From 3a097c15c838315dad5c43ddd0fa060cf7cccd96 Mon Sep 17 00:00:00 2001
From: mrleo1nid <43583385+mrleo1nid@users.noreply.github.com>
Date: Wed, 21 Oct 2026 22:49:10 +0300
Subject: [PATCH] perf(web): preload restored audio before playback

---
 apps/web/src/player/player.ts       | 52 ++++++++++++++-----
 apps/web/src/player/preload.test.ts | 79 +++++++++++++++++++++++++++++
 2 files changed, 119 insertions(+), 12 deletions(-)
 create mode 100644 apps/web/src/player/preload.test.ts

diff --git a/apps/web/src/player/player.ts b/apps/web/src/player/player.ts
index ae27c9e..2baaae1 100644
--- a/apps/web/src/player/player.ts
+++ b/apps/web/src/player/player.ts
@@ -97,6 +97,7 @@ export class Player {
   private timers: ReturnType<typeof setInterval>[] = [];
   private waveFeedback: { track_id: string; outcome: WaveOutcome }[] = [];
   private waveLoading = false;
+  private restoreVersion = 0;
   /** Реакция сохранена на сервере — списки на экране нужно перечитать. */
   onReaction: (() => void) | null = null;
 
@@ -159,6 +160,7 @@ export class Player {
     const playable = tracks.filter((t) => t.available && t.stream_url);
     const target = tracks[index];
     if (!target || !playable.length) return;
+    this.restoreVersion++;
     this.finishAttempt('skip');
     this.leaveWave();
     this.context = context;
@@ -171,6 +173,7 @@ export class Player {
 
   /** Запустить волну (или перезапустить с новым контекстом). */
   async startWave(activity: string | null, mood: string | null, seed?: { type: 'artist' | 'album' | 'track'; id: string; label: string }) {
+    this.restoreVersion++;
     this.finishAttempt('skip');
     this.leaveWave();
     const res = unwrap(
@@ -275,7 +278,7 @@ export class Player {
 
   play() {
     if (!this.queue.current) return;
-    if (!this.audio.src) {
+    if (!this.audio.src || !this.attempt) {
       void this.load(true, this.state.positionMs);
       return;
     }
@@ -388,9 +391,12 @@ export class Player {
   private async load(autoplay: boolean, startMs = 0) {
     const track = this.queue.current;
     if (!track?.stream_url) return;
-    this.update({ loading: true, error: null, positionMs: startMs, durationMs: track.duration_ms });
-    this.audio.src = track.stream_url;
-    if (startMs > 0) this.audio.currentTime = startMs / 1000;
+    this.update({ loading: autoplay, error: null, positionMs: startMs, durationMs: track.duration_ms });
+    // Keep the restored element's buffer when the user presses Play.
+    if (this.audio.getAttribute('src') !== track.stream_url) this.audio.src = track.stream_url;
+    if (this.audio.currentTime !== startMs / 1000) this.audio.currentTime = startMs / 1000;
+    this.updateMediaMetadata(track);
+    if (!autoplay) return;
     this.applyLoudness();
     this.attempt = new PlayAttempt(track, startMs);
     this.preloaded = null;
@@ -401,7 +407,6 @@ export class Player {
       context_type: this.context?.type,
       context_id: this.context?.id,
     });
-    this.updateMediaMetadata(track);
     this.saveServer();
     void this.refillWave();
     if (autoplay) {
@@ -597,22 +602,28 @@ export class Player {
       if (a.ended) return;
       this.update({ playing: false });
       const t = this.queue.current;
-      if (t) this.events.push({ type: 'pause', track_id: t.id, position_ms: this.state.positionMs });
-      this.saveServer();
+      if (t && this.attempt) {
+        this.events.push({ type: 'pause', track_id: t.id, position_ms: this.state.positionMs });
+        this.saveServer();
+      }
+    });
+    a.addEventListener('waiting', () => {
+      if (this.attempt) this.update({ loading: true });
     });
-    a.addEventListener('waiting', () => this.update({ loading: true }));
     a.addEventListener('timeupdate', () => {
       const ms = Math.round(a.currentTime * 1000);
       this.attempt?.tick(ms);
       this.update({ positionMs: ms });
       this.updatePositionState();
-      this.maybePreload(ms);
-      this.maybeCrossfade(ms);
+      if (this.state.playing) {
+        this.maybePreload(ms);
+        this.maybeCrossfade(ms);
+      }
       if (this.state.playing && Date.now() - this.lastServerSave > SAVE_EVERY_MS) this.saveServer();
       this.saveLocal();
     });
     a.addEventListener('ended', () => {
-      if (this.ignoreEnded || this.fading) return;
+      if (this.ignoreEnded || this.fading || !this.attempt) return;
       this.finishAttempt('play_end');
       if (this.queue.next(true)) {
         this.syncQueue();
@@ -629,11 +640,18 @@ export class Player {
   private async onError() {
     const track = this.queue.current;
     if (!track) return;
+    // A speculative load must never start playback or skip the saved track.
+    if (!this.attempt) {
+      this.audio.removeAttribute('src');
+      this.audio.load();
+      return;
+    }
     if (this.refreshedFor !== track.id) {
       this.refreshedFor = track.id;
       try {
         const res = unwrap(await this.session.client.POST('/api/v1/tracks/batch', { body: { ids: [track.id] } }));
         const fresh = res.items[0];
+        if (this.queue.current !== track || !this.attempt) return;
         if (fresh?.stream_url) {
           Object.assign(track, fresh);
           void this.load(true, this.state.positionMs);
@@ -775,6 +793,7 @@ export class Player {
    * если она новее и с другого устройства. Автозапуска нет — плеер на паузе в сохранённой позиции.
    */
   async restore() {
+    const version = ++this.restoreVersion;
     let local: Saved | null = null;
     try {
       const raw = localStorage.getItem(LOCAL_KEY);
@@ -804,8 +823,9 @@ export class Player {
     } catch {
       // офлайн — остаёмся с локальной копией
     }
-    if (!saved?.queue.length) return;
+    if (version !== this.restoreVersion || !saved?.queue.length) return;
     const res = unwrap(await this.session.client.POST('/api/v1/tracks/batch', { body: { ids: saved.queue } }));
+    if (version !== this.restoreVersion) return;
     const wanted = saved.queue[saved.index];
     const tracks = res.items.filter((t) => t.available && t.stream_url);
     if (!tracks.length) return;
@@ -819,12 +839,20 @@ export class Player {
     this.syncQueue();
     this.update({ positionMs: pos, durationMs: tracks[idx]!.duration_ms, volume: saved.volume });
     this.updateMediaMetadata(tracks[idx]!);
+    // Prepare at the saved position without creating a listening attempt.
+    await this.load(false, pos);
   }
 
