/*
 * Copyright (C) 2008-2017, Juick
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.juick.server.www.controllers;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.github.scribejava.apis.FacebookApi;
import com.github.scribejava.apis.TwitterApi;
import com.github.scribejava.apis.VkontakteApi;
import com.github.scribejava.core.builder.ServiceBuilder;
import com.github.scribejava.core.model.*;
import com.github.scribejava.core.oauth.OAuth10aService;
import com.github.scribejava.core.oauth.OAuth20Service;
import com.juick.server.util.HttpBadRequestException;
import com.juick.server.util.UserUtils;
import com.juick.service.CrosspostService;
import com.juick.service.EmailService;
import com.juick.service.TelegramService;
import com.juick.service.UserService;
import com.juick.server.www.Utils;
import com.juick.server.www.facebook.User;
import com.juick.server.www.vk.UsersResponse;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.codec.digest.HmacAlgorithms;
import org.apache.commons.codec.digest.HmacUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.math.NumberUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.CookieValue;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;

import javax.annotation.PostConstruct;
import javax.inject.Inject;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ExecutionException;
import java.util.stream.Collectors;

/**
 *
 * @author Ugnich Anton
 */
@Controller
public class SocialLogin {

    private static final Logger logger = LoggerFactory.getLogger(SocialLogin.class);

    @Value("${facebook_appid:appid}")
    private String FACEBOOK_APPID;
    @Value("${facebook_secret:secret}")
    private String FACEBOOK_SECRET;
    private static final String FACEBOOK_REDIRECT = "https://juick.com/_fblogin";
    private static final String VK_REDIRECT = "http://juick.com/_vklogin";
    private static final String TWITTER_VERIFY_URL = "https://api.twitter.com/1.1/account/verify_credentials.json";
    @Inject
    private ObjectMapper jsonMapper;
    private ServiceBuilder facebookBuilder, twitterBuilder, vkBuilder;

    @Value("${twitter_consumer_key:appid}")
    private String twitterConsumerKey;
    @Value("${twitter_consumer_secret:secret}")
    private String twitterConsumerSecret;
    @Value("${vk_appid:appid}")
    private String VK_APPID;
    @Value("${vk_secret:secret}")
    private String VK_SECRET;
    @Value("${telegram_token:secret}")
    private String telegramToken;

    @Inject
    private CrosspostService crosspostService;
    @Inject
    private UserService userService;
    @Inject
    private EmailService emailService;
    @Inject
    private TelegramService telegramService;

    @PostConstruct
    public void init() {
        facebookBuilder = new ServiceBuilder(FACEBOOK_APPID);
        twitterBuilder = new ServiceBuilder(twitterConsumerKey);
        vkBuilder = new ServiceBuilder(VK_APPID);
    }

    @GetMapping("/_fblogin")
    protected String doFacebookLogin(HttpServletRequest request,
                         @RequestParam(required = false) String code,
                         @RequestParam(required = false) String state,
                         HttpServletResponse response) throws IOException, ExecutionException, InterruptedException {
        if (StringUtils.isBlank(code)) {
            String fbstate = UUID.randomUUID().toString();
            if (StringUtils.isBlank(state)) {
                state = Utils.getPreviousPageByRequest(request).orElse("https://juick.com/");
            }
            crosspostService.addFacebookState(fbstate, state);
            OAuth20Service facebookAuthService = facebookBuilder
                    .apiSecret(FACEBOOK_SECRET)
                    .callback(FACEBOOK_REDIRECT)
                    .scope("email")
                    .state(fbstate)
                    .build(FacebookApi.instance());
            return "redirect:" + facebookAuthService.getAuthorizationUrl();
        }

        String redirectUrl = crosspostService.verifyFacebookState(state);
        if (StringUtils.isEmpty(redirectUrl)) {
            logger.error("state is missing");
            throw new HttpBadRequestException();
        }
        OAuth20Service facebookService = facebookBuilder
                .apiKey(FACEBOOK_APPID)
                .apiSecret(FACEBOOK_SECRET)
                .callback(FACEBOOK_REDIRECT)
                .scope("email")
                .state(state)
                .build(FacebookApi.instance());
        OAuth2AccessToken token = facebookService.getAccessToken(code);
        final OAuthRequest meRequest = new OAuthRequest(Verb.GET, "https://graph.facebook.com/v2.10/me?fields=id,name,link,verified,email");
        facebookService.signRequest(token, meRequest);
        String graph = facebookService.execute(meRequest).getBody();
        if (StringUtils.isBlank(graph)) {
            logger.error("FACEBOOK GRAPH ERROR");
            throw new HttpBadRequestException();
        }
        User fb = jsonMapper.readValue(graph, User.class);
        long fbID = NumberUtils.toLong(fb.getId(), 0);
        if (fbID == 0 || StringUtils.isBlank(fb.getName()) || StringUtils.isBlank(fb.getLink())) {
            logger.error("Missing required fields, id: {}, name: {}, link: {}", fbID, fb.getName(), fb.getLink());
            throw new HttpBadRequestException();
        }

