/*
    * 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.commons.renderOne;
  
  import java.io.IOException;
  import java.util.Iterator;
  
  import javax.faces.component.UIComponent;
  import javax.faces.component.UIComponentBase;
  import javax.faces.context.FacesContext;
  
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFComponent;
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFProperty;
  
  /**
   * Tag that allows rendering the first child either by index or the first
   * rendered one.
   * <p>
   * A component that only renders the first child either by index or the first
   * visible one..
   * </p>
   *   
   * @author Andrew Robinson (latest modification by $Author: lu4242 $)
   * @version $Revision: 1021614 $ $Date: 2010-10-11 22:44:07 -0500 (Mon, 11 Oct 2010) $
   */
  @JSFComponent(
          name = "mc:renderOne",
          clazz = "org.apache.myfaces.commons.renderOne.UIRenderOne",
          tagClass = "org.apache.myfaces.commons.renderOne.UIRenderOneTag")
  public abstract class AbstractUIRenderOne extends UIComponentBase
  {
      public static final String COMPONENT_FAMILY = "javax.faces.Data";
      public static final String COMPONENT_TYPE = "org.apache.myfaces.commons.UILimitRendered";
      private static final String RENDERONE_TYPE_FIRST = "first";
      private static final String RENDERONE_TYPE_INDEX = "index";
      private static final Integer FIRST_ITEM_INDEX = new Integer("0");
  
      /**
       * The filter type: first|index. first: the first list value should evaluate to a Number 
       * or a value that can be parsed into an integer. index: A collection, 
       * array or comma-separated list of numbers. (Default: "first")
       * 
       * @return the type
       */
      @JSFProperty
      public abstract String getType();
  
      /**
       * @param type the type to set
       */
      public abstract void setType(String type);
  
      /**
       *  The value valid for the type. If this evaluates to null, the first child will 
       *  be rendered. 
       *  If the type is "first", this value will be ignored, as "first" always
       *  renders the first rendered item. 
       *  If the type is "index", the value must be a number.      
       *   
       * @return the value
       */
      @JSFProperty
      public abstract Integer getValue();
  
      /**
       * @param value the value to set
       */
      public abstract void setValue(Integer value);
  
      /**
       * @see javax.faces.component.UIComponentBase#getRendersChildren()
       */
      public boolean getRendersChildren()
      {
          return true;
      }
  
      /**
       * @see javax.faces.component.UIComponentBase#encodeChildren(javax.faces.context.FacesContext)
       */
      public void encodeChildren(FacesContext context) throws IOException
      {
          if (!isRendered())
         {
             return;
         }
 
         renderChild(context, (UIComponent) selectOneChild());
     }
 
     /**
      * TODO:Copied from shared_tomahawk.renderkit.RendererUtils
      * It could be good to move it to myfaces commons utils
      */
     private static void renderChild(FacesContext facesContext, UIComponent child)
             throws IOException
     {
         if (!child.isRendered())
         {
             return;
         }
 
         child.encodeBegin(facesContext);
         if (child.getRendersChildren())
         {
             child.encodeChildren(facesContext);
         }
         else
         {
             renderChildren(facesContext, child);
         }
         child.encodeEnd(facesContext);
     }
 
     /**
      * TODO:Copied from shared_tomahawk.renderkit.RendererUtils
      * It could be good to move it to myfaces commons utils
      */
     private static void renderChildren(FacesContext facesContext,
             UIComponent component) throws IOException
     {
         if (component.getChildCount() > 0)
         {
             for (Iterator it = component.getChildren().iterator(); it.hasNext();)
             {
                 UIComponent child = (UIComponent) it.next();
                 renderChild(facesContext, child);
             }
         }
     }
 
     protected Object selectOneChild()
     {
 
         Integer value = getValue();
         String type = getType();
 
         // default is render by count.
         if (type == null)
         {
             type = RENDERONE_TYPE_FIRST;
         }
 
         // render by index case.
         if (RENDERONE_TYPE_INDEX.equals(type))
         {
 
             // if value by index is not specified then the first element will be 
             // rendered only.
             if (value == null)
             {
                 value = FIRST_ITEM_INDEX;
             }
 
             // select the child by index.
             return selectFirstChildByIndex(value);
         }
 
         // render by count case.
         if (RENDERONE_TYPE_FIRST.equals(type))
         {
 
             // select the first child that has rendered="true".
             return selectFirstChildOnly();
         }
         else
         {
             throw new IllegalArgumentException("type");
         }
     }
 
     protected Object selectFirstChildOnly()
     {
         for (Iterator iter = getChildren().iterator(); iter.hasNext();)
         {
             UIComponent child = (UIComponent) iter.next();
             if (child.isRendered())
             {
                 return child;
             }
         }
 
         return null;
     }
 
     protected Object selectFirstChildByIndex(Integer value)
     {
         return getChildren().get(value.intValue());
     }
 }