/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2012, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.keycloak.services.resources;

import org.jboss.resteasy.logging.Logger;
import org.jboss.resteasy.specimpl.MultivaluedMapImpl;
import org.jboss.resteasy.spi.HttpRequest;
import org.jboss.resteasy.spi.HttpResponse;
import org.keycloak.models.KeycloakSession;
import org.keycloak.models.RealmModel;
import org.keycloak.models.SocialLinkModel;
import org.keycloak.models.UserModel;
import org.keycloak.services.managers.AuthenticationManager;
import org.keycloak.services.managers.RealmManager;
import org.keycloak.services.managers.TokenManager;
import org.keycloak.services.resources.flows.Flows;
import org.keycloak.services.resources.flows.OAuthFlows;
import org.keycloak.services.resources.flows.Urls;
import org.keycloak.social.AuthCallback;
import org.keycloak.social.AuthRequest;
import org.keycloak.social.RequestDetails;
import org.keycloak.social.SocialConstants;
import org.keycloak.social.SocialProvider;
import org.keycloak.social.SocialProviderConfig;
import org.keycloak.social.SocialProviderException;
import org.keycloak.services.managers.SocialRequestManager;
import org.keycloak.social.SocialUser;

import javax.imageio.spi.ServiceRegistry;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.QueryParam;
import javax.ws.rs.container.ResourceContext;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.Cookie;
import javax.ws.rs.core.HttpHeaders;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.NewCookie;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;
import javax.ws.rs.core.UriInfo;
import java.net.URISyntaxException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.UUID;

/**
 * @author <a href="mailto:sthorger@redhat.com">Stian Thorgersen</a>
 */
@Path("/social")
public class SocialResource {

    protected static Logger logger = Logger.getLogger(SocialResource.class);

    @Context
    protected UriInfo uriInfo;

    @Context
    protected HttpHeaders headers;

    @Context
    private HttpRequest request;

    @Context
    private HttpResponse response;

    @Context
    ResourceContext resourceContext;

    @Context
    protected KeycloakSession session;


    private SocialRequestManager socialRequestManager;

    private TokenManager tokenManager;

    private AuthenticationManager authManager = new AuthenticationManager();

    public SocialResource(TokenManager tokenManager, SocialRequestManager socialRequestManager) {
        this.tokenManager = tokenManager;
        this.socialRequestManager = socialRequestManager;
    }

    @GET
    @Path("callback")
    public Response callback() throws URISyntaxException {
        Map<String, String[]> queryParams = getQueryParams();

        RequestDetails requestData = getRequestDetails(queryParams);
        SocialProvider provider = getProvider(requestData.getProviderId());

        String realmId = requestData.getClientAttribute("realmId");

        RealmManager realmManager = new RealmManager(session);
        RealmModel realm = realmManager.getRealm(realmId);

        OAuthFlows oauth = Flows.oauth(realm, request, uriInfo, authManager, tokenManager);

        if (!realm.isEnabled()) {
            return oauth.forwardToSecurityFailure("Realm not enabled.");
        }

        String clientId = requestData.getClientAttributes().get("clientId");

        UserModel client = realm.getUser(clientId);
        if (client == null) {
            return oauth.forwardToSecurityFailure("Unknown login requester.");
        }
        if (!client.isEnabled()) {
            return oauth.forwardToSecurityFailure("Login requester not enabled.");
        }

        String key = realm.getSocialConfig().get(requestData.getProviderId() + ".key");
        String secret = realm.getSocialConfig().get(requestData.getProviderId() + ".secret");
        String callbackUri = Urls.socialCallback(uriInfo.getBaseUri()).toString();
        SocialProviderConfig config = new SocialProviderConfig(key, secret, callbackUri);

        AuthCallback callback = new AuthCallback(requestData.getSocialAttributes(), queryParams);

        SocialUser socialUser = null;
        try {
            socialUser = provider.processCallback(config, callback);
        } catch (SocialProviderException e) {
            logger.warn("Failed to process social callback", e);
            return oauth.forwardToSecurityFailure("Failed to process social callback");
        }

        SocialLinkModel socialLink = new SocialLinkModel(provider.getId(), socialUser.getUsername());
        UserModel user = realm.getUserBySocialLink(socialLink);

        if (user == null) {
            if (!realm.isRegistrationAllowed()) {
                return oauth.forwardToSecurityFailure("Registration not allowed");
            }

