fix deleting local comic, favorites

lib/foundation/image_provider/local_favorite_image.dart

@@ -0,0 +1,53 @@
+import 'dart:async' show Future, StreamController;
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:venera/foundation/app.dart';
+import 'package:venera/foundation/comic_source/comic_source.dart';
+import 'package:venera/network/images.dart';
+import 'package:venera/utils/io.dart';
+import 'base_image_provider.dart';
+import 'local_favorite_image.dart' as image_provider;
+
+class LocalFavoriteImageProvider
+    extends BaseImageProvider<image_provider.LocalFavoriteImageProvider> {
+  /// Image provider for normal image.
+  const LocalFavoriteImageProvider(this.url, this.id, this.intKey);
+
+  final String url;
+
+  final String id;
+
+  final int intKey;
+
+  @override
+  Future<Uint8List> load(StreamController<ImageChunkEvent> chunkEvents) async {
+    var sourceKey = ComicSource.fromIntKey(intKey)?.key;
+    var fileName = key.hashCode.toString();
+    var file = File(FilePath.join(App.dataPath, 'favorite_cover', fileName));
+    if (await file.exists()) {
+      return await file.readAsBytes();
+    } else {
+      await file.create(recursive: true);
+    }
+    await for (var progress in ImageDownloader.loadThumbnail(url, sourceKey)) {
+      chunkEvents.add(ImageChunkEvent(
+        cumulativeBytesLoaded: progress.currentBytes,
+        expectedTotalBytes: progress.totalBytes,
+      ));
+      if(progress.imageBytes != null) {
+        var data = progress.imageBytes!;
+        await file.writeAsBytes(data);
+        return data;
+      }
+    }
+    throw "Error: Empty response body.";
+  }
+
+  @override
+  Future<LocalFavoriteImageProvider> obtainKey(ImageConfiguration configuration) {
+    return SynchronousFuture(this);
+  }
+
+  @override
+  String get key => id + intKey.toString();
+}