MoodCanvas/lib/widgets/animated_background.dart

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

class AnimatedBackground extends StatefulWidget {
  final Widget child;
  final Color primaryColor;
  final Color secondaryColor;

  const AnimatedBackground({
    super.key,
    required this.child,
    this.primaryColor = Colors.pinkAccent,
    this.secondaryColor = Colors.purpleAccent,
  });

  @override
  State<AnimatedBackground> createState() => _AnimatedBackgroundState();
}

class _AnimatedBackgroundState extends State<AnimatedBackground>
    with TickerProviderStateMixin {
  late AnimationController _controller;
  late List<Particle> particles;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      duration: const Duration(seconds: 10),
      vsync: this,
    )..repeat();

    particles = List.generate(20, (index) => Particle());
  }

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

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        // 渐变背景
        Container(
          decoration: BoxDecoration(
            gradient: LinearGradient(
              begin: Alignment.topLeft,
              end: Alignment.bottomRight,
              colors: [Colors.black, Colors.grey[900]!, Colors.black],
            ),
          ),
        ),
        // 粒子效果
        AnimatedBuilder(
          animation: _controller,
          builder: (context, child) {
            return CustomPaint(
              painter: ParticlePainter(
                particles: particles,
                animationValue: _controller.value,
                primaryColor: widget.primaryColor,
                secondaryColor: widget.secondaryColor,
              ),
              size: Size.infinite,
            );
          },
        ),
        // 主要内容
        widget.child,
      ],
    );
  }
}

class Particle {
  late double x;
  late double y;
  late double size;
  late double speed;
  late double opacity;
  late Color color;

  Particle() {
    reset();
  }

  void reset() {
    x = Random().nextDouble();
    y = Random().nextDouble();
    size = Random().nextDouble() * 3 + 1;
    speed = Random().nextDouble() * 0.02 + 0.01;
    opacity = Random().nextDouble() * 0.5 + 0.1;
  }

  void update() {
    y -= speed;
    if (y < 0) {
      y = 1;
      x = Random().nextDouble();
    }
  }
}

class ParticlePainter extends CustomPainter {
  final List<Particle> particles;
  final double animationValue;
  final Color primaryColor;
  final Color secondaryColor;

  ParticlePainter({
    required this.particles,
    required this.animationValue,
    required this.primaryColor,
    required this.secondaryColor,
  });

  @override
  void paint(Canvas canvas, Size size) {
    for (var particle in particles) {
      particle.update();

      final paint = Paint()
        ..color = (Random().nextBool() ? primaryColor : secondaryColor)
            .withValues(alpha: particle.opacity)
        ..style = PaintingStyle.fill;

      final center = Offset(particle.x * size.width, particle.y * size.height);

      // 绘制粒子
      canvas.drawCircle(center, particle.size, paint);

      // 添加发光效果
      final glowPaint = Paint()
        ..color = paint.color.withValues(alpha: particle.opacity * 0.3)
        ..maskFilter = const MaskFilter.blur(BlurStyle.normal, 3);

      canvas.drawCircle(center, particle.size * 2, glowPaint);
    }
  }

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

// 底部导航栏的发光效果组件
class GlowingBottomNavBar extends StatefulWidget {
  final Widget child;

  const GlowingBottomNavBar({super.key, required this.child});

  @override
  State<GlowingBottomNavBar> createState() => _GlowingBottomNavBarState();
}

class _GlowingBottomNavBarState extends State<GlowingBottomNavBar>
    with SingleTickerProviderStateMixin {
  late AnimationController _glowController;
  late Animation<double> _glowAnimation;

  @override
  void initState() {
    super.initState();
    _glowController = AnimationController(
      duration: const Duration(seconds: 2),
      vsync: this,
    )..repeat(reverse: true);

    _glowAnimation = Tween<double>(begin: 0.3, end: 0.8).animate(
      CurvedAnimation(parent: _glowController, curve: Curves.easeInOut),
    );
  }

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

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      animation: _glowAnimation,
      builder: (context, child) {
        return Container(
          decoration: BoxDecoration(
            boxShadow: [
              BoxShadow(
                color: Colors.pinkAccent.withValues(
                  alpha: _glowAnimation.value * 0.3,
                ),
                blurRadius: 20,
                spreadRadius: 2,
                offset: const Offset(0, -5),
              ),
              BoxShadow(
                color: Colors.purpleAccent.withValues(
                  alpha: _glowAnimation.value * 0.2,
                ),
                blurRadius: 30,
                spreadRadius: 1,
                offset: const Offset(0, -8),
              ),
            ],
          ),
          child: widget.child,
        );
      },
    );
  }
}