/*
 * This file is part of the Meeds project (https://meeds.io/).
 * Copyright (C) 2020 - 2022 Meeds Association contact@meeds.io
 * This program 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 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
 * Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
package io.meeds.oauth.web;

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang.StringUtils;
import org.gatein.sso.agent.filter.api.AbstractSSOInterceptor;

import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.log.Log;
import org.exoplatform.services.organization.User;
import org.exoplatform.web.security.AuthenticationRegistry;

import io.meeds.oauth.common.OAuthConstants;
import io.meeds.oauth.spi.OAuthPrincipal;
import io.meeds.oauth.spi.OAuthPrincipalProcessor;
import io.meeds.oauth.spi.SocialNetworkService;
import io.meeds.oauth.utils.OAuthUtils;

/**
 * This filter has already access to authenticated OAuth principal, so it's work
 * starts after successful OAuth authentication. Filter is useful only for
 * anonymous user Responsibility of this filter is to handle integration with
 * GateIn (Redirect to GateIn registration if needed, establish context and
 * redirect to JAAS to finish GateIn authentication etc)
 *
 * @author <a href="mailto:mposolda@redhat.com">Marek Posolda</a>
 */
public class OAuthAuthenticationFilter extends AbstractSSOInterceptor {

  private static Log             log = ExoLogger.getLogger(OAuthAuthenticationFilter.class);

  private String                 loginUrl;

  private String                 registrationUrl;

  private boolean                attachUsernamePasswordToLoginURL;

  private SocialNetworkService   socialNetworkService;

  private AuthenticationRegistry authenticationRegistry;

  @Override
  protected void initImpl() {
    this.loginUrl = getInitParameter("loginUrl");
    this.registrationUrl = getInitParameter("registrationUrl");
    if (registrationUrl == null) {
      registrationUrl = "/" + getExoContainer().getContext().getName() + "/";
    }

    String attachUsernamePasswordToLoginURLConfig = getInitParameter("attachUsernamePasswordToLoginURL");
    this.attachUsernamePasswordToLoginURL =
                                          attachUsernamePasswordToLoginURLConfig == null ? true
                                                                                         : Boolean.parseBoolean(attachUsernamePasswordToLoginURLConfig);

    log.debug("OAuthAuthenticationFilter configuration: loginURL=" + loginUrl +
        ", registrationUrl=" + this.registrationUrl +
        ", attachUsernamePasswordToLoginURL=" + this.attachUsernamePasswordToLoginURL);

    socialNetworkService = getExoContainer().getComponentInstanceOfType(SocialNetworkService.class);
    authenticationRegistry = getExoContainer().getComponentInstanceOfType(AuthenticationRegistry.class);
  }

  @Override
  public void destroy() {
  }

  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    HttpServletRequest httpRequest = (HttpServletRequest) request;
    HttpServletResponse httpResponse = (HttpServletResponse) response;

    // Simply continue with request if we are already authenticated
    if (httpRequest.getRemoteUser() != null) {
      chain.doFilter(request, response);
      return;
    }

    // Simply continue with request if we are in the middle of registration
    // process
    User oauthAuthenticatedUser =
                                (User) authenticationRegistry.getAttributeOfClient(httpRequest,
                                                                                   OAuthConstants.ATTRIBUTE_AUTHENTICATED_PORTAL_USER);
    if (oauthAuthenticatedUser != null) {
      chain.doFilter(request, response);
      return;
    }

    OAuthPrincipal principal =
                             (OAuthPrincipal) authenticationRegistry.getAttributeOfClient(httpRequest,
                                                                                          OAuthConstants.ATTRIBUTE_AUTHENTICATED_OAUTH_PRINCIPAL);

    if (principal != null) {
      processPrincipal(httpRequest, httpResponse, principal);
    } else {
      chain.doFilter(request, response);
    }
  }

  protected void processPrincipal(HttpServletRequest httpRequest, HttpServletResponse httpResponse,
                                  OAuthPrincipal principal) throws IOException {
    User portalUser;
    if (StringUtils.isNotBlank(principal.getUserName())) {
      portalUser =
                 socialNetworkService.findUserByOAuthProviderUsername(principal.getOauthProviderType(), principal.getUserName());
    } else {
      portalUser = socialNetworkService.findUserByEmail(principal.getEmail());
    }

