/*
    * Copyright 2001,2004 The Apache Software Foundation.
    * 
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    * 
    *      http://www.apache.org/licenses/LICENSE-2.0
    * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.jetspeed.modules.actions;
  
  // Turbine Classes
  import org.apache.turbine.TurbineConstants;
  import org.apache.turbine.util.RunData;
  import org.apache.turbine.modules.actions.sessionvalidator.SessionValidator;
  import org.apache.jetspeed.services.rundata.JetspeedRunData;
  import org.apache.jetspeed.services.resources.JetspeedResources;
  import org.apache.jetspeed.services.JetspeedSecurity;
  
  /***
   * SessionValidator for use with the Template Service, the
   * TemplateSessionValidator is virtually identical to the
   * TemplateSecureValidator except that it does not tranfer to the
   * login page when it detects a null user (or a user not logged in).
   *
   * <p>The Template Service requires a different Session Validator
   * because of the way it handles screens.
   *
   * @see TemplateSecureSessionValidator
   * @author <a href="mailto:john.mcnally@clearink.com">John D. McNally</a>
   * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
   * @version $Id: TemplateSessionValidator.java,v 1.3 2004/02/23 02:59:06 jford Exp $
   */
  public class TemplateSessionValidator extends SessionValidator
  {
      /***
       * Execute the action.
       *
       * @param data Turbine information.
       * @exception Exception, a generic exception.
       */
      public void doPerform( RunData rundata ) throws Exception
      {
          JetspeedRunData data = (JetspeedRunData)rundata;
          /*
           * Pull user from session.
           */
          data.populate();
  
          // The user may have not logged in, so create a "guest" user.
          if ( data.getUser() == null)
          {
              data.setUser(JetspeedSecurity.getAnonymousUser());
              data.save();
          }
  
          // make sure we have some way to return a response
          if ( !data.hasScreen() &&
               data.getTemplateInfo().getScreenTemplate() == null )
          {
              String template = JetspeedResources.getString(
                  TurbineConstants.TEMPLATE_HOMEPAGE);
  
              if (template != null)
              {
                  data.getTemplateInfo().setScreenTemplate(template);
              }
              else
              {
                  data.setScreen(JetspeedResources.getString(
                      TurbineConstants.SCREEN_HOMEPAGE));
              }
          }
          // the session_access_counter can be placed as a hidden field in
          // forms.  This can be used to prevent a user from using the
          // browsers back button and submitting stale data.
          else if ( data.getParameters().containsKey("_session_access_counter") )
          {
              // See comments in screens.error.InvalidState.
              if ( data.getParameters().getInt("_session_access_counter") <
                  (((Integer)data.getUser().getTemp("_session_access_counter"))
                  .intValue()-1) )
              {
                  if (data.getTemplateInfo().getScreenTemplate() != null)
                  {
                      data.getUser().setTemp( "prev_template",
                          data.getTemplateInfo().getScreenTemplate()
                          .replace('/', ',') );
                      data.getTemplateInfo().setScreenTemplate(
                          JetspeedResources.getString(
                          TurbineConstants.TEMPLATE_INVALID_STATE) );
                  }
                  else
                 {
                     data.getUser().setTemp( "prev_screen",
                         data.getScreen().replace('/', ',') );
                     data.setScreen( JetspeedResources.getString(
                         TurbineConstants.SCREEN_INVALID_STATE) );
                 }
                 data.getUser().setTemp("prev_parameters", data.getParameters());
                 data.setAction( "" );
             }
         }
 
         // we do not want to allow both a screen and template parameter.
         // The template parameter is dominant.
         if ( data.getTemplateInfo().getScreenTemplate() != null )
         {
             data.setScreen(null);
         }
     }
 
     /***
      * By default, this is true. It says that we require a new session
      * in order to allow people to access the system. We accomplish
      * this by doing a redirect and using the HttpSession spec.
      *
      * @param data Turbine information.
      * @return True if we require a new session in order to allow
      * people to access the system.
      */
     public boolean requiresNewSession(RunData data)
     {
         return true;
     }
 }