package com.mycompany.myapp.service;

import com.mycompany.myapp.domain.Authority;
import com.mycompany.myapp.domain.User;
import com.mycompany.myapp.repository.AuthorityRepository;
import com.mycompany.myapp.repository.UserRepository;
import com.mycompany.myapp.security.AuthoritiesConstants;
import org.apache.commons.lang3.RandomStringUtils;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.social.connect.*;
import org.springframework.social.facebook.connect.FacebookConnectionFactory;
import org.springframework.social.google.connect.GoogleConnectionFactory;
import org.springframework.social.oauth1.OAuthToken;
import org.springframework.social.oauth2.AccessGrant;
import org.springframework.social.twitter.connect.TwitterConnectionFactory;
import org.springframework.stereotype.Service;

import java.util.*;

@Service
public class SocialService {

    private final Logger log = LoggerFactory.getLogger(SocialService.class);

    private final UsersConnectionRepository usersConnectionRepository;

    private final AuthorityRepository authorityRepository;

    private final PasswordEncoder passwordEncoder;

    private final UserRepository userRepository;

    private final UserDetailsService userDetailsService;

    private final ConnectionFactoryLocator connectionFactoryLocator;

    private final MailService mailService;

    public SocialService(UsersConnectionRepository usersConnectionRepository, AuthorityRepository authorityRepository,
                         PasswordEncoder passwordEncoder, UserRepository userRepository, UserDetailsService userDetailsService, ConnectionFactoryLocator connectionFactoryLocator, MailService mailService) {

        this.usersConnectionRepository = usersConnectionRepository;
        this.authorityRepository = authorityRepository;
        this.passwordEncoder = passwordEncoder;
        this.userRepository = userRepository;
        this.userDetailsService = userDetailsService;
        this.connectionFactoryLocator = connectionFactoryLocator;
        this.mailService = mailService;
    }

    public void deleteUserSocialConnection(String login) {
        ConnectionRepository connectionRepository = usersConnectionRepository.createConnectionRepository(login);
        connectionRepository.findAllConnections().keySet().stream()
            .forEach(providerId -> {
                connectionRepository.removeConnections(providerId);
                log.debug("Delete user social connection providerId: {}", providerId);
            });
    }

    public User createSocialUser(Connection<?> connection, String langKey) {
        if (connection == null) {
            log.error("Cannot create social user because connection is null");
            throw new IllegalArgumentException("Connection cannot be null");
        }
        UserProfile userProfile = connection.fetchUserProfile();
        String providerId = connection.getKey().getProviderId();
        String imageUrl = connection.getImageUrl();
        User user = createUserIfNotExist(userProfile, langKey, providerId, imageUrl);
        createSocialConnection(user.getLogin(), connection);
        mailService.sendSocialRegistrationValidationEmail(user, providerId);
        return user;
    }

    private User createUserIfNotExist(UserProfile userProfile, String langKey, String providerId, String imageUrl) {
        String email = userProfile.getEmail();
        String userName = userProfile.getUsername();
        if (!StringUtils.isBlank(userName)) {
            userName = userName.toLowerCase(Locale.ENGLISH);
        }
        if (StringUtils.isBlank(email) && StringUtils.isBlank(userName)) {
            log.error("Cannot create social user because email and login are null");
            throw new IllegalArgumentException("Email and login cannot be null");
        }
        if (StringUtils.isBlank(email) && userRepository.findOneByLogin(userName).isPresent()) {
            log.error("Cannot create social user because email is null and login already exist, login -> {}", userName);
            throw new IllegalArgumentException("Email cannot be null with an existing login");
        }
        if (!StringUtils.isBlank(email)) {
            Optional<User> user = userRepository.findOneByEmailIgnoreCase(email);
            if (user.isPresent()) {
                log.info("User already exist associate the connection to this account");
                return user.get();
            }
        }

        String login = getLoginDependingOnProviderId(userProfile, providerId);
        String encryptedPassword = passwordEncoder.encode(RandomStringUtils.random(10));
        Set<Authority> authorities = new HashSet<>(1);
        authorities.add(authorityRepository.findOne(AuthoritiesConstants.USER));

        User newUser = new User();
        newUser.setLogin(login);
        newUser.setPassword(encryptedPassword);
        newUser.setFirstName(userProfile.getFirstName());
        newUser.setLastName(userProfile.getLastName());
        newUser.setEmail(email);
        newUser.setActivated(true);
        newUser.setAuthorities(authorities);
        newUser.setLangKey(langKey);
        newUser.setImageUrl(imageUrl);

        return userRepository.save(newUser);
    }

    /**
     * @return login if provider manage a login like Twitter or GitHub otherwise email address.
     *         Because provider like Google or Facebook didn't provide login or login like "12099388847393"
     */
    public String getLoginDependingOnProviderId(UserProfile userProfile, String providerId) {
        switch (providerId) {
            case "twitter":
                return userProfile.getUsername().toLowerCase();
            default:
                return userProfile.getFirstName().toLowerCase() + "_" + userProfile.getLastName().toLowerCase();
        }
    }

    private void createSocialConnection(String login, Connection<?> connection) {
        ConnectionRepository connectionRepository = usersConnectionRepository.createConnectionRepository(login);
        connectionRepository.addConnection(connection);
    }

    public void loadConnectionFromToken(String token, String secret, String provider) {
        Connection connection = null;
        UserProfile userProfile = null;
        if ("facebook".equals(provider)) {
            AccessGrant accessGrant = new AccessGrant(token);
            connection = ((FacebookConnectionFactory)connectionFactoryLocator.getConnectionFactory(provider)).createConnection(accessGrant);
            userProfile = connection.fetchUserProfile();
        } else if ("twitter".equals(provider)) {
            OAuthToken oAuthToken = new OAuthToken(token, secret);
            connection = ((TwitterConnectionFactory)connectionFactoryLocator.getConnectionFactory("twitter")).createConnection(oAuthToken);
            userProfile = connection.fetchUserProfile();
        } else if ("google".equals(provider)) {
            AccessGrant accessGrant = new AccessGrant(token);
            connection = ((GoogleConnectionFactory)connectionFactoryLocator.getConnectionFactory(provider)).createConnection(accessGrant);
            userProfile = connection.fetchUserProfile();
        }

        // check if the user exists
        List<String> userIds = usersConnectionRepository.findUserIdsWithConnection(connection);
        String userLogin;
        if (userIds.size() == 0) {
            log.debug("User needs to be created");
            userLogin = createSocialUser(connection, "en").getLogin();
        } else {
            log.debug("User already exists, logging in");
            userLogin = getLoginDependingOnProviderId(userProfile, provider);
        }
        UserDetails user = userDetailsService.loadUserByUsername(userLogin);
        Authentication newAuth = new UsernamePasswordAuthenticationToken(user, null, user.getAuthorities());
        SecurityContextHolder.getContext().setAuthentication(newAuth);
    }
}