            // Automatically register user into realm with his social username (don't redirect to registration screen)
            if (realm.isAutomaticRegistrationAfterSocialLogin()) {

                if (realm.getUser(socialUser.getUsername()) != null) {
                    // TODO: Username is already in realm. Show message and let user to bind accounts after he re-authenticate
                    throw new IllegalStateException("Username " + socialUser.getUsername() +
                            " already registered in the realm. TODO: bind accounts...");

                    // TODO: Maybe we should search also by email and bind accounts if user with this email is
                    // already registered. But actually Keycloak allows duplicate emails
                } else {
                    user = realm.addUser(socialUser.getUsername());
                    user.setEnabled(true);
                    user.setFirstName(socialUser.getFirstName());
                    user.setLastName(socialUser.getLastName());
                    user.setEmail(socialUser.getEmail());
                }

                realm.addSocialLink(user, socialLink);
            }  else {
                // Redirect user to registration screen with prefilled data from social provider
                MultivaluedMap<String, String> formData = fillRegistrationFormWithSocialData(socialUser);

                String requestId = UUID.randomUUID().toString();
                socialRequestManager.addRequest(requestId, RequestDetails.create(requestData).build());
                boolean secureOnly = !realm.isSslNotRequired();
                String cookiePath = Urls.socialBase(uriInfo.getBaseUri()).build().getPath();
                logger.debug("creating cookie for social registration - name: {0} path: {1}", SocialConstants.SOCIAL_REGISTRATION_COOKIE,
                        cookiePath);
                NewCookie newCookie = new NewCookie(SocialConstants.SOCIAL_REGISTRATION_COOKIE, requestId,
                        cookiePath, null, "Added social cookie", NewCookie.DEFAULT_MAX_AGE, secureOnly);
                response.addNewCookie(newCookie);

                return Flows.forms(realm, request, uriInfo).setFormData(formData).setSocialRegistration(true)
                        .forwardToRegistration();
            }
        }

        if (!user.isEnabled()) {
            return oauth.forwardToSecurityFailure("Your account is not enabled.");
        }

        String scope = requestData.getClientAttributes().get("scope");
        String state = requestData.getClientAttributes().get("state");
        String redirectUri = requestData.getClientAttributes().get("redirectUri");

        return oauth.processAccessCode(scope, state, redirectUri, client, user);
    }

    @GET
    @Path("{realm}/login")
    public Response redirectToProviderAuth(@PathParam("realm") final String realmId,
            @QueryParam("provider_id") final String providerId, @QueryParam("client_id") final String clientId,
            @QueryParam("scope") final String scope, @QueryParam("state") final String state,
            @QueryParam("redirect_uri") final String redirectUri) {
        RealmManager realmManager = new RealmManager(session);
        RealmModel realm = realmManager.getRealm(realmId);

        SocialProvider provider = getProvider(providerId);
        if (provider == null) {
            return Flows.forms(realm, request, uriInfo).setError("Social provider not found").forwardToErrorPage();
        }

        String key = realm.getSocialConfig().get(providerId + ".key");
        String secret = realm.getSocialConfig().get(providerId + ".secret");
        String callbackUri = Urls.socialCallback(uriInfo.getBaseUri()).toString();

        SocialProviderConfig config = new SocialProviderConfig(key, secret, callbackUri);

        try {
            AuthRequest authRequest = provider.getAuthUrl(config);

            RequestDetails socialRequest = RequestDetails.create(providerId)
                    .putSocialAttributes(authRequest.getAttributes()).putClientAttribute("realmId", realmId)
                    .putClientAttribute("clientId", clientId).putClientAttribute("scope", scope)
                    .putClientAttribute("state", state).putClientAttribute("redirectUri", redirectUri).build();

            socialRequestManager.addRequest(authRequest.getId(), socialRequest);

            return Response.status(Status.FOUND).location(authRequest.getAuthUri()).build();
        } catch (Throwable t) {
            return Flows.forms(realm, request, uriInfo).setError("Failed to redirect to social auth").forwardToErrorPage();
        }
    }

    @POST
    @Path("{realm}/socialRegistration")
    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    public Response socialRegistration(@PathParam("realm") final String realmId,
                                       final MultivaluedMap<String, String> formData) {
        RealmManager realmManager = new RealmManager(session);
        RealmModel realm = realmManager.getRealm(realmId);

