//
   //  ========================================================================
   //  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.http2.client.http;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.ArrayDeque;
  import java.util.Locale;
  import java.util.Queue;
  
  import org.eclipse.jetty.client.HttpChannel;
  import org.eclipse.jetty.client.HttpExchange;
  import org.eclipse.jetty.client.HttpReceiver;
  import org.eclipse.jetty.client.HttpResponse;
  import org.eclipse.jetty.http.HttpField;
  import org.eclipse.jetty.http.HttpFields;
  import org.eclipse.jetty.http.HttpStatus;
  import org.eclipse.jetty.http.MetaData;
  import org.eclipse.jetty.http2.ErrorCode;
  import org.eclipse.jetty.http2.api.Stream;
  import org.eclipse.jetty.http2.frames.DataFrame;
  import org.eclipse.jetty.http2.frames.HeadersFrame;
  import org.eclipse.jetty.http2.frames.PushPromiseFrame;
  import org.eclipse.jetty.http2.frames.ResetFrame;
  import org.eclipse.jetty.io.ByteBufferPool;
  import org.eclipse.jetty.util.BufferUtil;
  import org.eclipse.jetty.util.Callback;
  import org.eclipse.jetty.util.IteratingCallback;
  
  public class HttpReceiverOverHTTP2 extends HttpReceiver implements Stream.Listener
  {
      private final ContentNotifier contentNotifier = new ContentNotifier();
  
      public HttpReceiverOverHTTP2(HttpChannel channel)
      {
          super(channel);
      }
  
      @Override
      protected HttpChannelOverHTTP2 getHttpChannel()
      {
          return (HttpChannelOverHTTP2)super.getHttpChannel();
      }
  
      @Override
      public void onHeaders(Stream stream, HeadersFrame frame)
      {
          HttpExchange exchange = getHttpExchange();
          if (exchange == null)
              return;
  
          HttpResponse response = exchange.getResponse();
          MetaData.Response metaData = (MetaData.Response)frame.getMetaData();
          response.version(metaData.getVersion()).status(metaData.getStatus()).reason(metaData.getReason());
  
          if (responseBegin(exchange))
          {
              HttpFields headers = metaData.getFields();
              for (HttpField header : headers)
              {
                  if (!responseHeader(exchange, header))
                      return;
              }
  
              if (responseHeaders(exchange))
              {
                  int status = metaData.getStatus();
                  boolean informational = HttpStatus.isInformational(status) && status != HttpStatus.SWITCHING_PROTOCOLS_101;
                  if (frame.isEndStream() || informational)
                      responseSuccess(exchange);
              }
          }
      }
  
      @Override
      public Stream.Listener onPush(Stream stream, PushPromiseFrame frame)
      {
          // Not supported.
          stream.reset(new ResetFrame(stream.getId(), ErrorCode.REFUSED_STREAM_ERROR.code), Callback.NOOP);
          return null;
      }
  
      @Override
     public void onData(Stream stream, DataFrame frame, Callback callback)
     {
         HttpExchange exchange = getHttpExchange();
         if (exchange == null)
         {
             callback.failed(new IOException("terminated"));
             return;
         }
 
         // We must copy the data since we do not know when the
         // application will consume the bytes and the parsing
         // will continue as soon as this method returns, eventually
         // leading to reusing the underlying buffer for more reads.
         ByteBufferPool byteBufferPool = getHttpDestination().getHttpClient().getByteBufferPool();
         ByteBuffer original = frame.getData();
         int length = original.remaining();
         final ByteBuffer copy = byteBufferPool.acquire(length, original.isDirect());
         BufferUtil.clearToFill(copy);
         copy.put(original);
         BufferUtil.flipToFlush(copy, 0);
 
         contentNotifier.offer(new DataInfo(exchange, copy, callback, frame.isEndStream()));
         contentNotifier.iterate();
     }
 
     @Override
     public void onReset(Stream stream, ResetFrame frame)
     {
         HttpExchange exchange = getHttpExchange();
         if (exchange == null)
             return;
 
         ErrorCode error = ErrorCode.from(frame.getError());
         String reason = error == null ? "reset" : error.name().toLowerCase(Locale.ENGLISH);
         exchange.getRequest().abort(new IOException(reason));
     }
 
     @Override
     public boolean onIdleTimeout(Stream stream, Throwable x)
     {
         responseFailure(x);
         return true;
     }
 
     private class ContentNotifier extends IteratingCallback
     {
         private final Queue<DataInfo> queue = new ArrayDeque<>();
         private DataInfo dataInfo;
 
         private boolean offer(DataInfo dataInfo)
         {
             synchronized (this)
             {
                 return queue.offer(dataInfo);
             }
         }
 
         @Override
         protected Action process() throws Exception
         {
             DataInfo dataInfo;
             synchronized (this)
             {
                 dataInfo = queue.poll();
             }
 
             if (dataInfo == null)
             {
                 DataInfo prevDataInfo = this.dataInfo;
                 if (prevDataInfo != null && prevDataInfo.last)
                     return Action.SUCCEEDED;
                 return Action.IDLE;
             }
 
             this.dataInfo = dataInfo;
             responseContent(dataInfo.exchange, dataInfo.buffer, this);
             return Action.SCHEDULED;
         }
 
         @Override
         public void succeeded()
         {
             ByteBufferPool byteBufferPool = getHttpDestination().getHttpClient().getByteBufferPool();
             byteBufferPool.release(dataInfo.buffer);
             dataInfo.callback.succeeded();
             super.succeeded();
         }
 
         @Override
         protected void onCompleteSuccess()
         {
             responseSuccess(dataInfo.exchange);
         }
 
         @Override
         protected void onCompleteFailure(Throwable failure)
         {
             ByteBufferPool byteBufferPool = getHttpDestination().getHttpClient().getByteBufferPool();
             byteBufferPool.release(dataInfo.buffer);
             dataInfo.callback.failed(failure);
             responseFailure(failure);
         }
     }
 
     private static class DataInfo
     {
         private final HttpExchange exchange;
         private final ByteBuffer buffer;
         private final Callback callback;
         private final boolean last;
 
         private DataInfo(HttpExchange exchange, ByteBuffer buffer, Callback callback, boolean last)
         {
             this.exchange = exchange;
             this.buffer = buffer;
             this.callback = callback;
             this.last = last;
         }
     }
 }