feat: enhance discovery, vibe sessions, and library enrichment

frontend/src/services/vibeSession.ts

@@ -0,0 +1,51 @@
+import type { Track } from '../types';
+import { usePlaybackStore } from '../store/usePlaybackStore';
+import { useVibeStore } from '../store/useVibeStore';
+import { fetchNextBatch, vibeService, type VibeBatchStatus } from './vibeService';
+
+export const INITIAL_VIBE_BATCH_SIZE = 5;
+
+export interface StartedVibeSession {
+  status: VibeBatchStatus;
+  tracks: Track[];
+}
+
+let startInFlight: Promise<StartedVibeSession> | null = null;
+
+/**
+ * Start a V2 plan and immediately hand its first recommendations to playback.
+ * Keeping this in one place prevents entry points from accidentally replacing a
+ * generated Vibe queue with a normal browse queue.
+ */
+export async function startVibeSession(seed: Track): Promise<StartedVibeSession> {
+  if (startInFlight) return startInFlight;
+  startInFlight = beginVibeSession(seed);
+  try {
+    return await startInFlight;
+  } finally {
+    startInFlight = null;
+  }
+}
+
+async function beginVibeSession(seed: Track): Promise<StartedVibeSession> {
+  const { sessionId } = await vibeService.start(seed.id);
+  const vibe = useVibeStore.getState();
+  // Do not replace a working Vibe until the new session has produced a usable
+  // initial batch. This also keeps the page prefetcher attached to the old
+  // session while this request is in flight.
+  const result = await fetchNextBatch(INITIAL_VIBE_BATCH_SIZE, sessionId);
+  if (result.tracks.length === 0) return result;
+
+  vibe.setInitialBatchStatus('loading');
+  vibe.setActiveSession({ sessionId, seedTrackId: seed.id });
+  vibe.setSeedTrackId(seed.id);
+  vibe.setCenterTrack(seed);
+  vibe.setBuffer(result.tracks);
+  vibe.setInitialBatchStatus('idle');
+
+  const playback = usePlaybackStore.getState();
+  playback.setQueue(result.tracks);
+  playback.playTrack(result.tracks[0]);
+
+  return result;
+}