        int uid = crosspostService.getUIDbyFBID(fbID);
        if (uid > 0) {
            if (!crosspostService.updateFacebookUser(fbID, token.getAccessToken(), fb.getName(), fb.getLink())) {
                logger.error("error updating facebook user, id: {}, token: {}", fbID, token.getAccessToken());
                throw new HttpBadRequestException();
            }
            Cookie c = new Cookie("hash", userService.getHashByUID(uid));
            c.setMaxAge(50 * 24 * 60 * 60);
            response.addCookie(c);
            return "redirect:" + redirectUrl;
        } else if (fb.getVerified()) {
            if (!crosspostService.createFacebookUser(fbID, state, token.getAccessToken(), fb.getName(), fb.getLink())) {
                if (StringUtils.isNotEmpty(fb.getEmail())) {
                    logger.info("found {} for facebook user {}", fb.getEmail(), fb.getLink());
                    Integer userId = crosspostService.getUIDbyFBID(fbID);
                    if (!emailService.getEmails(userId, false).contains(fb.getEmail())) {
                        emailService.addEmail(userId, fb.getEmail());
                    }
                }
                logger.info("email not found for facebook user {}", fb.getLink());
                throw new HttpBadRequestException();
            }
            return "redirect:/signup?type=fb&hash=" + state;
        } else {
            logger.error("Facebook account is not verified, id: {}", fbID);
            throw new HttpBadRequestException();
        }
    }
    @GetMapping("/_twitter")
    protected void doTwitterLogin(HttpServletRequest request, HttpServletResponse response)
            throws IOException, ExecutionException, InterruptedException {
        String hash = StringUtils.EMPTY, request_token = StringUtils.EMPTY, request_token_secret = StringUtils.EMPTY;
        String verifier = request.getParameter("oauth_verifier");
        Cookie[] cookies = request.getCookies();
        for (Cookie cookie : cookies) {
            if (cookie.getName().equals("hash")) {
                hash = cookie.getValue();
            }
            if (cookie.getName().equals("request_token")) {
                request_token = cookie.getValue();
            }
            if (cookie.getName().equals("request_token_secret")) {
                request_token_secret = cookie.getValue();
            }
        }
        com.juick.User user = UserUtils.getCurrentUser();
        OAuth10aService oAuthService = twitterBuilder
                .apiSecret(twitterConsumerSecret)
                .callback("https://juick.com/_twitter")
                .build(TwitterApi.instance());

        if (request_token.isEmpty() && request_token_secret.isEmpty()
                && (verifier == null || verifier.isEmpty())) {
            OAuth1RequestToken requestToken = oAuthService.getRequestToken();
            String authUrl = oAuthService.getAuthorizationUrl(requestToken);
            response.addCookie(new Cookie("request_token", requestToken.getToken()));
            response.addCookie(new Cookie("request_token_secret", requestToken.getTokenSecret()));
            response.setStatus(HttpServletResponse.SC_FOUND);
            response.setHeader("Location", authUrl);
        } else {
            if (verifier != null && verifier.length() > 0) {
                OAuth1RequestToken requestToken = new OAuth1RequestToken(request_token, request_token_secret);
                OAuth1AccessToken accessToken = oAuthService.getAccessToken(requestToken, verifier);
                OAuthRequest oAuthRequest = new OAuthRequest(Verb.GET, TWITTER_VERIFY_URL);
                oAuthService.signRequest(accessToken, oAuthRequest);
                com.juick.server.www.twitter.User twitterUser = jsonMapper.readValue(oAuthService.execute(oAuthRequest).getBody(),
                        com.juick.server.www.twitter.User.class);
                if (userService.linkTwitterAccount(user, accessToken.getToken(), accessToken.getTokenSecret(),
                        twitterUser.getScreenName())) {
                    response.setStatus(HttpServletResponse.SC_FOUND);
                    response.setHeader("Location", "http://juick.com/settings");
                } else {
                    response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
                }
            }
        }
    }
    @GetMapping("/_vklogin")
    protected String doVKLogin(HttpServletRequest request,
                           @RequestParam(required = false) String code,
                           @RequestParam(required = false) String state,
                           @CookieValue(required = false) String vkstate,
                           HttpServletResponse response) throws IOException, ExecutionException, InterruptedException {
        if (StringUtils.isBlank(code)) {
            vkstate = UUID.randomUUID().toString();
            Cookie c = new Cookie("vkstate", vkstate);
            response.addCookie(c);
            OAuth20Service vkAuthService = vkBuilder
                    .apiSecret(VK_SECRET)
                    .scope("friends,wall,offline")
                    .state(vkstate)
                    .callback(VK_REDIRECT)
                    .build(VkontakteApi.instance());
            return "redirect:" + vkAuthService.getAuthorizationUrl();
        }

