feat: add todo cache repository and precise invalidation

apps/lib/core/cache/cache_invalidator.dart

@@ -1,19 +1,12 @@
-import 'dart:async';
-
 import 'hybrid_cache_store.dart';
 
 class CacheInvalidator {
-  final HybridCacheStore? _store;
   final Set<String> _invalidated = <String>{};
 
-  CacheInvalidator({HybridCacheStore? store}) : _store = store;
+  CacheInvalidator({HybridCacheStore? store});
 
   void invalidate(String key) {
     _invalidated.add(key);
-    final removeFuture = _store?.remove(key);
-    if (removeFuture != null) {
-      unawaited(removeFuture);
-    }
   }
 
   void invalidateCalendarDay(DateTime date) {

apps/lib/core/di/injection.dart

@@ -29,6 +29,7 @@ import '../../features/settings/data/services/settings_user_cache.dart';
 import '../../features/settings/data/services/user_profile_cache_repository.dart';
 import '../../features/users/data/users_api.dart';
 import '../../features/todo/data/todo_api.dart';
+import '../../features/todo/data/todo_repository.dart';
 
 final sl = GetIt.instance;
 
@@ -124,6 +125,13 @@ Future<void> configureDependencies() async {
 
   final todoApi = TodoApi(apiClient);
   sl.registerSingleton<TodoApi>(todoApi);
+  sl.registerSingleton<TodoRepository>(
+    TodoRepository(
+      api: todoApi,
+      store: hybridCacheStore,
+      invalidator: sl<CacheInvalidator>(),
+    ),
+  );
 
   final authRepository = AuthRepositoryImpl(
     api: authApi,

apps/lib/features/todo/data/todo_api.dart

@@ -17,6 +17,10 @@ class TodoApi {
     return data.map((json) => TodoResponse.fromJson(json)).toList();
   }
 
+  Future<List<TodoResponse>> getPendingTodos() {
+    return getTodos(status: 'pending');
+  }
+
   Future<TodoResponse> getTodo(String id) async {
     final response = await _client.get('$_prefix/$id');
     return TodoResponse.fromJson(response.data);

apps/lib/features/todo/data/todo_repository.dart

@@ -0,0 +1,79 @@
+import 'dart:async';
+
+import '../../../core/cache/cache_entry.dart';
+import '../../../core/cache/cache_invalidator.dart';
+import '../../../core/cache/hybrid_cache_store.dart';
+import 'todo_api.dart';
+
+class TodoRepository {
+  static const String pendingListKey = 'todo:list:pending';
+
+  final TodoApi api;
+  final HybridCacheStore store;
+  final CacheInvalidator invalidator;
+  final DateTime Function() now;
+
+  TodoRepository({
+    required this.api,
+    required this.store,
+    required this.invalidator,
+    DateTime Function()? now,
+  }) : now = now ?? DateTime.now;
+
+  Future<List<TodoResponse>> getPendingTodos({
+    bool forceRefresh = false,
+  }) async {
+    if (!forceRefresh) {
+      final cached = await store.read<CacheEntry<List<TodoResponse>>>(
+        pendingListKey,
+      );
+      if (cached != null) {
+        return cached.value;
+      }
+    }
+
+    final remote = await api.getPendingTodos();
+    await store.write<CacheEntry<List<TodoResponse>>>(
+      pendingListKey,
+      CacheEntry(value: remote, fetchedAt: now()),
+    );
+    return remote;
+  }
+
+  Future<void> completeTodo(String id) async {
+    final cached = await store.read<CacheEntry<List<TodoResponse>>>(
+      pendingListKey,
+    );
+    if (cached != null) {
+      final next = cached.value
+          .map(
+            (todo) => todo.id == id
+                ? todo.copyWith(status: 'completed', completedAt: now())
+                : todo,
+          )
+          .toList(growable: false);
+      await store.write<CacheEntry<List<TodoResponse>>>(
+        pendingListKey,
+        CacheEntry(value: next, fetchedAt: now()),
+      );
+    }
+
+    invalidator.invalidate(pendingListKey);
+    try {
+      await api.completeTodo(id);
+    } catch (error) {
+      if (cached != null) {
+        await store.write<CacheEntry<List<TodoResponse>>>(
+          pendingListKey,
+          cached,
+        );
+      }
+      rethrow;
+    }
+  }
+
+  Future<void> invalidatePending() {
+    invalidator.invalidate(pendingListKey);
+    return Future<void>.value();
+  }
+}

