feature(updater): Implement auto-updating system using AppCast protocol

lib/config.dart

@@ -2,6 +2,9 @@ final class Config {
   static const launcherApiBaseUrl = String.fromEnvironment(
     'MOONWELL_API_BASE_URL',
   );
+  static const launcherAppcastUrl = String.fromEnvironment(
+    'MOONWELL_APPCAST_URL',
+  );
   static const launcherLogFileName = 'launcher.log';
   static const gameExecutableName = 'Wow.exe';
   static const cacheDirectoryName = 'Cache';

lib/features/launcher/data/launcher_update_service.dart

@@ -0,0 +1,99 @@
+import 'dart:io';
+
+import 'package:auto_updater/auto_updater.dart';
+import 'package:injectable/injectable.dart';
+import 'package:moonwell_launcher/config.dart';
+import 'package:moonwell_launcher/features/launcher/data/launcher_log_service.dart';
+
+abstract interface class LauncherUpdateClient {
+  Future<void> setFeedUrl(String feedUrl);
+
+  Future<void> disableScheduledChecks();
+
+  Future<void> checkInBackground();
+}
+
+final class AutoUpdaterLauncherUpdateClient implements LauncherUpdateClient {
+  @override
+  Future<void> setFeedUrl(String feedUrl) => autoUpdater.setFeedURL(feedUrl);
+
+  @override
+  Future<void> disableScheduledChecks() =>
+      autoUpdater.setScheduledCheckInterval(0);
+
+  @override
+  Future<void> checkInBackground() =>
+      autoUpdater.checkForUpdates(inBackground: true);
+}
+
+@lazySingleton
+class LauncherUpdateService {
+  LauncherUpdateService(LauncherLogService launcherLogService)
+    : this.forTesting(
+        launcherLogService: launcherLogService,
+        updateClient: AutoUpdaterLauncherUpdateClient(),
+        isWindows: Platform.isWindows,
+      );
+
+  LauncherUpdateService.forTesting({
+    required LauncherLogService launcherLogService,
+    required LauncherUpdateClient updateClient,
+    required bool isWindows,
+  }) : _launcherLogService = launcherLogService,
+       _updateClient = updateClient,
+       _isWindows = isWindows;
+
+  final LauncherLogService _launcherLogService;
+  final LauncherUpdateClient _updateClient;
+  final bool _isWindows;
+
+  bool _hasChecked = false;
+
+  Future<void> checkForUpdates({
+    String feedUrl = Config.launcherAppcastUrl,
+  }) async {
+    if (!_isWindows || _hasChecked) {
+      return;
+    }
+
+    final normalizedFeedUrl = feedUrl.trim();
+    if (normalizedFeedUrl.isEmpty) {
+      await _launcherLogService.info(
+        'Launcher self-update is disabled because no AppCast URL is configured.',
+      );
+      return;
+    }
+
+    final uri = Uri.tryParse(normalizedFeedUrl);
+    if (uri == null ||
+        !uri.isAbsolute ||
+        uri.scheme != 'https' ||
+        !uri.hasAuthority ||
+        uri.host.isEmpty) {
+      await _launcherLogService.error(
+        'Launcher self-update AppCast URL is invalid.',
+        details: <String, Object?>{'feedUrl': normalizedFeedUrl},
+      );
+      return;
+    }
+
+    _hasChecked = true;
+
+    try {
+      await _updateClient.setFeedUrl(normalizedFeedUrl);
+      await _updateClient.disableScheduledChecks();
+      await _updateClient.checkInBackground();
+      await _launcherLogService.info(
+        'Launcher self-update check started.',
+        details: <String, Object?>{'feedUrl': normalizedFeedUrl},
+      );
+    } catch (error, stackTrace) {
+      await _launcherLogService.error(
+        'Launcher self-update check failed.',
+        details: <String, Object?>{'feedUrl': normalizedFeedUrl},
+        error: error,
+        stackTrace: stackTrace,
+      );
+    }
+  }
+}

lib/main.dart

@@ -3,6 +3,7 @@ import 'dart:async';
 
 import 'package:flutter/material.dart';
 import 'package:moonwell_launcher/app/mw_app.dart';
+import 'package:moonwell_launcher/features/launcher/data/launcher_update_service.dart';
 import 'package:moonwell_launcher/service_container.dart';
 import 'package:window_manager/window_manager.dart';
 
@@ -10,6 +11,9 @@ Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
   await windowManager.ensureInitialized();
 
+  await configureDependencies(env: 'flutter');
+  final launcherUpdateService = getIt<LauncherUpdateService>();
+
   WindowOptions windowOptions = WindowOptions(
     size: Size(960, 540),
     center: true,
@@ -22,10 +26,9 @@ Future<void> main() async {
     windowManager.waitUntilReadyToShow(windowOptions, () async {
       await windowManager.show();
       await windowManager.focus();
+      await launcherUpdateService.checkForUpdates();
     }),
   );
 
-  await configureDependencies(env: 'flutter');
-
   runApp(const MoonWellApp());
 }

lib/service_container.config.dart

@@ -18,6 +18,7 @@ import 'features/launcher/application/client_sync_use_case.dart' as _i757;
 import 'features/launcher/data/game_installation_service.dart' as _i315;
 import 'features/launcher/data/launcher_api_client.dart' as _i703;
 import 'features/launcher/data/launcher_log_service.dart' as _i43;
+import 'features/launcher/data/launcher_update_service.dart' as _i605;
 import 'features/preferences/data/repositories/local_preferences_repository.dart'
     as _i658;
 import 'features/preferences/domain/repositories/preferences_repository.dart'
@@ -47,6 +48,9 @@ extension GetItInjectableX on _i174.GetIt {
     gh.lazySingleton<_i558.FlutterSecureStorage>(
       () => flutterSecureStorageModule.storage,
     );
+    gh.lazySingleton<_i605.LauncherUpdateService>(
+      () => _i605.LauncherUpdateService(gh<_i43.LauncherLogService>()),
+    );
     gh.lazySingleton<_i703.LauncherApiClient>(
       () => _i703.LauncherApiClient(
         launcherLogService: gh<_i43.LauncherLogService>(),