fix(player): 修复竖滑上一集不自动播放

lib/core/data/services/playback_neighbors.dart

@@ -67,15 +67,19 @@ Future<void> _placeNeighbor(PlaybackSession session, _PlayerSlot? slot) async {
   await session._retire(slot);
 }
 
-/// 当前集已经出画后，静默准备上一集和下一集。
-void _warmNeighbors(PlaybackSession session) {
+/// 当前集已经出画后，按手势方向静默准备上一集和下一集。
+void _warmNeighbors(PlaybackSession session, {bool preferredNext = true}) {
   final request = session._generation;
-  session._preloadTask = () async {
-    await Future.wait([
-      _warmOne(session, request, session._nextIndex, next: true),
-      _warmOne(session, request, session._previousIndex, next: false),
-    ]);
-  }();
+  final nextTask = _warmOne(session, request, session._nextIndex, next: true);
+  final previousTask = _warmOne(
+    session,
+    request,
+    session._previousIndex,
+    next: false,
+  );
+  session._preloadTask = Future.wait(
+    preferredNext ? [nextTask, previousTask] : [previousTask, nextTask],
+  ).then<void>((_) {});
 }
 
 Future<void> _warmOne(

lib/core/data/services/playback_session.dart

@@ -8,6 +8,7 @@ import '../models/player_port.dart';
 import 'video_player_port.dart';
 
 part 'playback_neighbors.dart';
+part 'playback_session_controls.dart';
 
 /// 新纹理第一帧常是黑的，旧画面只盖住这一小段。
 const Duration _qualityHandoffHold = Duration(milliseconds: 200);
@@ -40,6 +41,7 @@ class PlaybackSession extends ChangeNotifier {
   final Future<void> Function()? waitForFrame;
   final PlaybackCoordinator _coordinator;
   final Set<_PlayerSlot> _live = {};
+  final Set<String> _pausedEpisodeIds = {};
   _PlayerSlot? _active;
   _PlayerSlot? _next;
   _PlayerSlot? _previous;
@@ -106,15 +108,6 @@ class PlaybackSession extends ChangeNotifier {
     return null;
   }
 
-  /// 清晰度切换时盖住黑帧的旧播放器。只在仍由会话持有时交给界面。
-  PlayerPort? handoffAt(int index) {
-    final slot = _handoff;
-    if (_closed || slot == null || slot.retiring || slot.index != index) {
-      return null;
-    }
-    return slot.player;
-  }
-
   /// 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, int? previousIndex}) {
     if (_closed || index < 0 || index >= episodes.length) return;
@@ -214,10 +207,9 @@ class PlaybackSession extends ChangeNotifier {
     int? previousIndex,
   }) async {
     if (_closed || index < 0 || index >= episodes.length) return;
-    // 切到另一集时，上一集按下的暂停不跟着走：滑过去就应该自动播放。
-    // 重复选中同一集（例如页面重新可见）不在这里恢复，尊重用户按下的暂停。
+    // 新集默认起播；用户手动暂停过的同一集滑回时继续尊重暂停。
     if (!_selected || index != _currentIndex) {
-      _userWantsPlay = true;
+      _userWantsPlay = !_pausedEpisodeIds.contains(episodes[index].id);
     }
     final request = ++_generation;
     _selected = true;
@@ -256,7 +248,10 @@ class PlaybackSession extends ChangeNotifier {
         target = old;
         return;
       }
-      if (old != null) await old.player.pause();
+      if (old != null) {
+        await old.player.pause();
+        old.playing = false;
+      }
       final warmNext = _next;
       final warmPrevious = _previous;
       _active = null;
@@ -369,7 +364,10 @@ class PlaybackSession extends ChangeNotifier {
       _handoff = previous;
       _active = slot;
       shown = true;
-      if (previous != null) await previous!.player.pause();
+      if (previous != null) {
+        await previous!.player.pause();
+        previous!.playing = false;
+      }
       _notify();
     });
     if (!shown || _active != slot) return null;
@@ -422,27 +420,6 @@ class PlaybackSession extends ChangeNotifier {
     slot.playing = shouldPlay;
   }
 
-  void setAppResumed(bool value) {
-    _appResumed = value;
-    _syncPlayback();
-  }
-
-  void setRouteVisible(bool value) {
-    _routeVisible = value;
-    _syncPlayback();
-  }
-
-  void setOverlayOpen(bool value) {
-    _overlayOpen = value;
-    _syncPlayback();
-  }
-
-  void setUserWantsPlay(bool value) {
-    _userWantsPlay = value;
-    _syncPlayback();
-    _notify();
-  }
-
   void _syncPlayback() {
     if (_closed) return;
     if (_visible && _selected && active == null) {

lib/core/data/services/playback_session_controls.dart

@@ -0,0 +1,54 @@
+// Author: fruit.com.cn
+
+part of 'playback_session.dart';
+
+/// 播放会话的可见性、用户意图与相邻集预热控制。
+extension PlaybackSessionControls on PlaybackSession {
+  /// 滑动手势开始时按方向优先准备相邻集，不改变当前集播放状态。
+  void prewarmNeighbors({required bool forward}) {
+    if (!_visible || _overlayOpen || _active?.prepared != true) return;
+    _warmNeighbors(this, preferredNext: forward);
+  }
+
+  /// 清晰度切换时盖住黑帧的旧播放器。只在仍由会话持有时交给界面。
+  PlayerPort? handoffAt(int index) {
+    final slot = _handoff;
+    if (_closed || slot == null || slot.retiring || slot.index != index) {
+      return null;
+    }
+    return slot.player;
+  }
+
+  /// 同步应用前台状态并恢复或暂停当前集。
+  void setAppResumed(bool value) {
+    _appResumed = value;
+    _syncPlayback();
+  }
+
+  /// 同步播放器路由是否可见。
+  void setRouteVisible(bool value) {
+    _routeVisible = value;
+    _syncPlayback();
+  }
+
+  /// 同步浮层是否遮挡播放器。
+  void setOverlayOpen(bool value) {
+    _overlayOpen = value;
+    _syncPlayback();
+  }
+
+  /// 记录用户播放意图；手动暂停的剧集滑回时不再自动起播。
+  void setUserWantsPlay(bool value) {
+    if (episodes.isNotEmpty) {
+      final episodeId = episodes[_currentIndex].id;
+      if (value) {
+        _pausedEpisodeIds.remove(episodeId);
+      } else {
+        _pausedEpisodeIds.add(episodeId);
+      }
+    }
+    _userWantsPlay = value;
+    _syncPlayback();
+    _notify();
+  }
+}