package com.moon.server.interceptor;

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.service.all.PermsService;
import com.moon.server.service.all.SysService;
import com.moon.server.service.sys.ResLogService;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

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

/**
 * 代理过滤器
 * @author WWW
 * @date 2023-07-04
 */
@WebFilter(urlPatterns = {"/proxy/*"})
public class ProxyFilter implements Filter {
    @Resource
    private SysService sysService;

    @Resource
    private PermsService permsService;

    @Resource
    private ResLogService resLogService;

    private final static int LEN = "/proxy/".length();

    private static final Log log = LogFactory.getLog(ProxyFilter.class);

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

    @Override
    public void init(FilterConfig filterConfig) {
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) {
        try {
            HttpServletRequest req = (HttpServletRequest) request;
            HttpServletResponse res = (HttpServletResponse) response;

            // 2.获取令牌
            String token = getToken(req);

            // 3.获取用户
            UserEntity ue = getUser(res, token);
            if (null == ue) {
                return;
            }

            int resId = getResId(req.getRequestURI(), LEN + token.length() + 1);
            if (!check(req, res, ue, token)) {
                return;
            }

            // 9.获取资源实体
            ResEntity entity = getResEntity(ue, resId);
            if (null == entity) {
                WebHelper.writeStr2Page(res, ILLEGAL_RESOURCE);
                return;
            }

            insertLog(req, ue, resId);
            String url = getSourceUrl(req, entity);
            proxy(req, res, url);
        } catch (Exception ex) {
            log.error(ex.getMessage(), ex);
        }
    }

    @Override
    public void destroy() {
    }

    /**
     * 获取令牌
     */
    private String getToken(HttpServletRequest req) {
        return req.getRequestURI().substring(LEN, req.getRequestURI().indexOf("/", LEN));
    }

    /**
     * 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;
    }

    /**
     * 获取资源ID
     */
    private int getResId(String uri, int start) {
        int end = uri.indexOf("/", start);
        String str = -1 == end ? uri.substring(start) : uri.substring(start, end);

        return Integer.parseInt(str);
    }

    /**
     * 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.selectResList(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) {
        AsyncHelper helper = new AsyncHelper();
        helper.execute(new TimerTask() {
            @Override
            public void run() {
                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());

                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) {

        return "";
    }

    /**
     * 代理服务
     */
    private void proxy(HttpServletRequest request, HttpServletResponse response, String url) throws Exception {
        HttpHelper httpHelper = new HttpHelper();
        httpHelper.service(request, response, url, null);
    }
}