apps/lib/features/todo/ui/screens/todo_quadrants_screen.dart

@@ -16,6 +16,7 @@ import '../../../../shared/widgets/toast/toast_type.dart';
 import '../../../calendar/ui/calendar_state_manager.dart';
 import '../../../calendar/ui/widgets/bottom_dock.dart';
 import '../../data/todo_api.dart';
+import '../../data/todo_repository.dart';
 
 class TodoQuadrantsScreen extends StatefulWidget {
   const TodoQuadrantsScreen({super.key});
@@ -26,6 +27,7 @@ class TodoQuadrantsScreen extends StatefulWidget {
 
 class _TodoQuadrantsScreenState extends State<TodoQuadrantsScreen> {
   final TodoApi _todoApi = sl<TodoApi>();
+  final TodoRepository _todoRepository = sl<TodoRepository>();
 
   List<TodoResponse> _todos = [];
   bool _isLoading = true;
@@ -210,7 +212,9 @@ class _TodoQuadrantsScreenState extends State<TodoQuadrantsScreen> {
     });
 
     try {
-      final todos = await _todoApi.getTodos(status: 'pending');
+      final todos = await _todoRepository.getPendingTodos(
+        forceRefresh: !showPageLoader,
+      );
       if (!mounted) {
         return;
       }
@@ -263,7 +267,7 @@ class _TodoQuadrantsScreenState extends State<TodoQuadrantsScreen> {
 
   Future<void> _completeTodo(TodoResponse todo) async {
     try {
-      await _todoApi.completeTodo(todo.id);
+      await _todoRepository.completeTodo(todo.id);
       if (mounted) {
         Toast.show(context, '已完成', type: ToastType.success);
       }

apps/test/features/todo/todo_repository_test.dart

@@ -0,0 +1,57 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:social_app/core/cache/cache_entry.dart';
+import 'package:social_app/core/cache/cache_invalidator.dart';
+import 'package:social_app/core/cache/hybrid_cache_store.dart';
+import 'package:social_app/core/cache/memory_cache_store.dart';
+import 'package:social_app/core/cache/persistent_cache_store.dart';
+import 'package:social_app/features/todo/data/todo_api.dart';
+import 'package:social_app/features/todo/data/todo_repository.dart';
+
+class _MockTodoApi extends Mock implements TodoApi {}
+
+void main() {
+  test(
+    'complete todo should optimistically update and invalidate pending list key',
+    () async {
+      final api = _MockTodoApi();
+      final store = HybridCacheStore(
+        memory: MemoryCacheStore(),
+        persistent: PersistentCacheStore(),
+      );
+      final invalidator = CacheInvalidator(store: store);
+      final repository = TodoRepository(
+        api: api,
+        store: store,
+        invalidator: invalidator,
+      );
+
+      final cached = TodoResponse(
+        id: 'todo_1',
+        ownerId: 'u1',
+        title: 't1',
+        priority: 1,
+        order: 0,
+        status: 'pending',
+        createdAt: DateTime(2026, 3, 20, 10),
+        updatedAt: DateTime(2026, 3, 20, 10),
+      );
+      await store.write<CacheEntry<List<TodoResponse>>>(
+        TodoRepository.pendingListKey,
+        CacheEntry(value: [cached], fetchedAt: DateTime(2026, 3, 20, 10, 0)),
+      );
+
+      when(
+        () => api.completeTodo('todo_1'),
+      ).thenAnswer((_) async => cached.copyWith(status: 'completed'));
+
+      await repository.completeTodo('todo_1');
+
+      final updated = await store.read<CacheEntry<List<TodoResponse>>>(
+        TodoRepository.pendingListKey,
+      );
+      expect(updated?.value.first.status, 'completed');
+      expect(invalidator.wasInvalidated(TodoRepository.pendingListKey), true);
+    },
+  );
+}