现阶段通知中心播放暂停切换功能已实现，但是上下一曲功能暂时消失，需要后续优化，这个commit是snapshot

lib/services/audio_player_handler.dart

@@ -1,78 +1,53 @@
-import 'package:flutter/material.dart';
-import 'package:audio_service/audio_service.dart';
-import 'playback_service.dart';
-import 'audio_service.dart' as local_audio;
+// lib/services/audio_player_handler.dart
+import 'package:flutter/foundation.dart';
+import 'package:audio_service/audio_service.dart' as audio_service;
+import '../audio/player_controller.dart';
+import '../audio/playback_state_manager.dart';
+import '../services/audio_service.dart'; // 你的业务 AudioService
 
-class AudioPlayerHandler extends BaseAudioHandler {
-  final PlaybackService _playback = PlaybackService();
-  late final local_audio.AudioService _localAudio;
-
-  // ⭐ 切歌锁，防止重复命令
-  bool _switchingTrack = false;
+class AudioPlayerHandler extends audio_service.BaseAudioHandler {
+  final PlayerController _player = PlayerController();
+  final PlaybackStateManager _state = PlaybackStateManager();
 
   AudioPlayerHandler() {
-    _localAudio = local_audio.AudioService();
-
-    // ⭐ 唯一状态来源：media_kit 的 playing 流
-    _playback.player.stream.playing.listen((playing) {
-      debugPrint('🎵 [stream] playing changed: $playing');
-      _updatePlaybackState(playing: playing);
+    _player.playingStream.listen((playing) {
+      _state.updatePlaying(playing);
+      _publishState();
     });
 
-    // ⭐ 播放完成 → 触发下一首（不直接广播状态）
-    _playback.player.stream.completed.listen((_) {
-      debugPrint('🎵 [stream] completed, auto next');
-      _localAudio.next();  // 触发切歌，playing 流会自然变化
-      // 不调用 _updatePlaybackState()
-    });
-
-    // ⭐ 歌曲变化 → 更新媒体信息（独立于播放状态）
-    // 这里用 duration 变化作为“歌曲已切换”的信号
-    _playback.player.stream.duration.listen((duration) {
-      if (duration.inMilliseconds > 0) {
-        _syncMediaItem();
-      }
-    });
-  }
-
-  // ============================================================
-  // 状态同步链（只能由 playing 流触发）
-  // ============================================================
-  void _updatePlaybackState({bool? playing}) {
-    final isPlaying = playing ?? _playback.player.state.playing;
-    debugPrint('🎵 _updatePlaybackState: isPlaying=$isPlaying');
-
-    final controls = [
-      MediaControl.skipToPrevious,
-      if (isPlaying) MediaControl.pause else MediaControl.play,
-      MediaControl.skipToNext,
-    ];
-
-    debugPrint('🎵 controls: ${controls.map((c) => c.action).join(', ')}');
-
-    playbackState.add(PlaybackState(
-      controls: controls,
-      processingState: AudioProcessingState.ready,
-      playing: isPlaying,
-      androidCompactActionIndices: const [0, 1, 2],
-      updateTime: DateTime.now(),
-    ));
-  }
-
-  // ============================================================
-  // 媒体信息同步链（独立于播放状态）
-  // ============================================================
-  void _syncMediaItem() {
-    final song = _localAudio.currentSong;
-    if (song != null) {
-      debugPrint('🎵 [sync] media item: ${song.title}');
-      mediaItem.add(MediaItem(
-        id: song.id,
-        title: song.title,
-        artist: song.artist,
-        duration: _playback.player.state.duration,
+    _player.positionStream.listen((position) {
+      _state.updatePosition(position);
+      final current = playbackState.value;
+      playbackState.add(audio_service.PlaybackState(
+        controls: current.controls,
+        processingState: current.processingState,
+        playing: current.playing,
+        androidCompactActionIndices: current.androidCompactActionIndices,
+        updateTime: DateTime.now(),
       ));
-    }
+    });
+
+    _player.durationStream.listen((duration) {
+      _state.updateDuration(duration);
+      _publishState();
+    });
+
+    _player.completedStream.listen((_) {
+      debugPrint('⏭️ [handler] completed, auto next');
+      AudioService().next();
+    });
+  }
+
+  void _publishState() {
+    final state = _state.playbackState;
+
+    debugPrint(
+      '📡 [publish] '
+      'playing=${state.playing}, '
+      'controls=${state.controls.map((e) => e.action).toList()}',
+    );
+
+    playbackState.add(state);
   }
 
   void updateNotification({
@@ -80,115 +55,77 @@ class AudioPlayerHandler extends BaseAudioHandler {
     required String title,
     required String artist,
   }) {
-    mediaItem.add(MediaItem(
+    debugPrint('📢 [handler] updateNotification: $title');
+    mediaItem.add(audio_service.MediaItem(
       id: id,
       title: title,
       artist: artist,
-      duration: _playback.player.state.duration,
+      duration: _player.duration,
     ));
-    _updatePlaybackState();
   }
 
