/*
    * 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.tomahawk.application;
  
  import java.io.IOException;
  import java.util.Map;
  
  import javax.faces.FacesException;
  import javax.faces.application.ViewHandler;
  import javax.faces.application.ViewHandlerWrapper;
  import javax.faces.component.UIComponent;
  import javax.faces.component.UIViewRoot;
  import javax.faces.context.FacesContext;
  
  import org.apache.myfaces.custom.autoscroll.AutoscrollBehaviorTagHandler;
  import org.apache.myfaces.custom.autoscroll.AutoscrollBodyScript;
  import org.apache.myfaces.custom.autoscroll.AutoscrollHiddenField;
  import org.apache.myfaces.renderkit.html.util.AddResource;
  import org.apache.myfaces.renderkit.html.util.AddResourceFactory;
  import org.apache.myfaces.shared_tomahawk.config.MyfacesConfig;
  import org.apache.myfaces.shared_tomahawk.renderkit.JSFAttr;
  import org.apache.myfaces.tomahawk.util.TomahawkResourceUtils;
  
  public class ResourceViewHandlerWrapper extends ViewHandlerWrapper
  {
      private ViewHandler _delegate;
  
      public ResourceViewHandlerWrapper(ViewHandler delegate)
      {
          super();
          _delegate = delegate;
      }
  
      @Override
      public ViewHandler getWrapped()
      {
          return _delegate;
      }
  
      @Override
      public void renderView(FacesContext context, UIViewRoot viewToRender)
              throws IOException, FacesException
      {
          if (MyfacesConfig.getCurrentInstance(context.getExternalContext()).isAutoScroll() ||
              viewToRender.getAttributes().containsKey(AutoscrollBehaviorTagHandler.AUTOSCROLL_TAG_ON_PAGE))
          {
              AddResource addResource = AddResourceFactory.getInstance(context);
  
              if (!addResource.requiresBuffer())
              {
                  //If the response is buffered, addResource instance takes
                  //the responsability of render this script.
                  AutoscrollBodyScript autoscrollBodyScript = (AutoscrollBodyScript) 
                      context.getApplication().createComponent(context, 
                          AutoscrollBodyScript.COMPONENT_TYPE,
                          AutoscrollBodyScript.DEFAULT_RENDERER_TYPE);
                  autoscrollBodyScript.setTransient(true);
                  autoscrollBodyScript.getAttributes().put(
                          JSFAttr.TARGET_ATTR, 
                          TomahawkResourceUtils.BODY_LOCATION);
                  viewToRender.addComponentResource(context, autoscrollBodyScript);
              }
              
              AutoscrollHiddenField autoscrollHiddenField = (AutoscrollHiddenField) context.getApplication().
                  createComponent(context, 
                          AutoscrollHiddenField.COMPONENT_TYPE,
                          AutoscrollHiddenField.DEFAULT_RENDERER_TYPE);
              autoscrollHiddenField.setTransient(true);
              autoscrollHiddenField.getAttributes().put(JSFAttr.TARGET_ATTR, TomahawkResourceUtils.FORM_LOCATION);
              viewToRender.addComponentResource(context, autoscrollHiddenField);
          }
          
          //Reset the added resource 
          TomahawkResourceUtils.resetAddedResources(context);
          
          _publishPreRenderViewAddResourceEvent(context, viewToRender);
          super.renderView(context, viewToRender);
      }
      
      private void _publishPreRenderViewAddResourceEvent(FacesContext context, UIComponent component)
      {
          context.getApplication().publishEvent(context,  PreRenderViewAddResourceEvent.class, UIComponent.class, component);
          
         //Scan children
         if (component.getChildCount() > 0)
         {
             for (UIComponent child : component.getChildren())
             {
                 _publishPreRenderViewAddResourceEvent(context, child);
             }
         }
 
         //Scan facets
         if (component.getFacetCount() > 0)
         {
             for (Map.Entry<String, UIComponent> entry : component.getFacets().entrySet())
             {
                 _publishPreRenderViewAddResourceEvent(context, entry.getValue());
             }
         }
     }
 }