/*
    * 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.ajaxchildcombobox;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.myfaces.custom.ajax.api.AjaxRenderer;
  import org.apache.myfaces.custom.dojo.DojoConfig;
  import org.apache.myfaces.custom.dojo.DojoUtils;
  import org.apache.myfaces.renderkit.html.ext.HtmlMenuRenderer;
  import org.apache.myfaces.renderkit.html.util.AddResource;
  import org.apache.myfaces.renderkit.html.util.AddResourceFactory;
  import org.apache.myfaces.shared_tomahawk.renderkit.JSFAttr;
  import org.apache.myfaces.shared_tomahawk.renderkit.RendererUtils;
  import org.apache.myfaces.shared_tomahawk.renderkit.html.HTML;
  import org.apache.myfaces.shared_tomahawk.renderkit.html.HtmlRendererUtils;
  
  import javax.faces.component.UIComponent;
  import javax.faces.component.UINamingContainer;
  import javax.faces.context.FacesContext;
  import javax.faces.context.ResponseWriter;
  import javax.faces.el.MethodBinding;
  import javax.faces.model.SelectItem;
  import javax.servlet.ServletResponse;
  import java.io.IOException;
  import java.io.PrintWriter;
  
  /**
   * Renderer for component HtmlAjaxChildComboBox
   * 
   * @JSFRenderer
   *   renderKitId = "HTML_BASIC" 
   *   family = "javax.faces.SelectOne"
   *   type = "org.apache.myfaces.AjaxChildComboBox"
   *
   * @author Sharath Reddy
   */
  public class HtmlAjaxChildComboBoxRenderer extends HtmlMenuRenderer implements AjaxRenderer
  {
      private static final String BEGIN_OPTION = "<option>";
      private static final String END_OPTION = "</option>";
      private static final String BEGIN_OPTION_TEXT = "<optionText>";
      private static final String END_OPTION_TEXT = "</optionText>";
      private static final String BEGIN_OPTION_VALUE = "<optionValue>";
      private static final String END_OPTION_VALUE = "</optionValue>";
  
      public static final int DEFAULT_MAX_SUGGESTED_ITEMS = 200;
  
      private static Log log = LogFactory.getLog(HtmlAjaxChildComboBoxRenderer.class);
  
      // Adds the javascript files needed by Dojo and the custom javascript for
      // this
      // component
      private void encodeJavascript(FacesContext context, UIComponent component)
          throws IOException
      {
          String javascriptLocation = (String) component.getAttributes().get(JSFAttr.JAVASCRIPT_LOCATION);
          DojoUtils.addMainInclude(context, component, javascriptLocation, new DojoConfig());
          DojoUtils.addRequire(context, component, "dojo.event.*");
          // not required - and results in an error
          // DojoUtils.addRequire(context, component, "dojo.io.bind");
  
          AddResource addResource = AddResourceFactory.getInstance(context);
  
          addResource.addJavaScriptAtPosition(context,
              AddResource.HEADER_BEGIN, AjaxChildComboBox.class, "javascript/ajaxChildComboBox.js");
      }
  
      public void encodeEnd(FacesContext context, UIComponent component) throws IOException
      {
          RendererUtils.checkParamValidity(context, component, AjaxChildComboBox.class);
  
          AjaxChildComboBox childComboBox = (AjaxChildComboBox) component;
  
          super.encodeEnd(context, component);
  
          String clientId = component.getClientId(context);
  
          UIComponent parentComboBox = this.getParentComboBox(childComboBox);
          if (parentComboBox == null)
          {
              log.error("Could not find parent combo box for AjaxChildComboBox " +
                  childComboBox.getClientId(context));
             return;
         }
 
         encodeJavascript(context, component);
 
         ResponseWriter writer = context.getResponseWriter();
 
         // Begin: Write out the javascript that hooks up this component with the
         // parent combo-box
         writer.startElement(HTML.SCRIPT_ELEM, component);
         writer.writeAttribute(HTML.SCRIPT_TYPE_ATTR, HTML.SCRIPT_TYPE_TEXT_JAVASCRIPT, null);
 
         writer.write("var parentCombo = document.getElementById('" +
             parentComboBox.getClientId(context) + "');");
         HtmlRendererUtils.writePrettyLineSeparator(context);
         writer.write("dojo.event.connect(parentCombo, 'onchange', function(evt) { ");
         HtmlRendererUtils.writePrettyLineSeparator(context);
         writer.write("var targetElement = evt.target;");
         writer.write("var targetValue = targetElement.options[targetElement.selectedIndex].value;");
         HtmlRendererUtils.writePrettyLineSeparator(context);
         writer.write("reloadChildComboBox('" + clientId + "', targetValue);");
         HtmlRendererUtils.writePrettyLineSeparator(context);
         writer.write("});");
         writer.endElement(HTML.SCRIPT_ELEM);
         // End: Javascript
     }
 
 
     // creates the XML response that is sent back to the browser
     public void encodeAjax(FacesContext context, UIComponent uiComponent)
         throws IOException
     {
 
         String parentValue = (String) context.getExternalContext().
             getRequestParameterMap().get("parentValue");
 
         ServletResponse response = (ServletResponse) context.getExternalContext().getResponse();
         PrintWriter writer = response.getWriter();
 
         StringBuffer xml = new StringBuffer();
 
         MethodBinding mb = ((AjaxChildComboBox) uiComponent).getAjaxSelectItemsMethod();
         SelectItem[] options = (SelectItem[])
             mb.invoke(context, new Object[]{parentValue});
 
         xml.append("<?xml version=\"1.0\"?>\n");
         xml.append("<response>\n");
         for (int i = 0; i < options.length; i++)
         {
             xml.append(BEGIN_OPTION);
             xml.append(BEGIN_OPTION_TEXT).append(options[i].getLabel()).append(END_OPTION_TEXT);
             xml.append(BEGIN_OPTION_VALUE).append(options[i].getValue()).append(END_OPTION_VALUE);
             xml.append(END_OPTION);
         }
         xml.append("</response>");
 
         writer.write(xml.toString());
 
     }
 
     private UIComponent getParentComboBox(AjaxChildComboBox comboBox)
     {
         String parentId = comboBox.getParentComboBox();
 
         UIComponent parentComboBox = comboBox.findComponent(parentId);
         if (parentComboBox != null)
         {
             return parentComboBox;
         }
 
         // try searching from the very root of the component tree
         return comboBox.findComponent(UINamingContainer.SEPARATOR_CHAR + parentId);
     }
 }