   dispose() {
+    this.restoreVersion++;
+    this.fading = false;
     this.finishAttempt('skip');
     this.audio.pause();
     this.audio.removeAttribute('src');
+    this.audio.load();
+    this.overlap.pause();
+    this.overlap.removeAttribute('src');
+    this.overlap.load();
     for (const t of this.timers) clearInterval(t);
     this.timers = [];
     void this.events.flush();
diff --git a/apps/web/src/player/preload.test.ts b/apps/web/src/player/preload.test.ts
new file mode 100644
index 0000000..26047fa
--- /dev/null
+++ b/apps/web/src/player/preload.test.ts
@@ -0,0 +1,79 @@
+import type { AuthSession, Track } from '@pipu/core';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { Player } from './player';
+
+const track: Track = {
+  id: 'a', title: 'A', duration_ms: 200_000, artists: [],
+  album: { id: 'album', title: 'Album', year: null, cover_url: null, cover_colors: [] },
+  genres: [], disc_no: null, track_no: null, available: true,
+  stream_url: '/s/a', reaction: null, features: null,
+};
+const ok = (data: unknown) => ({ data, response: new Response() });
+
+function fixture() {
+  localStorage.removeItem('pipu.player');
+  const client = {
+    GET: vi.fn().mockResolvedValue(ok({
+      track_id: 'a', queue: ['a'], queue_index: 0, position_ms: 42_000,
+      volume: 0.8, shuffle: false, repeat_mode: 'off', updated_at: '2026-10-21',
+    })),
+    POST: vi.fn().mockResolvedValue(ok({ items: [track] })),
+    PUT: vi.fn().mockResolvedValue(ok({})),
+  };
+  const audio = document.createElement('audio');
+  const player = new Player({ client, state: { status: 'signed_out' } } as unknown as AuthSession, audio);
+  return { player, audio, client };
+}
+
+afterEach(() => { vi.restoreAllMocks(); localStorage.removeItem('pipu.player'); });
+
+describe('restored audio preparation', () => {
+  it('buffers at the saved position without playback or listening events, then reuses the source', async () => {
+    const { player, audio, client } = fixture();
+    const play = vi.spyOn(audio, 'play');
+    const source = vi.spyOn(audio, 'src', 'set');
+    await player.restore();
+    expect(audio.getAttribute('src')).toBe('/s/a');
+    expect(audio.currentTime).toBe(42);
+    expect(audio.preload).toBe('auto');
+    expect(play).not.toHaveBeenCalled();
+    expect(client.PUT).not.toHaveBeenCalled();
+    expect(player.getState()).toMatchObject({ playing: false, loading: false, positionMs: 42_000 });
+    player.onHide();
+    expect(client.POST).toHaveBeenCalledTimes(1); // Only the track lookup, no listening events.
+    player.play();
+    expect(play).toHaveBeenCalledTimes(1);
+    expect(source).toHaveBeenCalledTimes(1);
+    expect(player.getState().playing).toBe(true);
+    player.dispose();
+  });
+
+  it('does not autoplay or skip after a preload failure; Play retries the source', async () => {
+    const { player, audio } = fixture();
+    const play = vi.spyOn(audio, 'play');
+    await player.restore();
+    audio.dispatchEvent(new Event('error'));
+    audio.dispatchEvent(new Event('ended'));
+    expect(play).not.toHaveBeenCalled();
+    expect(player.getState()).toMatchObject({ track: { id: 'a' }, positionMs: 42_000, playing: false });
+    player.play();
+    expect(audio.getAttribute('src')).toBe('/s/a');
+    expect(play).toHaveBeenCalledTimes(1);
+    player.dispose();
+  });
+
+  it.each(['selection', 'dispose'])('ignores a restore lookup completed after %s', async (action) => {
+    const { player, client, audio } = fixture();
+    let resolve!: (value: unknown) => void;
+    client.POST.mockReturnValueOnce(new Promise((done) => { resolve = done; }));
+    const restoring = player.restore();
+    await vi.waitFor(() => expect(client.POST).toHaveBeenCalled());
+    if (action === 'selection') player.playList([{ ...track, id: 'b', stream_url: '/s/b' }], 0, { type: 'search' });
+    else player.dispose();
+    resolve(ok({ items: [track] }));
+    await restoring;
+    expect(audio.getAttribute('src')).toBe(action === 'selection' ? '/s/b' : null);
+    if (action === 'selection') player.dispose();
+  });
+});