//
   // Copyright (c) 2003-2005, Caltha - Gajda, Krzewski, Mach, Potempski Sp.J. 
   // All rights reserved. 
   //
   // Redistribution and use in source and binary forms, with or without modification,  
   // are permitted provided that the following conditions are met: 
   //
   // * Redistributions of source code must retain the above copyright notice,  
   //   this list of conditions and the following disclaimer. 
  // * Redistributions in binary form must reproduce the above copyright notice,  
  //   this list of conditions and the following disclaimer in the documentation  
  //   and/or other materials provided with the distribution. 
  // * Neither the name of the Caltha - Gajda, Krzewski, Mach, Potempski Sp.J.  
  //   nor the names of its contributors may be used to endorse or promote products  
  //   derived from this software without specific prior written permission. 
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"  
  // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED  
  // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
  // IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,  
  // INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,  
  // BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
  // OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,  
  // WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)  
  // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE  
  // POSSIBILITY OF SUCH DAMAGE.
  //
  package org.objectledge.authentication;
  
  import java.security.Principal;
  import java.util.Date;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  import javax.servlet.http.HttpSession;
  import javax.servlet.http.HttpSessionBindingEvent;
  import javax.servlet.http.HttpSessionBindingListener;
  
  import org.objectledge.context.Context;
  import org.objectledge.pipeline.ProcessingException;
  import org.objectledge.pipeline.Valve;
  import org.objectledge.web.HttpContext;
  
  /***
   * A valve that 
   * 
   * @version $Id: UserTrackingValve.java,v 1.1 2005/07/26 09:25:47 rafal Exp $
   * @author <a href="mailto:rafal@caltha.pl">Rafal Krzewski</a>
   */
  public class UserTrackingValve
      implements Valve
  {
      private final Map<Principal,PunchCard> cardRack = new HashMap<Principal,PunchCard>();
      
      /***
       * {@inheritDoc}
       */
      public void process(Context context)
          throws ProcessingException
      {
          AuthenticationContext authContext = AuthenticationContext.getAuthenticationContext(context);
          if(authContext != null && authContext.isUserAuthenticated())
          {
              synchronized(cardRack)
              {
                  Principal principal = authContext.getUserPrincipal();
                  PunchCard card = cardRack.get(principal);
                  if(card == null)
                  {
                      card =  new PunchCard(principal);
                      cardRack.put(principal, card);
                      HttpContext httpContext = HttpContext.getHttpContext(context);
                      HttpSession session = httpContext.getRequest().getSession();
                      session.setAttribute(PunchCard.class.getName(), card);
                  }
                  else
                  {
                      card.touch();
                  }
              }
          }
      }
  
      /***
       * Returns the principals of all users that have an active session.
       * 
       * @return a set of principal objects.
       */
      public Set<Principal> getLoggedInUsers()
      {
          synchronized(cardRack)
          {
              return new HashSet<Principal>(cardRack.keySet());
          }
      }
      
      /***
      * Returns the timestamp of user's most recent click.
      * 
      * @param principal the users's principal.
      * @return the timestamp of user's most recent click, or null if user is not logged in.
      */
     public Date getLastClickTime(Principal principal)
     {
         synchronized(cardRack)
         {
             PunchCard card = cardRack.get(principal);
             if(card != null)
             {
                 return card.getLastClickTime();
             }
             else
             {
                 return null;
             }
         }
     }
     
     void checkOut(PunchCard card)
     {
         synchronized(cardRack)
         {
             cardRack.remove(card.getPrincipal());
         }        
     }
     
     /***
      * A user's puch card.
      */
     private class PunchCard 
         implements HttpSessionBindingListener
     {
         private final Principal principal;
         
         private Date lastClickTime;
 
         public PunchCard(Principal principal) {
             this.principal = principal;
             this.lastClickTime = new Date();
         }
         
         public Principal getPrincipal() {
             return principal;
         }
         
         public void touch() {
             lastClickTime = new Date();
         }
         
         public Date getLastClickTime() {
             return lastClickTime;
         }                
 
         /***
          * {@inheritDoc}
          */
         public void valueBound(HttpSessionBindingEvent arg0)
         {
             // ingnore
         }
 
         /***
          * {@inheritDoc}
          */
         public void valueUnbound(HttpSessionBindingEvent event)
         {
             if(event.getValue() instanceof PunchCard)
             {
                 checkOut((PunchCard)event.getValue());
             }
         }
     }
 }