Add in-app notitications

src/lib/notifications.svelte.ts

@@ -0,0 +1,112 @@
+import { GROUP_ID, MODE } from "$lib/config";
+import { queryForum, subscribeForum } from "$lib/relay";
+import { ensureProfile } from "$lib/profiles.svelte";
+import {
+  fetchNotifications,
+  fetchThreadTitles,
+  parseNotification,
+  type Notification,
+} from "$lib/forum/notifications";
+
+export type { Notification };
+
+const SEEN_KEY = "notifications_seen";
+
+let pubkey = $state<string | null>(null);
+let items = $state<Notification[] | null>(null);
+let seenAt = $state(0);
+let liveSub: { close(): void } | null = null;
+let req = 0; // supersedes an in-flight load on login/logout
+
+function readSeen(pk: string): number {
+  try {
+    return Number(localStorage.getItem(`${SEEN_KEY}_${pk}`)) || 0;
+  } catch {
+    return 0;
+  }
+}
+
+export const notificationsStore = {
+  get pubkey() {
+    return pubkey;
+  },
+  get items() {
+    return items;
+  },
+  get seenAt() {
+    return seenAt;
+  },
+  get unreadCount() {
+    return items?.filter((n) => n.createdAt > seenAt).length ?? 0;
+  },
+};
+
+function ingest(n: Notification) {
+  if (!items || items.some((x) => x.id === n.id)) return;
+  items = [n, ...items];
+  ensureProfile(n.pubkey);
+}
+
+// (Re)start for the logged-in user: one authenticated read of the latest
+// replies/mentions, then a live subscription that prepends new ones.
+export async function startNotifications(pk: string) {
+  if (pk === pubkey) return;
+  stopNotifications();
+  pubkey = pk;
+  seenAt = readSeen(pk);
+  const current = ++req;
+  const scope = MODE === "simple" ? GROUP_ID : undefined;
+
+  let result: Notification[] = [];
+  try {
+    result = await fetchNotifications(queryForum, pk, scope);
+  } catch (e) {
+    console.error("[notifications] load failed", e);
+  }
+  if (current !== req) return;
+  items = result;
+  for (const n of result) ensureProfile(n.pubkey);
+
+  liveSub = subscribeForum(
+    {
+      kinds: [1111, 9],
+      "#p": [pk],
+      ...(scope ? { "#h": [scope] } : {}),
+      since: Math.floor(Date.now() / 1000),
+    },
+    {
+      onevent: async (ev) => {
+        const n = parseNotification(ev, pk);
+        if (!n) return;
+        if (n.threadId) {
+          try {
+            await fetchThreadTitles(queryForum, [n]);
+          } catch {
+            // Shown without a title
+          }
+        }
+        if (current === req) ingest(n);
+      },
+    },
+  );
+}
+
+export function stopNotifications() {
+  req++;
+  liveSub?.close();
+  liveSub = null;
+  pubkey = null;
+  items = null;
+  seenAt = 0;
+}
+
+// Everything loaded so far counts as read.
+export function markNotificationsSeen() {
+  if (!pubkey) return;
+  seenAt = Math.floor(Date.now() / 1000);
+  try {
+    localStorage.setItem(`${SEEN_KEY}_${pubkey}`, String(seenAt));
+  } catch {
+    // Private mode: unread state lasts for the session only
+  }
+}