/*
    * 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.config;
  
  import java.io.IOException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Enumeration;
  import java.util.List;
  
  import javax.faces.context.ExternalContext;
  import org.apache.myfaces.shared.config.MyfacesConfig;
  
  import org.apache.myfaces.shared.util.ClassUtils;
  import org.apache.myfaces.spi.FacesConfigResourceProvider;
  import org.apache.myfaces.util.ContainerUtils;
  import org.apache.myfaces.config.util.GAEUtils;
  import org.apache.myfaces.view.facelets.util.Classpath;
  
  /**
   * 
   * @since 2.0.2
   * @author Leonardo Uribe
   */
  public class DefaultFacesConfigResourceProvider extends FacesConfigResourceProvider
  {
      private static final String META_INF_PREFIX = "META-INF/";
  
      private static final String FACES_CONFIG_SUFFIX = ".faces-config.xml";
      
      /**
       * <p>Resource path used to acquire implicit resources buried
       * inside application JARs.</p>
       */
      private static final String FACES_CONFIG_IMPLICIT = "META-INF/faces-config.xml";
  
  
      public DefaultFacesConfigResourceProvider()
      {
          super();
      }
  
      @Override
      public Collection<URL> getMetaInfConfigurationResources(
              ExternalContext context) throws IOException
      {
          List<URL> urlSet = new ArrayList<URL>();
          
          //This usually happens when maven-jetty-plugin is used
          //Scan jars looking for paths including META-INF/faces-config.xml
          Enumeration<URL> resources = getClassLoader().getResources(FACES_CONFIG_IMPLICIT);
          while (resources.hasMoreElements())
          {
              urlSet.add(resources.nextElement());
          }
  
          String jarFilesToScanParam = MyfacesConfig.getCurrentInstance(context).getGaeJsfJarFiles();
          jarFilesToScanParam = jarFilesToScanParam != null ? jarFilesToScanParam.trim() : null;
          if (ContainerUtils.isRunningOnGoogleAppEngine(context) && 
              jarFilesToScanParam != null &&
              jarFilesToScanParam.length() > 0)
          {
              Collection<URL> urlsGAE = GAEUtils.searchInWebLib(
                      context, getClassLoader(), jarFilesToScanParam, META_INF_PREFIX, FACES_CONFIG_SUFFIX);
              if (urlsGAE != null)
              {
                  urlSet.addAll(urlsGAE);
              }
          }
          else
          {
              //Scan files inside META-INF ending with .faces-config.xml
              URL[] urls = Classpath.search(getClassLoader(), META_INF_PREFIX, FACES_CONFIG_SUFFIX);
              for (int i = 0; i < urls.length; i++)
              {
                  urlSet.add(urls[i]);
              }
          }
          
          return urlSet;
      }
  
     private ClassLoader getClassLoader()
     {
         ClassLoader loader = ClassUtils.getContextClassLoader();
         if (loader == null)
         {
             loader = this.getClass().getClassLoader();
         }
         return loader;
     }
 }