实现排序功能

bin/domain/repositories/photo_repository.dart

@@ -13,19 +13,17 @@ class PhotoRepository {
 
   PhotoRepository(this.basePath);
 
-  /// 获取相册中所有照片（不分页，保留兼容）
-  Future<List<Photo>> getPhotosByAlbumId(int id) async {
-    final all = await _loadPhotosForAlbum(id);
-    return all;
-  }
 
   /// 获取相册中的照片（分页）
   Future<PageResult<Photo>> getPhotosByAlbumIdPaged(
     int id, {
     int page = 1,
     int size = 20,
+    String sortBy = 'fileName',
+    String order = 'asc',
   }) async {
     final all = await _loadPhotosForAlbum(id);
+    all.sort(_createComparator(sortBy, order));
     final total = all.length;
     final startIndex = (page - 1) * size;
     final endIndex = startIndex + size;
@@ -90,12 +88,55 @@ class PhotoRepository {
     });
 
     final photos = await Future.wait(photoFutures);
-    // 按文件名排序，确保跨平台分页结果一致
-    photos.sort((a, b) => a.fileName.compareTo(b.fileName));
     _map[id] = List.from(photos);
     return photos;
   }
 
+  /// 创建排序比较器
+  int Function(Photo, Photo) _createComparator(
+    String sortBy,
+    String order,
+  ) {
+    final ascending = order == 'asc';
+
+    int compare(Photo a, Photo b) {
+      // Null always sorts last regardless of ascending/descending
+      int nullAwareCompare(int? valueA, int? valueB) {
+        if (valueA == null && valueB == null) return 0;
+        if (valueA == null) return 1;
+        if (valueB == null) return -1;
+        return ascending
+            ? valueA.compareTo(valueB)
+            : valueB.compareTo(valueA);
+      }
+
+      switch (sortBy) {
+        case 'fileName':
+          return ascending
+              ? a.fileName.compareTo(b.fileName)
+              : b.fileName.compareTo(a.fileName);
+        case 'fileSize':
+          return ascending
+              ? a.fileSize.compareTo(b.fileSize)
+              : b.fileSize.compareTo(a.fileSize);
+        case 'createdAt':
+          return ascending
+              ? a.createdAt.compareTo(b.createdAt)
+              : b.createdAt.compareTo(a.createdAt);
+        case 'width':
+          return nullAwareCompare(a.width, b.width);
+        case 'height':
+          return nullAwareCompare(a.height, b.height);
+        default:
+          return ascending
+              ? a.fileName.compareTo(b.fileName)
+              : b.fileName.compareTo(a.fileName);
+      }
+    }
+
+    return compare;
+  }
+
   Future<Photo?> getPhotoById(int id) async {
     try {
       return _map.values.expand((l) => l).firstWhere((p) => p.id == id);