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

void main() {
  runApp(const MyApp());
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorSchemeSeed: Colors.deepPurple,
        useMaterial3: true,
      ),
      home: const MyWidget(),
    );
  }
}

class MyWidget extends StatefulWidget {
  const MyWidget({super.key});

  @override
  State<MyWidget> createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget>
    with SingleTickerProviderStateMixin {
  late AnimationController controller;

  @override
  void initState() {
    super.initState();
    controller =
        AnimationController(vsync: this, duration: const Duration(seconds: 5))
          ..repeat(reverse: true);
  }

  @override
  void dispose() {
    controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Padding(
          padding: const EdgeInsets.all(8.0),
          child: AnimatedBuilder(
              animation: controller,
              builder: (context, _) {
                return CustomPaint(
                  size: Size(MediaQuery.of(context).size.width,
                      MediaQuery.of(context).size.width),
                  painter: MyPaint(startAngle: pi / 2 * controller.value),
                );
              }),
        ),
      ),
    );
  }
}

class MyPaint extends CustomPainter {
  final double startAngle;
  MyPaint({
    required this.startAngle,
  });

  @override
  void paint(Canvas canvas, Size size) {
    final width = size.width;
    final height = size.height;
    final center = Offset(width / 2, height / 2);

    final paint = Paint()
      ..color = Colors.orangeAccent
      ..style = PaintingStyle.fill;
    final path = Path()
      ..addArc(Rect.fromCenter(center: center, width: width, height: height),
          startAngle, 1.99 * pi);
    canvas.saveLayer(
      Rect.fromCenter(center: center, width: width, height: height),
      Paint(),
    );
    canvas.drawPath(path, paint);
    canvas.restore();
  }

  @override
  bool shouldRepaint(MyPaint oldDelegate) =>
      oldDelegate.startAngle != startAngle;
}