feat: defined AlienBumper behaviours

lib/game/components/alien_zone/alien_bumper/behaviors/alien_bumper_contact_behavior.dart

@@ -0,0 +1,36 @@
+import 'package:flame/components.dart';
+import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_flame/pinball_flame.dart';
+
+class AlienBumperContactBehavior extends Component with ContactCallbacks {
+  @override
+  Future<void> onLoad() async {
+    await super.onLoad();
+
+    // TODO(alestiago): Refactor once the following is merged:
+    // https://github.com/flame-engine/flame/pull/1566
+    final parent = this.parent;
+    if (parent is! AlienBumper) return;
+
+    final userData = parent.body.userData;
+    if (userData is ContactCallbacksNotifer) {
+      userData.addCallback(this);
+    } else {
+      parent.body.userData = this;
+    }
+  }
+
+  @override
+  void beginContact(Object other, Contact contact) {
+    super.beginContact(other, contact);
+    if (other is! Ball) return;
+
+    // TODO(alestiago): Refactor once the following is merged:
+    // https://github.com/flame-engine/flame/pull/1566
+    final parent = this.parent;
+    if (parent is! AlienBumper) return;
+
+    parent.state = AlienBumperState.inactive;
+  }
+}

lib/game/components/alien_zone/alien_bumper/behaviors/alien_bumper_sprite_behavior.dart

@@ -0,0 +1,51 @@
+import 'package:flame/components.dart';
+import 'package:pinball_components/pinball_components.dart';
+
+/// {@template alien_bumper_sprite_behavior}
+///
+/// {@endtemplate}
+class AlienBumperSpriteBehavior extends TimerComponent {
+  /// {@macro alien_bumper_sprite_behavior}
+  AlienBumperSpriteBehavior()
+      : super(
+          period: 0.05,
+          removeOnFinish: false,
+        );
+
+  void _onNewState(AlienBumperState state) {
+    switch (state) {
+      case AlienBumperState.active:
+        timer.stop();
+        break;
+      case AlienBumperState.inactive:
+        timer
+          ..reset()
+          ..start();
+        break;
+    }
+  }
+
+  @override
+  Future<void> onLoad() async {
+    await super.onLoad();
+
+    // TODO(alestiago): Refactor once the following is merged:
+    // https://github.com/flame-engine/flame/pull/1566
+    final parent = this.parent;
+    if (parent is! AlienBumper) return;
+
+    timer.stop();
+    parent.stream.listen(_onNewState);
+  }
+
+  @override
+  void onTick() {
+    super.onTick();
+    // TODO(alestiago): Refactor once the following is merged:
+    // https://github.com/flame-engine/flame/pull/1566
+    final parent = this.parent;
+    if (parent is! AlienBumper) return;
+
+    parent.state = AlienBumperState.active;
+  }
+}

lib/game/components/alien_zone/alien_bumper/behaviors/behaviors.dart

@@ -0,0 +1,2 @@
+export 'alien_bumper_contact_behavior.dart';
+export 'alien_bumper_sprite_behavior.dart';

lib/game/components/alien_zone/alien_zone.dart

@@ -1,7 +1,7 @@
 // ignore_for_file: avoid_renaming_method_parameters
 
-import 'package:flame/components.dart';
 import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:pinball/game/components/alien_zone/alien_bumper/behaviors/behaviors.dart';
 import 'package:pinball/game/game.dart';
 import 'package:pinball_components/pinball_components.dart';
 import 'package:pinball_flame/pinball_flame.dart';
@@ -20,28 +20,17 @@ class AlienZone extends Blueprint {
             AlienBumper.a(
               children: [
                 ScoringBehaviour(points: 20),
+                AlienBumperContactBehavior(),
+                AlienBumperSpriteBehavior(),
               ],
             )..initialPosition = Vector2(-32.52, -9.1),
             AlienBumper.b(
               children: [
                 ScoringBehaviour(points: 20),
+                AlienBumperContactBehavior(),
+                AlienBumperSpriteBehavior(),
               ],
             )..initialPosition = Vector2(-22.89, -17.35),
           ],
         );
 }
-
-/// Listens when a [Ball] bounces against an [AlienBumper].
-// TODO(alestiago): Add Bumper animation behaviour.
-// @visibleForTesting
-// class AlienBumperBallContactCallback
-//     extends ContactCallback<AlienBumper, Ball> {
-//   @override
-//   void begin(
-//     AlienBumper alienBumper,
-//     Ball _,
-//     Contact __,
-//   ) {
-//     alienBumper.animate();
-//   }
-// }

lib/game/components/components.dart

@@ -1,4 +1,4 @@
-export 'alien_zone.dart';
+export 'alien_zone/alien_zone.dart';
 export 'board.dart';
 export 'camera_controller.dart';
 export 'controlled_ball.dart';

