Moved away from singleton pattern

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

apps/wolf_3d_gui/lib/main.dart

@@ -5,11 +5,11 @@ import 'package:wolf_3d_gui/screens/game_select_screen.dart';
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
 
-  await Wolf3d.I.init();
+  final Wolf3d wolf3d = await Wolf3d().init();
 
   runApp(
-    const MaterialApp(
+    MaterialApp(
-      home: GameSelectScreen(),
+      home: GameSelectScreen(wolf3d: wolf3d),
     ),
   );
 }

apps/wolf_3d_gui/lib/screens/difficulty_screen.dart

@@ -4,8 +4,11 @@ import 'package:wolf_3d_flutter/wolf_3d.dart';
 import 'package:wolf_3d_gui/screens/game_screen.dart';
 
 class DifficultyScreen extends StatefulWidget {
+  final Wolf3d wolf3d;
+
   const DifficultyScreen({
     super.key,
+    required this.wolf3d,
   });
 
   @override
@@ -13,24 +16,25 @@ class DifficultyScreen extends StatefulWidget {
 }
 
 class _DifficultyScreenState extends State<DifficultyScreen> {
-  bool get isShareware => Wolf3d.I.activeGame.version == GameVersion.shareware;
+  bool get isShareware =>
+      widget.wolf3d.activeGame.version == GameVersion.shareware;
 
   @override
   void dispose() {
-    Wolf3d.I.audio.stopMusic();
+    widget.wolf3d.audio.stopMusic();
     super.dispose();
   }
 
   void _startGame(Difficulty difficulty, {bool showGallery = false}) {
-    Wolf3d.I.audio.stopMusic();
+    widget.wolf3d.audio.stopMusic();
 
     Navigator.of(context).pushReplacement(
       MaterialPageRoute(
         builder: (context) => GameScreen(
-          data: Wolf3d.I.activeGame,
+          data: widget.wolf3d.activeGame,
           difficulty: difficulty,
-          startingEpisode: Wolf3d.I.activeEpisode,
+          startingEpisode: widget.wolf3d.activeEpisode,
-          audio: Wolf3d.I.audio,
+          audio: widget.wolf3d.audio,
         ),
       ),
     );
@@ -59,8 +63,6 @@ class _DifficultyScreenState extends State<DifficultyScreen> {
               ),
             ),
             const SizedBox(height: 40),
-
-            // --- Difficulty Buttons ---
             ListView.builder(
               shrinkWrap: true,
               itemCount: Difficulty.values.length,

apps/wolf_3d_gui/lib/screens/episode_screen.dart

@@ -6,7 +6,9 @@ import 'package:wolf_3d_gui/screens/sprite_gallery.dart';
 import 'package:wolf_3d_gui/screens/vga_gallery.dart';
 
 class EpisodeScreen extends StatefulWidget {
-  const EpisodeScreen({super.key});
+  final Wolf3d wolf3d;
+
+  const EpisodeScreen({super.key, required this.wolf3d});
 
   @override
   State<EpisodeScreen> createState() => _EpisodeScreenState();
@@ -16,21 +18,21 @@ class _EpisodeScreenState extends State<EpisodeScreen> {
   @override
   void initState() {
     super.initState();
-    Wolf3d.I.audio.playMenuMusic();
+    widget.wolf3d.audio.playMenuMusic();
   }
 
   void _selectEpisode(int index) {
-    Wolf3d.I.setActiveEpisode(index);
+    widget.wolf3d.setActiveEpisode(index);
     Navigator.of(context).push(
       MaterialPageRoute(
-        builder: (context) => DifficultyScreen(),
+        builder: (context) => DifficultyScreen(wolf3d: widget.wolf3d),
       ),
     );
   }
 
