package storage

import (
	"io"
	"net/http"
	"os"
	"strconv"
	"strings"
)

func contentType2Ext(contentType string) string {
	if strings.Contains(contentType, "image/jpeg") {
		return "jpg"
	} else if strings.Contains(contentType, "audio/mpeg") {
		return "mp3"
	} else if strings.Contains(contentType, "video/mp4") {
		return "mp4"
	}
	return ""
}

func ext2ContentType(ext string) string {
	ext = strings.ToLower(ext)
	if ext == "jpg" || ext == "jpeg" {
		return "image/jpeg"
	} else if ext == "png" {
		return "image/png"
	} else if ext == "mp3" {
		return "audio/mpeg"
	} else if ext == "mp4" {
		return "video/mp4"
	}
	return ""
}

func Download(url, path string) error {
	f, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
	stat, err := f.Stat()
	if err != nil {
		return err
	}
	defer f.Close()

	req, _ := http.NewRequest("GET", url, nil)
	req.Header.Set("Range", "bytes="+strconv.FormatInt(stat.Size(), 10)+"-")
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	_, err = io.Copy(f, resp.Body)
	if err != nil {
		return err
	}

	return nil
}