feat(service): Add working database persistency

lib/src/data/anime.dart

@@ -1,50 +1,64 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+part 'anime.freezed.dart';
+part 'anime.g.dart';
+
 /// The watch state of an anime
 enum AnimeTrackingState {
-  watching,
-  completed,
-  planToWatch,
-  dropped,
+  watching,    // 0
+  completed,   // 1
+  planToWatch, // 2
+  dropped,     // 3
+}
+
+extension AnimeTrackStateExtension on AnimeTrackingState {
+  int toInteger() {
+    switch (this) {
+      case AnimeTrackingState.watching: return 0;
+      case AnimeTrackingState.completed: return 1;
+      case AnimeTrackingState.planToWatch: return 2;
+      case AnimeTrackingState.dropped: return 3;
+    }
+  }
+}
+
+class AnimeTrackingStateConverter implements JsonConverter<AnimeTrackingState, int> {
+  const AnimeTrackingStateConverter();
+
+  @override
+  AnimeTrackingState fromJson(int json) {
+    switch (json) {
+      case 0: return AnimeTrackingState.watching;
+      case 1: return AnimeTrackingState.completed;
+      case 2: return AnimeTrackingState.planToWatch;
+      case 3: return AnimeTrackingState.dropped;
+    }
+
+    return AnimeTrackingState.planToWatch;
+  }
+  
+  @override
+  int toJson(AnimeTrackingState state) => state.toInteger();
 }
 
 /// Data about a tracked anime
-class AnimeTrackingData {
-  const AnimeTrackingData(
-    this.id,
-    this.state,
-    this.title,
-    this.episodesWatched,
-    this.episodesTotal,
-    this.thumbnailUrl,
-  );
-
-  /// The ID of the anime
-  final String id;
-  
-  /// The state of the anime
-  final AnimeTrackingState state;
-
-  /// The title of the anime
-  final String title;
-  
-  /// Episodes in total.
-  final int? episodesTotal;
-
-  /// Episodes watched.
-  final int episodesWatched;
-
-  /// URL to the thumbnail/cover art for the anime.
-  final String thumbnailUrl;
-
-  AnimeTrackingData copyWith(
+@freezed
+class AnimeTrackingData with _$AnimeTrackingData{
+  factory AnimeTrackingData(
+    /// The ID of the anime
+    String id,
+    /// The state of the anime
+    @AnimeTrackingStateConverter() AnimeTrackingState state,
+    /// The title of the anime
+    String title,
+    /// Episodes in total.
     int episodesWatched,
-  ) {
-    return AnimeTrackingData(
-      id,
-      state,
-      title,
-      episodesWatched,
-      episodesTotal,
-      thumbnailUrl,
-    );
-  }
+    /// Episodes watched.
+    int? episodesTotal,
+    /// URL to the thumbnail/cover art for the anime.
+    String thumbnailUrl,
+  ) = _AnimeTrackingData;
+
+  /// JSON
+  factory AnimeTrackingData.fromJson(Map<String, dynamic> json) => _$AnimeTrackingDataFromJson(json);
 }