());
+        }
+
+        SharedString::from(shorten_pubkey(self.public_key))
+    }
+
+    pub fn picture(&self) -> Option<SharedString> {
+        self.metadata
+            .picture
+            .as_ref()
+            .filter(|p| !p.is_empty())
+            .map(|p| SharedString::from(p.clone()))
+    }
+
+    /// The newest profile per author from metadata events.
+    fn latest_profiles(events: impl IntoIterator<Item = Event>) -> Vec<Self> {
+        let mut latest: HashMap<PublicKey, (Timestamp, Metadata)> = HashMap::new();
+
+        for event in events {
+            match latest.get(&event.pubkey) {
+                Some((created_at, _)) if *created_at >= event.created_at => {}
+                _ => {
+                    let metadata = Metadata::from_json(&event.content).unwrap_or_default();
+                    latest.insert(event.pubkey, (event.created_at, metadata));
+                }
+            }
+        }
+
+        latest
+            .into_iter()
+            .map(|(public_key, (_, metadata))| Profile::new(public_key, metadata))
+            .collect()
+    }
+}
+
+/// Metadata for these authors may have changed in the local database.
+#[derive(Debug, Clone)]
+pub enum ProfileEvent {
+    Updated(Vec<PublicKey>),
+}
+
+/// Batches metadata requests into relay syncs feeding the local database.
+pub struct ProfileStore {
+    in_flight: RefCell<HashSet<PublicKey>>,
+    sender: Sender<PublicKey>,
+    _task: Task<Result<(), anyhow::Error>>,
+    _subscription: Subscription,
+}
+
+struct GlobalProfileStore(Entity<ProfileStore>);
+
+impl Global for GlobalProfileStore {}
+
+impl EventEmitter<ProfileEvent> for ProfileStore {}
+
+impl ProfileStore {
+    pub(crate) fn global(cx: &App) -> Entity<Self> {
+        cx.global::<GlobalProfileStore>().0.clone()
+    }
+
+    pub(crate) fn set_global(entity: Entity<Self>, cx: &mut App) {
+        cx.set_global(GlobalProfileStore(entity));
+    }
+
+    pub(crate) fn new(cx: &mut Context<Self>) -> Self {
+        let backend = Backend::global(cx);
+        let client = backend.read(cx).client();
+
+        let (sender, receiver) = flume::unbounded::<PublicKey>();
+
+        let subscription = cx.subscribe(&backend, |this, _backend, event, cx| {
+            if let BackendEvent::ProfileUpdates(authors) = event {
+                this.emit_updated(authors.clone(), cx);
+            }
+        });
+
+        let task = cx.spawn(async move |this, cx| {
+            let mut batch: HashSet<PublicKey> = HashSet::new();
+
+            loop {
+                match receiver.recv_async().await {
+                    Ok(public_key) => {
+                        batch.insert(public_key);
+                    }
+                    Err(_) => return Ok(()),
+                }
+
+                // The channel has no async timeout, race the receive against a timer.
+                let deadline = Instant::now() + BATCH_TIMEOUT;
+
+                loop {
+                    let now = Instant::now();
+
+                    if now >= deadline {
+                        break;
+                    }
+
+                    let timer = cx.background_executor().timer(deadline - now);
+                    futures::pin_mut!(timer);
+
+                    let recv = receiver.recv_async();
+                    futures::pin_mut!(recv);
+
+                    match futures::future::select(recv, timer).await {
+                        futures::future::Either::Left((Ok(public_key), _)) => {
+                            batch.insert(public_key);
+                        }
+                        futures::future::Either::Left((Err(_), _)) => return Ok(()),
+                        futures::future::Either::Right(_) => break,
+                    }
+                }
+
+                let authors: Vec<PublicKey> = batch.drain().collect();
+
+                for chunk in authors.chunks(REQUEST_CHUNK) {
+                    let opts = SyncOptions::default();
+                    let filter = Filter::new()
+                        .kind(Kind::Metadata)
+                        .authors(chunk.iter().copied());
+
+                    if let Err(e) = sync_bootstrap_only(&client, filter, opts).await {
+                        log::warn!("profile fetch failed: {e}");
+                    }
+                }
+
+                // Emit even when the sync failed, the database may hold newer data.
+                this.update(cx, |this, cx| {
+                    this.emit_updated(authors, cx);
+                })?;
+            }
+        });
+
+        Self {
+            in_flight: RefCell::new(HashSet::new()),
+            sender,
+            _task: task,
+            _subscription: subscription,
+        }
+    }
+
+    /// Queue a batched relay sync for keys without one in flight.
+    pub fn fetch(&self, keys: impl IntoIterator<Item = PublicKey>) {
+        let mut queue = Vec::new();
+        {
+            let mut in_flight = self.in_flight.borrow_mut();
+
+            for key in keys {
+                if in_flight.insert(key) {
+                    queue.push(key);
+                }
+            }
+        }
+        for public_key in queue {
+            if let Err(e) = self.sender.send(public_key) {
+                log::warn!("failed to queue profile fetch: {e}");
+            }
+        }
+    }
+
+    // Releases the in-flight keys so future fetches can be queued again.