-  // ============================================================
-  // 控制命令（只发命令，不宣布状态）
-  // ============================================================
+  // ---- 控制命令（系统回调） ----
   @override
   Future<void> play() async {
-    debugPrint('🎵 [audio_service] play() called');
-    await _playback.resume();
-    // ⭐ 不调用 _updatePlaybackState()
-    // 等待 playing 流触发
+    debugPrint('▶️ [handler] play() called');
+    await _player.play();
   }
 
   @override
   Future<void> pause() async {
-    debugPrint('🎵 [audio_service] pause() called');
-    await _playback.pause();
-    // ⭐ 不调用 _updatePlaybackState()
+    debugPrint('⏸️ [handler] pause() called');
+    await _player.pause();
   }
 
   @override
   Future<void> stop() async {
-    debugPrint('🎵 [audio_service] stop() called');
-    await _playback.stop();
-    // ⭐ 不调用 _updatePlaybackState()
+    debugPrint('⏹️ [handler] stop() called');
+    _player.stop();
   }
 
   @override
   Future<void> seek(Duration position) async {
-    debugPrint('🎵 [audio_service] seek() called: $position');
-    await _playback.seek(position);
+    debugPrint('⏩ [handler] seek() called: $position');
+    _player.seek(position);
   }
 
   @override
   Future<void> skipToNext() async {
-    if (_switchingTrack) {
-      debugPrint('🎵 skipToNext ignored: already switching');
-      return;
-    }
-    _switchingTrack = true;
-    try {
-      debugPrint('🎵 [audio_service] skipToNext() called');
-      await _localAudio.next();
-      // ⭐ 不调用 _updatePlaybackState()
-      // playing 流和 duration 流会自然触发状态更新
-    } finally {
-      // ⭐ 用真实状态释放锁，不用时间
-      await Future.delayed(const Duration(milliseconds: 50));
-      _switchingTrack = false;
-    }
+    debugPrint('⏭️ [handler] skipToNext() called');
+    AudioService().next();
   }
 
   @override
   Future<void> skipToPrevious() async {
-    if (_switchingTrack) {
-      debugPrint('🎵 skipToPrevious ignored: already switching');
-      return;
-    }
-    _switchingTrack = true;
-    try {
-      debugPrint('🎵 [audio_service] skipToPrevious() called');
-      await _localAudio.previous();
-    } finally {
-      await Future.delayed(const Duration(milliseconds: 50));
-      _switchingTrack = false;
-    }
+    debugPrint('⏮️ [handler] skipToPrevious() called');
+    AudioService().previous();
   }
 
-  // ============================================================
-  // click()：薄路由层，不操作播放器
-  // ============================================================
+  // ⭐ 统一点击处理（仅使用 MediaButton 存在的枚举）
   @override
-  Future<void> click([MediaButton button = MediaButton.media]) async {
-    debugPrint('🎵 [audio_service] click(): ${button.name} (index: ${button.index})');
-
-    // ⭐ 用 button.name 判断，不用 index
-    final name = button.name.toLowerCase();
-
-    // 路由到标准方法
-    if (name.contains('next') || name == 'next') {
-      await skipToNext();
-      return;
-    }
-    if (name.contains('previous') || name == 'previous') {
-      await skipToPrevious();
-      return;
-    }
-    if (name.contains('pause')) {
-      await pause();
-      return;
-    }
-    if (name.contains('play') || name.contains('media')) {
-      await play();
-      return;
-    }
-
-    // fallback: 根据当前播放状态 toggle
-    debugPrint('🎵 → fallback toggle');
-    if (_playback.player.state.playing) {
-      await pause();
-    } else {
-      await play();
+  Future<void> click(
+      [audio_service.MediaButton button =
+          audio_service.MediaButton.media]) async {
+    debugPrint('🎯 [handler] click() called with button: ${button.name}');
+    switch (button) {
+      case audio_service.MediaButton.next:
+        await skipToNext();
+        break;
+      case audio_service.MediaButton.previous:
+        await skipToPrevious();
+        break;
+      case audio_service.MediaButton.media:
+        // 播放/暂停切换
+        if (_player.isPlaying) {
+          await pause();
+        } else {
+          await play();
+        }
+        break;
+      default:
+        // 其他按钮（fastForward, rewind等）忽略或fallback
+        debugPrint('⚠️ [handler] unhandled MediaButton: $button');
+        break;
     }
   }
-}
+}

lib/services/playback_service.dart

@@ -44,27 +44,27 @@ class PlaybackService {
   }
 
   // ---------- 控制 ----------
-  void pause() {
+  Future<void> pause() async {
     if (_initialized && _player != null) {
-      _player!.pause();
+      await _player!.pause();
     }
   }
 
-  void resume() {
+  Future<void> resume() async {
     if (_initialized && _player != null) {
-      _player!.play();
+      await _player!.play();
     }
   }
 
-  void stop() {
+  Future<void> stop() async {
     if (_initialized && _player != null) {
-      _player!.stop();
+      await _player!.stop();
     }
   }
 
-  void seek(Duration position) {
+  Future<void> seek(Duration position) async {
     if (_initialized && _player != null) {
-      _player!.seek(position);
+      await _player!.seek(position);
     }
   }