package cn.huge.gateway.filter;

import cn.huge.gateway.utils.JsonMapper;
import cn.huge.gateway.utils.ReturnBO;
import cn.huge.gateway.utils.SpringContextUtil;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.auth0.jwt.interfaces.DecodedJWT;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.util.UriComponentsBuilder;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @title: 网关拦截器
 * @description: 网关拦截器
 * @company: hugeinfo
 * @author: liyj
 * @time: 2021-11-05 16:51:48
 * @version: 1.0.0
 */
@Slf4j
@Component
public class AuthFilter implements GlobalFilter, Ordered {

    @Value("${jwt.secret-key}")
    private String secretKey;

    @Value("${jwt.iss-user}")
    private String issUser;

    @Value("${jwt.auth-skip-urls}")
    private String[] skipAuthUrls;

    @Value("${jwt.blacklist-key.format}")
    private String jwtBlacklistKeyFormat;

    @Override
    public int getOrder() {
        return -100;
    }

    /**
     * 拦截方法
     * @param exchange
     * @param chain
     * @return
     */
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        String url = exchange.getRequest().getURI().getPath();
        //跳过不需要验证的路径
        List<String> skipAuthUrlList = Arrays.asList(skipAuthUrls);
        Boolean status = false;
        if (!CollectionUtils.isEmpty(skipAuthUrlList)) {
            for (String skipAuthUrl : skipAuthUrlList) {
                if (url.indexOf(skipAuthUrl) != -1) {
                    status = true;
                    break;
                }
            }
        }
        if (status) {
            return chain.filter(exchange);
        } else {
            JsonMapper jsonMapper = new JsonMapper();
            ReturnBO returnBO = new ReturnBO();
            //从请求头中取出token
            String token = exchange.getRequest().getHeaders().getFirst("Authorization");
            //未携带token或token在黑名单内
            if (StringUtils.isEmpty(token) || isBlackToken(token)) {
                ServerHttpResponse originalResponse = exchange.getResponse();
                originalResponse.setStatusCode(HttpStatus.OK);
                originalResponse.getHeaders().add("Content-Type", "application/json;charset=UTF-8");
                returnBO.setCode(401);
                returnBO.setMsg("您尚未登录，请登录后重试！");
                byte[] response = jsonMapper.toJson(returnBO).getBytes(StandardCharsets.UTF_8);
                DataBuffer buffer = originalResponse.bufferFactory().wrap(response);
                return originalResponse.writeWith(Flux.just(buffer));
            } else {
                //取出token包含的身份
                returnBO = verifyJWT(token);
                if (returnBO.getCode() != 0) {
                    ServerHttpResponse originalResponse = exchange.getResponse();
                    originalResponse.setStatusCode(HttpStatus.OK);
                    originalResponse.getHeaders().add("Content-Type", "application/json;charset=UTF-8");
                    byte[] response = jsonMapper.toJson(returnBO).getBytes(StandardCharsets.UTF_8);
                    DataBuffer buffer = originalResponse.bufferFactory().wrap(response);
                    return originalResponse.writeWith(Flux.just(buffer));
                } else {
                    //将现在的request，添加当前身份
                    String userId = (String) returnBO.getData();
                    ServerHttpRequest mutableReq = null;
                    exchange.getRequest().mutate().header("Authorization-userId", userId).build();
                    ServerWebExchange mutableExchange = exchange.mutate().request(mutableReq).build();
                    return chain.filter(mutableExchange);
                }
            }
        }
    }

    /**
     * JWT验证
     * @param token 授权信息
     * @return Map
     */
    private ReturnBO verifyJWT(String token){
        ReturnBO returnBO = new ReturnBO();
        try {
            Algorithm algorithm = Algorithm.HMAC256(secretKey);
            JWTVerifier verifier = JWT.require(algorithm)
                    .withIssuer(issUser)
                    .build();
            DecodedJWT jwt = verifier.verify(token);
            String userId = jwt.getClaim("userId").asString();
            if (userId.isEmpty()){
                returnBO.setCode(401);
                returnBO.setMsg("您尚未登录，请登录后重试！");
            }else{
                returnBO.setCode(0);
                returnBO.setData(userId);
            }
        } catch (JWTVerificationException e){
            log.error("AuthFilter方法[verifyJWT]调用异常："+e, e);
            if (e.getMessage().indexOf("The Token has expired") != -1){
                returnBO.setCode(401);
                returnBO.setMsg("您尚未登录，请登录后重试！");
            }else{
                returnBO.setCode(401);
                returnBO.setMsg("您尚未登录，请登录后重试！");
            }
        }
        return returnBO;
    }

    /**
     * 判断token是否在黑名单内
     * @param token 授权信息
     * @return boolean
     */
    private boolean isBlackToken(String token){
        assert token != null;
//        return stringRedisTemplate.hasKey(String.format(jwtBlacklistKeyFormat, token));
        return false;
    }

    /**
     * usi追加custId
     * @param uri uri
     * @param custId custId参数
     * @return
     * @throws UnsupportedEncodingException
     */
    private URI assembleUri(URI uri, String custId) {
        StringBuilder query = new StringBuilder();
        //追加custId参数
        if(query.length() != 0){
            query.append("&");
        }
        query.append("custId=");
        query.append(custId);
        //转码，生成新的URI
        URI newUri = UriComponentsBuilder.fromUri(uri).replaceQuery(query.toString()).build(true).toUri();
        return newUri;
    }
}
/**
 * -------------------_ooOoo_-------------------
 * ------------------o8888888o------------------
 * ------------------88" . "88------------------
 * ------------------(| -_- |)------------------
 * ------------------O\  =  /O------------------
 * ---------------____/`---'\____---------------
 * -------------.'  \\|     |//  `.-------------
 * ------------/  \\|||  :  |||//  \------------
 * -----------/  _||||| -:- |||||-  \-----------
 * -----------|   | \\\  -  /// |   |-----------
 * -----------| \_|  ''\---/''  |   |-----------
 * -----------\  .-\__  `-`  ___/-. /-----------
 * ---------___`. .'  /--.--\  `. . __----------
 * ------."" '<  `.___\_<|>_/___.'  >'"".-------
 * -----| | :  `- \`.;`\ _ /`;.`/ - ` : | |-----
 * -----\  \ `-.   \_ __\ /__ _/   .-` /  /-----
 * ======`-.____`-.___\_____/___.-`____.-'======
 * -------------------`=---='
 * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 * ---------佛祖保佑---hugeinfo---永无BUG----------
 */