Add follow updates feature. Close #189

lib/foundation/appdata.dart

@@ -159,6 +159,7 @@ class _Settings with ChangeNotifier {
     'autoAddLanguageFilter': 'none', // none, chinese, english, japanese
     'comicSourceListUrl': "https://cdn.jsdelivr.net/gh/venera-app/venera-configs@latest/index.json",
     'preloadImageCount': 4,
+    'followUpdatesFolder': null,
   };
 
   operator [](String key) {

lib/foundation/comic_source/models.dart

@@ -295,6 +295,41 @@ class ComicDetails with HistoryMixin {
     }
     return null;
   }
+
+  String? _validateUpdateTime(String time) {
+    time = time.split(" ").first;
+    var segments = time.split("-");
+    if (segments.length != 3) return null;
+    var year = int.tryParse(segments[0]);
+    var month = int.tryParse(segments[1]);
+    var day = int.tryParse(segments[2]);
+    if (year == null || month == null || day == null) return null;
+    if (year < 2000 || year > 3000) return null;
+    if (month < 1 || month > 12) return null;
+    if (day < 1 || day > 31) return null;
+    return "$year-$month-$day";
+  }
+
+  String? findUpdateTime() {
+    if (updateTime != null) {
+      return _validateUpdateTime(updateTime!);
+    }
+    const acceptedNamespaces = [
+      "更新",
+      "最後更新",
+      "最后更新",
+      "update",
+      "last update",
+    ];
+    for (var entry in tags.entries) {
+      if (acceptedNamespaces.contains(entry.key.toLowerCase()) &&
+          entry.value.isNotEmpty) {
+        var value = entry.value.first;
+        return _validateUpdateTime(value);
+      }
+    }
+    return null;
+  }
 }
 
 class ArchiveInfo {

lib/foundation/favorites.dart

@@ -6,6 +6,7 @@ import 'package:venera/foundation/appdata.dart';
 import 'package:venera/foundation/image_provider/local_favorite_image.dart';
 import 'package:venera/foundation/local.dart';
 import 'package:venera/foundation/log.dart';
+import 'package:venera/pages/follow_updates_page.dart';
 import 'package:venera/utils/tags_translation.dart';
 import 'dart:io';
 
@@ -154,6 +155,38 @@ class FavoriteItemWithFolderInfo extends FavoriteItem {
         );
 }
 
+class FavoriteItemWithUpdateInfo extends FavoriteItem {
+  String? updateTime;
+
+  DateTime? lastCheckTime;
+
+  bool hasNewUpdate;
+
+  FavoriteItemWithUpdateInfo(
+    FavoriteItem item,
+    this.updateTime,
+    this.hasNewUpdate,
+    int? lastCheckTime,
+  )   : lastCheckTime = lastCheckTime == null
+            ? null
+            : DateTime.fromMillisecondsSinceEpoch(lastCheckTime),
+        super(
+          id: item.id,
+          name: item.name,
+          coverPath: item.coverPath,
+          author: item.author,
+          type: item.type,
+          tags: item.tags,
+        );
+
+  @override
+  String get description {
+    var updateTime = this.updateTime ?? "Unknown";
+    var sourceName = type.comicSource?.name ?? "Unknown";
+    return "$updateTime | $sourceName";
+  }
+}
+
 class LocalFavoritesManager with ChangeNotifier {
   factory LocalFavoritesManager() =>
       cache ?? (cache = LocalFavoritesManager._create());
@@ -599,6 +632,7 @@ class LocalFavoritesManager with ChangeNotifier {
       return;
     }
     _modifiedAfterLastCache = true;
+    var followUpdatesFolder = appdata.settings['followUpdatesFolder'];
     for (final folder in folderNames) {
       var rows = _db.select("""
         select * from "$folder"
@@ -627,9 +661,13 @@ class LocalFavoritesManager with ChangeNotifier {
             UPDATE "$folder"
             SET 
               $updateLocationSql
+              ${followUpdatesFolder == folder ? "has_new_update = 0," : ""}
               time = ?
-            WHERE id == ?;
-          """, [newTime, id]);
+            WHERE id == ? and type == ?;
+          """, [newTime, id, type.value]);
+        if (followUpdatesFolder == folder) {
+          updateFollowUpdatesUI();
+        }
       }
     }
     notifyListeners();
@@ -783,6 +821,114 @@ class LocalFavoritesManager with ChangeNotifier {
     }
   }
 
+  void prepareTableForFollowUpdates(String table) {
+    // check if the table has the column "last_update_time" "has_new_update" "last_check_time"
+    var columns = _db.select("""
+      pragma table_info("$table");
+    """);
+    if (!columns.any((element) => element["name"] == "last_update_time")) {
+      _db.execute("""
+        alter table "$table"
+        add column last_update_time TEXT;
+      """);
+    }
+    if (!columns.any((element) => element["name"] == "has_new_update")) {
+      _db.execute("""
+        alter table "$table"
+        add column has_new_update int;
+      """);
+    }
+    _db.execute("""
+        update "$table"
+        set has_new_update = 0;
+      """);
+    if (!columns.any((element) => element["name"] == "last_check_time")) {
+      _db.execute("""
+        alter table "$table"
+        add column last_check_time int;
+      """);
+    }
+  }
+
+  void updateUpdateTime(
+    String folder,
+    String id,
+    ComicType type,
+    String updateTime,
+  ) {
+    var oldTime = _db.select("""
+      select last_update_time from "$folder"
+      where id == ? and type == ?;
+    """, [id, type.value]).first['last_update_time'];
+    var hasNewUpdate = oldTime != updateTime;
+    _db.execute("""
+      update "$folder"
+      set last_update_time = ?, has_new_update = ?, last_check_time = ?
+      where id == ? and type == ?;
+    """, [
+      updateTime,
+      hasNewUpdate ? 1 : 0,
+      DateTime.now().millisecondsSinceEpoch,
+      id,
+      type.value,
+    ]);
+  }
+
+  int countUpdates(String folder) {
+    return _db.select("""
+      select count(*) as c from "$folder"
+      where has_new_update == 1;
+    """).first['c'];
+  }
+
+  List<FavoriteItemWithUpdateInfo> getUpdates(String folder) {
+    if (!existsFolder(folder)) {
+      return [];
+    }
+    var res = _db.select("""
+      select * from "$folder"
+      where has_new_update == 1;
+    """);
+    return res
+        .map(
+          (e) => FavoriteItemWithUpdateInfo(
+            FavoriteItem.fromRow(e),
+            e['last_update_time'],
+            e['has_new_update'] == 1,
+            e['last_check_time'],
+          ),
+        )
+        .toList();
+  }
+
+  List<FavoriteItemWithUpdateInfo> getComicsWithUpdatesInfo(String folder) {
+    if (!existsFolder(folder)) {
+      return [];
+    }
+    var res = _db.select("""
+      select * from "$folder";
+    """);
+    return res
+        .map(
+          (e) => FavoriteItemWithUpdateInfo(
+            FavoriteItem.fromRow(e),
+            e['last_update_time'],
+            e['has_new_update'] == 1,
+            e['last_check_time'],
+          ),
+        )
+        .toList();
+  }
+
+  void markAsRead(String folder, String id, ComicType type) {
+    var folder = appdata.settings['followUpdatesFolder'];
+    _db.execute("""
+      update "$folder"
+      set has_new_update = 0
+      where id == ? and type == ?;
+    """, [id, type.value]);
+  }
+
   void close() {
     _db.dispose();
   }