package com.panzhihua.common.model.helper;

import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.spec.KeySpec;
import java.util.Arrays;
import java.util.Base64;

import javax.crypto.*;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * AES 工具类
 */
public class AESUtil {

    private static SecretKeySpec secretKey;
    private static byte[] key;

    /**
     * AES 256 加密
     *
     * @param strToEncrypt
     *            要加密的字符串
     * @param secKey
     *            秘钥
     * @param salt
     *            盐
     * @return 加密后的字符串
     */
    public static String encrypt256(String strToEncrypt, String secKey, String salt) {
        try {
            byte[] iv = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
            IvParameterSpec ivspec = new IvParameterSpec(iv);

            SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
            KeySpec spec = new PBEKeySpec(secKey.toCharArray(), salt.getBytes(), 65536, 256);
            SecretKey tmp = factory.generateSecret(spec);
            SecretKeySpec secretKey = new SecretKeySpec(tmp.getEncoded(), "AES");

            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivspec);
            return Base64.getEncoder().encodeToString(cipher.doFinal(strToEncrypt.getBytes(StandardCharsets.UTF_8)));
        } catch (Exception e) {
            System.out.println("Error while encrypting: " + e.toString());
        }
        return null;
    }

    /**
     * AES 256 解密
     *
     * @param strToDecrypt
     *            要解密的字符串
     * @param secKey
     *            秘钥
     * @param salt
     *            盐
     * @return 解密后的字符串
     */
    public static String decrypt256(String strToDecrypt, String secKey, String salt) {
        try {
            byte[] iv = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
            IvParameterSpec ivspec = new IvParameterSpec(iv);

            SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
            KeySpec spec = new PBEKeySpec(secKey.toCharArray(), salt.getBytes(), 65536, 256);
            SecretKey tmp = factory.generateSecret(spec);
            SecretKeySpec secretKey = new SecretKeySpec(tmp.getEncoded(), "AES");

            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
            cipher.init(Cipher.DECRYPT_MODE, secretKey, ivspec);
            return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));
        } catch (Exception e) {
            System.out.println("Error while decrypting: " + e.toString());
        }
        return null;
    }

    public static void setKey(String myKey) {
        MessageDigest sha = null;
        try {
            key = myKey.getBytes(StandardCharsets.UTF_8);
            sha = MessageDigest.getInstance("SHA-1");
            key = sha.digest(key);
            key = Arrays.copyOf(key, 16);
            secretKey = new SecretKeySpec(key, "AES");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
    }

    /**
     * AES 128(base64)加密
     * 
     * @param strToEncrypt
     *            要加密的字符串
     * @param secret
     *            秘钥
     * @return 加密后的字符串
     */
    public static String encrypt128(String strToEncrypt, String secret)
        throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidKeyException, UnsupportedEncodingException,
        BadPaddingException, IllegalBlockSizeException {
        setKey(secret);
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        return Base64.getEncoder().encodeToString(cipher.doFinal(strToEncrypt.getBytes(StandardCharsets.UTF_8)));
    }

    /**
     * AES 128(base64) 解密
     * 
     * @param strToDecrypt
     *            要解密的字符串
     * @param secret
     *            秘钥
     * @return 解密后的字符串
     */
    public static String decrypt128(String strToDecrypt, String secret) throws NoSuchPaddingException,
        NoSuchAlgorithmException, BadPaddingException, IllegalBlockSizeException, InvalidKeyException {
        setKey(secret);
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        return new String(cipher.doFinal(Base64.getDecoder().decode(strToDecrypt)));
    }

}

class AES256Example {
    public static void main(String[] args) {
        String originalString = "howtodoinjava.com";

        String secKey = "this is my super secrt key";
        String salt = "salt for me!!!";
        String encryptedString = AESUtil.encrypt256(originalString, secKey, salt);
        String decryptedString = AESUtil.decrypt256(encryptedString, secKey, salt);

        System.out.println(originalString);
        System.out.println(encryptedString);
        System.out.println(decryptedString);
    }
}

class AES128Example {
    public static void main(String[] args) {
        String[] originalString = new String[] {"51011234567892013", "13612345678", "四川省成都市高新区", "四川省成都市高新"};

        String key = "5165465461dsfas";

        Arrays.stream(originalString).forEach(os -> {
            try {
                String encryptedString = AESUtil.encrypt128(os, key);
                String decryptedString = AESUtil.decrypt128(encryptedString, key);

                System.out.println(os);
                System.out.println(encryptedString);
                System.out.println(decryptedString);
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
    }
}