lib/game/components/scoring_behaviour.dart

@@ -10,7 +10,7 @@ import 'package:pinball_flame/pinball_flame.dart';
 ///
 /// {@endtemplate}
 class ScoringBehaviour extends Component
-    with ContactCallbacks, HasGameRef<PinballGame> {
+    with ContactCallbacksNotifer, HasGameRef<PinballGame> {
   /// {@macro scoring_behaviour}
   ScoringBehaviour({
     required int points,
@@ -28,8 +28,8 @@ class ScoringBehaviour extends Component
     if (parent is! BodyComponent) return;
 
     final userData = parent.body.userData;
-    if (userData is ContactCallbacks) {
-      userData.add(this);
+    if (userData is ContactCallbacksNotifer) {
+      userData.addCallback(this);
     } else {
       parent.body.userData = this;
     }
@@ -42,7 +42,6 @@ class ScoringBehaviour extends Component
 
     gameRef.read<GameBloc>().add(Scored(points: _points));
     gameRef.audio.score();
-
     gameRef.add(
       ScoreText(
         text: _points.toString(),

lib/game/pinball_game.dart

@@ -53,7 +53,8 @@ class PinballGame extends Forge2DGame
     final launcher = Launcher();
     unawaited(addFromBlueprint(launcher));
     unawaited(add(Board()));
-    unawaited(add(AlienZone()));
+    await addFromBlueprint(AlienZone());
+
     await addFromBlueprint(SparkyFireZone());
     unawaited(addFromBlueprint(Slingshots()));
     unawaited(addFromBlueprint(DinoWalls()));

packages/pinball_components/lib/src/components/alien_bumper.dart

@@ -2,13 +2,39 @@ import 'dart:async';
 
 import 'package:flame/components.dart';
 import 'package:flame_forge2d/flame_forge2d.dart';
-import 'package:flutter/material.dart';
 import 'package:pinball_components/pinball_components.dart';
 
+abstract class State<T> {
+  // TODO(alestiago): Investigate approaches to avoid having this as late.
+  late T _state;
+
+  T get state => _state;
+
+  set state(T value) {
+    if (value == _state) return;
+    _state = value;
+    _stream.sink.add(value);
+  }
+
+  final StreamController<T> _stream = StreamController<T>.broadcast();
+
+  Stream<T> get stream => _stream.stream;
+}
+
+/// Indicates the [AlienBumper]'s current sprite state.
+enum AlienBumperState {
+  /// A lit up bumper.
+  active,
+
+  /// A dimmed bumper.
+  inactive,
+}
+
 /// {@template alien_bumper}
 /// Bumper for area under the [Spaceship].
 /// {@endtemplate}
-class AlienBumper extends BodyComponent with InitialPosition {
+class AlienBumper extends BodyComponent
+    with InitialPosition, State<AlienBumperState> {
   /// {@macro alien_bumper}
   AlienBumper._({
     required double majorRadius,
@@ -21,14 +47,17 @@ class AlienBumper extends BodyComponent with InitialPosition {
         super(
           priority: RenderPriority.alienBumper,
           children: [
-            _AlienBumperSpriteGroupComponent(
-              onAssetPath: onAssetPath,
-              offAssetPath: offAssetPath,
-            ),
             if (children != null) ...children,
           ],
           renderBody: false,
-        );
+        ) {
+    _state = AlienBumperState.active;
+    _spriteGroupComponent = _AlienBumperSpriteGroupComponent(
+      offAssetPath: offAssetPath,
+      onAssetPath: onAssetPath,
+      state: state,
+    );
+  }
 
   /// {@macro alien_bumper}
   AlienBumper.a({
@@ -53,8 +82,17 @@ class AlienBumper extends BodyComponent with InitialPosition {
         );
 
   final double _majorRadius;
+
   final double _minorRadius;
 
+  late final _AlienBumperSpriteGroupComponent _spriteGroupComponent;
+
+  @override
+  Future<void> onLoad() async {
+    await super.onLoad();
+    await add(_spriteGroupComponent);
+  }
+
   @override
   Body createBody() {
     final shape = EllipseShape(
@@ -68,41 +106,24 @@ class AlienBumper extends BodyComponent with InitialPosition {
     );
     final bodyDef = BodyDef(
       position: initialPosition,
-      userData: this,
     );
 
     return world.createBody(bodyDef)..createFixture(fixtureDef);
   }
-
-  /// Animates the [AlienBumper].
-  Future<void> animate() async {
-    final spriteGroupComponent = firstChild<_AlienBumperSpriteGroupComponent>()
-      ?..current = AlienBumperSpriteState.inactive;
-    await Future<void>.delayed(const Duration(milliseconds: 50));
-    spriteGroupComponent?.current = AlienBumperSpriteState.active;
-  }
-}
-
-/// Indicates the [AlienBumper]'s current sprite state.
-@visibleForTesting
-enum AlienBumperSpriteState {
-  /// A lit up bumper.
-  active,
-
-  /// A dimmed bumper.
-  inactive,
 }
 
