/*
 * Copyright (C) 2008-2019, 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.AppleClientSecretGenerator;
import com.github.scribejava.apis.AppleSignInApi;
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.model.facebook.User;
import com.juick.model.vk.UsersResponse;
import com.juick.server.Utils;
import com.juick.server.util.HttpBadRequestException;
import com.juick.service.CrosspostService;
import com.juick.service.EmailService;
import com.juick.service.TelegramService;
import com.juick.service.UserService;
import com.juick.service.security.annotation.Visitor;
import com.nimbusds.jose.JOSEException;
import com.nimbusds.jose.JWSAlgorithm;
import com.nimbusds.jose.jwk.source.JWKSource;
import com.nimbusds.jose.jwk.source.RemoteJWKSet;
import com.nimbusds.jose.proc.BadJOSEException;
import com.nimbusds.jose.proc.JWSKeySelector;
import com.nimbusds.jose.proc.JWSVerificationKeySelector;
import com.nimbusds.jose.proc.SecurityContext;
import com.nimbusds.jwt.proc.ConfigurableJWTProcessor;
import com.nimbusds.jwt.proc.DefaultJWTClaimsVerifier;
import com.nimbusds.jwt.proc.DefaultJWTProcessor;
import net.minidev.json.JSONObject;
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.RandomStringUtils;
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.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.util.UriComponentsBuilder;

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.net.URL;
import java.text.ParseException;
import java.util.List;
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;
    @Value("${ap_base_uri:http://localhost:8080/}")
    private String baseUri;
    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 twitterBuilder;
    private OAuth20Service facebookAuthService, vkAuthService, appleSignInService;

    @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("${telegram_token:secret}")
    private String telegramToken;
    @Value("${apple_app_id:appid}")
    private String appleApplicationId;
    @Inject
    private CrosspostService crosspostService;
    @Inject
    private UserService userService;
    @Inject
    private EmailService emailService;
    @Inject
    private TelegramService telegramService;
    @Inject
    private AppleClientSecretGenerator clientSecretGenerator;

    @PostConstruct
    public void init() {
        ServiceBuilder facebookBuilder = new ServiceBuilder(FACEBOOK_APPID);
        twitterBuilder = new ServiceBuilder(twitterConsumerKey);
        ServiceBuilder vkBuilder = new ServiceBuilder(VK_APPID);
        UriComponentsBuilder redirectBuilder = UriComponentsBuilder.fromUriString(baseUri);
        String facebookRedirectUri = redirectBuilder.replacePath("/_fblogin").build().toUriString();
        facebookAuthService = facebookBuilder
                .apiSecret(FACEBOOK_SECRET)
                .callback(facebookRedirectUri)
                .defaultScope("email")
                .build(FacebookApi.instance());
        vkAuthService = vkBuilder
                .apiSecret(VK_SECRET)
                .defaultScope("friends,wall,offline")
                .callback(VK_REDIRECT)
                .build(VkontakteApi.instance());
        ServiceBuilder appleSignInBuilder = new ServiceBuilder(appleApplicationId);
        String appleSignInRedirectUri = redirectBuilder.replacePath("/_apple").build().toUriString();
        appleSignInService = appleSignInBuilder
                .callback(appleSignInRedirectUri)
                .defaultScope("email")
                .build(new AppleSignInApi(clientSecretGenerator));
    }

    @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);
            return "redirect:" + facebookAuthService.getAuthorizationUrl(fbstate);
        }

        String redirectUrl = crosspostService.verifyFacebookState(state);
        if (StringUtils.isEmpty(redirectUrl)) {
            logger.error("state is missing");
            throw new HttpBadRequestException();
        }
        OAuth2AccessToken token = facebookAuthService.getAccessToken(code);
        final OAuthRequest meRequest = new OAuthRequest(Verb.GET, "https://graph.facebook.com/v3.2/me?fields=id,name,link,verified,email");
        facebookAuthService.signRequest(token, meRequest);
        String graph = facebookAuthService.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())) {
            logger.error("Missing required fields, id: {}, name: {}", fbID, fb.getName());
            throw new HttpBadRequestException();
        }

