Refactoring

lib/main.dart

@@ -1,18 +1,22 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:media_kit/media_kit.dart';
 import 'package:window_manager/window_manager.dart';
 import 'package:trainhub_flutter/core/router/app_router.dart';
 import 'package:trainhub_flutter/core/theme/app_theme.dart';
+import 'package:trainhub_flutter/domain/services/ai_process_manager.dart';
 import 'package:trainhub_flutter/injection.dart' as di;
+import 'package:trainhub_flutter/presentation/settings/ai_model_settings_controller.dart';
+import 'package:trainhub_flutter/presentation/settings/ai_model_settings_state.dart';
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  MediaKit.ensureInitialized();
   await windowManager.ensureInitialized();
 
-  // Initialize dependency injection
   di.init();
 
-  WindowOptions windowOptions = const WindowOptions(
+  const windowOptions = WindowOptions(
     size: Size(1280, 800),
     minimumSize: Size(800, 600),
     center: true,
@@ -30,17 +34,75 @@ void main() async {
   runApp(const ProviderScope(child: TrainHubApp()));
 }
 
-class TrainHubApp extends StatelessWidget {
+// =============================================================================
+// Root application widget
+// =============================================================================
+class TrainHubApp extends ConsumerStatefulWidget {
   const TrainHubApp({super.key});
 
+  @override
+  ConsumerState<TrainHubApp> createState() => _TrainHubAppState();
+}
+
+class _TrainHubAppState extends ConsumerState<TrainHubApp>
+    with WindowListener {
+  // Create the router once and reuse it across rebuilds.
+  final _appRouter = AppRouter();
+
+  // Guard flag so we never start the servers more than once per app session.
+  bool _serversStarted = false;
+
+  // -------------------------------------------------------------------------
+  // Lifecycle
+  // -------------------------------------------------------------------------
+
+  @override
+  void initState() {
+    super.initState();
+    windowManager.addListener(this);
+    // Intercept the OS close event so we can kill child processes first.
+    windowManager.setPreventClose(true);
+  }
+
+  @override
+  void dispose() {
+    windowManager.removeListener(this);
+    super.dispose();
+  }
+
+  // -------------------------------------------------------------------------
+  // WindowListener — critical: kill servers before the window is destroyed
+  // so they don't become zombie processes consuming 5 GB of RAM.
+  // -------------------------------------------------------------------------
+
+  @override
+  void onWindowClose() async {
+    await di.getIt<AiProcessManager>().stopServers();
+    await windowManager.destroy();
+  }
+
+  // -------------------------------------------------------------------------
+  // Build
+  // -------------------------------------------------------------------------
+
   @override
   Widget build(BuildContext context) {
-    final appRouter = AppRouter();
+    // Watch the model-settings state and start servers exactly once, the
+    // first time models are confirmed to be present on disk.
+    ref.listen<AiModelSettingsState>(
+      aiModelSettingsControllerProvider,
+      (prev, next) {
+        if (!_serversStarted && next.areModelsValidated) {
+          _serversStarted = true;
+          di.getIt<AiProcessManager>().startServers();
+        }
+      },
+    );
 
     return MaterialApp.router(
       title: 'TrainHub',
       theme: AppTheme.dark,
-      routerConfig: appRouter.config(),
+      routerConfig: _appRouter.config(),
       debugShowCheckedModeBanner: false,
     );
   }