package com.nova.sankuai.domain.api.externalInterface.yxqb;

import com.google.common.base.Charsets;
import com.google.common.base.Strings;
import com.nova.sankuai.infra.utils.Base64Utils;
import org.apache.tomcat.util.codec.binary.Base64;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

/**
 * @Author Lilinhong
 * @Date 2022/7/7 17:32
 */
public class AESUtil {

    /**
     * 生成128位随机密钥
     */
    public static byte[] randomKey() {
        return randomKey(128);
    }

    /**
     * 生成随机密钥
     *
     * @param keySize 密钥位数
     */
    private static byte[] randomKey(int keySize) {
        if (keySize != 128) {
            throw new RuntimeException("AES密钥长度不合法. keySize:" + keySize);
        }
        KeyGenerator kg = null;
        try {
            kg = KeyGenerator.getInstance("AES");
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
        kg.init(keySize, new SecureRandom());
//        kg.init(keySize);
        byte[] key = kg.generateKey().getEncoded();
        return key;
    }

    /**
     * 加密数据
     *
     * @param data 待加密数据
     * @param key  密钥
     */
    public static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        if (key.length != 16) {
            throw new RuntimeException("AES加密失败, 密钥不是128位");
        }
        Cipher cipher = Cipher.getInstance("AES");
        SecretKeySpec keySpec = new SecretKeySpec(key, "AES");
        cipher.init(Cipher.ENCRYPT_MODE, keySpec);
        return cipher.doFinal(data);
    }

    /**
     * 解密数据
     *
     * @param value 待解密数据
     * @param key   密钥
     */
    public static byte[] decrypt(byte[] value, byte[] key) throws Exception {
        if (key.length != 16) {
            throw new RuntimeException("AES解密失败, 密钥不是128位");
        }
        Cipher cipher = Cipher.getInstance("AES");
        SecretKey keySpec = new SecretKeySpec(key, "AES");
        cipher.init(Cipher.DECRYPT_MODE, keySpec);
        return cipher.doFinal(value);
    }

    /**
     * 默认的AES加密字符串方法，可以内部使用
     * 对明文的UTF-8编码字节进行加密，然后使用Base64转码
     * 密钥使用UTF-8编码
     *
     * @param data 明文
     * @param key  加密密钥
     */
    public static String encrypt(String data, String key) throws Exception {
        if (Strings.isNullOrEmpty(data) || Strings.isNullOrEmpty(key)) {
            throw new RuntimeException("AES加密失败, 参数有误. data: " + data + ", key: " + key);
        }
        byte[] keyBytes = key.getBytes(Charsets.UTF_8);
        byte[] dataBytes = data.getBytes(Charsets.UTF_8);
        byte[] encryptBytes = encrypt(dataBytes, keyBytes);
        return Base64Utils.encode(encryptBytes);
    }

    /**
     * 默认的AES解密字符串方法，可以内部使用
     * 对密文使用Base64转码后，再进行解密，然后再转为UTF-8编码
     * 密钥使用UTF-8编码
     *
     * @param ciphertext 密文
     * @param key        加密密钥
     */
    public static String decrypt(String ciphertext, String key) throws Exception {
        if (Strings.isNullOrEmpty(ciphertext) || Strings.isNullOrEmpty(key)) {
            throw new RuntimeException("AES解密失败, 参数有误. ciphertext: " + ciphertext + ", key: " + key);
        }
        byte[] keyBytes = key.getBytes(Charsets.UTF_8);
        byte[] dataBytes = com.nova.sankuai.infra.utils.Base64Utils.decode(ciphertext);
        byte[] keyBytesDecrypt = decrypt(dataBytes, keyBytes);
        return new String(keyBytesDecrypt, Charsets.UTF_8);
    }

    public static void main(String[] args) throws Exception {
        try {
            KeyGenerator kg = KeyGenerator.getInstance("AES");
            //下面调用方法的参数决定了生成密钥的长度，可以修改为128, 192或256
            kg.init(128);
            SecretKey sk = kg.generateKey();
            byte[] b = sk.getEncoded();
            String secret = Base64.encodeBase64String(b);
            System.out.println(secret);
        }
        catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            throw new RuntimeException("没有此算法");
        }
//        System.out.println(AESUtil.encrypt("都送给了返回观看链接", "1234567890asdfgh"));
        System.out.println(AESUtil.encrypt("都送给了返回观看链接", "M+g4NLb8yotZfSHv"));
//        System.out.println(AESUtil.decrypt("KvjpPd24UwoGoq6zTzIsURkv+wvkJ9R77eFFtYqKv5M=", "M+g4NLb8yotZfSHv"));
        System.out.println(AESUtil.decrypt("FcNqD7PH/jOCg75OM1SeDWDpkcBE4ZvKHfzEFZ+wuyM=", "M+g4NLb8yotZfSHv"));
    }
}