import 'dart:math';

import 'package:flutter/material.dart';

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

  @override
  State<CircularFlowAnimation> createState() => _CircularFlowAnimationState();
}

class _CircularFlowAnimationState extends State<CircularFlowAnimation>
    with SingleTickerProviderStateMixin {
  late AnimationController _controller;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      vsync: this,
      duration: const Duration(seconds: 20),
    )..repeat();
  }

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

  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      painter: CircularFlowPainter(_controller),
      size: Size.infinite,
    );
  }
}

class CircularFlowPainter extends CustomPainter {
  final Animation<double> animation;

  CircularFlowPainter(this.animation) : super(repaint: animation);

  @override
  void paint(Canvas canvas, Size size) {
    final center = Offset(size.width / 2, size.height / 2);
    const baseRadius = 150.0;
    final time = animation.value * 2 * pi;

    // 绘制圆形路径
    _drawCircularPath(canvas, center, baseRadius);

    // 绘制三个围绕圆形运动的渐变云朵
    _drawOrbitingCloud(
      canvas: canvas,
      center: center,
      time: time,
      colors: [Colors.blue, Colors.purple],
      orbitRadius: baseRadius,
      speed: 0.5,
      direction: 1,
    );

    _drawOrbitingCloud(
      canvas: canvas,
      center: center,
      time: time,
      colors: [Colors.pink, Colors.orange],
      orbitRadius: baseRadius * 0.8,
      speed: 1.0,
      direction: -1,
    );

    _drawOrbitingCloud(
      canvas: canvas,
      center: center,
      time: time,
      colors: [Colors.green, Colors.yellow],
      orbitRadius: baseRadius * 1.2,
      speed: 0.3,
      direction: 1,
    );

    _drawOrbitingCloud(
      canvas: canvas,
      center: center,
      time: time,
      colors: [Colors.red, Colors.deepOrangeAccent],
      orbitRadius: baseRadius * 0.5,
      speed: 0.8,
      direction: -1,
    );
  }

  void _drawCircularPath(Canvas canvas, Offset center, double radius) {
    final paint = Paint()
      ..color = Colors.red
      ..style = PaintingStyle.stroke
      ..strokeWidth = 2
      ..maskFilter = MaskFilter.blur(BlurStyle.normal, 4);

    canvas.drawCircle(center, radius, paint);
  }

  void _drawOrbitingCloud({
    required Canvas canvas,
    required Offset center,
    required double time,
    required List<Color> colors,
    required double orbitRadius,
    required double speed,
    required int direction,
  }) {
    final angle = time * speed * direction;
    final position = Offset(
      center.dx + orbitRadius * cos(angle),
      center.dy + orbitRadius * sin(angle),
    );

    final gradient = RadialGradient(
      colors: colors,
      stops: const [0.3, 1.0],
      radius: 0.6,
      focal: Alignment(
        0.1 + cos(angle * 2) * 0.3,
        0.1 + sin(angle * 2) * 0.3,
      ),
    );

    final paint = Paint()
      ..shader = gradient.createShader(Rect.fromCircle(
        center: position,
        radius: 100 + 30 * sin(time * 3),
      ))
      ..maskFilter = MaskFilter.blur(BlurStyle.normal, 40)
      ..blendMode = BlendMode.plus;

    canvas.drawCircle(position, 80 + 20 * cos(time * 2), paint);
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => true;
}