package utils

import (
	"bufio"
	"encoding/base64"
	"fmt"
	"image"
	"image/png"
	"io"
	"net/http"
	"os"
	"path"
)

// SaveToFile
// @Description: 将字节内容保存到本地文件
// @author: Roc
// @datetime 2024-09-05 18:12:55
// @param content []byte
// @param fileName string
// @return error
func SaveToFile(content []byte, fileName string) error {
	file, err := os.Create(fileName)
	if err != nil {
		return err
	}
	defer func() {
		_ = file.Close()
	}()

	_, err = file.Write(content)
	if err != nil {
		return err
	}

	return nil
}

// FileIsExist
// @Description: 判断文件是否存在
// @author: Roc
// @datetime 2024-09-05 18:12:49
// @param filePath string
// @return bool
func FileIsExist(filePath string) bool {
	_, err := os.Stat(filePath)
	return err == nil || os.IsExist(err)
}

// GetImgExt
// @Description: 获取图片扩展名
// @author: Roc
// @datetime 2024-09-05 18:12:44
// @param file string
// @return ext string
// @return err error
func GetImgExt(file string) (ext string, err error) {
	var headerByte []byte
	headerByte = make([]byte, 8)
	fd, err := os.Open(file)
	if err != nil {
		return "", err
	}
	defer fd.Close()
	_, err = fd.Read(headerByte)
	if err != nil {
		return "", err
	}
	xStr := fmt.Sprintf("%x", headerByte)
	switch {
	case xStr == "89504e470d0a1a0a":
		ext = ".png"
	case xStr == "0000010001002020":
		ext = ".ico"
	case xStr == "0000020001002020":
		ext = ".cur"
	case xStr[:12] == "474946383961" || xStr[:12] == "474946383761":
		ext = ".gif"
	case xStr[:10] == "0000020000" || xStr[:10] == "0000100000":
		ext = ".tga"
	case xStr[:8] == "464f524d":
		ext = ".iff"
	case xStr[:8] == "52494646":
		ext = ".ani"
	case xStr[:4] == "4d4d" || xStr[:4] == "4949":
		ext = ".tiff"
	case xStr[:4] == "424d":
		ext = ".bmp"
	case xStr[:4] == "ffd8":
		ext = ".jpg"
	case xStr[:2] == "0a":
		ext = ".pcx"
	default:
		ext = ""
	}
	return ext, nil
}

// SaveImage 保存图片

// SaveImage
// @Description: 保存图片
// @author: Roc
// @datetime 2024-09-05 18:09:02
// @param img image.Image
// @param path string
// @return err error
func SaveImage(img image.Image, path string) (err error) {
	//需要保持的文件
	imgFile, err := os.Create(path)
	defer func() {
		_ = imgFile.Close()
	}()
	// 以PNG格式保存文件
	err = png.Encode(imgFile, img)

	return err
}

// DownloadImage
// @Description: 下载图片
// @author: Roc
// @datetime 2024-09-05 18:10:37
// @param imgUrl string
// @return filePath string
// @return err error
func DownloadImage(imgUrl string) (filePath string, err error) {
	imgPath := "./static/imgs/"
	fileName := path.Base(imgUrl)
	res, err := http.Get(imgUrl)
	if err != nil {
		fmt.Println("A error occurred!")
		return
	}
	defer res.Body.Close()
	// 获得get请求响应的reader对象
	reader := bufio.NewReaderSize(res.Body, 32*1024)

	filePath = imgPath + fileName
	file, err := os.Create(filePath)
	if err != nil {
		return
	}
	// 获得文件的writer对象
	writer := bufio.NewWriter(file)

	_, err = io.Copy(writer, reader)
	//fmt.Printf("Total length: %d \n", written)

	return
}

// SaveBase64ToFile
// @Description: 保存base64数据为文件
// @author: Roc
// @datetime 2024-09-05 18:11:47
// @param content string
// @param path string
// @return error
func SaveBase64ToFile(content, path string) error {
	data, err := base64.StdEncoding.DecodeString(content)
	if err != nil {
		return err
	}

	f, err := os.Create(path)
	defer func() {
		_ = f.Close()
	}()
	if err != nil {
		return err
	}
	_, err = f.Write(data)

	return nil
}

// SaveBase64ToFileBySeek
func SaveBase64ToFileBySeek(content, path string) (err error) {
	data, err := base64.StdEncoding.DecodeString(content)
	exist, err := PathExists(path)
	if err != nil {
		return
	}
	if !exist {
		f, err := os.Create(path)
		if err != nil {
			return err
		}
		n, _ := f.Seek(0, 2)
		// 从末尾的偏移量开始写入内容
		_, err = f.WriteAt([]byte(data), n)
		defer f.Close()
	} else {
		f, err := os.OpenFile(path, os.O_WRONLY, 0644)
		if err != nil {
			return err
		}
		n, _ := f.Seek(0, 2)
		// 从末尾的偏移量开始写入内容
		_, err = f.WriteAt([]byte(data), n)
		defer f.Close()
	}

	return nil
}