Chat system refactor

packages/app/src/chat/nip29.ts

@@ -0,0 +1,81 @@
+import { ExternalStore, FeedCache, dedupe } from "@snort/shared";
+import { RequestBuilder, NostrEvent, EventKind, SystemInterface } from "@snort/system";
+import { unwrap } from "SnortUtils";
+import { Chat, ChatSystem, ChatType, lastReadInChat } from "chat";
+
+export class Nip29ChatSystem extends ExternalStore<Array<Chat>> implements ChatSystem {
+  readonly #cache: FeedCache<NostrEvent>;
+
+  constructor(cache: FeedCache<NostrEvent>) {
+    super();
+    this.#cache = cache;
+  }
+
+  takeSnapshot(): Chat[] {
+    return this.listChats();
+  }
+
+  subscription(id: string) {
+    const gs = id.split("/", 2);
+    const rb = new RequestBuilder(`nip29:${id}`);
+    const last = this.listChats().find(a => a.id === id)?.lastMessage;
+    rb.withFilter()
+      .relay(`wss://${gs[0]}`)
+      .kinds([EventKind.SimpleChatMessage])
+      .tag("g", [`/${gs[1]}`])
+      .since(last);
+    rb.withFilter()
+      .relay(`wss://${gs[0]}`)
+      .kinds([EventKind.SimpleChatMetadata])
+      .tag("d", [`/${gs[1]}`]);
+    return rb;
+  }
+
+  async onEvent(evs: NostrEvent[]) {
+    const msg = evs.filter(a => a.kind === EventKind.SimpleChatMessage);
+    if (msg.length > 0) {
+      await this.#cache.bulkSet(msg);
+      this.notifyChange();
+    }
+  }
+
+  listChats(): Chat[] {
+    const allMessages = this.#nip29Chats();
+    const groups = dedupe(
+      allMessages
+        .map(a => a.tags.find(b => b[0] === "g"))
+        .filter(a => a !== undefined)
+        .map(a => unwrap(a))
+        .map(a => `${a[2]}${a[1]}`)
+    );
+    return groups.map(g => {
+      const [relay, channel] = g.split("/", 2);
+      const messages = allMessages.filter(
+        a => `${a.tags.find(b => b[0] === "g")?.[2]}${a.tags.find(b => b[0] === "g")?.[1]}` === g
+      );
+      const lastRead = lastReadInChat(g);
+      return {
+        type: ChatType.PublicGroupChat,
+        id: g,
+        unread: messages.reduce((acc, v) => (v.created_at > lastRead ? acc++ : acc), 0),
+        lastMessage: messages.reduce((acc, v) => (v.created_at > acc ? v.created_at : acc), 0),
+        messages,
+        createMessage: (msg, pub) => {
+          return pub.generic(eb => {
+            return eb
+              .kind(EventKind.SimpleChatMessage)
+              .tag(["g", `/${channel}`, relay])
+              .content(msg);
+          });
+        },
+        sendMessage: async (ev: NostrEvent, system: SystemInterface) => {
+          await system.WriteOnceToRelay(`wss://${relay}`, ev);
+        },
+      } as Chat;
+    });
+  }
+
+  #nip29Chats() {
+    return this.#cache.snapshot().filter(a => a.kind === EventKind.SimpleChatMessage);
+  }
+}