//
   //  ========================================================================
   //  Copyright (c) 1995-2014 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.common.events;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.websocket.api.InvalidWebSocketException;
  import org.eclipse.jetty.websocket.api.WebSocketPolicy;
  
  /**
   * Create EventDriver implementations.
   */
  public class EventDriverFactory
  {
      private static final Logger LOG = Log.getLogger(EventDriverFactory.class);
      private final WebSocketPolicy policy;
      private final List<EventDriverImpl> implementations;
  
      public EventDriverFactory(WebSocketPolicy policy)
      {
          this.policy = policy;
          this.implementations = new ArrayList<>();
  
          addImplementation(new JettyListenerImpl());
          addImplementation(new JettyAnnotatedImpl());
      }
  
      public void addImplementation(EventDriverImpl impl)
      {
          if (implementations.contains(impl))
          {
              LOG.warn("Ignoring attempt to add duplicate EventDriverImpl: " + impl);
              return;
          }
  
          implementations.add(impl);
      }
  
      public void clearImplementations()
      {
          this.implementations.clear();
      }
  
      protected String getClassName(Object websocket)
      {
          return websocket.getClass().getName();
      }
  
      public List<EventDriverImpl> getImplementations()
      {
          return implementations;
      }
  
      public boolean removeImplementation(EventDriverImpl impl)
      {
          return this.implementations.remove(impl);
      }
  
      @Override
      public String toString()
      {
          StringBuilder msg = new StringBuilder();
          msg.append(this.getClass().getSimpleName());
          msg.append("[implementations=[");
          boolean delim = false;
          for (EventDriverImpl impl : implementations)
          {
              if (delim)
              {
                  msg.append(',');
              }
              msg.append(impl.toString());
              delim = true;
          }
          msg.append("]");
          return msg.toString();
      }
  
      /**
       * Wrap the given WebSocket object instance in a suitable EventDriver
      * 
      * @param websocket
      *            the websocket instance to wrap. Must either implement {@link WebSocketListener} or be annotated with {@link WebSocket &#064WebSocket}
      * @return appropriate EventDriver for this websocket instance.
      */
     public EventDriver wrap(Object websocket)
     {
         if (websocket == null)
         {
             throw new InvalidWebSocketException("null websocket object");
         }
 
         for (EventDriverImpl impl : implementations)
         {
             if (impl.supports(websocket))
             {
                 try
                 {
                     return impl.create(websocket,policy.clonePolicy());
                 }
                 catch (Throwable e)
                 {
                     throw new InvalidWebSocketException("Unable to create websocket",e);
                 }
             }
         }
 
         // Create a clear error message for the developer
         StringBuilder err = new StringBuilder();
         err.append(getClassName(websocket));
         err.append(" is not a valid WebSocket object.");
         err.append("  Object must obey one of the following rules: ");
 
         int len = implementations.size();
         for (int i = 0; i < len; i++)
         {
             EventDriverImpl impl = implementations.get(i);
             if (i > 0)
             {
                 err.append(" or ");
             }
             err.append("\n(").append(i + 1).append(") ");
             err.append(impl.describeRule());
         }
 
         throw new InvalidWebSocketException(err.toString());
     }
 }