package servlets;

import com.onelogin.saml2.Auth;
import com.onelogin.saml2.exception.Error;
import com.onelogin.saml2.exception.SettingsException;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.commons.lang3.StringUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import utils.LoginMethod;
import utils.ShepherdLogManager;
import utils.Validate;

/**
 * Control class for the SSO logout operation <br>
 * <br>
 * This file is part of the Security Shepherd Project.
 *
 * <p>The Security Shepherd project is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.<br>
 *
 * <p>The Security Shepherd project 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 General Public License for more details.<br>
 *
 * <p>You should have received a copy of the GNU General Public License along with the Security
 * Shepherd project. If not, see <http://www.gnu.org/licenses/>.
 *
 * @author Mark Denihan
 */
public class SLS extends HttpServlet {

  private static final long serialVersionUID = -5824919455464886874L;
  private static final Logger log = LogManager.getLogger(SLS.class);

  /**
   * Initiated in index.jsp. Invalidates session and Security Shepherd tokens are removed. The user
   * is logged out.
   *
   * @param csrfToken
   */
  public void handleRequest(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    // Setting IpAddress To Log and taking header for original IP if forwarded from
    // proxy
    ShepherdLogManager.setRequestIp(request.getRemoteAddr(), request.getHeader("X-Forwarded-For"));
    log.debug("**** servlets.SLS ***");
    response.setCharacterEncoding("UTF-8");
    request.setCharacterEncoding("UTF-8");
    HttpSession ses = request.getSession(true);
    if (Validate.validateSession(ses)) {
      ShepherdLogManager.setRequestIp(
          request.getRemoteAddr(),
          request.getHeader("X-Forwarded-For"),
          ses.getAttribute("userName").toString());
      log.debug("Current User: " + ses.getAttribute("userName").toString());
      Cookie tokenCookie = Validate.getToken(request.getCookies());
      Object tokenParmeter = request.getParameter("csrfToken");

      if (LoginMethod.isSaml()) {

        Auth auth;
        try {
          auth = new Auth(request, response);
        } catch (SettingsException e) {
          throw new RuntimeException("SAML not configured: " + e.toString());
        } catch (Error e) {
          throw new RuntimeException("SAML error : " + e.toString());
        }

        try {
          auth.processSLO();
        } catch (Exception e) {
          throw new RuntimeException("SAML error when processing response: " + e.toString());
        }

        List<String> errors = auth.getErrors();

        if (errors.isEmpty()) {
          log.debug("SSO Logout completed");
        } else {
          log.debug("Error when performing SSO Logout: " + StringUtils.join(errors, ", "));
        }

        if (Validate.validateTokens(tokenCookie, tokenParmeter)) {
          // Remove Everything
          ses.removeAttribute("userStamp");
          ses.removeAttribute("userName");
          ses.removeAttribute("userRole");
          // Invalid Session on server
          ses.invalidate();
          ses = request.getSession(true);
          // Remove cookie
          Cookie emptyCookie = new Cookie("token", "");
          emptyCookie.setPath("/");
          response.addCookie(emptyCookie);
          log.debug("User Logged Out");
          response.sendRedirect("../login.jsp");
        } else {
          log.error("CSRF Attack Detected");
          response.sendRedirect("../index.jsp");
        }
      }
    } else {
      log.error("SLS Function Called with no valid session");
      response.sendRedirect("../login.jsp");
    }
    log.debug("*** END SLS ***");
  }
}