feat: finish the upload, playback, and test gaps from the docs

Quality upgrades, batch covers, staging preview, and resume after reload are in the queue. Loudness and crossfade work on web and Android, and the documented checks now have suites.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/mobile/src/player/controller.ts

@@ -2,6 +2,7 @@ import NetInfo from '@react-native-community/netinfo';
 import {
   EventBuffer,
   PlayAttempt,
+  normalizeGain,
   unwrap,
   type AuthSession,
   type PlayContext,
@@ -18,6 +19,9 @@ import TrackPlayer, {
 import { playerCache, qualityPrefs, type Quality } from '../lib/prefs';
 import { downloads } from '../offline/downloads';
 import { PersistentEvents } from '../offline/events';
+import { offlineWave } from './offlineWave';
+
+export { offlineWave };
 
 export interface WaveInfo {
   sessionId: string;
@@ -45,15 +49,6 @@ const WAVE_REFILL_AT = 2;
 const EARLY_SKIP_MS = 30_000;
 const SAVE_EVERY_MS = 10_000;
 
-/** Офлайн-волна: скачанные треки без дизлайков, лайкнутые чаще оказываются ближе к началу. */
-export function offlineWave(tracks: Track[], random: () => number = Math.random): Track[] {
-  return tracks
-    .filter((t) => t.reaction !== 'dislike')
-    .map((t) => ({ t, key: random() * (t.reaction === 'like' ? 0.5 : 1) }))
-    .sort((a, b) => a.key - b.key)
-    .map((x) => x.t);
-}
-
 const playable = (t: Track) => t.available && (!!t.stream_url || downloads.isDownloaded(t.id));
 
 /** Ссылки API относительные — для приложения нужен полный адрес сервера. */
@@ -159,6 +154,10 @@ class Controller {
       this.lastPositionMs = ms;
       this.update({ positionMs: ms, durationMs: Math.round(duration * 1000) || this.state.durationMs });
       if (this.state.playing && Date.now() - this.lastSave > SAVE_EVERY_MS) this.save();
+      const cf = Math.min(6, Math.max(0, this.userPrefs()?.crossfade_s ?? 0));
+      const left = duration - position;
+      const fade = cf > 0 && left < cf ? Math.max(0, left / cf) : 1;
+      void this.applyVolume(this.state.track, fade);
     });
     TrackPlayer.addEventListener(Event.PlaybackActiveTrackChanged, ({ index, lastPosition }) => {
       this.finishAttempt(lastPosition);
@@ -167,6 +166,7 @@ class Controller {
       if (!track) return;
       this.attempt = new PlayAttempt(track, 0);
       this.update({ track, index, positionMs: 0, durationMs: track.duration_ms });
+      void this.applyVolume(track, 1);
       this.events?.push({
         type: 'play_start', track_id: track.id, position_ms: 0, context_type: this.state.context?.type,
         context_id: this.state.context?.id,
@@ -209,6 +209,17 @@ class Controller {
     }
   }
 
+  private userPrefs() {
+    const st = this.session?.state;
+    return st?.status === 'signed_in' ? st.user.ui_prefs : undefined;
+  }
+
+  /** Громкость 0..1: нормализация вниз к −14 LUFS и затухание кроссфейда в конце трека. */
+  private async applyVolume(track: Track | null, fade: number) {
+    const gain = Math.min(1, normalizeGain(track?.features?.loudness_lufs, this.userPrefs()?.normalize !== false) * fade);
+    await TrackPlayer.setVolume(gain).catch(() => undefined);
+  }
+
   private async toRntp(tracks: Track[]): Promise<RntpTrack[]> {
     const q = await quality();
     // Скачанный трек играется из файла (и без сети), остальные — стримом по качеству сети.