fix(player): 记住拖动后的实际播放位置

lib/core/data/services/playback_position_cache.dart

@@ -2,6 +2,15 @@
 
 const Duration _defaultMaxAge = Duration(hours: 12);
 
+/// 将播放位置限制在当前媒体时长内。
+Duration clampPlaybackPosition(Duration position, Duration duration) {
+  if (position <= Duration.zero || duration <= Duration.zero) {
+    return Duration.zero;
+  }
+  if (position >= duration) return duration;
+  return position;
+}
+
 /// 进程内最近播放位置。
 class CachedPlaybackPosition {
   const CachedPlaybackPosition({
@@ -37,13 +46,14 @@ class PlaybackPositionCache {
     required Duration position,
     required Duration duration,
   }) {
-    if (episodeId.isEmpty || dramaId.isEmpty || position <= Duration.zero) {
+    final safePosition = clampPlaybackPosition(position, duration);
+    if (episodeId.isEmpty || dramaId.isEmpty || safePosition <= Duration.zero) {
       return;
     }
     _positions[episodeId] = CachedPlaybackPosition(
       episodeId: episodeId,
       dramaId: dramaId,
-      position: position,
+      position: safePosition,
       duration: duration,
       updatedAt: _now(),
     );

lib/core/data/services/video_player_port.dart

@@ -61,6 +61,9 @@ class VideoPlayerPort implements PlayerPort {
     if (!_disposed && controller.value.isInitialized) await controller.pause();
   }
 
+  /// 跳转到指定播放位置。
+  Future<void> seekTo(Duration position) => controller.seekTo(position);
+
   @override
   Future<void> dispose() async {
     if (_disposed) return;

lib/pages/player/player_logic.dart

@@ -34,6 +34,12 @@ import 'player_view.dart';
 import 'widgets/drama_comments_sheet.dart';
 import 'widgets/episode_picker_sheet.dart';
 
+typedef _PlaybackSnapshot = ({
+  Duration position,
+  Duration duration,
+  bool completed,
+});
+
 class PlayerLogic extends ChangeNotifier {
   PlayerLogic({
     required this.history,
@@ -119,6 +125,7 @@ class PlayerLogic extends ChangeNotifier {
   bool _deferredFeedNotifyScheduled = false;
   int _feedJumpSerial = 0;
   Future<void> _feedUpdateFuture = Future<void>.value();
+  Future<void>? _pendingSeek;
 
   /// [start] 是否已经跑过：没跑过时 session/pages 还是 late 未初始化，
   /// dispose 不能直接碰它们（例如页面构建失败或纯逻辑测试）。
@@ -693,29 +700,24 @@ class PlayerLogic extends ChangeNotifier {
     var completionHandled = false;
     var completionProgressSaved = false;
     player.controller.addListener(() {
-      if (session.active != player || !player.controller.value.isInitialized) {
-        return;
-      }
-      positionCache.save(
-        episodeId: episode.id,
-        dramaId: drama.id,
-        position: player.controller.value.position,
-        duration: player.controller.value.duration,
-      );
-      if (player.controller.value.isCompleted && !completionProgressSaved) {
+      if (session.active != player) return;
+      final snapshot = _readPlaybackSnapshot(player);
+      if (snapshot == null) return;
+      _cachePlaybackPosition(drama, episode, snapshot);
+      if (snapshot.completed && !completionProgressSaved) {
         completionProgressSaved = true;
         unawaited(
           queueProgress(
             drama,
             episode,
-            player.controller.value.duration,
-            duration: player.controller.value.duration,
+            snapshot.duration,
+            duration: snapshot.duration,
             finished: true,
           ),
         );
       }
       if (!completionHandled &&
-          player.controller.value.isCompleted &&
+          snapshot.completed &&
           session.canAutoAdvance &&
           session.currentIndex == index) {
         completionHandled = true;
@@ -723,7 +725,12 @@ class PlayerLogic extends ChangeNotifier {
       }
       if (!shouldReportProgress(DateTime.now())) return;
       unawaited(
-        queueProgress(drama, episode, player.controller.value.position),
+        queueProgress(
+          drama,
+          episode,
+          snapshot.position,
+          duration: snapshot.duration,
+        ),
       );
     });
   }
@@ -775,27 +782,63 @@ class PlayerLogic extends ChangeNotifier {
     return pendingWrite;
   }
 