   @override
   Widget build(BuildContext context) {
-    final List<Episode> episodes = Wolf3d.I.activeGame.episodes;
+    final List<Episode> episodes = widget.wolf3d.activeGame.episodes;
 
     return Scaffold(
       backgroundColor: Colors.teal,
@@ -43,7 +45,7 @@ class _EpisodeScreenState extends State<EpisodeScreen> {
               Navigator.of(context).push(
                 MaterialPageRoute(
                   builder: (context) {
-                    return VgaGallery(images: Wolf3d.I.vgaImages);
+                    return VgaGallery(images: widget.wolf3d.vgaImages);
                   },
                 ),
               );
@@ -55,7 +57,9 @@ class _EpisodeScreenState extends State<EpisodeScreen> {
               Navigator.of(context).push(
                 MaterialPageRoute(
                   builder: (context) {
-                    return SpriteGallery(sprites: Wolf3d.I.sprites);
+                    return SpriteGallery(
+                      wolf3d: widget.wolf3d,
+                    );
                   },
                 ),
               );

apps/wolf_3d_gui/lib/screens/game_select_screen.dart

@@ -4,25 +4,27 @@ import 'package:wolf_3d_flutter/wolf_3d.dart';
 import 'package:wolf_3d_gui/screens/episode_screen.dart';
 
 class GameSelectScreen extends StatelessWidget {
-  const GameSelectScreen({super.key});
+  final Wolf3d wolf3d;
+
+  const GameSelectScreen({super.key, required this.wolf3d});
 
   @override
   Widget build(BuildContext context) {
     return Scaffold(
       body: ListView.builder(
-        itemCount: Wolf3d.I.availableGames.length,
+        itemCount: wolf3d.availableGames.length,
         itemBuilder: (context, i) {
-          final WolfensteinData data = Wolf3d.I.availableGames[i];
+          final WolfensteinData data = wolf3d.availableGames[i];
           final GameVersion version = data.version;
 
           return Card(
             child: ListTile(
               title: Text(version.name),
               onTap: () {
-                Wolf3d.I.setActiveGame(data);
+                wolf3d.setActiveGame(data);
                 Navigator.of(context).push(
                   MaterialPageRoute(
-                    builder: (context) => const EpisodeScreen(),
+                    builder: (context) => EpisodeScreen(wolf3d: wolf3d),
                   ),
                 );
               },

apps/wolf_3d_gui/lib/screens/sprite_gallery.dart

@@ -5,11 +5,11 @@ import 'package:wolf_3d_flutter/wolf_3d.dart';
 import 'package:wolf_3d_renderer/wolf_3d_asset_painter.dart';
 
 class SpriteGallery extends StatelessWidget {
-  final List<Sprite> sprites;
+  final Wolf3d wolf3d;
 
-  const SpriteGallery({super.key, required this.sprites});
+  const SpriteGallery({super.key, required this.wolf3d});
 
-  bool get isShareware => Wolf3d.I.activeGame.version == GameVersion.shareware;
+  bool get isShareware => wolf3d.activeGame.version == GameVersion.shareware;
 
   @override
   Widget build(BuildContext context) {
@@ -25,9 +25,8 @@ class SpriteGallery extends StatelessWidget {
           crossAxisSpacing: 8,
           mainAxisSpacing: 8,
         ),
-        itemCount: sprites.length,
+        itemCount: wolf3d.sprites.length,
         itemBuilder: (context, index) {
-          // --- Check which enemy owns this sprite ---
           String label = "Sprite Index: $index";
           for (final enemy in EnemyType.values) {
             if (enemy.claimsSpriteIndex(index, isShareware: isShareware)) {
@@ -36,14 +35,10 @@ class SpriteGallery extends StatelessWidget {
                 isShareware: isShareware,
               );
 
-              // Appends the enum name (e.g., "guard", "dog")
               label += "\n${enemy.name}";
-
-              // Appends the animation name
               if (animation != null) {
                 label += "\n${animation.name}";
               }
-
               break;
             }
           }
@@ -61,7 +56,7 @@ class SpriteGallery extends StatelessWidget {
                 Expanded(
                   child: AspectRatio(
                     aspectRatio: 4 / 3,
-                    child: WolfAssetPainter.sprite(sprites[index]),
+                    child: WolfAssetPainter.sprite(wolf3d.sprites[index]),
                   ),
                 ),
               ],

packages/wolf_3d_flutter/lib/audio/audio_adaptor.dart

@@ -3,48 +3,52 @@ import 'package:wolf_3d_dart/wolf_3d_engine.dart';
 import 'package:wolf_3d_flutter/wolf_3d.dart';
 
 class FlutterAudioAdapter implements EngineAudio {
+  final Wolf3d wolf3d;
+
+  FlutterAudioAdapter(this.wolf3d);
+
   @override
   void playLevelMusic(WolfLevel level) {
-    Wolf3d.I.audio.playLevelMusic(level);
+    wolf3d.audio.playLevelMusic(level);
   }
 
