feat: bind user metadata to per-view directories (#64)

Reviewed-on: #64

crates/person/src/directory.rs

@@ -0,0 +1,234 @@
+use std::cmp::Reverse;
+use std::collections::{HashMap, HashSet};
+use std::sync::RwLock;
+
+use anyhow::Error;
+use common::emojis_from_tags;
+use gpui::{App, AppContext, Context, Entity, Subscription, Task};
+use nostr_sdk::prelude::*;
+use smallvec::{SmallVec, smallvec};
+use state::NostrRegistry;
+
+use crate::{Person, PersonEvent, PersonRegistry};
+
+/// Directory of persons tracked by a view
+#[derive(Debug)]
+pub struct Directory {
+    persons: HashMap<PublicKey, Person>,
+    /// Keys awaiting their first update, guarded for render-time access
+    pending: RwLock<HashSet<PublicKey>>,
+    tasks: SmallVec<[Task<()>; 2]>,
+    _subscriptions: SmallVec<[Subscription; 1]>,
+}
+
+impl Directory {
+    /// Create a directory following the registry's events
+    pub fn new(cx: &mut App) -> Entity<Self> {
+        let registry = PersonRegistry::global(cx);
+
+        cx.new(|cx| {
+            let subscription = cx.subscribe(&registry, |this: &mut Self, _registry, event, cx| {
+                this.handle_event(event.clone(), cx);
+            });
+
+            Self {
+                persons: HashMap::new(),
+                pending: RwLock::new(HashSet::new()),
+                tasks: SmallVec::new(),
+                _subscriptions: smallvec![subscription],
+            }
+        })
+    }
+
+    /// Load known profiles from the database, request the rest
+    pub fn track(&mut self, keys: impl IntoIterator<Item = PublicKey>, cx: &mut Context<Self>) {
+        /// Profiles and emoji lists loaded from the database
+        type Loaded = (Vec<Person>, Vec<(PublicKey, Vec<(String, Url)>)>);
+
+        let missing: Vec<PublicKey> = keys
+            .into_iter()
+            .filter(|key| {
+                !self.persons.contains_key(key)
+                    && !self.with_pending(|pending| pending.contains(key))
+            })
+            .collect();
+
+        if missing.is_empty() {
+            return;
+        }
+
+        // Accept events that arrive while the database query is running
+        self.with_pending(|pending| {
+            pending.extend(missing.iter().copied());
+        });
+
+        let nostr = NostrRegistry::global(cx);
+        let client = nostr.read(cx).client();
+        let authors = missing.clone();
+
+        let task: Task<Result<Loaded, Error>> = cx.background_spawn(async move {
+            let mut metadata_events: Vec<Event> = client
+                .database()
+                .query(Filter::new().kind(Kind::Metadata).authors(authors.clone()))
+                .await?
+                .into_iter()
+                .collect();
+
+            // Keep only the newest event per author
+            metadata_events.sort_by_key(|event| Reverse(event.created_at));
+            let mut seen = HashSet::new();
+
+            let persons = metadata_events
+                .into_iter()
+                .filter(|event| seen.insert(event.pubkey))
+                .map(|event| {
+                    let metadata = Metadata::from_json(event.content).unwrap_or_default();
+                    Person::new(event.pubkey, metadata)
+                })
+                .collect();
+
+            let mut emoji_events: Vec<Event> = client
+                .database()
+                .query(Filter::new().kind(Kind::Emojis).authors(authors))
+                .await?
+                .into_iter()
+                .collect();
+
+            // Keep only the newest event per author
+            emoji_events.sort_by_key(|event| Reverse(event.created_at));
+            let mut seen = HashSet::new();
+
+            let emojis = emoji_events
+                .into_iter()
+                .filter(|event| seen.insert(event.pubkey))
+                .map(|event| (event.pubkey, emojis_from_tags(&event.tags)))
+                .collect();
+
+            Ok((persons, emojis))
+        });
+
+        self.tasks.push(cx.spawn(async move |this, cx| {
+            let loaded = task.await;
+
+            this.update(cx, |this, cx| {
+                let remaining = match loaded {
+                    Ok((persons, emojis)) => {
+                        let found: HashSet<PublicKey> =