-  Future<void> saveCurrentProgress() {
+  Future<void> saveCurrentProgress() async {
+    final pendingSeek = _pendingSeek;
+    if (pendingSeek != null) await pendingSeek;
+    await _saveCurrentProgressNow();
+  }
+
+  Future<void> _saveCurrentProgressNow() {
     final player = trackedPlayer;
     final episode = trackedEpisode;
     final drama = trackedDrama;
-    if (player == null ||
-        episode == null ||
-        drama == null ||
-        !player.controller.value.isInitialized) {
-      return pendingWrite;
+    if (player == null || episode == null || drama == null) return pendingWrite;
+    final snapshot = _readPlaybackSnapshot(player);
+    if (snapshot == null) return pendingWrite;
+    return _persistPlaybackSnapshot(drama, episode, snapshot);
+  }
+
+  _PlaybackSnapshot? _readPlaybackSnapshot(VideoPlayerPort player) {
+    final value = player.controller.value;
+    if (!value.isInitialized || value.duration <= Duration.zero) return null;
+    return (
+      position: clampPlaybackPosition(value.position, value.duration),
+      duration: value.duration,
+      completed: value.isCompleted,
+    );
+  }
+
+  void _cachePlaybackPosition(
+    Drama drama,
+    Episode episode,
+    _PlaybackSnapshot snapshot,
+  ) {
+    if (session.isLocked ||
+        ticketError != null ||
+        blockedEpisodeId == episode.id) {
+      return;
     }
     positionCache.save(
       episodeId: episode.id,
       dramaId: drama.id,
-      position: player.controller.value.position,
-      duration: player.controller.value.duration,
+      position: snapshot.position,
+      duration: snapshot.duration,
     );
+  }
+
+  Future<void> _persistPlaybackSnapshot(
+    Drama drama,
+    Episode episode,
+    _PlaybackSnapshot snapshot, {
+    bool finished = false,
+  }) {
+    _cachePlaybackPosition(drama, episode, snapshot);
     return queueProgress(
       drama,
       episode,
-      player.controller.value.position,
-      duration: player.controller.value.duration,
+      snapshot.position,
+      duration: snapshot.duration,
+      finished: finished,
     );
   }
 
@@ -856,23 +899,44 @@ class PlayerLogic extends ChangeNotifier {
     BuildContext context,
     VideoPlayerPort player,
     Duration position,
+  ) {
+    final operation = _performSeek(context, player, position);
+    _pendingSeek = operation;
+    return operation.whenComplete(() {
+      if (identical(_pendingSeek, operation)) _pendingSeek = null;
+    });
+  }
+
+  Future<void> _performSeek(
+    BuildContext context,
+    VideoPlayerPort player,
+    Duration position,
   ) async {
     if (scrubbingPlayer != player || session.active != player) return;
     try {
       await session.playbackSettled;
       if (scrubbingPlayer != player || session.active != player) return;
-      await player.controller.seekTo(position);
-      if (session.active == player) {
-        // 暂停时拖动进度后直接恢复播放，避免画面停在旧位置。
-        resumeAfterSeek();
-        await saveCurrentProgress();
-      }
+      final duration = player.controller.value.duration;
+      final target = clampPlaybackPosition(position, duration);
+      if (target <= Duration.zero) return;
+      await player.seekTo(target);
+      if (session.active != player) return;
+      final snapshot = _readPlaybackSnapshot(player);
+      if (snapshot == null) return;
+      final entry = queue.entryAt(session.currentIndex);
+      final save = _persistPlaybackSnapshot(
+        entry.drama,
+        entry.episode,
+        snapshot,
+      );
+      // 暂停时拖动进度后直接恢复播放，避免画面停在旧位置。
+      resumeAfterSeek();
+      await save;
     } catch (_) {
       if (context.mounted && session.active == player) {
         final l10n = AppLocalizations.of(context)!;
-        ScaffoldMessenger.of(
-          context,
-        ).showSnackBar(SnackBar(content: Text(l10n.seekFailed)));
+        ScaffoldMessenger.of(context)
+            .showSnackBar(SnackBar(content: Text(l10n.seekFailed)));
       }
     } finally {
       if (scrubbingPlayer == player) cancelScrub();
@@ -1013,9 +1077,8 @@ class PlayerLogic extends ChangeNotifier {
     await session.playbackSettled;
     await saveCurrentProgress();
     if (!context.mounted) return;
-    final action = await Navigator.of(
-      context,
-    ).push<MyPageAction>(MaterialPageRoute(builder: (_) => const MyPage()));
+    final action = await Navigator.of(context)
+        .push<MyPageAction>(MaterialPageRoute(builder: (_) => const MyPage()));
     if (!context.mounted) return;
     if (action == MyPageAction.discover) {
       await showDiscover(context);