feat: included ParentIsA mixin

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

@@ -3,16 +3,12 @@ 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 {
+class AlienBumperContactBehavior extends Component
+    with ContactCallbacks, ParentIsA<AlienBumper> {
   @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);
@@ -25,12 +21,6 @@ class AlienBumperContactBehavior extends Component with ContactCallbacks {
   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

@@ -1,10 +1,12 @@
 import 'package:flame/components.dart';
 import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_flame/pinball_flame.dart';
 
 /// {@template alien_bumper_sprite_behavior}
 ///
 /// {@endtemplate}
-class AlienBumperSpriteBehavior extends TimerComponent {
+class AlienBumperSpriteBehavior extends TimerComponent
+    with ParentIsA<AlienBumper> {
   /// {@macro alien_bumper_sprite_behavior}
   AlienBumperSpriteBehavior()
       : super(
@@ -28,12 +30,6 @@ class AlienBumperSpriteBehavior extends TimerComponent {
   @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);
   }
@@ -41,11 +37,6 @@ class AlienBumperSpriteBehavior extends TimerComponent {
   @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/scoring_behaviour.dart

@@ -10,7 +10,10 @@ import 'package:pinball_flame/pinball_flame.dart';
 ///
 /// {@endtemplate}
 class ScoringBehaviour extends Component
-    with ContactCallbacksNotifer, HasGameRef<PinballGame> {
+    with
+        ContactCallbacksNotifer,
+        HasGameRef<PinballGame>,
+        ParentIsA<BodyComponent> {
   /// {@macro scoring_behaviour}
   ScoringBehaviour({
     required int points,
@@ -22,11 +25,6 @@ class ScoringBehaviour extends Component
   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! BodyComponent) return;
-
     final userData = parent.body.userData;
     if (userData is ContactCallbacksNotifer) {
       userData.addCallback(this);

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

@@ -3,6 +3,7 @@ import 'dart:async';
 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';
 
 abstract class State<T> {
   // TODO(alestiago): Investigate approaches to avoid having this as late.
@@ -19,6 +20,10 @@ abstract class State<T> {
   final StreamController<T> _stream = StreamController<T>.broadcast();
 
   Stream<T> get stream => _stream.stream;
+
+  void close() {
+    _stream.close();
+  }
 }
 
 /// Indicates the [AlienBumper]'s current sprite state.
@@ -93,6 +98,12 @@ class AlienBumper extends BodyComponent
     await add(_spriteGroupComponent);
   }
 
+  @override
+  void onRemove() {
+    close();
+    super.onRemove();
+  }
+
   @override
   Body createBody() {
     final shape = EllipseShape(
@@ -113,7 +124,8 @@ class AlienBumper extends BodyComponent
 }
 
 class _AlienBumperSpriteGroupComponent
-    extends SpriteGroupComponent<AlienBumperState> with HasGameRef {
+    extends SpriteGroupComponent<AlienBumperState>
+    with HasGameRef, ParentIsA<AlienBumper> {
   _AlienBumperSpriteGroupComponent({
     required String onAssetPath,
     required String offAssetPath,
@@ -143,11 +155,6 @@ class _AlienBumperSpriteGroupComponent
     this.sprites = sprites;
     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_flame/lib/pinball_flame.dart

@@ -4,4 +4,5 @@ export 'src/blueprint.dart';
 export 'src/component_controller.dart';
 export 'src/contacts_callbacks_adder.dart';
 export 'src/keyboard_input_controller.dart';
+export 'src/parent_is_a.dart';
 export 'src/sprite_animation.dart';

packages/pinball_flame/lib/src/parent_is_a.dart

@@ -0,0 +1,16 @@
+import 'package:flame/components.dart';
+
+// TODO(alestiago): Remove once the following is merged:
+// https://github.com/flame-engine/flame/pull/1566
+
+/// A mixin that ensures a parent is of the given type [T].
+mixin ParentIsA<T extends Component> on Component {
+  @override
+  T get parent => super.parent! as T;
+
+  @override
+  Future<void>? addToParent(Component parent) {
+    assert(parent is T, 'Parent must be of type $T');
+    return super.addToParent(parent);
+  }
+}