feat: defined component controller

lib/flame/component_controller.dart

@@ -0,0 +1,31 @@
+import 'package:flame/components.dart';
+import 'package:flame_bloc/flame_bloc.dart';
+
+/// {@template component_controller}
+/// A [ComponentController] is a [Component] in charge of handling the logic
+/// associated with another [Component].
+///
+/// [ComponentController]s usually implement [BlocComponent].
+/// {@endtemplate}
+abstract class ComponentController<T extends Component> extends Component {
+  /// {@macro component_controller}
+  ComponentController(this.component);
+
+  /// The [Component] controlled by this [ComponentController].
+  final T component;
+
+  /// Ads the [ComponentController] to its [component].
+  Future<void> attach() async {
+    await component.add(this);
+  }
+
+  @override
+  Future<void> onLoad() async {
+    await super.onLoad();
+    assert(
+      parent! == component,
+      'ComponentController should be child of $component. '
+      'Use attach() instead.',
+    );
+  }
+}