        if (StringUtils.isBlank(vkstate) || !vkstate.equals(state)) {
            throw new HttpBadRequestException();
        } else {
            Cookie c = new Cookie("vkstate", "-");
            c.setMaxAge(0);
            response.addCookie(c);
        }

        OAuth20Service vkService = vkBuilder
                .apiKey(VK_APPID)
                .apiSecret(VK_SECRET)
                .build(VkontakteApi.instance());
        OAuth2AccessToken token = vkService.getAccessToken(code);

        OAuthRequest meRequest = new OAuthRequest(Verb.GET, "https://api.vk.com/method/users.get?fields=screen_name&v=5.73");
        vkService.signRequest(token, meRequest);
        String graph = vkService.execute(meRequest).getBody();

        com.juick.server.www.vk.User jsonUser = jsonMapper.readValue(graph, UsersResponse.class).getUsers().get(0);
        String vkName = jsonUser.getFirstName() + " " + jsonUser.getLastName();
        String vkLink = jsonUser.getScreenName();

        if (vkName.length() == 1 || StringUtils.isBlank(vkLink)) {
            logger.error("vk user error");
            throw new HttpBadRequestException();
        }

        Long vkID = NumberUtils.toLong(jsonUser.getId(), 0);
        int uid = crosspostService.getUIDbyVKID(vkID);
        if (uid > 0) {
            Cookie c = new Cookie("hash", userService.getHashByUID(uid));
            c.setMaxAge(50 * 24 * 60 * 60);
            response.addCookie(c);
            return "redirect:/" + Utils.getPreviousPageByRequest(request).orElse(StringUtils.EMPTY);
        } else {
            String loginhash = UUID.randomUUID().toString();
            if (!crosspostService.createVKUser(vkID, loginhash, token.getAccessToken(), vkName, vkLink)) {
                logger.error("create vk user error");
                throw new HttpBadRequestException();
            }
            return "redirect:/signup?type=vk&hash=" + loginhash;
        }
    }

    @GetMapping("/_tglogin")
    public String doDurovLogin(HttpServletRequest request,
                               @RequestParam Map<String, String> params,
                               HttpServletResponse response) {
        String dataCheckString = params.entrySet().stream()
                .filter(p -> !p.getKey().equals("hash"))
                .sorted(Map.Entry.comparingByKey())
                .map(p -> p.getKey() + "=" + p.getValue())
                .collect(Collectors.joining("\n"));
        String hash = params.get("hash");
        byte[] secretKey = DigestUtils.sha256(telegramToken);
        String resultString = new HmacUtils(HmacAlgorithms.HMAC_SHA_256, secretKey).hmacHex(dataCheckString);
        if (hash.equals(resultString)) {
            Long tgUser = Long.valueOf(params.get("id"));
            int uid = telegramService.getUser(tgUser);
            if (uid > 0) {
                Cookie c = new Cookie("hash", userService.getHashByUID(uid));
                c.setMaxAge(50 * 24 * 60 * 60);
                response.addCookie(c);
                return "redirect:/" + Utils.getPreviousPageByRequest(request).orElse(StringUtils.EMPTY);
            } else {
                String username = StringUtils.defaultString(params.get("username"), params.get("first_name"));
                telegramService.createTelegramUser(tgUser, username);
                return "redirect:/signup?type=durov&hash=" + userService.getSignUpHashByTelegramID(tgUser, username);
            }
        } else {
            logger.warn("invalid tg hash {} for {}", resultString, hash);
        }
        throw new HttpBadRequestException();
    }
}