feat: 支持 agent 运行取消功能

apps/lib/features/chat/data/services/ag_ui_service.dart

@@ -50,6 +50,8 @@ class AgUiService {
   Completer<void>? _activeSseDoneCompleter;
 
   String? _threadId;
+  String? _activeThreadIdForRun;
+  String? _activeRunId;
   bool _hasMoreHistory = false;
 
   AgUiService({EventCallback? onEvent, required IApiClient apiClient})
@@ -83,11 +85,20 @@ class AgUiService {
       throw StateError('Missing runId in /agent/runs response');
     }
     _threadId = threadId;
-    await _streamEventsFromApi(
-      threadId,
-      expectedRunId: runId,
-      streamToken: streamToken,
-    );
+    _activeThreadIdForRun = threadId;
+    _activeRunId = runId;
+    try {
+      await _streamEventsFromApi(
+        threadId,
+        expectedRunId: runId,
+        streamToken: streamToken,
+      );
+    } finally {
+      if (_activeThreadIdForRun == threadId && _activeRunId == runId) {
+        _activeThreadIdForRun = null;
+        _activeRunId = null;
+      }
+    }
     return SendMessageResult(
       uploadedAttachments: runInputPayload.uploadedAttachments,
     );
@@ -151,6 +162,19 @@ class AgUiService {
   }
 
   Future<void> cancelCurrentRun() async {
+    final activeThreadId = _activeThreadIdForRun;
+    final activeRunId = _activeRunId;
+    if (activeThreadId != null && activeRunId != null) {
+      final encodedRunId = Uri.encodeQueryComponent(activeRunId);
+      await _apiClient.post<Map<String, dynamic>>(
+        '/api/v1/agent/runs/$activeThreadId/cancel?runId=$encodedRunId',
+      );
+      _activeThreadIdForRun = null;
+      _activeRunId = null;
+      _activeStreamToken += 1;
+      await _cancelActiveSseSubscription();
+      return;
+    }
     _activeStreamToken += 1;
     await _cancelActiveSseSubscription();
   }

apps/lib/features/chat/presentation/bloc/chat_bloc.dart

@@ -123,10 +123,16 @@ class ChatBloc extends Cubit<ChatState> {
         );
       case AgUiEventType.runError:
         final errorEvent = event as RunErrorEvent;
+        final isCanceledByUser = errorEvent.code == 'RUN_CANCELED';
         emit(
           _resetRunState(
-            error: errorEvent.message,
-          ).copyWith(items: _markActiveToolCallsFailed(state.items)),
+            error: isCanceledByUser ? null : errorEvent.message,
+          ).copyWith(
+            items: _markActiveToolCallsFailed(
+              state.items,
+              reason: isCanceledByUser ? '本次运行已取消' : '本次运行已失败',
+            ),
+          ),
         );
       case AgUiEventType.stepStarted:
         _handleStepStarted(event as StepStartedEvent);
@@ -286,7 +292,10 @@ class ChatBloc extends Cubit<ChatState> {
     return items.where((item) => item is! ToolCallItem).toList();
   }
 
-  List<ChatListItem> _markActiveToolCallsFailed(List<ChatListItem> items) {
+  List<ChatListItem> _markActiveToolCallsFailed(
+    List<ChatListItem> items, {
+    required String reason,
+  }) {
     return items.map((item) {
       if (item is! ToolCallItem) {
         return item;
@@ -297,10 +306,7 @@ class ChatBloc extends Cubit<ChatState> {
       if (item.status == ToolCallStatus.completed) {
         return item;
       }
-      return item.copyWith(
-        status: ToolCallStatus.error,
-        errorMessage: '本次运行已失败',
-      );
+      return item.copyWith(status: ToolCallStatus.error, errorMessage: reason);
     }).toList();
   }
 

