import 'dart:ui' as ui;
import 'package:flutter/material.dart';
import 'package:aesthetica_wallpaper/models/recipe.dart';

// 壁纸预览绘制器
class WallpaperPreviewPainter extends CustomPainter {
  final ui.Image image;
  final Recipe recipe;

  WallpaperPreviewPainter({required this.image, required this.recipe});

  // 构建颜色矩阵
  ColorFilter _buildColorMatrix() {
    final double brightness = recipe.brightness;
    final double contrast = recipe.contrast;
    final double saturation = recipe.saturation;

    List<double> matrix = [
      1,
      0,
      0,
      0,
      0,
      0,
      1,
      0,
      0,
      0,
      0,
      0,
      1,
      0,
      0,
      0,
      0,
      0,
      1,
      0,
    ];

    // 应用饱和度
    if (saturation != 1.0) {
      final sat = saturation;
      const lumR = 0.3086;
      const lumG = 0.6094;
      const lumB = 0.0820;
      matrix = [
        lumR * (1 - sat) + sat,
        lumG * (1 - sat),
        lumB * (1 - sat),
        0,
        0,
        lumR * (1 - sat),
        lumG * (1 - sat) + sat,
        lumB * (1 - sat),
        0,
        0,
        lumR * (1 - sat),
        lumG * (1 - sat),
        lumB * (1 - sat) + sat,
        0,
        0,
        0,
        0,
        0,
        1,
        0,
      ];
    }

    // 应用对比度
    if (contrast != 1.0) {
      final translate = (1.0 - contrast) * 128;
      matrix[0] *= contrast;
      matrix[5] *= contrast;
      matrix[10] *= contrast;
      matrix[4] += translate;
      matrix[9] += translate;
      matrix[14] += translate;
    }

    // 应用亮度
    if (brightness != 0.0) {
      final b = brightness * 255;
      matrix[4] += b;
      matrix[9] += b;
      matrix[14] += b;
    }

    return ColorFilter.matrix(matrix);
  }

  @override
  void paint(Canvas canvas, Size size) {
    // 裁剪画布
    canvas.clipRect(Offset.zero & size);

    // 准备画笔
    final Paint paint = Paint()..filterQuality = FilterQuality.low;

    // 定义源矩形和目标矩形
    final Rect srcRect = Rect.fromLTWH(
      0,
      0,
      image.width.toDouble(),
      image.height.toDouble(),
    );
    final Rect dstRect = Rect.fromLTWH(0, 0, size.width, size.height);

    // 应用颜色矩阵
    paint.colorFilter = _buildColorMatrix();

    // 应用模糊
    if (recipe.blur > 0.0) {
      paint.imageFilter = ui.ImageFilter.blur(
        sigmaX: recipe.blur,
        sigmaY: recipe.blur,
      );
    }

    // 绘制图片
    canvas.drawImageRect(image, srcRect, dstRect, paint);

    // 绘制文字叠加
    if (recipe.overlayText.isNotEmpty) {
      final textPainter = TextPainter(
        text: TextSpan(
          text: recipe.overlayText,
          style: TextStyle(
            fontSize: 32,
            color: Color(recipe.textColor),
            fontWeight: FontWeight.bold,
          ),
        ),
        textDirection: ui.TextDirection.ltr,
        textAlign: TextAlign.center,
      );

      textPainter.layout(maxWidth: size.width - 40);
      final offset = Offset(
        (size.width - textPainter.width) / 2,
        (size.height - textPainter.height) / 2,
      );
      textPainter.paint(canvas, offset);
    }
  }

  @override
  bool shouldRepaint(covariant WallpaperPreviewPainter oldDelegate) {
    return oldDelegate.image != image ||
        oldDelegate.recipe.brightness != recipe.brightness ||
        oldDelegate.recipe.contrast != recipe.contrast ||
        oldDelegate.recipe.saturation != recipe.saturation ||
        oldDelegate.recipe.blur != recipe.blur ||
        oldDelegate.recipe.overlayText != recipe.overlayText ||
        oldDelegate.recipe.textColor != recipe.textColor;
  }
}