        int uid = crosspostService.getUIDbyFBID(fbID);
        if (uid > 0) {
            if (!crosspostService.updateFacebookUser(fbID, token.getAccessToken(), fb.getName())) {
                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 (!crosspostService.createFacebookUser(fbID, state, token.getAccessToken(), fb.getName())) {
                if (StringUtils.isNotEmpty(fb.getEmail())) {
                    logger.info("found {} for facebook user {}", fb.getEmail(), fb.getName());
                    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.getName());
                throw new HttpBadRequestException();
            }
            return "redirect:/signup?type=fb&hash=" + state;
        }
    }
    @GetMapping("/_twitter")
    protected void doTwitterLogin(
            @Visitor com.juick.User user,
            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();
            }
        }
        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.model.twitter.User twitterUser = jsonMapper.readValue(oAuthService.execute(oAuthRequest).getBody(),
                        com.juick.model.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);
            return "redirect:" + vkAuthService.getAuthorizationUrl(vkstate);
        }

        if (StringUtils.isBlank(vkstate) || !vkstate.equals(state)) {
            throw new HttpBadRequestException();
        } else {
            Cookie c = new Cookie("vkstate", "-");
            c.setMaxAge(0);
            response.addCookie(c);
        }
        OAuth2AccessToken token = vkAuthService.getAccessToken(code);

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

        com.juick.model.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.parseLong(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"));
                List<Long> chats = telegramService.getAnonymous();
                if (!chats.contains(tgUser)) {
                    logger.info("added chat with {}", username);
                    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();
    }

    @GetMapping("/_apple")
    public String doAppleLogin(HttpServletRequest request,
                               @RequestParam(required = false) String code,
                               HttpServletResponse response) {
        if (StringUtils.isBlank(code)) {
            String state = UUID.randomUUID().toString();
            Cookie c = new Cookie("astate", state);
            response.addCookie(c);
            return "redirect:" + appleSignInService.getAuthorizationUrl(state);
        }
        throw new HttpBadRequestException();
    }
    @PostMapping("/_apple")
    public String doVerifyAppleResponse(HttpServletRequest request, HttpServletResponse response, @RequestParam Map<String, String> body) throws InterruptedException, ExecutionException, IOException, ParseException, JOSEException, BadJOSEException {
        OAuth2AccessToken token = appleSignInService.getAccessToken(body.get("code"));
        var jsonNode = jsonMapper.readTree(token.getRawResponse());
        var idToken = jsonNode.get("id_token").textValue();

// Create a JWT processor for the access tokens
        ConfigurableJWTProcessor<SecurityContext> jwtProcessor =
                new DefaultJWTProcessor<>();

// The public RSA keys to validate the signatures will be sourced from the
// OAuth 2.0 server's JWK set, published at a well-known URL. The RemoteJWKSet
// object caches the retrieved keys to speed up subsequent look-ups and can
// also handle key-rollover
        JWKSource<SecurityContext> keySource =
                new RemoteJWKSet<>(new URL("https://appleid.apple.com/auth/keys"));

// The expected JWS algorithm of the access tokens (agreed out-of-band)
        JWSAlgorithm expectedJWSAlg = JWSAlgorithm.RS256;

// Configure the JWT processor with a key selector to feed matching public
// RSA keys sourced from the JWK set URL
        JWSKeySelector<SecurityContext> keySelector =
                new JWSVerificationKeySelector<>(expectedJWSAlg, keySource);

        jwtProcessor.setJWSKeySelector(keySelector);

// Set the required JWT claims for access tokens issued by the Connect2id
// server, may differ with other servers
        jwtProcessor.setJWTClaimsSetVerifier(new DefaultJWTClaimsVerifier<>());

// Process the token
        JSONObject claimsSet = jwtProcessor.process(idToken, null).toJSONObject();

        var email = claimsSet.getAsString("email");
        var verified = claimsSet.getAsString("email_verified").equals("true");

        if (verified) {
            com.juick.User user = userService.getUserByEmail(email);
            if (!user.isAnonymous()) {
                Cookie c = new Cookie("hash", userService.getHashByUID(user.getUid()));
                c.setMaxAge(50 * 24 * 60 * 60);
                response.addCookie(c);
                return "redirect:/";
            } else {
                String verificationCode = RandomStringUtils.randomAlphanumeric(8).toUpperCase();
                emailService.addVerificationCode(null, email, verificationCode);
                return "redirect:/signup?type=email&hash=" + verificationCode;
            }
        }
        throw new HttpBadRequestException();
    }
}