package service

import (
	"bytes"
	"fmt"
	"github.com/disintegration/imaging"
	"github.com/fogleman/gg"
	"github.com/gogf/gf/v2/util/gconv"
	"github.com/nfnt/resize"
	"github.com/skip2/go-qrcode"
	"image"
	"image/color"
	"image/draw"
	"image/jpeg"
	"image/png"
	"math"
	"net/http"
)

func CompositeImage(backgroundURL, qrContent string) (err error, imgByte []byte) {
	// 配置参数
	//backgroundURL := "https://images.unsplash.com/photo-1501854140801-50d01698950b" // 示例背景图片
	//qrContent := "https://github.com/zeromicro/go-zero"                           // 二维码内容
	//outputPath := "output.jpg" // 输出文件路径
	//margin := 20         // 二维码距边缘的边距
	rightMargin := 60
	bottomMargin := 100
	qrSize := 140       // 二维码原始大小（像素）
	cornerRadius := 5.0 // 二维码圆角半径
	borderCornerRadius := 10.0
	borderSize := 10     // 二维码白色边框大小
	shadowBlur := 0.0    // 阴影模糊度
	shadowOpacity := 0.0 // 阴影透明度

	// 创建带效果的二维码并合成到背景右下角
	imgByte, err = createQRComposite(backgroundURL, qrContent, rightMargin, bottomMargin, qrSize, cornerRadius, borderCornerRadius, gconv.Float64(borderSize), shadowBlur, shadowOpacity)
	if err != nil {
		return err, nil
	}
	return nil, imgByte
}

// 创建二维码合成图片
func createQRComposite(backgroundURL, qrContent string, rightMargin, bottomMargin, qrSize int, cornerRadius, borderCornerRadius, borderSize, shadowBlur, shadowOpacity float64) ([]byte, error) {
	// 1. 下载背景图片
	bgImg, imgType, err := downloadImage(backgroundURL)
	if err != nil {
		return nil, err
	}

	// 2. 生成带效果的二维码
	qrImg, err := generateStyledQRCode(qrContent, qrSize, color.Black, color.White, cornerRadius, borderCornerRadius, borderSize, shadowBlur, shadowOpacity)
	if err != nil {
		return nil, err
	}

	// 3. 计算二维码在右下角的位置
	bgBounds := bgImg.Bounds()
	qrBounds := qrImg.Bounds()
	pos := image.Point{
		X: bgBounds.Dx() - qrBounds.Dx() - rightMargin,
		Y: bgBounds.Dy() - qrBounds.Dy() - bottomMargin,
	}

	// 4. 调整二维码大小（如果需要）
	finalQR := qrImg
	if bgBounds.Dx() < 800 {
		// 背景图较小，缩小二维码
		targetWidth := bgBounds.Dx() / 4
		finalQR = resize.Resize(uint(targetWidth), 0, qrImg, resize.Lanczos3)
		// 重新计算位置
		pos = image.Point{
			X: bgBounds.Dx() - finalQR.Bounds().Dx() - rightMargin,
			Y: bgBounds.Dy() - finalQR.Bounds().Dy() - bottomMargin,
		}
	}

	// 5. 合成图片
	resultImg := image.NewRGBA(bgBounds)
	draw.Draw(resultImg, bgBounds, bgImg, image.Point{}, draw.Src)
	draw.Draw(resultImg, finalQR.Bounds().Add(pos), finalQR, image.Point{}, draw.Over)

	// 6. 保存结果
	//return saveImage(outputPath, resultImg, 95)
	imgByte, err := encodeImageToBytes(resultImg, imgType, 90)
	if err != nil {
		return nil, err
	}
	return imgByte, nil
}

// 下载图片
func downloadImage(url string) (image.Image, string, error) {
	resp, err := http.Get(url)
	if err != nil {
		return nil, "", err
	}
	defer resp.Body.Close()

	img, imgType, err := image.Decode(resp.Body)
	if err != nil {
		return nil, "", err
	}

	return img, imgType, nil
}

func generateStyledQRCode(content string, size int, fgColor, bgColor color.Color, cornerRadius, borderCornerRadius, borderSize, shadowBlur, shadowOpacity float64) (image.Image, error) {
	// 生成基本二维码
	qr, err := qrcode.New(content, qrcode.Highest)
	if err != nil {
		return nil, err
	}
	qr.ForegroundColor = fgColor
	qr.BackgroundColor = bgColor
	qr.DisableBorder = true

	// 创建基本二维码图片
	baseImg := qr.Image(size)

	// 计算带边框的总大小
	borderWidth := int(math.Ceil(borderSize))
	totalSize := size + 2*borderWidth

	// 创建带透明背景的总画布
	dc := gg.NewContext(totalSize, totalSize)
	dc.SetColor(color.Transparent)
	dc.Clear()

	// 1. 绘制圆角白色边框
	dc.SetColor(color.White)
	dc.DrawRoundedRectangle(0, 0, float64(totalSize), float64(totalSize), borderCornerRadius+borderSize)
	dc.Fill()

	// 2. 创建二维码的圆角蒙版
	qrDC := gg.NewContext(size, size)
	qrDC.SetColor(color.Transparent)
	qrDC.Clear()

	if cornerRadius > 0 {
		qrDC.DrawRoundedRectangle(0, 0, float64(size), float64(size), cornerRadius)
		qrDC.Clip()
	}

	// 3. 绘制二维码到蒙版
	qrDC.DrawImage(baseImg, 0, 0)

	// 4. 将带蒙版的二维码绘制到总画布（居中）
	dc.DrawImage(qrDC.Image(), borderWidth, borderWidth)

	// 添加阴影效果
	if shadowBlur > 0 && shadowOpacity > 0 {
		shadowImg := addShadow(dc.Image(), shadowBlur, shadowOpacity)
		return shadowImg, nil
	}

	return dc.Image(), nil
}

// 添加阴影效果
func addShadow(img image.Image, blur, opacity float64) image.Image {
	bounds := img.Bounds()
	dc := gg.NewContext(bounds.Dx()+int(blur*2), bounds.Dy()+int(blur*2))

	// 绘制阴影
	dc.SetRGBA(0, 0, 0, opacity)
	dc.DrawRectangle(blur, blur, float64(bounds.Dx()), float64(bounds.Dy()))
	dc.Fill()

	// 应用高斯模糊
	shadow := dc.Image()
	blurred := imaging.Blur(shadow, blur)

	// 创建新画布绘制二维码和阴影
	dc = gg.NewContext(bounds.Dx()+int(blur*2), bounds.Dy()+int(blur*2))
	dc.DrawImage(blurred, 0, 0)
	dc.DrawImage(img, int(blur), int(blur))

	return dc.Image()
}

// 编码图片为字节流
func encodeImageToBytes(img image.Image, format string, quality int) ([]byte, error) {
	buf := new(bytes.Buffer)

	switch format {
	case "png":
		if err := png.Encode(buf, img); err != nil {
			return nil, err
		}
	case "jpg", "jpeg":
		if err := jpeg.Encode(buf, img, &jpeg.Options{Quality: quality}); err != nil {
			return nil, err
		}
	default:
		return nil, fmt.Errorf("不支持的图片格式: %s", format)
	}

	return buf.Bytes(), nil
}