updates

lib/playback/playback_engine.dart

@@ -406,6 +406,52 @@ class PlaybackController extends StateNotifier<PlaybackState> {
     await player.removeAudioSourceAt(index);
   }
 
+  /// Move the queue entry from [oldIndex] to [newIndex] (drag-and-drop reorder).
+  ///
+  /// Indices are "clean" post-removal targets — the same convention as
+  /// just_audio's `moveAudioSource` and Flutter's `ReorderableListView` after
+  /// its standard `newIndex -= 1` adjustment (done by the caller). Reorder
+  /// mutates the currently-active order: applied while shuffled, the move sticks
+  /// among the shuffled tail; hitting shuffle afterwards re-randomizes as usual.
+  /// A single targeted `moveAudioSource` keeps the current track playing without
+  /// the re-buffer a full source rebuild ([_applyOrder]) would cause.
+  Future<void> reorderQueue(int oldIndex, int newIndex) async {
+    final q = state.queue;
+    if (oldIndex < 0 || oldIndex >= q.length) return;
+    if (newIndex < 0 || newIndex >= q.length) return;
+    if (oldIndex == newIndex) return;
+
+    final next = [...q];
+    next.insert(newIndex, next.removeAt(oldIndex));
+
+    final player = _player;
+    if (player == null) {
+      // Desktop/no-audio: no stream will correct the index for us, so follow
+      // the current track to its new slot by hand.
+      final cur = state.currentIndex;
+      var newCur = cur;
+      if (cur != null) {
+        if (cur == oldIndex) {
+          newCur = newIndex;
+        } else {
+          var c = cur;
+          if (oldIndex < c) c -= 1;
+          if (newIndex <= c) c += 1;
+          newCur = c;
+        }
+      }
+      state = state.copyWith(queue: next, currentIndex: newCur);
+      _notifyCurrent();
+      return;
+    }
+
+    // Mobile: just_audio adjusts its own current index and re-emits
+    // `currentIndexStream`; the id dedupe in [_notifyCurrent] avoids a spurious
+    // re-scrobble when the playing track didn't actually change.
+    state = state.copyWith(queue: next);
+    await player.moveAudioSource(oldIndex, newIndex);
+  }
+
   Future<void> togglePlayPause() async {
     final player = _player;
     if (player == null) return;