/**
    * This file Copyright (c) 2003-2011 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.cms.security;
  
  import info.magnolia.cms.beans.config.ContentRepository;
  import info.magnolia.cms.core.Content;
  import info.magnolia.cms.security.auth.callback.CredentialsCallbackHandler;
  import info.magnolia.cms.security.auth.callback.PlainTextCallbackHandler;
  import info.magnolia.cms.util.ObservationUtil;
  
  import javax.jcr.RepositoryException;
  import javax.jcr.observation.EventIterator;
  import javax.jcr.observation.EventListener;
  import javax.security.auth.Subject;
  import javax.security.auth.login.LoginContext;
  import javax.security.auth.login.LoginException;
  
  import org.apache.commons.lang.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Responsible to handle system users like anonymous and superuser.
   * @author philipp
   * @version $Id: SystemUserManager.java 46856 2011-06-30 12:51:19Z had $
   */
  public class SystemUserManager extends MgnlUserManager {
  
      /**
       * Logger.
       */
      private static Logger log = LoggerFactory.getLogger(SystemUserManager.class);
  
      /**
       * kept as static for performance reasons on live instance. reinitialized on any modification event on anonymous
       * role
       */
      private User anonymousUser;
  
      public SystemUserManager() {
  
          EventListener anonymousListener = new EventListener() {
  
              public void onEvent(EventIterator events) {
                  anonymousUser = null;
                  log.debug("Anonymous user reloaded");
              }
  
          };
  
          final String anonymousUserPath = "/" + Realm.REALM_SYSTEM + "/" + UserManager.ANONYMOUS_USER;
          ObservationUtil.registerChangeListener(
                  ContentRepository.USERS,
                  anonymousUserPath,
                  true,
                  "mgnl:user",
                  anonymousListener);
  
          ObservationUtil.registerChangeListener(
                  ContentRepository.USER_GROUPS,
                  "/",
                  true,
                  "mgnl:group",
                  anonymousListener);
  
          ObservationUtil.registerDeferredChangeListener(
                  ContentRepository.USER_ROLES,
                 "/",
                 true,
                 "mgnl:role",
                 anonymousListener,
                 1000,
                 5000);
     }
 
     @Override
     public String getRealmName() {
         String name = super.getRealmName();
         // attempt to fix: MAGNOLIA-1839
         if (StringUtils.isEmpty(name)) {
             log.error("realm of system user manager is not set!");
             return Realm.REALM_SYSTEM;
         }
         return name;
     }
 
     @Override
     public User getSystemUser() {
         return getOrCreateUser(UserManager.SYSTEM_USER, UserManager.SYSTEM_PSWD);
     }
 
     @Override
     public User getAnonymousUser() {
         if (anonymousUser == null) {
             // see MAGNOLIA-2029
             anonymousUser = getRequiredSystemUser(UserManager.ANONYMOUS_USER, UserManager.ANONYMOUS_USER);
         }
         return anonymousUser;
     }
 
     /**
      * Load a system user from the repository, but don't try to create it if missing.
      */
     private User getRequiredSystemUser(String username, String password) {
         MgnlUser user = null;
         Content node;
         try {
             node = getHierarchyManager().getContent("/" + Realm.REALM_SYSTEM + "/" + username);
         }
         catch (RepositoryException e) {
             log.error("Error caught while loading the system user "
                 + username
                 + ": "
                 + e.getClass().getName()
                 + ": "
                 + e.getMessage(), e);
             return null;
         }
         if (node == null) {
             log.error("User not found: {}.", username);
             return null;
         }
 
         user = userInstance(node);
         Subject subject = getSubject(username, password);
         user.setSubject(subject);
         return user;
     }
 
     protected User getOrCreateUser(String userName, String password) {
         User user = getUser(userName);
         if (user == null) {
             log.error(
                     "Failed to get system user [{}], will try to create new system user with default password",
                     userName);
             user = this.createUser(userName, password);
         }
         return user;
     }
 
     private Subject getSubject(String userName, String password) {
         CredentialsCallbackHandler callbackHandler = new PlainTextCallbackHandler(
                 userName,
                 password.toCharArray(),
                 getRealmName());
         try {
             LoginContext loginContext = new LoginContext("magnolia", callbackHandler);
             loginContext.login();
             return loginContext.getSubject();
         }
         catch (LoginException le) {
             log.error("Failed to login as " + userName + " user", le);
         }
         return null;
     }
 }