fix deleting local comic, favorites

lib/foundation/favorites.dart

@@ -3,6 +3,7 @@ import 'package:venera/foundation/appdata.dart';
 import 'dart:io';
 
 import 'app.dart';
+import 'comic_source/comic_source.dart';
 import 'comic_type.dart';
 
 String _getCurTime() {
@@ -12,11 +13,13 @@ String _getCurTime() {
       .substring(0, 19);
 }
 
-class FavoriteItem {
+class FavoriteItem implements Comic {
   String name;
   String author;
   ComicType type;
+  @override
   List<String> tags;
+  @override
   String id;
   String coverPath;
   String time = _getCurTime();
@@ -57,6 +60,38 @@ class FavoriteItem {
     }
     return s;
   }
+
+  @override
+  String get cover => coverPath;
+
+  @override
+  String get description => "$time | ${type.comicSource?.name ?? "Unknown"}";
+
+  @override
+  String? get favoriteId => null;
+
+  @override
+  String? get language => null;
+
+  @override
+  int? get maxPage => null;
+
+  @override
+  String get sourceKey => type.comicSource?.key ?? "Unknown:${type.value}";
+
+  @override
+  double? get stars => null;
+
+  @override
+  String? get subtitle => author;
+
+  @override
+  String get title => name;
+
+  @override
+  Map<String, dynamic> toJson() {
+    throw UnimplementedError();
+  }
 }
 
 class FavoriteItemWithFolderInfo {

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();
+}

lib/foundation/local.dart

@@ -26,7 +26,7 @@ class LocalComic with HistoryMixin implements Comic {
   @override
   final List<String> tags;
 
-  /// name of the directory, which is in `LocalManager.path`
+  /// The name of the directory where the comic is stored
   final String directory;
 
   /// key: chapter id, value: chapter title
@@ -143,6 +143,7 @@ class LocalManager with ChangeNotifier {
 
   late Database _db;
 
+  /// path to the directory where all the comics are stored
   late String path;
 
   // return error message if failed
@@ -413,4 +414,11 @@ class LocalManager with ChangeNotifier {
     saveCurrentDownloadingTasks();
     downloadingTasks.first.resume();
   }
+
+  void deleteComic(LocalComic c) {
+    var dir = Directory(FilePath.join(path, c.directory));
+    dir.deleteSync(recursive: true);
+    remove(c.id, c.comicType);
+    notifyListeners();
+  }
 }