/*
    * 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.resource;
  
  import java.io.IOException;
  import java.net.URL;
  import java.util.HashSet;
  import java.util.Set;
  import javax.faces.application.ResourceHandler;
  import javax.faces.context.ExternalContext;
  import org.apache.myfaces.shared.util.ClassUtils;
  import org.apache.myfaces.shared.util.WebConfigParamUtils;
  import org.apache.myfaces.spi.ResourceLibraryContractsProvider;
  import org.apache.myfaces.view.facelets.util.Classpath;
  
  /**
   *
   * @author Leonardo Uribe
   */
  public class DefaultResourceLibraryContractsProvider extends ResourceLibraryContractsProvider
  {
      private static final String META_INF_CONTRACTS_PREFIX = "META-INF/contracts/";
      private static final String META_INF_CONTRACTS_SUFFIX = "javax.faces.contract.xml";
      private static final String META_INF_CONTRACTS_FILE = "/javax.faces.contract.xml";
      private static final String CONTRACTS = "contracts";
  
      @Override
      public Set<String> getExternalContextResourceLibraryContracts(ExternalContext context)
          throws IOException
      {
          String directory = WebConfigParamUtils.getStringInitParameter(context, 
              ResourceHandler.WEBAPP_CONTRACTS_DIRECTORY_PARAM_NAME, CONTRACTS);
          
          if (directory.startsWith("/"))
          {
              throw new IllegalStateException("javax.faces.WEBAPP_CONTRACTS_DIRECTORY cannot start with '/");
          }
          if (directory.endsWith("/"))
          {
              directory = directory.substring(0, directory.length()-1);
          }
          
          directory = "/"+directory+"/";
          Set<String> contracts = new HashSet<String>();
          Set<String> paths = context.getResourcePaths(directory);
          if (paths != null)
          {
              for (String path : paths)
              {
                  if (path.endsWith("/"))
                  {
                      //Add all subdirectories no questions asked.
                      contracts.add(path.substring(directory.length(), path.length()-1));
                  }
              }
          }
          return contracts;
      }
  
      @Override
      public Set<String> getClassloaderResourceLibraryContracts(ExternalContext context)
          throws IOException
      {
          Set<String> contracts = new HashSet<String>();
          URL[] urls = Classpath.search(getClassLoader(), 
              META_INF_CONTRACTS_PREFIX, META_INF_CONTRACTS_SUFFIX);
          for (int i = 0; i < urls.length; i++)
          {
              String urlString = urls[i].toExternalForm();
              int suffixPos = urlString.lastIndexOf(META_INF_CONTRACTS_FILE);
              int slashPos = urlString.lastIndexOf('/', suffixPos-1);
              if (suffixPos > 0 && slashPos > 0)
              {
                  contracts.add(urlString.substring(slashPos+1, suffixPos));
              }
          }
          return contracts;
      }
  
      private ClassLoader getClassLoader()
      {
          ClassLoader loader = ClassUtils.getContextClassLoader();
          if (loader == null)
         {
             loader = this.getClass().getClassLoader();
         }
         return loader;
     }
 }