Implement a minimal chat system for the sidebar

src/lib/chat.svelte.ts

@@ -0,0 +1,148 @@
+import { SimplePool, type Event } from "@nostr/tools";
+import { loadNostrUser, type NostrUser } from "@nostr/gadgets/metadata";
+import { RELAY_URL, GROUP_ID } from "$lib/config";
+import { auth } from "$lib/auth.svelte";
+import { ingestNostrUser } from "$lib/profiles.svelte";
+
+export type ChatMessageData = {
+  id: string;
+  pubkey: string;
+  createdAt: number;
+  content: string;
+  replyToId?: string;
+  replyToPubkey?: string;
+};
+
+let messages = $state<ChatMessageData[]>([]);
+let profiles = $state<Record<string, NostrUser>>({});
+let started = false;
+let livePool: SimplePool | null = null;
+let liveSub: { close(): void } | null = null;
+
+export const chatStore = {
+  get messages() {
+    return messages;
+  },
+  get profiles() {
+    return profiles;
+  },
+};
+
+export function getChatMessage(id: string): ChatMessageData | undefined {
+  return messages.find((m) => m.id === id);
+}
+
+async function loadProfile(pubkey: string) {
+  if (profiles[pubkey]) return;
+  try {
+    const user = await loadNostrUser(pubkey);
+    profiles = { ...profiles, [pubkey]: user };
+    ingestNostrUser(user);
+  } catch (e) {
+    console.error("[chat] profile load failed", pubkey, e);
+  }
+}
+
+function eventToMessage(ev: Event): ChatMessageData {
+  const qTag = ev.tags.find((t) => t[0] === "q");
+  return {
+    id: ev.id,
+    pubkey: ev.pubkey,
+    createdAt: ev.created_at,
+    content: ev.content,
+    replyToId: qTag?.[1],
+    replyToPubkey: qTag?.[3],
+  };
+}
+
+function ingestEvent(ev: Event) {
+  if (messages.some((m) => m.id === ev.id)) return;
+  const m = eventToMessage(ev);
+  let idx = messages.length;
+  while (idx > 0 && messages[idx - 1].createdAt > m.createdAt) idx--;
+  messages = [...messages.slice(0, idx), m, ...messages.slice(idx)];
+  loadProfile(ev.pubkey);
+}
+
+export async function startChat() {
+  if (started) return;
+  started = true;
+
+  const pool = new SimplePool();
+  try {
+    const events = await pool.querySync([RELAY_URL], {
+      kinds: [9],
+      "#h": [GROUP_ID],
+      limit: 100,
+    });
+    for (const ev of events) ingestEvent(ev);
+  } catch (e) {
+    console.error("[chat] initial load failed", e);
+  } finally {
+    pool.close([RELAY_URL]);
+  }
+
+  livePool = new SimplePool();
+  liveSub = livePool.subscribeMany(
+    [RELAY_URL],
+    {
+      kinds: [9],
+      "#h": [GROUP_ID],
+      since: Math.floor(Date.now() / 1000),
+    },
+    { onevent: (ev) => ingestEvent(ev) },
+  );
+}
+
+export function stopChat() {
+  liveSub?.close();
+  livePool?.close([RELAY_URL]);
+  liveSub = null;
+  livePool = null;
+  started = false;
+}
+
+export async function sendChatMessage(
+  content: string,
+  replyTo?: { id: string; pubkey: string },
+) {
+  if (!auth.signer) throw new Error("Not logged in");
+  const ownPubkey = await auth.signer.getPublicKey();
+
+  const previousRefs = messages
+    .filter((m) => m.pubkey !== ownPubkey)
+    .slice(-3)
+    .map((m) => m.id.slice(0, 8));
+
+  const tags: string[][] = [["h", GROUP_ID]];
+  if (replyTo) {
+    tags.push(["q", replyTo.id, RELAY_URL, replyTo.pubkey]);
+    if (replyTo.pubkey !== ownPubkey) tags.push(["p", replyTo.pubkey]);
+  }
+  if (previousRefs.length > 0) tags.push(["previous", ...previousRefs]);
+
+  const signed = await auth.signer.signEvent({
+    kind: 9,
+    created_at: Math.floor(Date.now() / 1000),
+    tags,
+    content,
+  });
+
+  const pool = new SimplePool();
+  try {
+    const timeout = new Promise<never>((_, reject) =>
+      setTimeout(
+        () => reject(new Error("Relay did not respond in time")),
+        8000,
+      ),
+    );
+    await Promise.race([
+      Promise.all(pool.publish([RELAY_URL], signed)),
+      timeout,
+    ]);
+  } finally {
+    pool.destroy();
+  }
+
+  ingestEvent(signed);
+}