import 'package:flame/components.dart';
import 'package:flame/events.dart';
import 'package:flame/game.dart';
import 'package:flame/input.dart';
import 'package:flame/palette.dart';
import 'package:flutter/material.dart';

class ScaleDragGame extends StatelessWidget {
  const ScaleDragGame({super.key});

  @override
  Widget build(BuildContext context) {
    final game = ScaleDragFlameGame();

    return GameWidget(game: game);
  }
}

/// `onScale` methods are not called when a Component with DragCallbacks is added as a child.
/// Green rectangle can be dragged around but scale gestures don't work. But if I remove DragCallbacks from
/// [DraggableRectangle] scale gestures start to work.
class ScaleDragFlameGame extends FlameGame with ScaleDetector {
  late final CameraComponent cameraComponent;
  late double startZoom;

  ScaleDragFlameGame();

  @override
  Color backgroundColor() => Colors.yellow;

  @override
  Future<void> onLoad() async {
    final world = World();
    cameraComponent = CameraComponent(world: world)
      ..viewfinder.anchor = Anchor.center
      ..viewport.anchor = Anchor.center;
    addAll([world, cameraComponent]);

    world.add(DraggableRectangle(
      size: size / 4,
      position: size / 6,
      paint: BasicPalette.darkGreen.paint(),
    ));
  }

  @override
  void onScaleStart(ScaleStartInfo info) {
    startZoom = cameraComponent.viewfinder.zoom;
  }

  @override
  void onScaleUpdate(ScaleUpdateInfo info) {
    /// not called when Component with DragCallbacks was added

    final currentScale = info.scale.global;
    if (!currentScale.isIdentity()) {
      final newZoom = (startZoom * currentScale.y).clamp(1.0, 6.0);
      cameraComponent.viewfinder.zoom = newZoom;
    } else {
      final delta = info.delta.game;
      cameraComponent.viewfinder.position.translate(-delta.x, -delta.y);
    }
  }
}

/// Remove [DragCallbacks] and see that pinch-to-zoom gestures start working
class DraggableRectangle extends RectangleComponent with DragCallbacks {
  DraggableRectangle({
    super.position,
    super.size,
    super.paint,
  });

  @override
  void onDragUpdate(DragUpdateEvent event) {
    super.onDragUpdate(event);
    position += event.delta;
  }
}

[✓] Flutter (Channel stable, 3.10.5, on macOS 13.2.1 22D68 darwin-arm64, locale en-US)
    • Flutter version 3.10.5 on channel stable at /Users/wojciechplesiak/Development/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 796c8ef792 (7 weeks ago), 2023-06-13 15:51:02 -0700
    • Engine revision 45f6e00911
    • Dart version 3.0.5
    • DevTools version 2.23.1