//
   //  ========================================================================
   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.websocket.jsr356.server;
  
  import java.util.List;
  import java.util.ServiceLoader;
  
  import javax.websocket.Extension;
  import javax.websocket.HandshakeResponse;
  import javax.websocket.server.HandshakeRequest;
  import javax.websocket.server.ServerEndpointConfig;
  import javax.websocket.server.ServerEndpointConfig.Configurator;
  
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.websocket.api.util.QuoteUtil;
  
  /**
   * The "Container Default Configurator" per the JSR-356 spec.
   * 
   * @see ServiceLoader behavior of {@link javax.websocket.server.ServerEndpointConfig.Configurator}
   */
  public final class ContainerDefaultConfigurator extends Configurator
  {
      private static final Logger LOG = Log.getLogger(ContainerDefaultConfigurator.class);
      private static final String NO_SUBPROTOCOL = "";
      
      /**
       * Default Constructor required, as
       * javax.websocket.server.ServerEndpointConfig$Configurator.fetchContainerDefaultConfigurator()
       * will be the one that instantiates this class in most cases.
       */
      public ContainerDefaultConfigurator()
      {
          super();
      }
  
      @Override
      public boolean checkOrigin(String originHeaderValue)
      {
          return true;
      }
  
      @Override
      public <T> T getEndpointInstance(Class<T> endpointClass) throws InstantiationException
      {
          if (LOG.isDebugEnabled())
          {
              LOG.debug(".getEndpointInstance({})",endpointClass);
          }
          
          try
          {
              // Since this is started via a ServiceLoader, this class has no Scope or context
              // that can be used to obtain a ObjectFactory from.
              return endpointClass.newInstance();
          }
          catch (IllegalAccessException e)
          {
              throw new InstantiationException(String.format("%s: %s",e.getClass().getName(),e.getMessage()));
          }
      }
  
      @Override
      public List<Extension> getNegotiatedExtensions(List<Extension> installed, List<Extension> requested)
      {
          return requested;
      }
  
      @Override
      public String getNegotiatedSubprotocol(List<String> supported, List<String> requested)
      {
          if ((requested == null) || (requested.size() == 0))
          {
              // nothing requested, don't return anything
              return NO_SUBPROTOCOL;
          }
  
          // Nothing specifically called out as being supported by the endpoint
          if ((supported == null) || (supported.isEmpty()))
          {
              // Just return the first hit in this case
              LOG.warn("Client requested Subprotocols on endpoint with none supported: {}",QuoteUtil.join(requested,","));
             return NO_SUBPROTOCOL;
         }
 
         // Return the first matching hit from the list of supported protocols.
         for (String possible : requested)
         {
             if (possible == null)
             {
                 // skip null
                 continue;
             }
 
             if (supported.contains(possible))
             {
                 return possible;
             }
         }
 
         LOG.warn("Client requested subprotocols {} do not match any endpoint supported subprotocols {}",QuoteUtil.join(requested,","),
                 QuoteUtil.join(supported,","));
         return NO_SUBPROTOCOL;
     }
 
     @Override
     public void modifyHandshake(ServerEndpointConfig sec, HandshakeRequest request, HandshakeResponse response)
     {
         /* do nothing */
     }
 }