package pkg

import (
	"errors"
	"io"
	"mime/multipart"
	"os"
	"packet-ui/pkg/md5"
	"path/filepath"
)

func FileSave(r io.Reader, dst string) (err error) {
	var (
		fp  string
		out io.WriteCloser
	)
	fp, _ = filepath.Split(dst)
	err = DirCheck(fp)

	out, err = os.Create(dst)
	if err != nil {
		return err
	}
	defer out.Close()

	_, err = io.Copy(out, r)
	return
}

// FileMD5 计算文件 md5 值
func FileMD5(file string) (string, error) {
	f, err := os.Open(file)

	if err != nil {
		return "", err
	}

	info, err := f.Stat()
	if err != nil {
		return "", err
	}

	size := info.Size()
	return md5.Sum(f, size, BlockSize, ChunkSize)
}

func MultipartMD5(fh *multipart.FileHeader) (string, error) {
	f, err := fh.Open()

	if err != nil {
		return "", err
	}

	size := fh.Size
	return md5.Sum(f, size, BlockSize, ChunkSize)
}

const (
	BlockSize = 1 << 10
	ChunkSize = BlockSize << 2
)

var (
	ErrorIsNotDir = errors.New("path is not dir. ")
)

func DirCheck(dir string) (err error) {
	var fi os.FileInfo
	if fi, err = os.Stat(dir); err != nil {
		if !os.IsExist(err) || os.IsNotExist(err) {
			return DirMk(dir)
		}
	}

	if !fi.IsDir() {
		err = ErrorIsNotDir
	}

	return
}

func DirMk(dir string) error {
	return os.MkdirAll(dir, 0755)
}