feat(home): 首页按内容类型分频道 Feed 并支持分页

lib/core/data/services/home_feed_controller.dart

@@ -0,0 +1,165 @@
+// Author: fruit.com.cn
+
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+
+import '../../data/models/drama.dart';
+import '../../data/repositories/catalog_repository.dart';
+import '../../../pages/home/home_feed_channel.dart';
+
+/// 首页内容类型频道状态：每频道独立缓存、刷新和游标分页。
+class HomeFeedController extends ChangeNotifier {
+  HomeFeedController(this._repository)
+    : _states = {
+        for (final channel in HomeFeedChannel.values)
+          channel: _ChannelFeedState(),
+      };
+
+  static const int pageSize = 10;
+
+  final CatalogRepository _repository;
+  final Map<HomeFeedChannel, _ChannelFeedState> _states;
+  HomeFeedChannel _channel = HomeFeedChannel.recommend;
+  String? _lastError;
+  bool _disposed = false;
+
+  HomeFeedChannel get channel => _channel;
+  String? get lastError => _lastError;
+  List<Drama> get dramas => _state(_channel).dramas;
+  String? get cursor => _state(_channel).cursor;
+  bool get hasMore => _state(_channel).hasMore;
+  bool get loaded => _state(_channel).loaded;
+  bool get loadingMore => _state(_channel).loadingMore;
+  bool get loadingFirstPage => !loaded;
+
+  /// 用首页聚合接口打平的数据填充推荐首屏，不发起网络请求。
+  void seedRecommend(List<Drama> dramas) {
+    final state = _state(HomeFeedChannel.recommend);
+    state
+      ..requestSeq = state.requestSeq + 1
+      ..dramas = List.unmodifiable(dramas)
+      ..cursor = null
+      ..hasMore = false
+      ..loaded = true
+      ..loadingMore = false;
+    _lastError = null;
+    if (_channel == HomeFeedChannel.recommend) _notify();
+  }
+
+  /// 同步切到目标频道；有缓存先渲染，再在后台静默刷新。
+  Future<void> selectChannel(HomeFeedChannel next) async {
+    if (next == _channel) return;
+    _channel = next;
+    _lastError = null;
+    _notify();
+    final state = _state(next);
+    if (state.dramas.isNotEmpty) {
+      unawaited(_refresh(next, keepData: true));
+    } else {
+      await _loadFirst(next);
+    }
+  }
+
+  /// 刷新当前频道，失败时保留旧数据。
+  Future<bool> refreshCurrent() => _refresh(_channel, keepData: true);
+
+  /// 加载当前频道下一页并去重追加。
+  Future<void> loadMore() async {
+    final channel = _channel;
+    final state = _state(channel);
+    if (!state.hasMore || state.loadingMore || state.cursor == null) return;
+    final seq = ++state.requestSeq;
+    state.loadingMore = true;
+    _notify();
+    try {
+      final page = await _repository.fetchFeed(
+        types: channel.apiTypes,
+        cursor: state.cursor,
+        size: pageSize,
+      );
+      if (!_accept(channel, seq)) return;
+      final seen = state.dramas.map((drama) => drama.id).toSet();
+      final appended = page.dramas
+          .where((drama) => seen.add(drama.id))
+          .toList();
+      state
+        ..dramas = List.unmodifiable([...state.dramas, ...appended])
+        ..cursor = page.nextCursor
+        ..hasMore = page.hasMore
+        ..loaded = true;
+      _lastError = null;
+    } catch (error) {
+      if (_accept(channel, seq)) _lastError = error.toString();
+    } finally {
+      state.loadingMore = false;
+      if (_acceptChannel(channel)) _notify();
+    }
+  }
+
+  Future<void> _loadFirst(HomeFeedChannel channel) async {
+    final state = _state(channel);
+    state.loaded = false;
+    await _refresh(channel, keepData: state.dramas.isNotEmpty);
+  }
+
+  Future<bool> _refresh(
+    HomeFeedChannel channel, {
+    required bool keepData,
+  }) async {
+    final state = _state(channel);
+    final seq = ++state.requestSeq;
+    _lastError = null;
+    if (_acceptChannel(channel)) _notify();
+    try {
+      final page = await _repository.fetchFeed(
+        types: channel.apiTypes,
+        size: pageSize,
+      );
+      if (!_accept(channel, seq)) return false;
+      state
+        ..dramas = List.unmodifiable(page.dramas)
+        ..cursor = page.nextCursor
+        ..hasMore = page.hasMore
+        ..loaded = true
+        ..loadingMore = false;
+      _lastError = null;
+      _notify();
+      return true;
+    } catch (error) {
+      if (!_accept(channel, seq)) return false;
+      if (!keepData) state.dramas = const [];
+      state.loaded = true;
+      _lastError = error.toString();
+      _notify();
+      return false;
+    }
+  }
+
+  _ChannelFeedState _state(HomeFeedChannel channel) => _states[channel]!;
+
+  bool _accept(HomeFeedChannel channel, int seq) =>
+      !_disposed && channel == _channel && _state(channel).requestSeq == seq;
+
+  bool _acceptChannel(HomeFeedChannel channel) =>
+      !_disposed && channel == _channel;
+
+  void _notify() {
+    if (!_disposed) notifyListeners();
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+}
+
+class _ChannelFeedState {
+  List<Drama> dramas = const [];
+  String? cursor;
+  bool hasMore = true;
+  bool loaded = false;
+  bool loadingMore = false;
+  int requestSeq = 0;
+}

lib/core/data/services/playback_session.dart

@@ -105,6 +105,27 @@ class PlaybackSession extends ChangeNotifier {
     return null;
   }
 
+  /// 队列重排后把当前仍在播放的 slot 映射到新索引，不重新创建播放器。
+  void remapCurrentIndex(int index, {int? preloadIndex}) {
+    if (_closed || index < 0 || index >= episodes.length) return;
+    final activeSlot = _active;
+    if (activeSlot == null || activeSlot.index != _currentIndex) {
+      _currentIndex = index;
+      _nextIndex = preloadIndex;
+      _notify();
+      return;
+    }
+    _generation++;
+    activeSlot.index = index;
+    _currentIndex = index;
+    _nextIndex = preloadIndex;
+    final staleNext = _next;
+    _next = null;
+    _notify();
+    unawaited(_enqueue(() async => _retire(staleNext)));
+    if (_visible && !_overlayOpen) _schedulePreload();
+  }
+
   Future<void> _enqueue(Future<void> Function() operation) {
     final task = _operations.then((_) => operation());
     // A plugin failure must not poison subsequent transitions or cleanup.
@@ -363,7 +384,7 @@ class PlaybackSession extends ChangeNotifier {
 
 class _PlayerSlot {
   _PlayerSlot(this.index, this.player);
-  final int index;
+  int index;
   final PlayerPort player;
   late final Future<void> ready;
   bool prepared = false;