package com.qmth.teachcloud.cas.mq.gdpu.bean;

import com.qmth.teachcloud.exchange.common.contant.SystemConstant;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.lang3.StringUtils;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;

@SuppressWarnings("restriction")
public class AESEncryptUtils {
    /**
     * 算法
     */
    private static final String ALGORITHMSTR = "AES/ECB/PKCS5Padding";

    /**
     * base 64 encode
     *
     * @param bytes 待编码的byte[]
     * @return 编码后的base 64 code
     */
    private static String base64Encode(byte[] bytes) {
        return Base64.encodeBase64String(bytes);
    }

    /**
     * base 64 decode
     *
     * @param base64Code 待解码的base 64 code
     * @return 解码后的byte[]
     * @throws Exception 抛出异常
     */
    private static byte[] base64Decode(String base64Code) throws Exception {
        return StringUtils.isEmpty(base64Code) ? null :
                Base64.decodeBase64(base64Code);
    }

    /**
     * AES加密
     *
     * @param content    待加密的内容
     * @param encryptKey 加密密钥
     * @return 加密后的byte[]
     */
    private static byte[] aesEncryptToBytes(String content, String encryptKey)
            throws Exception {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        kgen.init(128);
        Cipher cipher = Cipher.getInstance(ALGORITHMSTR);
        cipher.init(Cipher.ENCRYPT_MODE, new
                SecretKeySpec(encryptKey.getBytes(), "AES"));
        return cipher.doFinal(content.getBytes(SystemConstant.CHARSET_NAME));
    }

    /**
     * AES加密为base 64 code
     *
     * @param content    待加密的内容
     * @param encryptKey 加密密钥
     * @return 加密后的base 64 code
     */
    public static String aesEncrypt(String content, String encryptKey) throws
            Exception {
        return base64Encode(aesEncryptToBytes(content, encryptKey));
    }

    /**
     * AES解密
     *
     * @param encryptBytes 待解密的byte[]
     * @param decryptKey   解密密钥
     * @return 解密后的String
     */
    private static String aesDecryptByBytes(byte[] encryptBytes, String
            decryptKey) throws Exception {
        KeyGenerator kgen = KeyGenerator.getInstance("AES");
        kgen.init(128);
        Cipher cipher = Cipher.getInstance(ALGORITHMSTR);
        cipher.init(Cipher.DECRYPT_MODE, new
                SecretKeySpec(decryptKey.getBytes(), "AES"));
        byte[] decryptBytes = cipher.doFinal(encryptBytes);
        return new String(decryptBytes);
    }

    /**
     * 将base 64 code AES解密
     *
     * @param encryptStr 待解密的base 64 code
     * @param decryptKey 解密密钥
     * @return 解密后的string
     */
    public static String aesDecrypt(String encryptStr, String decryptKey) throws
            Exception {
        return StringUtils.isEmpty(encryptStr) ? null :
                aesDecryptByBytes(base64Decode(encryptStr), decryptKey.substring(0, 16));
    }
}