更改播放逻辑

lib/shared/audio_player.dart

@@ -1,27 +1,152 @@
+// ignore_for_file: public_member_api_docs, sort_constructors_first
+import 'dart:async';
+
+import 'package:audio_service/audio_service.dart';
+import 'package:collection/collection.dart';
+import 'package:just_audio/just_audio.dart';
+import 'package:logging/logging.dart';
+import 'package:rxdart/rxdart.dart';
 import 'package:shelfsdk/audiobookshelf_api.dart';
-import 'package:vaani/features/player/core/audiobook_player.dart';
+
+import 'package:vaani/features/settings/app_settings_provider.dart';
+import 'package:vaani/features/settings/models/app_settings.dart';
+import 'package:vaani/shared/extensions/chapter.dart';
+import 'package:vaani/shared/extensions/model_conversions.dart';
+
+final offset = Duration(milliseconds: 10);
+
+final _logger = Logger('AbsAudioPlayer');
 
 abstract class AbsAudioPlayer {
-  AbsAudioPlayer._();
+  final _mediaItemController = BehaviorSubject<MediaItem?>.seeded(null);
+  final playerStateSubject =
+      BehaviorSubject.seeded(PlayerState(false, ProcessingState.idle));
+  final _bookStreamController = BehaviorSubject<BookExpanded?>.seeded(null);
+  final _chapterStreamController = BehaviorSubject<BookChapter?>.seeded(null);
 
-  BookExpanded? _book;
+  BookExpanded? get book => _bookStreamController.nvalue;
+  BookChapter? get currentChapter => _chapterStreamController.nvalue;
+  PlayerState get playerState => playerStateSubject.value;
+  Stream<MediaItem?> get mediaItemStream => _mediaItemController.stream;
+  Stream<PlayerState> get playerStateStream => playerStateSubject.stream;
 
-  BookExpanded? get book => _book;
+  Future<void> load(
+    BookExpanded book, {
+    required Uri baseUrl,
+    required String token,
+    Duration? initialPosition,
+    List<Uri>? downloadedUris,
+  }) async {
+    if (_bookStreamController.nvalue == book) {
+      _logger.info('Book is the same, doing nothing');
+      return;
+    }
+    _bookStreamController.add(book);
+    final appSettings = loadOrCreateAppSettings();
 
