/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.myfaces.shared.context;
  
  import javax.faces.context.ExceptionHandler;
  import javax.faces.context.ExceptionHandlerWrapper;
  import javax.faces.context.FacesContext;
  import javax.faces.context.PartialViewContext;
  import javax.faces.event.AbortProcessingException;
  import javax.faces.event.ExceptionQueuedEvent;
  import javax.faces.event.ExceptionQueuedEventContext;
  import javax.faces.event.SystemEvent;
  
  /**
   * This wrapper is a switch to choose in a lazy way between ajax and
   * normal exceptionHandler wrapping, because FacesContext is initialized after
   * ExceptionHandler, so it is not safe to get it when
   * ExceptionHandlerFactory.getExceptionHandler() is called.
   */
  public class SwitchAjaxExceptionHandlerWrapperImpl extends ExceptionHandlerWrapper
  {
      private ExceptionHandler _requestExceptionHandler;
      private ExceptionHandler _ajaxExceptionHandler;
      private Boolean _isAjaxRequest;
      
      public SwitchAjaxExceptionHandlerWrapperImpl(
              ExceptionHandler requestExceptionHandler,
              ExceptionHandler ajaxExceptionHandler)
      {
          _requestExceptionHandler = requestExceptionHandler;
          _ajaxExceptionHandler = ajaxExceptionHandler;
      }
      
      @Override
      public void processEvent(SystemEvent exceptionQueuedEvent)
              throws AbortProcessingException
      {
          //Check if this is an ajax request, but take advantage of exceptionQueuedEvent facesContext
          isAjaxRequest(exceptionQueuedEvent);
          super.processEvent(exceptionQueuedEvent);
      }
  
      protected boolean isAjaxRequest(SystemEvent exceptionQueuedEvent)
      {
          if (_isAjaxRequest == null)
          {
              if (exceptionQueuedEvent instanceof ExceptionQueuedEvent)
              {
                  ExceptionQueuedEvent eqe = (ExceptionQueuedEvent)exceptionQueuedEvent;
                  ExceptionQueuedEventContext eqec = eqe.getContext();
                  if (eqec != null)
                  {
                      FacesContext facesContext = eqec.getContext();
                      if (facesContext != null)
                      {
                          return isAjaxRequest(facesContext);
                      }
                  }
              }
              return isAjaxRequest();
          }
          return _isAjaxRequest;
      }
      
      protected boolean isAjaxRequest(FacesContext facesContext)
      {
          if (_isAjaxRequest == null)
          {
              facesContext = (facesContext == null) ? FacesContext.getCurrentInstance() : facesContext;
              PartialViewContext pvc = facesContext.getPartialViewContext();
              if (pvc == null)
              {
                  return false;
              }
              _isAjaxRequest = pvc.isAjaxRequest();
          }
          return _isAjaxRequest;
      }
      
      protected boolean isAjaxRequest()
      {
          if (_isAjaxRequest == null)
          {
             FacesContext facesContext = FacesContext.getCurrentInstance();
             PartialViewContext pvc = facesContext.getPartialViewContext();
             if (pvc == null)
             {
                 return false;
             }
             _isAjaxRequest = pvc.isAjaxRequest();
         }
         return _isAjaxRequest;
     }
     
     @Override
     public ExceptionHandler getWrapped()
     {
         if (isAjaxRequest())
         {
             return _ajaxExceptionHandler;
         }
         else
         {
             return _requestExceptionHandler;
         }
     }
 }