package cryptokit

import (
	"bytes"
	"crypto/aes"
	"crypto/cipher"
	"encoding/base64"
	"github.com/mizuki1412/go-core-kit/class/exception"
)

// Encrypt 实现 AES-CBC 加密（返回 Base64 编码结果）
func Encrypt(plainText string) string {
	key := "1234567890123456"
	iv := "1234567890123456"
	block, err := aes.NewCipher([]byte(key))
	if err != nil {
		panic(exception.New(err.Error()))
	}
	// PKCS7 填充
	paddedText := pkcs7Padding([]byte(plainText), block.BlockSize())
	// CBC 模式加密
	blockMode := cipher.NewCBCEncrypter(block, []byte(iv))
	ciphertext := make([]byte, len(paddedText))
	blockMode.CryptBlocks(ciphertext, paddedText)
	// Base64 编码
	return base64.StdEncoding.EncodeToString(ciphertext)
}

func pkcs7Padding(ciphertext []byte, blockSize int) []byte {
	padding := blockSize - len(ciphertext)%blockSize
	padtext := bytes.Repeat([]byte{byte(padding)}, padding)
	return append(ciphertext, padtext...)
}