/*
    * 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.view.facelets.tag.composite;
  
  import java.lang.reflect.Method;
  import java.net.URL;
  
  import javax.faces.FacesException;
  import javax.faces.application.Resource;
  import javax.faces.application.ResourceHandler;
  import javax.faces.context.FacesContext;
  import javax.faces.view.facelets.ComponentConfig;
  import javax.faces.view.facelets.FaceletHandler;
  import javax.faces.view.facelets.Tag;
  import javax.faces.view.facelets.TagConfig;
  import javax.faces.view.facelets.TagHandler;
  
  import org.apache.myfaces.view.facelets.tag.TagLibrary;
  
  /**
   * This class create composite component tag handlers for "http://java.sun.com/jsf/composite/"
   * namespace. Note that the class that create composite component tag handlers using its own 
   * namespace defined in facelet taglib .xml file see TagLibraryConfig.TagLibraryImpl
   * 
   * @author Leonardo Uribe (latest modification by $Author: lu4242 $)
   * @version $Revision: 1300254 $ $Date: 2012-03-13 12:38:40 -0500 (Tue, 13 Mar 2012) $
   */
  public class CompositeResourceLibrary implements TagLibrary
  {
      public final static String NAMESPACE_PREFIX = "http://java.sun.com/jsf/composite/";
      
      private final ResourceHandler _resourceHandler;
      
      public CompositeResourceLibrary(FacesContext facesContext)
      {
          _resourceHandler = facesContext.getApplication().getResourceHandler();
      }
      
      public boolean containsFunction(String ns, String name)
      {
          // Composite component tag library does not suport functions
          return false;
      }
  
      public boolean containsNamespace(String ns)
      {
          if (ns != null && ns.startsWith(NAMESPACE_PREFIX))
          {
              if (ns.length() > NAMESPACE_PREFIX.length())
              {
                  String libraryName = ns.substring(NAMESPACE_PREFIX.length());
                  return _resourceHandler.libraryExists(libraryName);
              }
          }        
          return false;
      }
  
      public boolean containsTagHandler(String ns, String localName)
      {
          if (ns != null && ns.startsWith(NAMESPACE_PREFIX))
          {
              if (ns.length() > NAMESPACE_PREFIX.length())
              {
                  String libraryName = ns.substring(NAMESPACE_PREFIX.length());
                  String resourceName = localName + ".xhtml";
                  Resource compositeComponentResource = _resourceHandler.createResource(resourceName, libraryName);
                  if (compositeComponentResource != null)
                  {
                      URL url = compositeComponentResource.getURL();
                      return (url != null);
                  }
              }
          }
          return false;
      }
  
      public Method createFunction(String ns, String name)
      {
          // Composite component tag library does not suport functions
          return null;
      }
  
      public TagHandler createTagHandler(String ns, String localName,
             TagConfig tag) throws FacesException
     {
         if (ns != null && ns.startsWith(NAMESPACE_PREFIX))
         {
             if (ns.length() > NAMESPACE_PREFIX.length())
             {
                 String libraryName = ns.substring(NAMESPACE_PREFIX.length());
                 String resourceName = localName + ".xhtml";
                 // MYFACES-3308 If a composite component exists, it requires to 
                 // be always resolved. In other words, it should always exists a default.
                 // The call here for resourceHandler.createResource, just try to get
                 // the Resource and if it does not exists, it just returns null.
                 // The intention of this code is just create an instance and pass to
                 // CompositeComponentResourceTagHandler. Then, its values 
                 // (resourceName, libraryName) will be used to derive the real instance
                 // to use in a view, based on the locale used.
                 Resource compositeComponentResource = new CompositeResouceWrapper(
                     _resourceHandler.createResource(resourceName, libraryName));
                 if (compositeComponentResource != null)
                 {
                     ComponentConfig componentConfig = new ComponentConfigWrapper(tag,
                             "javax.faces.NamingContainer", null);
                     
                     return new CompositeComponentResourceTagHandler(componentConfig, compositeComponentResource);
                 }
             }
         }
         return null;
     }
 
     private static class ComponentConfigWrapper implements ComponentConfig
     {
 
         protected final TagConfig parent;
 
         protected final String componentType;
 
         protected final String rendererType;
 
         public ComponentConfigWrapper(TagConfig parent, String componentType,
                                       String rendererType)
         {
             this.parent = parent;
             this.componentType = componentType;
             this.rendererType = rendererType;
         }
 
         public String getComponentType()
         {
             return this.componentType;
         }
 
         public String getRendererType()
         {
             return this.rendererType;
         }
 
         public FaceletHandler getNextHandler()
         {
             return this.parent.getNextHandler();
         }
 
         public Tag getTag()
         {
             return this.parent.getTag();
         }
 
         public String getTagId()
         {
             return this.parent.getTagId();
         }
     }
 }