import 'dart:ui';
import 'package:flutter/material.dart';
import 'package:flutter_shaders/flutter_shaders.dart';

class VoiceMicFlow extends StatefulWidget {
  const VoiceMicFlow({super.key, this.size = 280, this.amp = 0.0});
  final double size;
  final double amp; // 音量振幅 0.0-1.0

  @override
  State<VoiceMicFlow> createState() => _VoiceMicFlowState();
}

class _VoiceMicFlowState extends State<VoiceMicFlow>
    with SingleTickerProviderStateMixin {
  late final AnimationController _ctl;

  @override
  void initState() {
    super.initState();
    _ctl = AnimationController(
      duration: const Duration(seconds: 100), // 100秒的长周期
      vsync: this,
    )..repeat();
  }

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

  @override
  Widget build(BuildContext context) {
    return ClipOval(
      child: ShaderBuilder(
        assetKey: 'shaders/mic_flow.frag',
        (context, shader, child) {
          return AnimatedBuilder(
            animation: _ctl,
            builder: (_, __) {
              // 将0.0-1.0的动画值映射到更大的时间范围
              final time = _ctl.value * 100.0;
              shader
                ..setFloat(0, widget.size)      // u_resolution.x
                ..setFloat(1, widget.size)      // u_resolution.y
                ..setFloat(2, time)             // u_time
                ..setFloat(3, widget.amp);      // u_amp (音量振幅)
              return CustomPaint(
                size: Size.square(widget.size),
                painter: _ShaderPainter(shader),
              );
            },
          );
        },
        // 着色器编译时的占位符
        child: Container(
          width: widget.size,
          height: widget.size,
          decoration: const BoxDecoration(
            shape: BoxShape.circle,
            gradient: LinearGradient(
              begin: Alignment.topLeft,
              end: Alignment.bottomRight,
              colors: [
                Color(0xFF1565C0), // 深蓝
                Color(0xFFE3F2FD), // 浅蓝
              ],
            ),
          ),
        ),
      ),
    );
  }
}

class _ShaderPainter extends CustomPainter {
  _ShaderPainter(this.shader);
  final FragmentShader shader;

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()..shader = shader;
    canvas.drawRect(Offset.zero & size, paint);
  }

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