fix: 完善直播结束通知与 WebSocket 连接

frontend/lib/pages/player_page.dart

@@ -43,6 +43,7 @@ class _PlayerPageState extends State<PlayerPage> {
   bool _isRefreshing = false;
   bool _isFullscreen = false;
   bool _controlsVisible = true;
+  bool _streamEnded = false;
   double _volume = kIsWeb ? 0.0 : 1.0;
   int _playerVersion = 0;
   String _selectedResolution = 'Source';
@@ -146,6 +147,10 @@ class _PlayerPageState extends State<PlayerPage> {
 
     _chatService.messages.listen((msg) {
       if (mounted) {
+        if (msg.type == "stream_end") {
+          _handleStreamEnded(msg.content);
+          return;
+        }
         setState(() {
           _messages.insert(0, msg);
           if (!msg.isHistory && (msg.type == "chat" || msg.type == "danmaku")) {
@@ -158,6 +163,44 @@ class _PlayerPageState extends State<PlayerPage> {
     });
   }
 
+  void _handleStreamEnded(String message) {
+    if (_streamEnded) {
+      return;
+    }
+
+    final l10n = AppLocalizations.of(context)!;
+    final streamEndedMessage = l10n.liveStreamEnded;
+
+    setState(() {
+      _streamEnded = true;
+      _isRefreshing = false;
+      _danmakus.clear();
+      _messages.insert(
+        0,
+        ChatMessage(
+          type: "system",
+          username: "System",
+          content: streamEndedMessage,
+          roomId: widget.roomId,
+        ),
+      );
+      if (!kIsWeb) {
+        _isError = true;
+        _errorMessage = streamEndedMessage;
+      }
+    });
+
+    ScaffoldMessenger.of(
+      context,
+    ).showSnackBar(SnackBar(content: Text(streamEndedMessage)));
+
+    Future<void>.delayed(const Duration(seconds: 2), () {
+      if (mounted && Navigator.canPop(context)) {
+        Navigator.pop(context);
+      }
+    });
+  }
+
   void _addDanmaku(String text) {
     final key = UniqueKey();
     final lane = DateTime.now().millisecondsSinceEpoch % 8;
@@ -180,7 +223,7 @@ class _PlayerPageState extends State<PlayerPage> {
   }
 
   void _sendMsg() {
-    if (_msgController.text.isNotEmpty) {
+    if (!_streamEnded && _msgController.text.isNotEmpty) {
       final auth = context.read<AuthProvider>();
       _chatService.sendMessage(
         _msgController.text,
@@ -195,6 +238,9 @@ class _PlayerPageState extends State<PlayerPage> {
     if (_isRefreshing) {
       return;
     }
+    if (_streamEnded) {
+      return;
+    }
 
     await _loadPlaybackOptions();
 
@@ -625,7 +671,7 @@ class _PlayerPageState extends State<PlayerPage> {
                   _buildControlButton(
                     icon: Icons.refresh,
                     label: l10n.refresh,
-                    onPressed: _refreshPlayer,
+                    onPressed: _streamEnded ? null : _refreshPlayer,
                   ),
                   _buildControlButton(
                     icon: _volume == 0
@@ -645,7 +691,9 @@ class _PlayerPageState extends State<PlayerPage> {
                     icon: _isFullscreen
                         ? Icons.fullscreen_exit
                         : Icons.fullscreen,
-                    label: _isFullscreen ? l10n.exitFullscreen : l10n.fullscreen,
+                    label: _isFullscreen
+                        ? l10n.exitFullscreen
+                        : l10n.fullscreen,
                     onPressed: _toggleFullscreen,
                   ),
                   _buildControlButton(
@@ -665,13 +713,15 @@ class _PlayerPageState extends State<PlayerPage> {
   Widget _buildControlButton({
     required IconData icon,
     required String label,
-    required FutureOr<void> Function() onPressed,
+    required FutureOr<void> Function()? onPressed,
   }) {
     return FilledButton.tonalIcon(
-      onPressed: () async {
-        _showControls();
-        await onPressed();
-      },
+      onPressed: onPressed == null
+          ? null
+          : () async {
+              _showControls();
+              await onPressed();
+            },
       icon: Icon(icon, size: 18),
       label: Text(label),
       style: FilledButton.styleFrom(
@@ -693,7 +743,10 @@ class _PlayerPageState extends State<PlayerPage> {
             children: [
               const Icon(Icons.chat_bubble_outline, size: 16),
               const SizedBox(width: 8),
-              Text(l10n.liveChat, style: const TextStyle(fontWeight: FontWeight.bold)),
+              Text(
+                l10n.liveChat,
+                style: const TextStyle(fontWeight: FontWeight.bold),
+              ),
             ],
           ),
         ),
@@ -716,8 +769,11 @@ class _PlayerPageState extends State<PlayerPage> {
               Expanded(
                 child: TextField(
                   controller: _msgController,
+                  enabled: !_streamEnded,
                   decoration: InputDecoration(
-                    hintText: l10n.sendMessage,
+                    hintText: _streamEnded
+                        ? l10n.liveStreamEndedShort
+                        : l10n.sendMessage,
                     border: OutlineInputBorder(
                       borderRadius: BorderRadius.circular(20),
                     ),
@@ -734,7 +790,7 @@ class _PlayerPageState extends State<PlayerPage> {
                   Icons.send,
                   color: Theme.of(context).colorScheme.primary,
                 ),
-                onPressed: _sendMsg,
+                onPressed: _streamEnded ? null : _sendMsg,
               ),
             ],
           ),