/*
    * ====================================================================
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.hc.core5.http.nio.support;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.List;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.apache.hc.core5.concurrent.FutureCallback;
  import org.apache.hc.core5.http.EntityDetails;
  import org.apache.hc.core5.http.Header;
  import org.apache.hc.core5.http.HttpException;
  import org.apache.hc.core5.http.HttpResponse;
  import org.apache.hc.core5.http.HttpStatus;
  import org.apache.hc.core5.http.nio.AsyncClientExchangeHandler;
  import org.apache.hc.core5.http.nio.AsyncRequestProducer;
  import org.apache.hc.core5.http.nio.AsyncResponseConsumer;
  import org.apache.hc.core5.http.nio.CapacityChannel;
  import org.apache.hc.core5.http.nio.DataStreamChannel;
  import org.apache.hc.core5.http.nio.RequestChannel;
  import org.apache.hc.core5.http.protocol.HttpContext;
  import org.apache.hc.core5.util.Args;
  
  /**
   * Basic {@link AsyncClientExchangeHandler} implementation that makes use
   * of {@link AsyncRequestProducer} to generate request message
   * and {@link AsyncResponseConsumer} to process the response message returned by the server.
   *
   * @since 5.0
   */
  public final class BasicClientExchangeHandler<T> implements AsyncClientExchangeHandler {
  
      private final AsyncRequestProducer requestProducer;
      private final AsyncResponseConsumer<T> responseConsumer;
      private final AtomicBoolean completed;
      private final FutureCallback<T> resultCallback;
      private final AtomicBoolean outputTerminated;
  
      public BasicClientExchangeHandler(
              final AsyncRequestProducer requestProducer,
              final AsyncResponseConsumer<T> responseConsumer,
              final FutureCallback<T> resultCallback) {
          this.requestProducer = Args.notNull(requestProducer, "Request producer");
          this.responseConsumer = Args.notNull(responseConsumer, "Response consumer");
          this.completed = new AtomicBoolean(false);
          this.resultCallback = resultCallback;
          this.outputTerminated = new AtomicBoolean(false);
      }
  
      @Override
      public void produceRequest(final RequestChannel requestChannel, final HttpContext httpContext) throws HttpException, IOException {
          requestProducer.sendRequest(requestChannel, httpContext);
      }
  
      @Override
      public int available() {
          return requestProducer.available();
      }
  
      @Override
      public void produce(final DataStreamChannel channel) throws IOException {
          if (outputTerminated.get()) {
              channel.endStream();
              return;
          }
          requestProducer.produce(channel);
      }
  
      @Override
      public void consumeInformation(final HttpResponse response, final HttpContext httpContext) throws HttpException, IOException {
          responseConsumer.informationResponse(response, httpContext);
      }
  
      @Override
     public void consumeResponse(final HttpResponse response, final EntityDetails entityDetails, final HttpContext httpContext) throws HttpException, IOException {
         if (response.getCode() >= HttpStatus.SC_CLIENT_ERROR) {
             outputTerminated.set(true);
             requestProducer.releaseResources();
         }
         responseConsumer.consumeResponse(response, entityDetails, httpContext, new FutureCallback<T>() {
 
             @Override
             public void completed(final T result) {
                 if (completed.compareAndSet(false, true)) {
                     try {
                         if (resultCallback != null) {
                             resultCallback.completed(result);
                         }
                     } finally {
                         internalReleaseResources();
                     }
                 }
             }
 
             @Override
             public void failed(final Exception ex) {
                 if (completed.compareAndSet(false, true)) {
                     try {
                         if (resultCallback != null) {
                             resultCallback.failed(ex);
                         }
                     } finally {
                         internalReleaseResources();
                     }
                 }
             }
 
             @Override
             public void cancelled() {
                 if (completed.compareAndSet(false, true)) {
                     try {
                         if (resultCallback != null) {
                             resultCallback.cancelled();
                         }
                     } finally {
                         internalReleaseResources();
                     }
                 }
             }
 
         });
     }
 
     @Override
     public void cancel() {
         if (completed.compareAndSet(false, true)) {
             try {
                 if (resultCallback != null) {
                     resultCallback.cancelled();
                 }
             } finally {
                 internalReleaseResources();
             }
         }
     }
 
     @Override
     public void updateCapacity(final CapacityChannel capacityChannel) throws IOException {
         responseConsumer.updateCapacity(capacityChannel);
     }
 
     @Override
     public void consume(final ByteBuffer src) throws IOException {
         responseConsumer.consume(src);
     }
 
     @Override
     public void streamEnd(final List<? extends Header> trailers) throws HttpException, IOException {
         responseConsumer.streamEnd(trailers);
     }
 
     @Override
     public void failed(final Exception cause) {
         try {
             requestProducer.failed(cause);
             responseConsumer.failed(cause);
         } finally {
             if (completed.compareAndSet(false, true)) {
                 try {
                     if (resultCallback != null) {
                         resultCallback.failed(cause);
                     }
                 } finally {
                     internalReleaseResources();
                 }
             }
         }
     }
 
     private void internalReleaseResources() {
         requestProducer.releaseResources();
         responseConsumer.releaseResources();
     }
 
     @Override
     public void releaseResources() {
     }
 
 }