feat: Introduce Wolf3dAppManager for managing audio shutdown and game data directory selection

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

packages/wolf_3d_flutter/lib/widgets/wolf3d_app.dart

@@ -21,37 +21,47 @@ class Wolf3dApp extends StatefulWidget {
 }
 
 class _Wolf3dAppState extends State<Wolf3dApp> with WidgetsBindingObserver {
-  Future<void>? _shutdownFuture;
+  late final Wolf3dAppManager _manager;
 
   @override
   void initState() {
     super.initState();
+    _manager = Wolf3dAppManager(engine: widget.engine);
     WidgetsBinding.instance.addObserver(this);
   }
 
   @override
   void dispose() {
     WidgetsBinding.instance.removeObserver(this);
-    unawaited(_ensureAudioShutdown());
+    unawaited(_manager.ensureAudioShutdown());
     super.dispose();
   }
 
   @override
   void didChangeAppLifecycleState(AppLifecycleState state) {
     if (state == AppLifecycleState.detached) {
-      unawaited(_ensureAudioShutdown());
+      unawaited(_manager.ensureAudioShutdown());
     }
   }
 
-  Future<void> _ensureAudioShutdown() {
-    final Future<void>? existing = _shutdownFuture;
-    if (existing != null) {
-      return existing;
-    }
+  Future<void> _pickGameDataDirectory() {
+    return _manager.pickGameDataDirectory(
+      notifyChanged: () {
+        if (mounted) {
+          setState(() {});
+        }
+      },
+    );
+  }
 
-    final Future<void> shutdown = widget.engine.shutdownAudio();
-    _shutdownFuture = shutdown;
-    return shutdown;
+  Future<void> _pickGameDataFiles() {
+    return _manager.pickGameDataFiles(
+      notifyChanged: () {
+        if (mounted) {
+          setState(() {});
+        }
+      },
+    );
   }
 
   @override
@@ -59,6 +69,10 @@ class _Wolf3dAppState extends State<Wolf3dApp> with WidgetsBindingObserver {
     return widget.engine.availableGames.isEmpty
         ? NoGameDataScreen(
             configuredDataDirectory: widget.engine.configuredDataDirectory,
+            onPickGameDataDirectory: _pickGameDataDirectory,
+            onPickGameDataFiles: _pickGameDataFiles,
+            isLoadingGameData: _manager.isLoadingGameData,
+            pickerError: _manager.pickerError,
           )
         : GameScreen(wolf3d: widget.engine);
   }