package com.hx.util.mysql.aes;

import com.hx.util.StringUtils;
import org.apache.commons.codec.binary.Hex;

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.util.regex.Pattern;

/**
 * mybatis数据库的AES_ENCRYPT（加密）和AES_DECRYPT（解密）
 * mybatis数据库的HEX（加壳）UNHEX（解壳）
 * @author CJH
 * @Date 2021-01-06
 */
public class MysqlHexAesTool {


    public static SecretKeySpec generateMySQLAESKey(final String key, final String encoding) {
        try {
            final byte[] finalKey = new byte[16];
            int i = 0;
            for(byte b : key.getBytes(encoding)) {
                finalKey[i++%16] ^= b;
            }
            return new SecretKeySpec(finalKey, "AES");
        } catch(UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
    }

    /**AES 解密
     * @param data 需要解密的数据
     * @param aesKey 秘钥
     * @param encoding 编码，不填默认UTF-8
     * @return 解密数据
     */
    public static String decryptData(String data,String aesKey,String encoding) {
        try{
            if(data == null){
                return null;
            }
            if(StringUtils.isEmpty(encoding)){
                encoding = "UTF-8";
            }
            // Decrypt
            final Cipher decryptCipher = Cipher.getInstance("AES");
            decryptCipher.init(Cipher.DECRYPT_MODE, generateMySQLAESKey(aesKey, encoding));
            data = new String(decryptCipher.doFinal(Hex.decodeHex(data.toCharArray())));
        }catch (Exception e){
            throw new RuntimeException(e);
        }
        return data;
    }

    /**AES加密
     * @param data 需要解密的数据
     * @param aesKey 秘钥
     * @param encoding 编码，不填默认UTF-8
     * @return 返回大写加密的数据
     */
    public static String encryptData(String data,String aesKey,String encoding) {
        try {
            if(data == null){
                return null;
            }
            if (StringUtils.isEmpty(encoding)) {
                encoding = "UTF-8";
            }
            // Encrypt
            final Cipher encryptCipher = Cipher.getInstance("AES");
            encryptCipher.init(Cipher.ENCRYPT_MODE, generateMySQLAESKey(aesKey, encoding));
            char[] code = Hex.encodeHex(encryptCipher.doFinal(data.getBytes(encoding)));
            StringBuilder builder = new StringBuilder();
            for (char d : code) {
                builder.append(d);
            }
            data = builder.toString().toUpperCase();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return data;
    }

    /**
     * 判断是不是十六进制的字符串（字母是大写的）
     * @param str 需要判断的字符串
     * @return true or false
     */
    public static boolean isHexStrValid(String str) {
        if(str == null){
            return false;
        }
        String pattern = "^[0-9A-F]+$";
        return Pattern.compile(pattern).matcher(str).matches();
    }



}