+                            persons.iter().map(Person::public_key).collect();
+                        this.bulk_insert(persons, cx);
+
+                        // Emojis apply on top of loaded or already received data
+                        let mut updated = false;
+
+                        for (public_key, emojis) in emojis {
+                            if emojis.is_empty() {
+                                continue;
+                            }
+
+                            let person = this
+                                .persons
+                                .entry(public_key)
+                                .or_insert_with(|| Person::new(public_key, Metadata::default()));
+                            person.set_emojis(emojis);
+                            updated = true;
+                        }
+
+                        if updated {
+                            cx.notify();
+                        }
+
+                        missing
+                            .into_iter()
+                            .filter(|key| !found.contains(key))
+                            .collect()
+                    }
+                    Err(e) => {
+                        log::warn!("Failed to load persons from the database: {e}");
+                        missing
+                    }
+                };
+
+                if !remaining.is_empty() {
+                    let registry = PersonRegistry::global(cx);
+                    registry.read(cx).fetch(remaining);
+                }
+            })
+            .ok();
+        }));
+    }
+
+    /// The person for a key, or a placeholder that queues a request
+    pub fn person(&self, public_key: &PublicKey, cx: &App) -> Person {
+        if let Some(person) = self.persons.get(public_key) {
+            return person.clone();
+        }
+
+        if self.with_pending(|pending| pending.insert(*public_key)) {
+            let registry = PersonRegistry::global(cx);
+            registry.read(cx).fetch([*public_key]);
+        }
+
+        Person::new(*public_key, Metadata::default())
+    }
+
+    /// Merge event data into the tracked person
+    fn handle_event(&mut self, event: PersonEvent, cx: &mut Context<Self>) {
+        let public_key = match &event {
+            PersonEvent::Metadata(person) => person.public_key(),
+            PersonEvent::Emojis { public_key, .. }
+            | PersonEvent::Announcement { public_key, .. }
+            | PersonEvent::MessagingRelays { public_key, .. } => *public_key,
+        };
+
+        if !self.persons.contains_key(&public_key)
+            && !self.with_pending(|pending| pending.remove(&public_key))
+        {
+            return;
+        }
+
+        let person = self
+            .persons
+            .entry(public_key)
+            .or_insert_with(|| Person::new(public_key, Metadata::default()));
+
+        match event {
+            PersonEvent::Metadata(updated) => person.set_metadata(updated.metadata()),
+            PersonEvent::Emojis { emojis, .. } => person.set_emojis(emojis),
+            PersonEvent::Announcement { announcement, .. } => {
+                person.set_announcement(announcement);
+            }
+            PersonEvent::MessagingRelays { relays, .. } => person.set_messaging_relays(relays),
+        }
+
+        cx.notify();
+    }
+
+    /// Insert loaded persons, keeping data already received from relays
+    fn bulk_insert(&mut self, persons: Vec<Person>, cx: &mut Context<Self>) {
+        let mut inserted = false;
+
+        for person in persons {
+            let public_key = person.public_key();
+
+            if self.persons.contains_key(&public_key) {
+                continue;
+            }
+
+            self.persons.insert(public_key, person);
+            inserted = true;
+        }
+
+        if inserted {
+            cx.notify();
+        }
+    }
+
+    /// Run `then` with the pending set, tolerating poisoning: it is only a dedupe cache
+    fn with_pending<R>(&self, then: impl FnOnce(&mut HashSet<PublicKey>) -> R) -> R {
+        let mut pending = match self.pending.write() {
+            Ok(pending) => pending,
+            Err(poisoned) => poisoned.into_inner(),
+        };
+        then(&mut pending)
+    }
+}