+    final currentTrack = book.findTrackAtTime(initialPosition ?? Duration.zero);
+    final indexTrack = book.tracks.indexOf(currentTrack);
+    final positionInTrack = initialPosition != null
+        ? initialPosition - currentTrack.startOffset
+        : null;
+    final title = appSettings.notificationSettings.primaryTitle
+        .formatNotificationTitle(book);
+    final artist = appSettings.notificationSettings.secondaryTitle
+        .formatNotificationTitle(book);
+    _chapterStreamController
+        .add(book.findChapterAtTime(initialPosition ?? Duration.zero));
+    final item = MediaItem(
+      id: book.libraryItemId,
+      title: title,
+      artist: artist,
+      duration: currentChapter?.duration ?? book.duration,
+      artUri: Uri.parse(
+        '$baseUrl/api/items/${book.libraryItemId}/cover?token=$token',
+      ),
+    );
+    _mediaItemController.sink.add(item);
+    final playlist = book.tracks
+        .map(
+          (track) => _getUri(currentTrack, downloadedUris,
+              baseUrl: baseUrl, token: token),
+        )
+        .toList();
+    setPlayList(playlist, index: indexTrack, position: positionInTrack);
+  }
+
+  Future<void> setPlayList(
+    List<Uri> playlist, {
+    int? index,
+    Duration? position,
+  });
   Future<void> play();
   Future<void> pause();
   Future<void> playOrPause();
-  Future<void> next();
-  Future<void> previous();
+
+  // 跳到下一章
+  Future<void> next() async {
+    final chapter = currentChapter;
+    if (book == null || chapter == null) {
+      return;
+    }
+    final chapterIndex = book!.chapters.indexOf(chapter);
+    if (chapterIndex < book!.chapters.length - 1) {
+      final nextChapter = book!.chapters[chapterIndex + 1];
+      await switchChapter(nextChapter.id);
+    }
+  }
+
+  // 跳到上一章
+  Future<void> previous() async {
+    final chapter = currentChapter;
+    if (book == null || chapter == null) {
+      return;
+    }
+    final currentIndex = book!.chapters.indexOf(chapter);
+    if (currentIndex > 0) {
+      final prevChapter = book!.chapters[currentIndex - 1];
+      await switchChapter(prevChapter.id);
+    } else {
+      // 已经是第一章，回到开头
+      await seekInBook(Duration.zero);
+    }
+  }
+
   Future<void> seek(Duration position, {int? index});
-  Future<void> seekInBook(Duration position);
+  Future<void> seekInBook(Duration position) async {
+    if (book == null) return;
+    // 找到目标位置所在音轨和音轨内的位置
+    final track = book!.findTrackAtTime(position);
+    final index = book!.tracks.indexOf(track);
+    Duration positionInTrack = position - track.startOffset;
+    if (positionInTrack <= Duration.zero) {
+      positionInTrack = offset;
+    }
+    // 切换到目标音轨具体位置
+    await seek(positionInTrack, index: index);
+  }
+
   Future<void> setSpeed(double speed);
   Future<void> setVolume(double volume);
-  Future<void> switchChapter(int chapterId);
+  Future<void> switchChapter(int chapterId) async {
+    if (book == null) return;
+
+    final chapter = book!.chapters.firstWhere(
+      (ch) => ch.id == chapterId,
+      orElse: () => throw Exception('Chapter not found'),
+    );
+    await seekInBook(chapter.start + offset);
+  }
+
+  Stream<bool> get playingStream;
+  Stream<BookExpanded?> get bookStream => _bookStreamController.stream;
+  Stream<BookChapter?> get chapterStream => _chapterStreamController.stream;
 
   int get currentIndex;
+  double get speed;
 
   Duration get position;
+  Stream<Duration> get positionStream;
 
   Duration get positionInChapter {
     final globalPosition = positionInBook;
@@ -32,10 +157,179 @@ abstract class AbsAudioPlayer {
   Duration get positionInBook =>
       position + (book?.tracks[currentIndex].startOffset ?? Duration.zero);
 
-  Stream<Duration> get positionStream;
+  Stream<Duration> get positionInChapterStream =>
+      positionStream.map((position) {
+        return positionInChapter;
+      });
 
-  Stream<Duration> get positionInChapterStream;
+  Stream<Duration> get positionInBookStream => positionStream.map((position) {
+        return positionInBook;
+      });
 