    if (portalUser == null) {
      // This means that user has been successfully authenticated via OAuth, but
      // doesn't exist in GateIn. So we need to establish context
      // with AuthenticationRegistry and redirect to GateIn registration form
      handleRedirectToRegistrationForm(httpRequest, httpResponse, principal);
    } else {
      // This means that user has been successfully authenticated via OAuth and
      // exists in GateIn. So we need to establish SSO context
      // and clean our own local context from AuthenticationRegistry. Then
      // redirect to loginUrl to perform GateIn WCI login
      handleRedirectToPortalLogin(httpRequest, httpResponse, portalUser, principal);
      cleanAuthenticationContext(httpRequest);
    }
  }

  protected void handleRedirectToRegistrationForm(HttpServletRequest httpRequest, HttpServletResponse httpResponse,
                                                  OAuthPrincipal principal)
                                                                            throws IOException {
    if (log.isTraceEnabled()) {
      log.trace("Not found portalUser with username " + principal.getUserName() + ". Redirecting to registration form");
    }

    User gateInUser;
    OAuthPrincipalProcessor principalProcessor = principal.getOauthProviderType().getOauthPrincipalProcessor();
    if (StringUtils.isNotBlank(principal.getUserName())) {
      gateInUser = socialNetworkService.findUserByEmail(principal.getUserName());
    } else {
      gateInUser = socialNetworkService.findUserByEmail(principal.getEmail());
    }
    if (gateInUser == null) {
      gateInUser = principalProcessor.convertToGateInUser(principal);
    }
    authenticationRegistry.setAttributeOfClient(httpRequest, OAuthConstants.ATTRIBUTE_AUTHENTICATED_PORTAL_USER, gateInUser);

    String registrationRedirectUrl = getRegistrationRedirectURL(httpRequest);
    registrationRedirectUrl = httpResponse.encodeRedirectURL(registrationRedirectUrl);
    httpResponse.sendRedirect(registrationRedirectUrl);
  }

  protected String getRegistrationRedirectURL(HttpServletRequest req) {
    String registrationURL = (String) req.getSession()
                                         .getAttribute(OAuthConstants.ATTRIBUTE_URL_TO_REDIRECT_AFTER_LINK_SOCIAL_ACCOUNT);
    if (registrationURL == null) {
      registrationURL = this.registrationUrl;
    }

    return registrationURL;
  }

  protected void handleRedirectToPortalLogin(HttpServletRequest httpRequest, HttpServletResponse httpResponse, User portalUser,
                                             OAuthPrincipal principal)
                                                                       throws IOException {
    if (log.isTraceEnabled()) {
      log.trace("Found portalUser " + portalUser + " corresponding to oauthPrincipal");
    }

    authenticationRegistry.setAttributeOfClient(httpRequest,
                                                OAuthConstants.ATTRIBUTE_AUTHENTICATED_PORTAL_USER_FOR_JAAS,
                                                portalUser);
    if (portalUser.isEnabled()) {
      socialNetworkService.updateOAuthAccessToken(principal.getOauthProviderType(),
                                                  portalUser.getUserName(),
                                                  principal.getAccessToken());
    }

    // Now Facebook/Google authentication handshake is finished and credentials
    // are in session. We can redirect to JAAS authentication
    String loginRedirectURL = httpResponse.encodeRedirectURL(getLoginRedirectUrl(httpRequest, portalUser.getUserName()));
    httpResponse.sendRedirect(loginRedirectURL);
  }

  protected String getLoginRedirectUrl(HttpServletRequest req, String username) {
    StringBuilder url = new StringBuilder(this.loginUrl);

    if (attachUsernamePasswordToLoginURL) {
      String fakePassword = req.getSession().getId() + "_" + String.valueOf(System.currentTimeMillis());

      // Use sessionId and system millis as password (similar like spnego is
      // doing)
      url.append("?username=").append(username).append("&password=").append(fakePassword);

      String initialURI = OAuthUtils.getURLToRedirectAfterLinkAccount(req, req.getSession());
      initialURI = OAuthUtils.encodeParam(initialURI);
      url.append("&").append("initialURI").append("=").append(initialURI);
    }

    return url.toString();
  }

  protected void cleanAuthenticationContext(HttpServletRequest httpRequest) {
    authenticationRegistry.removeAttributeOfClient(httpRequest, OAuthConstants.ATTRIBUTE_AUTHENTICATED_OAUTH_PRINCIPAL);
    authenticationRegistry.removeAttributeOfClient(httpRequest, OAuthConstants.ATTRIBUTE_AUTHENTICATED_PORTAL_USER);
  }

}
