允许排序

TodoList/ViewModels/MainViewModel.cs

@@ -37,6 +37,12 @@ namespace TodoList.ViewModels
         [NotifyPropertyChangedFor(nameof(FullShortcut))]
         private string shortcutModifiers;
 
+        [ObservableProperty]
+        private SortBy sortBy = SortBy.Priority;
+
+        [ObservableProperty]
+        private Models.SortOrder sortOrder = Models.SortOrder.Descending;
+
         public string AppVersion => System.Reflection.Assembly.GetExecutingAssembly().GetName().Version?.ToString() ?? "1.0.0";
 
         public string FullShortcut
@@ -90,6 +96,16 @@ namespace TodoList.ViewModels
             await LoadTasksAsync();
         }
 
+        async partial void OnSortByChanged(SortBy value)
+        {
+            await LoadTasksAsync();
+        }
+
+        async partial void OnSortOrderChanged(Models.SortOrder value)
+        {
+            await LoadTasksAsync();
+        }
+
         [RelayCommand]
         private async Task AddTaskAsync()
         {
@@ -118,12 +134,26 @@ namespace TodoList.ViewModels
                 ? allTasks 
                 : allTasks.Where(t => !t.IsCompleted).ToList();
 
-            // Sort: Uncompleted first, then by priority (High -> Low), then date
-            var sorted = filtered
-                .OrderBy(t => t.IsCompleted)
-                .ThenByDescending(t => t.Priority)
-                .ThenByDescending(t => t.CreatedAt)
-                .ToList();
+            IOrderedEnumerable<TodoItem> sorted;
+            
+            if (SortBy == SortBy.Priority)
+            {
+                sorted = SortOrder == Models.SortOrder.Ascending 
+                    ? filtered.OrderBy(t => t.Priority).ThenBy(t => t.CreatedAt)
+                    : filtered.OrderByDescending(t => t.Priority).ThenBy(t => t.CreatedAt);
+            }
+            else if (SortBy == SortBy.CreatedAt)
+            {
+                sorted = SortOrder == Models.SortOrder.Ascending 
+                    ? filtered.OrderBy(t => t.CreatedAt)
+                    : filtered.OrderByDescending(t => t.CreatedAt);
+            }
+            else
+            {
+                sorted = SortOrder == Models.SortOrder.Ascending 
+                    ? filtered.OrderBy(t => t.CompletedAt).ThenBy(t => t.CreatedAt)
+                    : filtered.OrderByDescending(t => t.CompletedAt).ThenBy(t => t.CreatedAt);
+            }
 
             Tasks.Clear();
             foreach (var t in sorted)
@@ -136,13 +166,19 @@ namespace TodoList.ViewModels
         private async Task ToggleCompleteAsync(TodoItem item)
         {
             if (item == null) return;
-            // item.IsCompleted is already toggled by UI binding before this command if TwoWay binding
-            // But usually CheckBox command parameter is the item.
-            // Let's assume the binding updates the property.
             
-            item.SyncStatus = SyncStatus.Pending; // Mark as pending sync
+            if (item.IsCompleted)
+            {
+                item.CompletedAt = DateTime.Now;
+            }
+            else
+            {
+                item.CompletedAt = null;
+            }
+            
+            item.SyncStatus = SyncStatus.Pending;
             await _dataService.SaveTaskAsync(item);
-            await LoadTasksAsync(); // Refresh list to apply filter
+            await LoadTasksAsync();
         }
 
         [RelayCommand]