-  Stream<Duration> get positionInBookStream;
-  Stream<Duration> get bufferedPositionInBookStream;
+  Duration get bufferedPosition;
+  Stream<Duration> get bufferedPositionStream;
+  Duration get bufferedPositionInBook =>
+      bufferedPosition +
+      (book?.tracks[currentIndex].startOffset ?? Duration.zero);
+  Stream<Duration> get bufferedPositionInBookStream =>
+      bufferedPositionStream.map((position) {
+        return bufferedPositionInBook;
+      });
+
+  dispose() {
+    _mediaItemController.close();
+    playerStateSubject.close();
+    _bookStreamController.close();
+    _chapterStreamController.close();
+  }
+}
+
+/// Enumerates the different processing states of a player.
+enum ProcessingState {
+  /// The player has not loaded an [AudioSource].
+  idle,
+
+  /// The player is loading an [AudioSource].
+  loading,
+
+  /// The player is buffering audio and unable to play.
+  buffering,
+
+  /// The player is has enough audio buffered and is able to play.
+  ready,
+
+  /// The player has reached the end of the audio.
+  completed,
+}
+
+/// Encapsulates the playing and processing states. These two states vary
+/// orthogonally, and so if [processingState] is [ProcessingState.buffering],
+/// you can check [playing] to determine whether the buffering occurred while
+/// the player was playing or while the player was paused.
+class PlayerState {
+  /// Whether the player will play when [processingState] is
+  /// [ProcessingState.ready].
+  final bool playing;
+
+  /// The current processing state of the player.
+  final ProcessingState processingState;
+
+  PlayerState(this.playing, this.processingState);
+
+  @override
+  String toString() => 'playing=$playing,processingState=$processingState';
+
+  @override
+  int get hashCode => Object.hash(playing, processingState);
+
+  @override
+  bool operator ==(Object other) =>
+      other.runtimeType == runtimeType &&
+      other is PlayerState &&
+      other.playing == playing &&
+      other.processingState == processingState;
+
+  PlayerState copyWith({
+    bool? playing,
+    ProcessingState? processingState,
+  }) {
+    return PlayerState(
+      playing ?? this.playing,
+      processingState ?? this.processingState,
+    );
+  }
+}
+
+Uri _getUri(
+  AudioTrack track,
+  List<Uri>? downloadedUris, {
+  required Uri baseUrl,
+  required String token,
+}) {
+  // check if the track is in the downloadedUris
+  final uri = downloadedUris?.firstWhereOrNull(
+    (element) {
+      return element.pathSegments.last == track.metadata?.filename;
+    },
+  );
+
+  return uri ??
+      Uri.parse('${baseUrl.toString()}${track.contentUrl}?token=$token');
+}
+
+/// Backwards compatible extensions on rxdart's ValueStream
+extension _ValueStreamExtension<T> on ValueStream<T> {
+  /// Backwards compatible version of valueOrNull.
+  T? get nvalue => hasValue ? value : null;
+}
+
+extension FormatNotificationTitle on String {
+  String formatNotificationTitle(BookExpanded book) {
+    return replaceAllMapped(
+      RegExp(r'\$(\w+)'),
+      (match) {
+        final type = match.group(1);
+        return NotificationTitleType.values
+                .firstWhere((element) => element.name == type)
+                .extractFrom(book) ??
+            match.group(0) ??
+            '';
+      },
+    );
+  }
+}
+
+extension NotificationTitleUtils on NotificationTitleType {
+  String? extractFrom(BookExpanded book) {
+    var bookMetadataExpanded = book.metadata.asBookMetadataExpanded;
+    switch (this) {
+      case NotificationTitleType.bookTitle:
+        return bookMetadataExpanded.title;
+      case NotificationTitleType.chapterTitle:
+        // TODO: implement chapter title; depends on https://github.com/Dr-Blank/Vaani/issues/2
+        return bookMetadataExpanded.title;
+      case NotificationTitleType.author:
+        return bookMetadataExpanded.authorName;
+      case NotificationTitleType.narrator:
+        return bookMetadataExpanded.narratorName;
+      case NotificationTitleType.series:
+        return bookMetadataExpanded.seriesName;
+      case NotificationTitleType.subtitle:
+        return bookMetadataExpanded.subtitle;
+      case NotificationTitleType.year:
+        return bookMetadataExpanded.publishedYear;
+    }
+  }
+}
+
+extension BookExpandedExtension on BookExpanded {
+  BookChapter findChapterAtTime(Duration position) {
+    return chapters.firstWhere(
+      (element) {
+        return element.start <= position && element.end >= position + offset;
+      },
+      orElse: () => chapters.first,
+    );
+  }
+
+  AudioTrack findTrackAtTime(Duration position) {
+    return tracks.firstWhere(
+      (element) {
+        return element.startOffset <= position &&
+            element.startOffset + element.duration >= position + offset;
+      },
+      orElse: () => tracks.first,
+    );
+  }
+
+  int findTrackIndexAtTime(Duration position) {
+    return tracks.indexWhere((element) {
+      return element.startOffset <= position &&
+          element.startOffset + element.duration >= position + offset;
+    });
+  }
+
+  Duration getTrackStartOffset(int index) {
+    return tracks[index].startOffset;
+  }
 }