package com.moon.server.service.sys;

import com.alibaba.fastjson.JSON;
import com.moon.server.entity.all.HttpStatus;
import com.moon.server.entity.all.ResponseMsg;
import com.moon.server.entity.all.StaticData;
import com.moon.server.entity.sys.ResEntity;
import com.moon.server.entity.sys.ResLogEntity;
import com.moon.server.entity.sys.TokenEntity;
import com.moon.server.entity.sys.UserEntity;
import com.moon.server.helper.AsyncHelper;
import com.moon.server.helper.HttpHelper;
import com.moon.server.helper.StringHelper;
import com.moon.server.helper.WebHelper;
import com.moon.server.interceptor.AuthInterceptor;
import com.moon.server.service.all.PermsService;
import com.moon.server.service.all.SysService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.List;
import java.util.TimerTask;

/**
 * 代理服务类
 * @author WWW
 * @date 2023-07-11
 */
@Service
public class ProxyService {

    @Resource
    private SysService sysService;

    @Resource
    private PermsService permsService;

    @Resource
    private ResLogService resLogService;

    public static final String ILLEGAL_RESOURCE = JSON.toJSONString(new ResponseMsg<String>(HttpStatus.UNAUTHORIZED, "没有资源访问权限"));

    /**
     * URL代理
     */
    public void proxyUrl(String token, int resId, HttpServletRequest req, HttpServletResponse res) throws Exception {
        // 3.获取用户
        UserEntity ue = getUser(res, token);
        if (null == ue) {
            return;
        }
        if (!check(req, res, ue, token)) {
            return;
        }

        // 9.获取资源实体
        ResEntity entity = getResEntity(ue, resId);
        if (null == entity || entity.getType() != 3|| StringHelper.isNull(entity.getProxy())||StringHelper.isNull(entity.getUrl())) {
            WebHelper.writeStr2Page(res, ILLEGAL_RESOURCE);
            return;
        }

        insertLog(req, ue, resId);

        String url = getSourceUrl(req, entity, token);
        res.setHeader("token", token);
        forward(req, res, entity, url);
    }

    /**
     * 获取用户
     */
    private UserEntity getUser(HttpServletResponse res, String token) {
        UserEntity ue = sysService.tokenService.getUserByToken(token);
        if (ue == null) {
            WebHelper.writeStr2Page(res, AuthInterceptor.NO_LOGIN);
            return null;
        }

        return ue;
    }

    /**
     * 检查
     */
    private boolean check(HttpServletRequest req, HttpServletResponse res, UserEntity ue, String token) {
        // 4.获取IP
        String ip = WebHelper.getIpAddress(req);
        if (StringHelper.isEmpty(ip)) {
            return WebHelper.writeStr2Page(res, AuthInterceptor.IP_NULL);
        }

        // 5.检查黑名单
        if (!checkBlackList(ip, req)) {
            return WebHelper.writeStr2Page(res, AuthInterceptor.BLACK_LIST);
        }

        // 6.admin跳过权限检测
        if (StaticData.ADMIN.equals(ue.getUid())) {
            return true;
        }

        // 7.检查白名单
        if (!checkWhiteList(ip, req)) {
            // 检查IP一致性
            if (!checkIpSource(ip, token)) {
                return WebHelper.writeStr2Page(res, AuthInterceptor.ILLEGAL_TOKEN);
            }
        }

        // 8.检查用户ID是否禁用
        if (sysService.tokenService.isUidDisable(ue)) {
            return WebHelper.writeStr2Page(res, AuthInterceptor.USER_LOCK);
        }

        return true;
    }

    /**
     * 检查黑名单
     */
    private boolean checkBlackList(String ip, HttpServletRequest request) {
        List<String> blackList = sysService.blacklistService.selectIpList(1);
        if (blackList == null || blackList.isEmpty()) {
            return true;
        }
        if (blackList.contains(ip)) {
            return false;
        }

        return true;
    }

    /**
     * 检查白名单
     */
    private boolean checkWhiteList(String ip, HttpServletRequest request) {
        List<String> whiteList = sysService.blacklistService.selectIpList(2);
        if (whiteList == null || whiteList.isEmpty()) {
            return false;
        }

        return whiteList.contains(ip);
    }

    /**
     * 检查IP一致性
     */
    private boolean checkIpSource(String ip, String token) {
        TokenEntity te = sysService.tokenService.getEntityByToken(token);

        return te.getIp().equals(ip);
    }

    /**
     * 检查资源权限
     */
    private ResEntity getResEntity(UserEntity ue, int resId) {
        String uid = StaticData.ADMIN.equals(ue.getUid()) ? null : ue.getUid();
        List<ResEntity> rs = permsService.selectRes(uid);
        if (null == rs || rs.isEmpty()) {
            return null;
        }

        // List<ResEntity> list = rs.stream().filter(resEntity -> resEntity.getId() == resId).collect(Collectors.toList())
        for (ResEntity entity : rs) {
            if (resId == entity.getId()) {
                return entity;
            }
        }

        return null;
    }

    /**
     * 插入日志
     */
    private void insertLog(HttpServletRequest req, UserEntity ue, int resId) {
        String ip = WebHelper.getIpAddress(req);

        ResLogEntity entity = new ResLogEntity();
        entity.setResid(resId);
        entity.setType(getRequestType(req.getMethod()));
        entity.setIp(ip);
        entity.setUrl(req.getRequestURL().toString());
        entity.setCreateUser(ue.getId());

        AsyncHelper helper = new AsyncHelper();
        helper.execute(new TimerTask() {
            @Override
            public void run() {
                resLogService.insert(entity);
            }
        });
    }

    /**
     * 获取请求类别
     */
    private int getRequestType(String method) {
        // 请求类：1-GET，2-POST，3-PUT，4-DELETE，5-TRACE，6-HEAD，7-OPTIONS，8-CONNECT';
        switch (method) {
            case "GET":
                return 1;
            case "POST":
                return 2;
            case "PUT":
                return 3;
            case "DELETE":
                return 4;
            case "TRACE":
                return 5;
            case "HEAD":
                return 6;
            case "OPTIONS":
                return 7;
            case "CONNECT":
                return 8;
            default:
                return -1;
        }
    }

    /**
     * 获取原始Url
     */
    private String getSourceUrl(HttpServletRequest req, ResEntity entity, String token) {
        String proxyUrl = entity.getProxy().replace("{token}", token);
        int end = req.getRequestURL().indexOf(proxyUrl) + proxyUrl.length();

        String url = entity.getUrl() + req.getRequestURL().substring(end);
        if (null != req.getQueryString()) {
            url = url + (entity.getUrl().contains("?") ? "&" : "?") + req.getQueryString();
        }

        return url;
    }

    /**
     * 转发请求
     */
    private void forward(HttpServletRequest request, HttpServletResponse response, ResEntity entity, String url) throws Exception {
        HttpHelper httpHelper = new HttpHelper();
        httpHelper.service(request, response, entity, url);
    }
}