/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project 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.jboss.netty.handler.codec.spdy;
  
  import org.jboss.netty.channel.ChannelHandlerContext;
  import org.jboss.netty.channel.MessageEvent;
  import org.jboss.netty.channel.SimpleChannelHandler;
  import org.jboss.netty.handler.codec.http.HttpMessage;
  import org.jboss.netty.handler.codec.http.HttpResponse;
  
  import java.util.Queue;
  import java.util.concurrent.ConcurrentLinkedQueue;
  
  /**
   * {@link SimpleChannelHandler} that takes care of adding the right streamId to the
   * {@link HttpResponse} if one is not present. This makes it possible to just re-use plan handlers current used
   * for HTTP.
   */
  public class SpdyHttpResponseStreamIdHandler extends SimpleChannelHandler {
      private static final Integer NO_ID = -1;
      private final Queue<Integer> ids = new ConcurrentLinkedQueue<Integer>();
  
      @Override
      public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
          if (e.getMessage() instanceof HttpMessage) {
              boolean contains = ((HttpMessage) e.getMessage()).headers().contains(SpdyHttpHeaders.Names.STREAM_ID);
              if (!contains) {
                  ids.add(NO_ID);
              } else {
                  ids.add(SpdyHttpHeaders.getStreamId((HttpMessage) e.getMessage()));
              }
          } else if (e.getMessage() instanceof SpdyRstStreamFrame) {
              // remove id from the queue
              ids.remove(((SpdyRstStreamFrame) e.getMessage()).getStreamId());
          }
          super.messageReceived(ctx, e);
      }
  
      @Override
      public void writeRequested(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
          if (e.getMessage() instanceof HttpResponse) {
              HttpResponse response = (HttpResponse) e.getMessage();
              Integer id = ids.poll();
              if (id != null && id.intValue() != NO_ID && !response.headers().contains(SpdyHttpHeaders.Names.STREAM_ID)) {
                  SpdyHttpHeaders.setStreamId(response, id);
              }
          }
          super.writeRequested(ctx, e);
      }
  
  }