apps/lib/features/home/ui/screens/home_screen_interactions.dart

@@ -75,7 +75,7 @@ extension _HomeScreenInteractions on _HomeScreenState {
       return;
     }
     if (canceled) {
-      Toast.show(context, '已停止等待回复', type: ToastType.info);
+      Toast.show(context, '已请求停止', type: ToastType.info);
     }
   }
 

apps/test/features/chat/data/services/ag_ui_service_test.dart

@@ -16,6 +16,7 @@ class _FakeApiClient implements IApiClient {
   final List<String> sseLines;
   final Stream<String> Function()? sseLineStreamFactory;
   final String Function()? runIdFactory;
+  final List<String> postPaths = <String>[];
 
   @override
   Future<Response<T>> delete<T>(String path, {data, Options? options}) {
@@ -51,6 +52,19 @@ class _FakeApiClient implements IApiClient {
 
   @override
   Future<Response<T>> post<T>(String path, {data, Options? options}) async {
+    postPaths.add(path);
+    if (path.contains('/cancel?runId=')) {
+      final payload = <String, dynamic>{
+        'threadId': 'thread-1',
+        'runId': 'run-new',
+        'accepted': true,
+      };
+      return Response<T>(
+        requestOptions: RequestOptions(path: path),
+        data: payload as T,
+        statusCode: 202,
+      );
+    }
     final runIdFactory = this.runIdFactory;
     final payload = <String, dynamic>{
       'taskId': 'task-1',
@@ -192,6 +206,39 @@ void main() {
     await streamController.close();
   });
 
+  test(
+    'cancelCurrentRun calls backend cancel endpoint for active run',
+    () async {
+      final streamController = StreamController<String>();
+      final fakeApi = _FakeApiClient(
+        sseLines: const <String>[],
+        sseLineStreamFactory: () => streamController.stream,
+      );
+      final service = AgUiService(apiClient: fakeApi);
+
+      final sendFuture = service.sendMessage('hello');
+      await Future<void>.delayed(Duration.zero);
+      for (final line in _buildSseEvent(
+        id: '51',
+        type: AgUiEventTypeWire.runStarted,
+        payload:
+            '{"type":"RUN_STARTED","threadId":"thread-1","runId":"run-new"}',
+      )) {
+        streamController.add(line);
+      }
+      await Future<void>.delayed(Duration.zero);
+
+      await service.cancelCurrentRun();
+      await sendFuture;
+
+      expect(
+        fakeApi.postPaths,
+        contains('/api/v1/agent/runs/thread-1/cancel?runId=run-new'),
+      );
+      await streamController.close();
+    },
+  );
+
   test(
     'new sendMessage cancels previous SSE subscription explicitly',
     () async {

apps/test/features/chat/presentation/chat_bloc_attachment_sync_test.dart

@@ -206,6 +206,28 @@ void main() {
       expect(bloc.state.error, 'runtime execution failed');
     });
 
+    test('run canceled error clears error and marks tool as canceled', () {
+      service.emitEvent(
+        ToolCallStartEvent(
+          toolCallId: 'tool-cancel',
+          toolCallName: 'ocr_image',
+        ),
+      );
+      service.emitEvent(ToolCallEndEvent(toolCallId: 'tool-cancel'));
+
+      service.emitEvent(
+        RunErrorEvent(message: 'run canceled by user', code: 'RUN_CANCELED'),
+      );
+
+      final toolItem = bloc.state.items.whereType<ToolCallItem>().single;
+      expect(toolItem.status, ToolCallStatus.error);
+      expect(toolItem.errorMessage, '本次运行已取消');
+      expect(bloc.state.error, isNull);
+      expect(bloc.state.isWaitingFirstToken, isFalse);
+      expect(bloc.state.isStreaming, isFalse);
+      expect(bloc.state.isCancelling, isFalse);
+    });
+
     test('text event with ui schema is rendered into chat items', () {
       service.emitEvent(RunStartedEvent(threadId: 'thread-1', runId: 'run-1'));