        Cookie cookie = headers.getCookies().get(SocialConstants.SOCIAL_REGISTRATION_COOKIE);
        if (cookie == null) {
            return Flows.forms(realm, request, uriInfo).setError("Social registration cookie not found").forwardToErrorPage();
        }

        String requestId = cookie.getValue();
        if (!socialRequestManager.isRequestId(requestId)) {
            logger.error("Unknown requestId found in cookie. Maybe it's expired. requestId=" + requestId);
            return Flows.forms(realm, request, uriInfo).setError("Unknown requestId found in cookie. Maybe it's expired.").forwardToErrorPage();
        }

        RequestDetails requestData = socialRequestManager.getData(requestId);

        if (realm == null || !realm.isEnabled()) {
            return Flows.forms(realm, request, uriInfo).setError("Realm doesn't exists or is not enabled.").forwardToErrorPage();
        }
        TokenService tokenService = new TokenService(realm, tokenManager);
        resourceContext.initResource(tokenService);

        String clientId = requestData.getClientAttribute("clientId");
        String scope = requestData.getClientAttribute("scope");
        String state = requestData.getClientAttribute("state");
        String redirectUri = requestData.getClientAttribute("redirectUri");

        Response response1 = tokenService.processRegisterImpl(clientId, scope, state, redirectUri, formData, true);

        // Some error occured during registration
        if (response1 != null || request.wasForwarded()) {
            logger.warn("Registration attempt wasn't successful. Request already forwarded or redirected.");
            return response1;
        }

        String username = formData.getFirst("username");
        UserModel user = realm.getUser(username);
        if (user == null) {
            // Normally shouldn't happen
            throw new IllegalStateException("User " + username + " not found in the realm");
        }
        realm.addSocialLink(user, new SocialLinkModel(requestData.getProviderId(), username));

        // Expire cookie and invalidate requestData
        String cookiePath = Urls.socialBase(uriInfo.getBaseUri()).build().getPath();
        NewCookie newCookie = new NewCookie(SocialConstants.SOCIAL_REGISTRATION_COOKIE, "", cookiePath, null,
                "Expire social cookie", 0, false);
        logger.debug("Expiring social registration cookie: {0}, path: {1}", SocialConstants.SOCIAL_REGISTRATION_COOKIE, cookiePath);
        response.addNewCookie(newCookie);
        socialRequestManager.retrieveData(requestId);

        return tokenService.processLogin(clientId, scope, state, redirectUri, formData);
    }

    private RequestDetails getRequestDetails(Map<String, String[]> queryParams) {
        Iterator<SocialProvider> itr = ServiceRegistry.lookupProviders(SocialProvider.class);

        while (itr.hasNext()) {
            SocialProvider provider = itr.next();

            if (queryParams.containsKey(provider.getRequestIdParamName())) {
                String requestId = queryParams.get(provider.getRequestIdParamName())[0];
                if (socialRequestManager.isRequestId(requestId)) {
                    return socialRequestManager.retrieveData(requestId);
                }
            }
        }

        return null;
    }

    private SocialProvider getProvider(String providerId) {
        Iterator<SocialProvider> itr = ServiceRegistry.lookupProviders(SocialProvider.class);

        while (itr.hasNext()) {
            SocialProvider provider = itr.next();
            if (provider.getId().equals(providerId)) {
                return provider;
            }
        }

        return null;
    }

    private Map<String, String[]> getQueryParams() {
        Map<String, String[]> queryParams = new HashMap<String, String[]>();
        for (Entry<String, List<String>> e : uriInfo.getQueryParameters().entrySet()) {
            queryParams.put(e.getKey(), e.getValue().toArray(new String[e.getValue().size()]));
        }
        return queryParams;
    }

    protected MultivaluedMap<String, String> fillRegistrationFormWithSocialData(SocialUser socialUser) {
        MultivaluedMap<String, String> formData = new MultivaluedMapImpl<String, String>();
        formData.putSingle("username", socialUser.getUsername());

        if (socialUser.getEmail() != null) {
            formData.putSingle("email", socialUser.getEmail());
        }

        String fullName = null;
        if (socialUser.getFirstName() == null) {
            fullName = socialUser.getLastName();
        } else if (socialUser.getLastName() == null) {
            fullName = socialUser.getFirstName();
        } else {
            fullName = socialUser.getFirstName() + " " + socialUser.getLastName();
        }

        formData.putSingle("name", fullName);
        return formData;
    }

}
