package com.nova.sankuai.infra.utils;


import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import java.util.Random;

/**
 * @Description AES对称加密算法工具类
 * @Author CWR
 * @Date 2022/3/21 20:26
 */
public final class AesSecretUtils {
    /**
     * 私有构造方法
     */
    private AesSecretUtils() {

    }

    private static final String AES = "AES";
    private static final String CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";
    private static final String SHA_1 = "SHA-1";

    /**
     * base64编码、解码对象
     */
    private static final Base64.Encoder ENCODER = Base64.getEncoder();
    private static final Base64.Decoder DECODER = Base64.getDecoder();

    /**
     * 加密
     *
     * @param plaintext 明文
     * @param secretKey 密钥
     * @return 密文base64
     */
    public static String encrypt(String plaintext, String secretKey) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
        // 获取密钥对象
        SecretKey key = new SecretKeySpec(secretKey.getBytes(StandardCharsets.UTF_8), AES);
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] plaintextBytes = plaintext.getBytes(StandardCharsets.UTF_8);
        // 加密
        byte[] ciphertextBytes = cipher.doFinal(plaintextBytes);
        return new String(ENCODER.encode(ciphertextBytes), StandardCharsets.UTF_8);
    }

    /**
     * 解密
     *
     * @param ciphertext 密文
     * @param secretKey  密钥
     * @return 密文base64
     */
    public static String decrypt(String ciphertext, String secretKey) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
        // 获取密钥对象
        SecretKey key = new SecretKeySpec(secretKey.getBytes(StandardCharsets.UTF_8), AES);
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] ciphertextBytes = ciphertext.getBytes(StandardCharsets.UTF_8);
        // 解密
        byte[] plaintextBytes = cipher.doFinal(DECODER.decode(ciphertextBytes));
        return new String(plaintextBytes, StandardCharsets.UTF_8);
    }

    /**
     * SHA-1加密
     *
     * @param plaintext
     * @return
     * @throws NoSuchAlgorithmException
     */
    public static String sha1(String plaintext) throws NoSuchAlgorithmException {
        MessageDigest digest = MessageDigest.getInstance(SHA_1);
        byte[] plaintextBytes = plaintext.getBytes(StandardCharsets.UTF_8);
        digest.update(plaintextBytes);
        // 获取字节数组
        byte[] messageDigest = digest.digest();
        StringBuilder hexString = new StringBuilder();
        // 字节数组转换为 ⼗六进制 数
        for (byte b : messageDigest) {
            String shaHex = Integer.toHexString(b & 0xFF);
            if (shaHex.length() < 2) {
                hexString.append(0);
            }
            hexString.append(shaHex);
        }
        return hexString.toString().toUpperCase();
    }

    /**
     * 随机生成字符串.
     *
     * @param length 字符串长度
     */
    public static String getRandomString(int length) {
        String base = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        Random random = new Random();
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < length; i++) {
            int number = random.nextInt(base.length());
            sb.append(base.charAt(number));
        }
        return sb.toString();
    }

    /**
     * 获取当前时间戳
     *
     * @return
     */
    public static Long getTimeStamp() {
        return System.currentTimeMillis() / 1000L;
    }

    public static void main(String[] args) throws NoSuchPaddingException, IllegalBlockSizeException, NoSuchAlgorithmException, BadPaddingException, InvalidKeyException {
        String plaintext = "this is aes";
        String ciphertext = encrypt(plaintext, "1234123412341234");
        System.out.println("明文:" + plaintext);
        System.out.println("密文:" + ciphertext);
        String decryptString = decrypt(ciphertext, "1234123412341234");
        System.out.println("解密后:" + decryptString);

        System.out.println("SHA-1:" + sha1(plaintext));
    }
}