package com.chuanghai.smartschool.tuitionpayment.utils;

import com.chuanghai.smartschool.tuitionpayment.config.WeixiaoConfig;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

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

/**
 * @Author: codingliang
 * @Description: 微校接口数据加解密
 * @Date: 2021-06-21 10:26
 * @Version: V1.0
 **/
@Component
public class MyAES {

    @Autowired
    private WeixiaoConfig weixiaoConfig;

    /**
     * 加密
     *
     * @param sSrc 需要加密的字串
     * @return
     * @throws Exception
     */
    public String encrypt(String sSrc) throws Exception {
        String sKey = weixiaoConfig.getAppKey();
        String sIv = weixiaoConfig.getAppSecret();

        sIv = sIv.substring(0, 16); // app_secret 取前16位

        Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
        int blockSize = cipher.getBlockSize();

        byte[] dataBytes = sSrc.getBytes();
        int plaintextLength = dataBytes.length;
        if (plaintextLength % blockSize != 0) {
            plaintextLength = plaintextLength + (blockSize - (plaintextLength % blockSize));
        }

        byte[] plaintext = new byte[plaintextLength];
        System.arraycopy(dataBytes, 0, plaintext, 0, dataBytes.length);

        SecretKeySpec keyspec = new SecretKeySpec(sKey.getBytes(), "AES");
        IvParameterSpec ivspec = new IvParameterSpec(sIv.getBytes());

        cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);
        byte[] encrypted = cipher.doFinal(plaintext);

        return byte2hex(encrypted).toLowerCase();
    }

    /**
     * 解密
     *
     * @param sSrc 需要解密的字串
     * @return
     * @throws Exception
     */
    public String decrypt(String sSrc) throws Exception {
        String sKey = weixiaoConfig.getAppKey();
        String sIv = weixiaoConfig.getAppSecret();
        sIv = sIv.substring(0, 16); // app_secret 取前16位

        byte[] encrypted1 = hex2byte(sSrc);

        Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
        SecretKeySpec keyspec = new SecretKeySpec(sKey.getBytes(), "AES");
        IvParameterSpec ivspec = new IvParameterSpec(sIv.getBytes());

        cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);

        byte[] original = cipher.doFinal(encrypted1);
        String originalString = new String(original);

        return originalString;
    }


    private byte[] hex2byte(String strhex) {
        if (strhex == null) {
            return null;
        }
        int l = strhex.length();
        if (l % 2 == 1) {
            return null;
        }
        byte[] b = new byte[l / 2];
        for (int i = 0; i != l / 2; i++) {
            b[i] = (byte) Integer.parseInt(strhex.substring(i * 2, i * 2 + 2),
                    16);
        }

        return b;
    }

    private String byte2hex(byte[] b) {
        String hs = "";
        String stmp = "";
        for (int n = 0; n < b.length; n++) {
            stmp = (Integer.toHexString(b[n] & 0XFF));
            if (stmp.length() == 1) {
                hs = hs + "0" + stmp;
            } else {
                hs = hs + stmp;
            }
        }
        return hs.toUpperCase();
    }
}