/*
    * 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.custom.autoscroll;
  
  import java.io.IOException;
  
  import javax.faces.component.UIComponent;
  import javax.faces.component.UIViewRoot;
  import javax.faces.view.facelets.BehaviorConfig;
  import javax.faces.view.facelets.BehaviorHandler;
  import javax.faces.view.facelets.FaceletContext;
  
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFFaceletTag;
  
  /**
   * @since 1.1.10
   * @author Leonardo Uribe (latest modification by $Author: lu4242 $)
   * @version $Revision: 691856 $ $Date: 2008-09-03 21:40:30 -0500 (mié, 03 sep 2008) $
   */
  @JSFFaceletTag(name="t:autoScroll", behaviorClass="org.apache.myfaces.custom.autoscroll.AutoscrollBehavior")
  public class AutoscrollBehaviorTagHandler extends BehaviorHandler
  {
  
      public static final String AUTOSCROLL_TAG_ON_PAGE = "oam.autoscroll.AUTOSCROLL_TAG_ON_PAGE";
      
      public AutoscrollBehaviorTagHandler(BehaviorConfig config)
      {
          super(config);
      }
  
      @Override
      public void apply(FaceletContext ctx, UIComponent parent)
              throws IOException
      {
          super.apply(ctx, parent);
          
          UIViewRoot root = getViewRoot(ctx, parent);
          
          if (!root.getAttributes().containsKey(AUTOSCROLL_TAG_ON_PAGE))
          {
              root.getAttributes().put(AUTOSCROLL_TAG_ON_PAGE, Boolean.TRUE);
          }
      }
      
      private UIViewRoot getViewRoot(FaceletContext ctx, UIComponent parent)
      {
          UIComponent c = parent;
          do
          {
              if (c instanceof UIViewRoot)
              {
                  return (UIViewRoot) c;
              }
              else
              {
                  c = c.getParent();
              }
          } while (c != null);
  
          return ctx.getFacesContext().getViewRoot();
      }
  }