package com.founder.mrp.util;

import java.nio.charset.StandardCharsets;

import java.security.Key;

import javax.crypto.Cipher;

import javax.crypto.spec.SecretKeySpec;

import com.founder.mrp.web.jsonEntity.AccountJson;

/**

 * 加密解密类

 * @author xiongzq

 *

 */

public class EncryptionDecryption {

    private static String strDefaultKey = "UvVi-s`75X-d9fO3";

    /** 加密工具 */

    private ThreadLocal<Cipher> encryptCipher = new ThreadLocal<Cipher>() {

        @Override

        protected Cipher initialValue() {

            try {

                Cipher encryptCipher = Cipher.getInstance(algorithmName);

                encryptCipher.init(Cipher.ENCRYPT_MODE, key);

                return encryptCipher;

            } catch (Exception e) {

                e.printStackTrace();

                return null;

            }

        }

    };

    /** 解密工具 */

    private ThreadLocal<Cipher> decryptCipher = new ThreadLocal<Cipher>() {

        @Override

        protected Cipher initialValue() {

            try {

                Cipher decryptCipher = Cipher.getInstance(algorithmName);

                decryptCipher.init(Cipher.DECRYPT_MODE, key);

                return decryptCipher;

            } catch (Exception e) {

                e.printStackTrace();

                return null;

            }

        }

    };

    private String algorithmName;

    private Key key;

    /**

     * 将byte数组转换为表示16进制值的字符串， 如：byte[]{8,18}转换为：0813， 和public static byte[]

     * hexStr2ByteArr(String strIn) 互为可逆的转换过程

     *

     * @param arrB

     *            需要转换的byte数组

     * @return 转换后的字符串

     * @throws Exception

     *

     */

    public static String byteArr2HexStr(byte[] arrB) throws Exception {

        // 每个byte用两个字符才能表示，所以字符串的长度是数组长度的两倍

        StringBuilder sb = new StringBuilder(arrB.length * 2);

        for (int b : arrB) {

            int intTmp = b;

            // 把负数转换为正数

            while (intTmp < 0) {

                intTmp = intTmp + 256;

            }

            // 小于0F的数需要在前面补0

            if (intTmp < 16) {

                sb.append("0");

            }

            sb.append(Integer.toString(intTmp, 16));

        }

        return sb.toString();

    }

    /**

     * 将表示16进制值的字符串转换为byte数组， 和public static String byteArr2HexStr(byte[] arrB)

     * 互为可逆的转换过程

     *

     * @param strIn 需要转换的字符串

     * @return 转换后的byte数组

     *

     */

    public static byte[] hexStr2ByteArr(String strIn) {

        byte[] arrB = strIn.getBytes();

        int iLen = arrB.length;

        // 两个字符表示一个字节，所以字节数组长度是字符串长度除以2

        byte[] arrOut = new byte[iLen / 2];

        for (int i = 0; i < iLen; i = i + 2) {

            String strTmp = new String(arrB, i, 2);

            arrOut[i / 2] = (byte) Integer.parseInt(strTmp, 16);

        }

        return arrOut;

    }

    /**

     * 默认构造方法，使用默认密钥

     *

     * @throws Exception

     */

    public EncryptionDecryption() throws Exception {

        this("AES/ECB/PKCS5Padding", strDefaultKey, 128);

    }

    /**

     * 指定密钥构造方法

     *

     * @param strKey  指定的密钥

     * @throws Exception

     */

    public EncryptionDecryption(String algorithmName, String strKey, int keySizeInBits) throws Exception {

        this.algorithmName = algorithmName;

        this.key = getKey(strKey.getBytes(StandardCharsets.UTF_8), keySizeInBits);

    }

    /**

     * 加密字节数组

     *

     * @param arrB

     *            需加密的字节数组

     * @return 加密后的字节数组

     * @throws Exception

     */

    public byte[] encrypt(byte[] arrB) throws Exception {

        return encryptCipher.get().doFinal(arrB);

    }

    /**

     * 加密字符串

     *

     * @param strIn

     *            需加密的字符串

     * @return 加密后的字符串

     * @throws Exception

     */

    public String encrypt(String strIn) throws Exception {

        return byteArr2HexStr(encrypt(strIn.getBytes()));

    }

    /**

     * 解密字节数组

     *

     * @param arrB

     *            需解密的字节数组

     * @return 解密后的字节数组

     * @throws Exception

     */

    public byte[] decrypt(byte[] arrB) throws Exception {

        return decryptCipher.get().doFinal(arrB);

    }

    /**

     * 解密字符串

     *

     * @param strIn

     *            需解密的字符串

     * @return 解密后的字符串

     * @throws Exception

     */

    public String decrypt(String strIn) throws Exception {

        try {

            return new String(decrypt(hexStr2ByteArr(strIn)));

        } catch (Exception e) {

            return "";

        }

    }

    /**

     * 从指定字符串生成密钥，密钥所需的字节数组长度为8位 不足8位时后面补0，超出8位只取前8位

     *

     * @param arrBTmp

     *            构成该字符串的字节数组

     * @param keySizeInBits

     * @return 生成的密钥

     * @throws java.lang.Exception

     */

    private Key getKey(byte[] arrBTmp, int keySizeInBits) throws Exception {

        // 创建一个空的字节数组（默认值为0）

        byte[] arrB = new byte[keySizeInBits / 8];

        // 将原始字节数组转换为8位

        for (int i = 0; i < arrBTmp.length && i < arrB.length; i++) {

            arrB[i] = arrBTmp[i];

        }

        // 生成密钥

        String keyAlg = algorithmName;

        int t = algorithmName.indexOf('/');

        if (t != -1) {

            keyAlg = algorithmName.substring(0, t);

        }

        return new SecretKeySpec(arrB, keyAlg);

    }

}