 class _AlienBumperSpriteGroupComponent
-    extends SpriteGroupComponent<AlienBumperSpriteState> with HasGameRef {
+    extends SpriteGroupComponent<AlienBumperState> with HasGameRef {
   _AlienBumperSpriteGroupComponent({
     required String onAssetPath,
     required String offAssetPath,
+    required AlienBumperState state,
   })  : _onAssetPath = onAssetPath,
         _offAssetPath = offAssetPath,
         super(
           anchor: Anchor.center,
           position: Vector2(0, -0.1),
+          current: state,
         );
 
   final String _onAssetPath;
@@ -113,14 +134,20 @@ class _AlienBumperSpriteGroupComponent
     await super.onLoad();
 
     final sprites = {
-      AlienBumperSpriteState.active:
-          Sprite(gameRef.images.fromCache(_onAssetPath)),
-      AlienBumperSpriteState.inactive:
+      AlienBumperState.active: Sprite(
+        gameRef.images.fromCache(_onAssetPath),
+      ),
+      AlienBumperState.inactive:
           Sprite(gameRef.images.fromCache(_offAssetPath)),
     };
     this.sprites = sprites;
-
-    current = AlienBumperSpriteState.active;
     size = sprites[current]!.originalSize / 10;
+
+    // TODO(alestiago): Refactor once the following is merged:
+    // https://github.com/flame-engine/flame/pull/1566
+    final parent = this.parent;
+    if (parent is! AlienBumper) return;
+
+    parent.stream.listen((state) => current = state);
   }
 }

packages/pinball_components/test/src/components/alien_bumper_test.dart

@@ -40,21 +40,17 @@ void main() {
 
       expect(
         spriteGroupComponent.current,
-        equals(AlienBumperSpriteState.active),
+        equals(AlienBumperState.active),
       );
 
-      final future = bumper.animate();
-
       expect(
         spriteGroupComponent.current,
-        equals(AlienBumperSpriteState.inactive),
+        equals(AlienBumperState.inactive),
       );
 
-      await future;
-
       expect(
         spriteGroupComponent.current,
-        equals(AlienBumperSpriteState.active),
+        equals(AlienBumperState.active),
       );
     });
   });

packages/pinball_flame/lib/src/contacts_callbacks_adder.dart

@@ -1,38 +1,60 @@
 import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:flutter/material.dart';
 
-/// {@template contact_callbacks_adder}
-///
-/// {@endtemplate}
-// TODO(alestiago): Consider adding streams to [ContactCallbacks].
-extension ContactCallbacksAdder on ContactCallbacks {
-  /// {@macro contact_callbacks_adder}
-  void add(ContactCallbacks contactCallbacks) {
-    if (contactCallbacks.onBeginContact != null) {
-      onBeginContact = (other, contact) {
-        onBeginContact?.call(other, contact);
-        contactCallbacks.beginContact(other, contact);
-      };
+class ContactCallbacksNotifer implements ContactCallbacks {
+  final List<ContactCallbacks> _callbacks = [];
+
+  @override
+  @mustCallSuper
+  void beginContact(Object other, Contact contact) {
+    onBeginContact?.call(other, contact);
+    for (final callback in _callbacks) {
+      callback.beginContact(other, contact);
     }
+  }
 
-    if (contactCallbacks.onEndContact != null) {
-      onEndContact = (other, contact) {
-        onEndContact?.call(other, contact);
-        contactCallbacks.endContact(other, contact);
-      };
+  @override
+  @mustCallSuper
+  void endContact(Object other, Contact contact) {
+    onEndContact?.call(other, contact);
+    for (final callback in _callbacks) {
+      callback.endContact(other, contact);
     }
+  }
 
-    if (contactCallbacks.onPreSolve != null) {
-      onPreSolve = (other, contact, oldManifold) {
-        onPreSolve?.call(other, contact, oldManifold);
-        contactCallbacks.preSolve(other, contact, oldManifold);
-      };
+  @override
+  @mustCallSuper
+  void preSolve(Object other, Contact contact, Manifold oldManifold) {
+    onPreSolve?.call(other, contact, oldManifold);
+    for (final callback in _callbacks) {
+      callback.preSolve(other, contact, oldManifold);
     }
+  }
 
-    if (contactCallbacks.onPostSolve != null) {
-      onPostSolve = (other, contact, impulse) {
-        onPostSolve?.call(other, contact, impulse);
-        contactCallbacks.postSolve(other, contact, impulse);
-      };
+  @override
+  @mustCallSuper
+  void postSolve(Object other, Contact contact, ContactImpulse impulse) {
+    onPostSolve?.call(other, contact, impulse);
+    for (final callback in _callbacks) {
+      callback.postSolve(other, contact, impulse);
     }
   }
+
+  void addCallback(ContactCallbacks callback) {
+    _callbacks.add(callback);
+  }
+
+  @override
+  void Function(Object other, Contact contact)? onBeginContact;
+
+  @override
+  void Function(Object other, Contact contact)? onEndContact;
+
+  @override
+  void Function(Object other, Contact contact, ContactImpulse impulse)?
+      onPostSolve;
+
+  @override
+  void Function(Object other, Contact contact, Manifold oldManifold)?
+      onPreSolve;
 }