Add ability to clear image cache on startup, and manually

lib/l10n/app_en.arb

@@ -109,6 +109,10 @@
   },
   "changeSort": "Change Sort",
   "@changeSort": {},
+  "clearCache": "Clear Cache ({cacheSize})",
+  "@clearCache": {
+    "description": "Label for action to clear cache in the dialog"
+  },
   "clearDatabase": "Clear Database",
   "@clearDatabase": {
     "description": "Label for action to clear local database in the dialog"
@@ -119,6 +123,10 @@
   },
   "clearSearch": "Clear Search",
   "@clearSearch": {},
+  "clearedCache": "Cleared cache successfully.",
+  "@clearedCache": {
+    "description": "Message indicating that cache was cleared successfully"
+  },
   "clearedDatabase": "Local database cleared. Restart Thunder for new changes to take effect.",
   "@clearedDatabase": {},
   "clearedUserPreferences": "Cleared all user preferences",

lib/main.dart

@@ -29,6 +29,7 @@ import 'package:thunder/core/theme/bloc/theme_bloc.dart';
 import 'package:thunder/core/auth/bloc/auth_bloc.dart';
 import 'package:thunder/thunder/thunder.dart';
 import 'package:thunder/user/bloc/user_bloc.dart';
+import 'package:thunder/utils/cache.dart';
 import 'package:thunder/utils/global_context.dart';
 import 'package:flutter/foundation.dart';
 
@@ -42,6 +43,9 @@ void main() async {
   // Load up sqlite database
   await DB.instance.database;
 
+  // Clear image cache
+  await clearExtendedImageCache();
+
   // Register dart_ping on iOS
   if (!kIsWeb && Platform.isIOS) {
     DartPingIOS.register();

lib/settings/pages/debug_settings_page.dart

@@ -2,18 +2,25 @@ import 'package:flutter/material.dart';
 
 import 'package:path/path.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:extended_image/extended_image.dart';
 import 'package:sqflite_common_ffi/sqflite_ffi.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
-import 'package:thunder/shared/dialogs.dart';
 
+import 'package:thunder/shared/dialogs.dart';
 import 'package:thunder/shared/snackbar.dart';
 import 'package:thunder/thunder/bloc/thunder_bloc.dart';
 import 'package:thunder/settings/widgets/settings_list_tile.dart';
+import 'package:thunder/utils/cache.dart';
 
-class DebugSettingsPage extends StatelessWidget {
+class DebugSettingsPage extends StatefulWidget {
   const DebugSettingsPage({super.key});
 
+  @override
+  State<DebugSettingsPage> createState() => _DebugSettingsPageState();
+}
+
+class _DebugSettingsPageState extends State<DebugSettingsPage> {
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
@@ -114,6 +121,41 @@ class DebugSettingsPage extends StatelessWidget {
               ),
             ),
           ),
+          SliverToBoxAdapter(
+            child: Divider(
+              indent: 32.0,
+              height: 32.0,
+              endIndent: 32.0,
+              thickness: 2.0,
+              color: theme.dividerColor.withOpacity(0.6),
+            ),
+          ),
+          SliverToBoxAdapter(
+            child: Padding(
+              padding: const EdgeInsets.symmetric(horizontal: 16.0),
+              child: FutureBuilder<int>(
+                future: getExtendedImageCacheSize(),
+                builder: (context, snapshot) {
+                  if (snapshot.hasData) {
+                    return SettingsListTile(
+                      icon: Icons.data_saver_off_rounded,
+                      description: l10n.clearCache('${(snapshot.data! / (1024 * 1024)).toStringAsFixed(2)} MB'),
+                      widget: const SizedBox(
+                        height: 42.0,
+                        child: Icon(Icons.chevron_right_rounded),
+                      ),
+                      onTap: () async {
+                        await clearDiskCachedImages();
+                        if (context.mounted) showSnackbar(context, l10n.clearedCache);
+                        setState(() {}); // Trigger a rebuild to refresh the cache size
+                      },
+                    );
+                  }
+                  return Container();
+                },
+              ),
+            ),
+          ),
         ],
       ),
     );

lib/utils/cache.dart

@@ -1,3 +1,9 @@
+import 'dart:io';
+
+import 'package:path/path.dart';
+import 'package:path_provider/path_provider.dart';
+import 'package:extended_image/extended_image.dart';
+
 /// Defines a cache class which can be used to store values in memory for a certain [expiration]
 /// or else re-fetch the value using the given [getValue] function.
 class Cache<T> {
@@ -12,3 +18,36 @@ class Cache<T> {
   T? _value;
   DateTime? _lastSetTime;
 }
+
+/// Returns the total size of the image cache from ExtendedImage
+Future<int> getExtendedImageCacheSize() async {
+  try {
+    final Directory cacheImagesDirectory = Directory(join((await getTemporaryDirectory()).path, cacheImageFolderName));
+    if (!cacheImagesDirectory.existsSync()) return 0;
+
+    int totalSize = 0;
+
+    // Iterate over the files in the directory
+    await for (final FileSystemEntity file in cacheImagesDirectory.list()) {
+      try {
+        final FileStat fs = file.statSync();
+        totalSize += fs.size;
+      } catch (e) {
+        // Ignore errors
+      }
+    }
+
+    return totalSize;
+  } catch (e) {
+    return -1; // Return -1 if an error occurs
+  }
+}
+
+/// Clears the image cache from ExtendedImage, by deleting all files older than [duration].
+/// If [duration] is not provided, it defaults to 7 days.
+Future<void> clearExtendedImageCache({Duration expiration = const Duration(days: 7)}) async {
+  final Directory cacheImagesDirectory = Directory(join((await getTemporaryDirectory()).path, cacheImageFolderName));
+  if (!cacheImagesDirectory.existsSync()) return;
+
+  await clearDiskCachedImages(duration: expiration);
+}