refactor(orbit): co-locate orbit feature into features/orbit

src/features/orbit/utils/sweep.ts

@@ -0,0 +1,66 @@
+import { getPlaylist, getPlaylists, updatePlaylist } from '@/api/subsonicPlaylists';
+import { type OrbitOutboxMeta } from '@/features/orbit/api/orbit';
+import { parseOutboxPlaylistName } from '@/features/orbit/utils/helpers';
+import { type OutboxSnapshot } from '@/features/orbit/utils/stateMath';
+
+/**
+ * Host: list all guest outbox playlists for the current session.
+ * Skips the host's own outbox — that's heartbeat-only, not a suggestion channel.
+ */
+async function listGuestOutboxes(sid: string, hostUsername: string): Promise<Array<{ id: string; name: string; user: string }>> {
+  const all = await getPlaylists(true).catch(() => []);
+  const result: Array<{ id: string; name: string; user: string }> = [];
+  for (const p of all) {
+    const user = parseOutboxPlaylistName(p.name, sid);
+    if (!user || user === hostUsername) continue;
+    result.push({ id: p.id, name: p.name, user });
+  }
+  return result;
+}
+
+/**
+ * Host: read one outbox's contents (suggested tracks + heartbeat ts).
+ */
+async function readOutbox(playlistId: string): Promise<{ trackIds: string[]; lastHeartbeat: number }> {
+  try {
+    const { playlist, songs } = await getPlaylist(playlistId);
+    let ts = 0;
+    if (playlist.comment) {
+      try {
+        const meta = JSON.parse(playlist.comment) as Partial<OrbitOutboxMeta>;
+        if (typeof meta.ts === 'number') ts = meta.ts;
+      } catch { /* malformed — treat as no heartbeat */ }
+    }
+    return { trackIds: songs.map(s => s.id), lastHeartbeat: ts };
+  } catch {
+    return { trackIds: [], lastHeartbeat: 0 };
+  }
+}
+
+/**
+ * Host: sweep every guest outbox once.
+ *
+ *   - Collects suggested track IDs from each outbox (returns them so the
+ *     caller can wire them into the state queue with `addedBy` = user).
+ *   - Captures the latest heartbeat ts per user for the participants list.
+ *   - Clears the outbox track list after reading — a single-pass consume
+ *     semantic: once the host has seen a track, the guest doesn't need to
+ *     show it as "pending" any longer. The outbox's heartbeat comment is
+ *     left untouched because the guest's own heartbeat hook keeps refreshing it.
+ *
+ * Returns a list of snapshots, one per live guest outbox. Errors on
+ * individual outboxes are swallowed — best-effort.
+ */
+export async function sweepGuestOutboxes(sid: string, hostUsername: string): Promise<OutboxSnapshot[]> {
+  const outboxes = await listGuestOutboxes(sid, hostUsername);
+  const snaps: OutboxSnapshot[] = [];
+  for (const ob of outboxes) {
+    const { trackIds, lastHeartbeat } = await readOutbox(ob.id);
+    snaps.push({ user: ob.user, outboxPlaylistId: ob.id, trackIds, lastHeartbeat });
+    if (trackIds.length > 0) {
+      // Clear the outbox tracks. Leaves the heartbeat comment untouched.
+      try { await updatePlaylist(ob.id, [], trackIds.length); } catch { /* best-effort */ }
+    }
+  }
+  return snaps;
+}