import 'package:flutter/material.dart';
import 'package:flutter/gestures.dart';

/// 遮罩层，icon 区域挖洞可交互
class HoleOverlay extends StatelessWidget {
  final Offset iconPosition;
  final double iconSize;
  final VoidCallback? onTap;

  const HoleOverlay({
    super.key,
    required this.iconPosition,
    required this.iconSize,
    this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    return Listener(
      behavior: HitTestBehavior.translucent,
      onPointerDown: (PointerDownEvent event) {
        final RenderBox box = context.findRenderObject() as RenderBox;
        final Offset local = box.globalToLocal(event.position);
        final iconRect = Rect.fromLTWH(
          iconPosition.dx,
          iconPosition.dy,
          iconSize,
          iconSize,
        );
        if (!iconRect.contains(local)) {
          // 遮罩区域，拦截并关闭弹窗
          if (onTap != null) {
            onTap!();
          }
        }
        // 如果点在icon区域，什么都不做，事件会传递到下层
      },
      child: CustomPaint(
        size: Size.infinite,
        painter: _HolePainter(
          iconPosition: iconPosition,
          iconSize: iconSize,
        ),
      ),
    );
  }
}

class _HolePainter extends CustomPainter {
  final Offset iconPosition;
  final double iconSize;

  _HolePainter({required this.iconPosition, required this.iconSize});

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = Colors.white.withOpacity(0.0)
      ..blendMode = BlendMode.srcOver;

    // 画全屏遮罩
    canvas.drawRect(Offset.zero & size, paint);

    // 挖洞
    final holeRect = Rect.fromLTWH(
      iconPosition.dx,
      iconPosition.dy,
      iconSize,
      iconSize,
    );
    final holePath = Path()..addOval(holeRect);
    paint.blendMode = BlendMode.clear;
    canvas.drawPath(holePath, paint);
  }

  @override
  bool shouldRepaint(covariant _HolePainter oldDelegate) {
    return iconPosition != oldDelegate.iconPosition || iconSize != oldDelegate.iconSize;
  }
}