   @override
   void stopMusic() {
-    Wolf3d.I.audio.stopMusic();
+    wolf3d.audio.stopMusic();
   }
 
   @override
   void playSoundEffect(int sfxId) {
-    Wolf3d.I.audio.playSoundEffect(sfxId);
+    wolf3d.audio.playSoundEffect(sfxId);
   }
 
   @override
   void playMenuMusic() {
-    Wolf3d.I.audio.playMenuMusic();
+    wolf3d.audio.playMenuMusic();
   }
 
   @override
   Future<void> init() async {
-    await Wolf3d.I.audio.init();
+    await wolf3d.audio.init();
   }
 
   @override
   void dispose() {
-    Wolf3d.I.audio.dispose();
+    wolf3d.audio.dispose();
   }
 
   @override
   Future<void> debugSoundTest() async {
-    Wolf3d.I.audio.debugSoundTest();
+    wolf3d.audio.debugSoundTest();
   }
 
   @override
-  WolfensteinData? get activeGame => Wolf3d.I.activeGame;
+  WolfensteinData? get activeGame => wolf3d.activeGame;
 
   @override
   set activeGame(WolfensteinData? value) {
     if (value != null) {
-      Wolf3d.I.setActiveGame(value);
+      wolf3d.setActiveGame(value);
     }
   }
 }

packages/wolf_3d_flutter/lib/wolf_3d.dart

@@ -6,9 +6,7 @@ import 'package:wolf_3d_dart/wolf_3d_engine.dart';
 import 'package:wolf_3d_dart/wolf_3d_synth.dart';
 
 class Wolf3d {
-  Wolf3d._();
+  Wolf3d();
-  static final Wolf3d _instance = Wolf3d._();
-  static Wolf3d get I => _instance;
 
   // --- State ---
   final List<WolfensteinData> availableGames = [];
@@ -31,6 +29,13 @@ class Wolf3d {
   int get activeEpisode => _activeEpisode;
 
   void setActiveEpisode(int episodeIndex) {
+    if (_activeGame == null) {
+      throw StateError("No active game selected. Call setActiveGame() first.");
+    }
+    if (episodeIndex < 0 || episodeIndex >= _activeGame!.episodes.length) {
+      throw RangeError("Episode index out of range for the active game.");
+    }
+
     _activeEpisode = episodeIndex;
   }
 
@@ -45,12 +50,22 @@ class Wolf3d {
 
   // --- Actions ---
   void setActiveGame(WolfensteinData game) {
+    if (!availableGames.contains(game)) {
+      throw ArgumentError(
+        "The provided game data is not in the list of available games.",
+      );
+    }
+
+    if (_activeGame == game) {
+      return; // No change needed
+    }
+
     _activeGame = game;
     audio.activeGame = game;
   }
 
   /// Initializes the engine by loading available game data.
-  Future<void> init({String? directory}) async {
+  Future<Wolf3d> init({String? directory}) async {
     await audio.init();
     availableGames.clear();
 
@@ -63,7 +78,6 @@ class Wolf3d {
     for (final version in versionsToTry) {
       try {
         final ext = version.version.fileExtension;
-        // final folder = 'assets/${version.path}';
         final folder = 'packages/wolf_3d_assets/assets/${version.path}';
 
         final data = WolfensteinLoader.loadFromBytes(
@@ -100,6 +114,8 @@ class Wolf3d {
         debugPrint("External discovery failed: $e");
       }
     }
+
+    return this;
   }
 
   Future<ByteData?> _tryLoad(String path) async {