package utils

import (
	"crypto/cipher"
	"crypto/des"
	"fmt"
)

type DES struct {
	block   cipher.Block
	key, iv []byte
}

// 定义Key与向量的值
var DES_KEY = []byte{102, 16, 93, 156, 78, 4, 218, 32}
var DES_IV = []byte{55, 103, 246, 79, 36, 99, 167, 3}

func DESEncrypt(src []byte) []byte {
	des, err := newDESInstance(DES_KEY, DES_IV)
	if err != nil {
		fmt.Println("DES Encrypt Error: ", err)
		return nil
	}
	return encrypt(des.block, src, des.key, des.iv)
}

func DESEncryptString(src string, base64Encoding bool) string {
	tmp := DESEncrypt([]byte(src))
	return bytes2String(tmp, base64Encoding)
}

func DESDecrypt(encrypted []byte) []byte {
	des, err := newDESInstance(DES_KEY, DES_IV)
	if err != nil {
		fmt.Println("DES Encrypt Error: ", err)
		return nil
	}
	return decrypt(des.block, encrypted, des.key, des.iv)
}

func DESDecryptString(encrypted string, base64Encoding bool) (string, error) {
	tmp, err := string2Bytes(encrypted, base64Encoding)
	if err != nil {
		return "", err
	}
	return string(DESDecrypt(tmp)), err
}

func newDESInstance(key, iv []byte) (*DES, error) {
	key = genBytes(key, KEY_LENGTH)
	block, err := des.NewCipher(key)
	if err != nil {
		return nil, err
	}
	return &DES{block: block, key: key, iv: iv}, err
}