Add functionality to delete specific comic chapters. Close #368

lib/foundation/local.dart

@@ -548,6 +548,41 @@ class LocalManager with ChangeNotifier {
     notifyListeners();
   }
 
+  void deleteComicChapters(LocalComic c, List<String> chapters) {
+    if (chapters.isEmpty) {
+      return;
+    }
+    var newDownloadedChapters = c.downloadedChapters
+        .where((e) => !chapters.contains(e))
+        .toList();
+    if (newDownloadedChapters.isNotEmpty) {
+      _db.execute(
+        'UPDATE comics SET downloadedChapters = ? WHERE id = ? AND comic_type = ?;',
+        [
+          jsonEncode(newDownloadedChapters),
+          c.id,
+          c.comicType.value,
+        ],
+      );
+    } else {
+      _db.execute(
+        'DELETE FROM comics WHERE id = ? AND comic_type = ?;',
+        [c.id, c.comicType.value],
+      );
+    }
+    var shouldRemovedDirs = <Directory>[];
+    for (var chapter in chapters) {
+      var dir = Directory(FilePath.join(c.baseDir, chapter));
+      if (dir.existsSync()) {
+        shouldRemovedDirs.add(dir);
+      }
+    }
+    if (shouldRemovedDirs.isNotEmpty) {
+      _deleteDirectories(shouldRemovedDirs);
+    }
+    notifyListeners();
+  }
+
   void batchDeleteComics(List<LocalComic> comics, [bool removeFileOnDisk = true]) {
     if (comics.isEmpty) {
       return;
@@ -587,6 +622,7 @@ class LocalManager with ChangeNotifier {
     }
   }
 
+  /// Deletes the directories in a separate isolate to avoid blocking the UI thread.
   static void _deleteDirectories(List<Directory> directories) {
     Isolate.run(() async {
       for (var dir in directories) {

lib/pages/local_comics_page.dart

@@ -374,6 +374,14 @@ class _LocalComicsPageState extends State<LocalComicsPage> {
               },
             ),
             actions: [
+              if (comics.length == 1 && comics.first.hasChapters)
+                TextButton(
+                  child: Text("Delete Chapters".tl),
+                  onPressed: () {
+                    context.pop();
+                    showDeleteChaptersPopWindow(context, comics.first);
+                  },
+                ),
               FilledButton(
                 onPressed: () {
                   context.pop();
@@ -495,3 +503,59 @@ class _LocalComicsPageState extends State<LocalComicsPage> {
 
 typedef ExportComicFunc = Future<File> Function(
     LocalComic comic, String outFilePath);
+
+void showDeleteChaptersPopWindow(BuildContext context, LocalComic comic) {
+  var chapters = <String>[];
+
+  showPopUpWidget(
+    context,
+    PopUpWidgetScaffold(
+      title: "Delete Chapters".tl,
+      body: StatefulBuilder(builder: (context, setState) {
+        return Column(
+          children: [
+            Expanded(
+              child: ListView.builder(
+                itemCount: comic.downloadedChapters.length,
+                itemBuilder: (context, index) {
+                  var id = comic.downloadedChapters[index];
+                  var chapter = comic.chapters![id] ?? "Unknown Chapter";
+                  return CheckboxListTile(
+                    title: Text(chapter),
+                    value: chapters.contains(id),
+                    onChanged: (v) {
+                      setState(() {
+                        if (v == true) {
+                          chapters.add(id);
+                        } else {
+                          chapters.remove(id);
+                        }
+                      });
+                    },
+                  );
+                },
+              ),
+            ),
+            Padding(
+              padding: const EdgeInsets.all(8.0),
+              child: Row(
+                mainAxisAlignment: MainAxisAlignment.end,
+                children: [
+                  FilledButton(
+                    onPressed: () {
+                      Future.delayed(const Duration(milliseconds: 200), () {
+                        LocalManager().deleteComicChapters(comic, chapters);
+                      });
+                      App.rootContext.pop();
+                    },
+                    child: Text("Submit".tl),
+                  )
+                ],
+              ),
+            )
+          ],
+        );
+      }),
+    ),
+  );
+}