package cn.com.goldenwater.dcproj.utils;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.collections.map.HashedMap;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;

import javax.crypto.Cipher;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

/**
 * Created by 61618 on 2019/4/11.
 */
public class Encryption {

    @Autowired
    private RedisTemplate redisTemplate;


    public static Map<String, Object> EncryptionPwd(String pwd) throws Exception {
        Map<String, Object> map = new HashedMap();
        Map<Integer, String> keyMap = genKeyPair();
        String messageEn = encrypt(pwd, keyMap.get(0));
        map.put("pubKey", keyMap.get(0));
        map.put("priKey", keyMap.get(1));
        map.put("pwd", messageEn);
        return map;
    }

    public static Map<Integer, String> genKeyPair(){
        Map<Integer, String> keyMap = new HashMap<>();
        try{
            // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
            KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
            // 初始化密钥对生成器，密钥大小为96-1024位
            keyPairGen.initialize(1024, new SecureRandom());
            // 生成一个密钥对，保存在keyPair中
            KeyPair keyPair = keyPairGen.generateKeyPair();
            RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
            // 得到私钥
            RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
            // 得到公钥
            String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
            // 得到私钥字符串
            String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
            // 将公钥和私钥保存到Map
            keyMap.put(0, publicKeyString);
            // 0表示公钥
            keyMap.put(1, privateKeyString); // 1表示私钥
        }catch (Exception e){
            e.printStackTrace();
        }
        return keyMap;
    }

    public static String encrypt(String str, String publicKey) throws Exception {
        // base64编码的公钥
        byte[] decoded = Base64.decodeBase64(publicKey);
        RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA")
                .generatePublic(new X509EncodedKeySpec(decoded));
        // RSA加密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);
        String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
        return outStr;
    }

    public static String decrypt(String str, String privateKey){
        String outStr = "";
        try{
            if(str.contains(" ")){
                str = str.replaceAll(" ","+");
            }
            // 64位解码加密后的字符串
            byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
            // base64编码的私钥
            byte[] decoded = Base64.decodeBase64(privateKey);
            RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA")
                    .generatePrivate(new PKCS8EncodedKeySpec(decoded));
            // RSA解密
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE, priKey);
            outStr = new String(cipher.doFinal(inputByte));
        }catch (Exception e){
            e.printStackTrace();
        }
        return outStr;
    }
}