package utils

import (
	"bytes"
	"crypto/aes"
	"crypto/cipher"

	"git.rosy.net.cn/baseapi"
)

func AESCBCEncpryt(data, aesKey, iv []byte) (encryptedData []byte, err error) {
	c, err := aes.NewCipher(aesKey)
	if err != nil {
		return nil, err
	}
	cfbdec := cipher.NewCBCEncrypter(c, iv[:c.BlockSize()])
	data = PKCSPadding(data, c.BlockSize())
	encryptedData = make([]byte, len(data))
	cfbdec.CryptBlocks(encryptedData, data)
	return encryptedData, nil
}

func AESCBCDecpryt(encryptedData, aesKey, iv []byte) (decryptedData []byte, err error) {
	c, err := aes.NewCipher(aesKey)
	if err != nil {
		return nil, err
	}
	cfbdec := cipher.NewCBCDecrypter(c, iv[:c.BlockSize()])
	decryptedData = make([]byte, len(encryptedData))
	cfbdec.CryptBlocks(decryptedData, encryptedData)
	decryptedData = PKCSUnPadding(decryptedData)
	return decryptedData, nil
}

func PKCSUnPadding(originData []byte) []byte {
	length := len(originData)
	unpadding := int(originData[length-1])
	baseapi.SugarLogger.Debugf("PKCSUnPadding originData:%s, length:%d, unpadding:%d", string(originData), length, unpadding)
	return originData[:(length - unpadding)]
}

func PKCSPadding(ciphertext []byte, blockSize int) []byte {
	padding := blockSize - len(ciphertext)%blockSize
	padtext := bytes.Repeat([]byte{byte(padding)}, padding)
	return append(ciphertext, padtext...)
}