package com.hxzkmonitor.util;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.JwtBuilder;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.bouncycastle.util.encoders.Base64;

import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.util.Date;

/**
 *
 * jwt工具类
 *
 **/
public class JwtUtil {

    /**
     * 签发JWT
     * @param subject    可以是JSON数据 尽可能少
     * @param ttlMillis  token有效时间
     * @return  String
     *
     */
    public static String createJWT(String subject, long ttlMillis) {
        SignatureAlgorithm signatureAlgorithm = SignatureAlgorithm.HS256;
        long nowMillis = System.currentTimeMillis();
        Date now = new Date(nowMillis);
        SecretKey secretKey = generalKey();
        JwtBuilder builder = Jwts.builder()
//                .setId(IdUtils.simpleUUID()) //唯一性
                .setSubject(subject)   // 主题
                .setIssuer("admin")    // 签发者
                .setIssuedAt(now)      // 签发时间
                .signWith(signatureAlgorithm, secretKey); // 签名算法以及密匙
        if (ttlMillis >= 0) {
            long expMillis = nowMillis + ttlMillis;
            Date expDate = new Date(expMillis);
            builder.setExpiration(expDate); // 过期时间
        }
        return builder.compact();
    }

    /**
     * 密钥
     * @return
     */
    public static SecretKey generalKey() {
        byte[] encodedKey = Base64.decode("xxxxxxxx"); //自定义密钥, 不能外泄
        SecretKey key = new SecretKeySpec(encodedKey, 0, encodedKey.length, "AES");
        return key;
    }

    /**
     *
     * 解析JWT字符串
     * @param jwt
     * @return
     * @throws Exception
     */
    public static Claims parseJWT(String jwt) throws Exception {
        SecretKey secretKey = generalKey();
        return Jwts.parser()
                .setSigningKey(secretKey)
                .parseClaimsJws(jwt)
                .getBody();
    }

    /**
     * 获取用户
     * @param token
     * @return
     * @throws Exception
     */
//    public synchronized static WxUser getUser(String token) {
//        WxUser user = null;
//        String subject = null;
//        try {
//            subject = parseJWT(token).getSubject();
//        } catch (Exception e) {
//            e.printStackTrace();
//        }
//        WxUser userModel = JsonListUtil.jsonToBean(subject, WxUser.class);
//        if (ObjectUtil.isNotEmpty(userModel)) {
//            user = SpringUtil.getBean(WxUserMapper.class).selectWxUserById(userModel.getId());
//        }
//        return user;
//    }
}