//
   //  ========================================================================
   //  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.server;
  
  import java.io.IOException;
  import java.util.EnumSet;
  
  import javax.servlet.DispatcherType;
  import javax.servlet.Filter;
  import javax.servlet.FilterChain;
  import javax.servlet.FilterConfig;
  import javax.servlet.ServletException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.eclipse.jetty.io.ByteBufferPool;
  import org.eclipse.jetty.io.MappedByteBufferPool;
  import org.eclipse.jetty.servlet.FilterHolder;
  import org.eclipse.jetty.servlet.ServletContextHandler;
  import org.eclipse.jetty.util.annotation.ManagedAttribute;
  import org.eclipse.jetty.util.annotation.ManagedObject;
  import org.eclipse.jetty.util.component.ContainerLifeCycle;
  import org.eclipse.jetty.util.component.Dumpable;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.websocket.api.WebSocketBehavior;
  import org.eclipse.jetty.websocket.api.WebSocketPolicy;
  import org.eclipse.jetty.websocket.server.pathmap.PathMappings;
  import org.eclipse.jetty.websocket.server.pathmap.PathMappings.MappedResource;
  import org.eclipse.jetty.websocket.server.pathmap.PathSpec;
  import org.eclipse.jetty.websocket.servlet.WebSocketCreator;
  
  /**
   * Inline Servlet Filter to capture WebSocket upgrade requests and perform path mappings to {@link WebSocketCreator} objects.
   */
  @ManagedObject("WebSocket Upgrade Filter")
  public class WebSocketUpgradeFilter extends ContainerLifeCycle implements Filter, MappedWebSocketCreator, Dumpable
  {
      private static final Logger LOG = Log.getLogger(WebSocketUpgradeFilter.class);
  
      public static WebSocketUpgradeFilter configureContext(ServletContextHandler context)
      {
          WebSocketPolicy policy = new WebSocketPolicy(WebSocketBehavior.SERVER);
  
          WebSocketUpgradeFilter filter = new WebSocketUpgradeFilter(policy);
          FilterHolder fholder = new FilterHolder(filter);
          fholder.setName("Jetty_WebSocketUpgradeFilter");
          fholder.setDisplayName("WebSocket Upgrade Filter");
          String pathSpec = "/*";
          context.addFilter(fholder,pathSpec,EnumSet.of(DispatcherType.REQUEST));
          LOG.debug("Adding {} mapped to {} to {}",filter,pathSpec,context);
  
          // Store reference to the WebSocketUpgradeFilter
          context.setAttribute(WebSocketUpgradeFilter.class.getName(),filter);
  
          return filter;
      }
  
      private final WebSocketServerFactory factory;
      private final PathMappings<WebSocketCreator> pathmap = new PathMappings<>();
  
      public WebSocketUpgradeFilter(WebSocketPolicy policy)
      {
          this(policy, new MappedByteBufferPool());
      }
      
      public WebSocketUpgradeFilter(WebSocketPolicy policy, ByteBufferPool bufferPool)
      {
          factory = new WebSocketServerFactory(policy,bufferPool);
          addBean(factory,true);
      }
  
      @Override
      public void addMapping(PathSpec spec, WebSocketCreator creator)
      {
          pathmap.put(spec,creator);
      }
  
      @Override
      public void destroy()
      {
         factory.cleanup();
         pathmap.reset();
         super.destroy();
     }
 
     @Override
     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
     {
         if (factory == null)
         {
             // no factory, cannot operate
             LOG.debug("WebSocketUpgradeFilter is not operational - no WebSocketServletFactory configured");
             chain.doFilter(request,response);
             return;
         }
 
         if ((request instanceof HttpServletRequest) && (response instanceof HttpServletResponse))
         {
             HttpServletRequest httpreq = (HttpServletRequest)request;
             HttpServletResponse httpresp = (HttpServletResponse)response;
 
             // Since this is a filter, we need to be smart about determining the target path
             String contextPath = httpreq.getContextPath();
             String target = httpreq.getRequestURI();
             if (target.startsWith(contextPath))
             {
                 target = target.substring(contextPath.length());
             }
 
             if (factory.isUpgradeRequest(httpreq,httpresp))
             {
                 LOG.debug("target = [{}]",target);
 
                 MappedResource<WebSocketCreator> resource = pathmap.getMatch(target);
                 if (resource == null)
                 {
                     if (LOG.isDebugEnabled())
                     {
                         LOG.debug("WebSocket Upgrade on {} has no associated endpoint",target);
                         LOG.debug("PathMappings: {}",pathmap.dump());
                     }
                     // no match.
                     chain.doFilter(request,response);
                     return;
                 }
                 LOG.debug("WebSocket Upgrade detected on {} for endpoint {}",target,resource);
 
                 WebSocketCreator creator = resource.getResource();
 
                 // Store PathSpec resource mapping as request attribute
                 httpreq.setAttribute(PathSpec.class.getName(),resource.getPathSpec());
 
                 // We have an upgrade request
                 if (factory.acceptWebSocket(creator,httpreq,httpresp))
                 {
                     // We have a socket instance created
                     return;
                 }
 
                 // If we reach this point, it means we had an incoming request to upgrade
                 // but it was either not a proper websocket upgrade, or it was possibly rejected
                 // due to incoming request constraints (controlled by WebSocketCreator)
                 if (response.isCommitted())
                 {
                     // not much we can do at this point.
                     return;
                 }
             }
         }
 
         // not an Upgrade request
         chain.doFilter(request,response);
     }
 
     @Override
     public String dump()
     {
         return ContainerLifeCycle.dump(this);
     }
 
     @Override
     public void dump(Appendable out, String indent) throws IOException
     {
         out.append(indent).append(" +- pathmap=").append(pathmap.toString()).append("\n");
         pathmap.dump(out,indent + "   ");
     }
 
     public WebSocketServerFactory getFactory()
     {
         return factory;
     }
 
     @ManagedAttribute(value = "mappings", readonly = true)
     @Override
     public PathMappings<WebSocketCreator> getMappings()
     {
         return pathmap;
     }
 
     @Override
     public void init(FilterConfig config) throws ServletException
     {
         try
         {
             WebSocketPolicy policy = factory.getPolicy();
 
             String max = config.getInitParameter("maxIdleTime");
             if (max != null)
             {
                 policy.setIdleTimeout(Long.parseLong(max));
             }
 
             max = config.getInitParameter("maxTextMessageSize");
             if (max != null)
             {
                 policy.setMaxTextMessageSize(Integer.parseInt(max));
             }
 
             max = config.getInitParameter("maxBinaryMessageSize");
             if (max != null)
             {
                 policy.setMaxBinaryMessageSize(Integer.parseInt(max));
             }
 
             max = config.getInitParameter("inputBufferSize");
             if (max != null)
             {
                 policy.setInputBufferSize(Integer.parseInt(max));
             }
 
             factory.start();
         }
         catch (Exception x)
         {
             throw new ServletException(x);
         }
     }
 
     @Override
     public String toString()
     {
         return String.format("%s[factory=%s,pathmap=%s]",this.getClass().getSimpleName(),factory,pathmap);
     }
 }