+    fn emit_updated(&mut self, authors: Vec<PublicKey>, cx: &mut Context<Self>) {
+        if authors.is_empty() {
+            return;
+        }
+
+        {
+            let mut in_flight = self.in_flight.borrow_mut();
+            for author in &authors {
+                in_flight.remove(author);
+            }
+        }
+
+        cx.emit(ProfileEvent::Updated(authors));
+    }
+}
+
+/// Profile cache bound to one panel or screen.
+pub struct ProfileDirectory {
+    profiles: HashMap<PublicKey, Profile>,
+    pending: RefCell<HashSet<PublicKey>>,
+    tasks: Vec<Task<()>>,
+    _subscriptions: Vec<Subscription>,
+}
+
+impl ProfileDirectory {
+    pub fn new(cx: &mut App) -> Entity<Self> {
+        let store = ProfileStore::global(cx);
+
+        cx.new(|cx| {
+            let subscription =
+                cx.subscribe(&store, |this: &mut Self, _store, event, cx| match event {
+                    ProfileEvent::Updated(authors) => this.refresh(authors, cx),
+                });
+
+            Self {
+                profiles: HashMap::new(),
+                pending: RefCell::new(HashSet::new()),
+                tasks: Vec::new(),
+                _subscriptions: vec![subscription],
+            }
+        })
+    }
+
+    /// Resolve keys from the local database, queue the rest for a relay sync.
+    pub fn track<K>(&mut self, keys: K, cx: &mut Context<Self>)
+    where
+        K: IntoIterator<Item = PublicKey>,
+    {
+        let missing: Vec<PublicKey> = keys
+            .into_iter()
+            .filter(|key| {
+                !self.profiles.contains_key(key)
+                    && !self.with_pending(|pending| pending.contains(key))
+            })
+            .collect();
+
+        if missing.is_empty() {
+            return;
+        }
+
+        self.load(missing, true, cx);
+    }
+
+    /// The profile for a key, or a placeholder that queues a relay sync.
+    pub fn profile(&self, public_key: &PublicKey, cx: &App) -> Profile {
+        if let Some(profile) = self.profiles.get(public_key) {
+            return profile.clone();
+        }
+
+        if self.with_pending(|pending| pending.insert(*public_key)) {
+            let store = ProfileStore::global(cx);
+            store.read(cx).fetch([*public_key]);
+        }
+
+        Profile::new(*public_key, Metadata::default())
+    }
+
+    /// Refreshes profiles for keys that are already tracked.
+    fn refresh(&mut self, authors: &[PublicKey], cx: &mut Context<Self>) {
+        let tracked: Vec<PublicKey> = authors
+            .iter()
+            .copied()
+            .filter(|key| {
+                self.profiles.contains_key(key)
+                    || self.with_pending(|pending| pending.contains(key))
+            })
+            .collect();
+
+        if tracked.is_empty() {
+            return;
+        }
+
+        self.load(tracked, false, cx);
+    }
+
+    /// Loads profiles from the local database, queueing a relay sync for any missing keys.
+    fn load(&mut self, keys: Vec<PublicKey>, queue_sync: bool, cx: &mut Context<Self>) {
+        // Accept events that arrive while the database query is running.
+        self.with_pending(|pending| {
+            pending.extend(keys.iter().copied());
+        });
+
+        let backend = Backend::global(cx);
+        let client = backend.read(cx).client();
+        let query_keys = keys.clone();
+
+        let work = cx.background_spawn(async move {
+            let authors = query_keys.iter().copied();
+            let filter = Filter::new().kind(Kind::Metadata).authors(authors);
+            let events = client.database().query(filter).await?;
+
+            Ok::<_, anyhow::Error>(Profile::latest_profiles(events))
+        });
+
+        self.tasks.push(cx.spawn(async move |this, cx| {
+            let loaded = work.await;
+
+            this.update(cx, |this, cx| {
+                let remaining = match loaded {
+                    Ok(profiles) => {
+                        let found: HashSet<PublicKey> =
+                            profiles.iter().map(Profile::public_key).collect();
+                        this.insert_loaded(profiles, cx);
+                        keys.into_iter()
+                            .filter(|key| !found.contains(key))
+                            .collect()
+                    }
+                    Err(e) => {
+                        log::warn!("failed to load profiles from the database: {e}");
+                        keys
+                    }
+                };
+
+                if queue_sync && !remaining.is_empty() {
+                    let store = ProfileStore::global(cx);
+                    store.read(cx).fetch(remaining);
+                }
+            })
+            .ok();
+        }));
+    }
+
+    // Inserts database results, replacing anything loaded earlier.
+    fn insert_loaded(&mut self, profiles: Vec<Profile>, cx: &mut Context<Self>) {
+        let mut inserted = false;
+
+        for profile in profiles {
+            let public_key = profile.public_key();
+            self.profiles.insert(public_key, profile);
+            self.with_pending(|pending| pending.remove(&public_key));
+            inserted = true;
+        }
+
+        if inserted {
+            cx.notify();
+        }
+    }
+
+    fn with_pending<R, T>(&self, then: T) -> R
+    where
+        T: FnOnce(&mut HashSet<PublicKey>) -> R,
+    {
+        let mut pending = self.pending.borrow_mut();
+        then(&mut pending)
+    }
+}