NK Admin: switching songs stops the previous one; player bar shows edited details

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

admin/lib/player.dart

@@ -13,19 +13,42 @@ class AdminPlayer {
   final audio = AudioPlayer();
   final current = ValueNotifier<AdminTrack?>(null);
 
+  /// Bumped on every switch, so only the latest click starts playing.
+  int _request = 0;
+
   Future<void> toggle(AdminTrack track) async {
     if (current.value?.id == track.id) {
-      audio.playing ? await audio.pause() : await audio.play();
+      // play() completes only when playback pauses, so it is not awaited.
+      audio.playing ? await audio.pause() : audio.play();
       return;
     }
     final url = track.audioUrl;
     if (url == null) return;
+    final request = ++_request;
     current.value = track;
+    try {
+      // Stop first: loading a new file while one plays can be interrupted on the web,
+      // leaving the old song playing.
+      await audio.stop();
       await audio.setUrl(url);
-    await audio.play();
+      if (request == _request) audio.play();
+    } catch (_) {
+      if (request != _request) return; // a newer click replaced this load
+      current.value = null;
+      rethrow;
+    }
+  }
+
+  /// Shows fresh details (after an edit) for the loaded song if it is in [tracks].
+  void refresh(Iterable<AdminTrack> tracks) {
+    final id = current.value?.id;
+    for (final t in tracks) {
+      if (t.id == id) current.value = t;
+    }
   }
 
   Future<void> close() async {
+    _request++;
     await audio.stop();
     current.value = null;
   }
@@ -51,7 +74,11 @@ class PlayButton extends StatelessWidget {
               const [ProcessingState.loading, ProcessingState.buffering].contains(snap.data?.processingState);
           return IconButton(
             tooltip: track.audioKey == null ? 'No audio file' : (playing ? 'Pause' : 'Play'),
-            onPressed: track.audioKey == null ? null : () => player.toggle(track),
+            onPressed: track.audioKey == null
+                ? null
+                : () => player.toggle(track).catchError((Object e) {
+                      if (context.mounted) showMessage(context, 'Could not play "${track.title}": $e');
+                    }),
             icon: loading && playing
                 ? const SizedBox.square(dimension: 20, child: CircularProgressIndicator(strokeWidth: 2))
                 : Icon(playing ? Icons.pause_circle_filled : Icons.play_circle_fill,

admin/lib/screens/songs_screen.dart

@@ -49,6 +49,7 @@ class _SongsScreenState extends State<SongsScreen> {
       page: _page,
       pageSize: _pageSize,
     );
+    AdminPlayer.instance.refresh(page.items);
     return page;
   }