/*
    * ====================================================================
    * 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.http.impl.nio.client;
  
  import java.io.IOException;
  
  import org.apache.commons.logging.Log;
  import org.apache.http.ConnectionReuseStrategy;
  import org.apache.http.HttpException;
  import org.apache.http.HttpHost;
  import org.apache.http.HttpRequest;
  import org.apache.http.HttpResponse;
  import org.apache.http.client.config.RequestConfig;
  import org.apache.http.client.methods.Configurable;
  import org.apache.http.client.methods.HttpExecutionAware;
  import org.apache.http.client.methods.HttpRequestWrapper;
  import org.apache.http.client.protocol.HttpClientContext;
  import org.apache.http.concurrent.BasicFuture;
  import org.apache.http.conn.ConnectionKeepAliveStrategy;
  import org.apache.http.conn.routing.HttpRoute;
  import org.apache.http.nio.ContentDecoder;
  import org.apache.http.nio.ContentEncoder;
  import org.apache.http.nio.IOControl;
  import org.apache.http.nio.NHttpClientConnection;
  import org.apache.http.nio.conn.NHttpClientConnectionManager;
  import org.apache.http.nio.protocol.HttpAsyncRequestProducer;
  import org.apache.http.nio.protocol.HttpAsyncResponseConsumer;
  import org.apache.http.protocol.HttpCoreContext;
  import org.apache.http.protocol.HttpProcessor;
  
  /**
   * Default implementation of {@link org.apache.http.nio.protocol.HttpAsyncClientExchangeHandler}.
   * <p>
   * Instances of this class are expected to be accessed by one thread at a time only.
   * The {@link #cancel()} method can be called concurrently by multiple threads.
   */
  class MinimalClientExchangeHandlerImpl<T> extends AbstractClientExchangeHandler {
  
      private final HttpAsyncRequestProducer requestProducer;
      private final HttpAsyncResponseConsumer<T> responseConsumer;
      private final HttpClientContext localContext;
      private final BasicFuture<T> resultFuture;
      private final HttpProcessor httpProcessor;
  
      public MinimalClientExchangeHandlerImpl(
              final Log log,
              final HttpAsyncRequestProducer requestProducer,
              final HttpAsyncResponseConsumer<T> responseConsumer,
              final HttpClientContext localContext,
              final BasicFuture<T> resultFuture,
              final NHttpClientConnectionManager connmgr,
              final HttpProcessor httpProcessor,
              final ConnectionReuseStrategy connReuseStrategy,
              final ConnectionKeepAliveStrategy keepaliveStrategy) {
          super(log, localContext, connmgr, connReuseStrategy, keepaliveStrategy);
          this.requestProducer = requestProducer;
          this.responseConsumer = responseConsumer;
          this.localContext = localContext;
          this.resultFuture = resultFuture;
          this.httpProcessor = httpProcessor;
      }
  
      @Override
      void releaseResources() {
          try {
              this.requestProducer.close();
          } catch (final IOException ex) {
              this.log.debug("I/O error closing request producer", ex);
          }
          try {
              this.responseConsumer.close();
          } catch (final IOException ex) {
              this.log.debug("I/O error closing response consumer", ex);
          }
      }
 
     @Override
     void executionFailed(final Exception ex) {
         this.requestProducer.failed(ex);
         this.responseConsumer.failed(ex);
     }
 
     @Override
     boolean executionCancelled() {
         final boolean cancelled = this.responseConsumer.cancel();
 
         final T result = this.responseConsumer.getResult();
         final Exception ex = this.responseConsumer.getException();
         if (ex != null) {
             this.resultFuture.failed(ex);
         } else if (result != null) {
             this.resultFuture.completed(result);
         } else {
             this.resultFuture.cancel();
         }
         return cancelled;
     }
 
     @Override
     public void start() throws HttpException, IOException {
         final HttpHost target = this.requestProducer.getTarget();
         final HttpRequest original = this.requestProducer.generateRequest();
 
         if (original instanceof HttpExecutionAware) {
             ((HttpExecutionAware) original).setCancellable(this);
         }
         if (this.log.isDebugEnabled()) {
             this.log.debug("[exchange: " + getId() + "] start execution");
         }
 
         if (original instanceof Configurable) {
             final RequestConfig config = ((Configurable) original).getConfig();
             if (config != null) {
                 this.localContext.setRequestConfig(config);
             }
         }
 
         final HttpRequestWrapper request = HttpRequestWrapper.wrap(original);
         final HttpRoute route = new HttpRoute(target);
         setCurrentRequest(request);
         setRoute(route);
 
         this.localContext.setAttribute(HttpCoreContext.HTTP_REQUEST, request);
         this.localContext.setAttribute(HttpCoreContext.HTTP_TARGET_HOST, target);
         this.localContext.setAttribute(HttpClientContext.HTTP_ROUTE, route);
 
         this.httpProcessor.process(request, this.localContext);
 
         requestConnection();
     }
 
     @Override
     public HttpRequest generateRequest() throws IOException, HttpException {
         verifytRoute();
         if (!isRouteEstablished()) {
             onRouteToTarget();
             onRouteComplete();
         }
 
         final NHttpClientConnection localConn = getConnection();
         this.localContext.setAttribute(HttpCoreContext.HTTP_CONNECTION, localConn);
         final RequestConfig config = this.localContext.getRequestConfig();
         if (config.getSocketTimeout() > 0) {
             localConn.setSocketTimeout(config.getSocketTimeout());
         }
         return getCurrentRequest();
     }
 
     @Override
     public void produceContent(
             final ContentEncoder encoder, final IOControl ioControl) throws IOException {
         if (this.log.isDebugEnabled()) {
             this.log.debug("[exchange: " + getId() + "] produce content");
         }
         this.requestProducer.produceContent(encoder, ioControl);
         if (encoder.isCompleted()) {
             this.requestProducer.resetRequest();
         }
     }
 
     @Override
     public void requestCompleted() {
         if (this.log.isDebugEnabled()) {
             this.log.debug("[exchange: " + getId() + "] Request completed");
         }
         this.requestProducer.requestCompleted(this.localContext);
     }
 
     @Override
     public void responseReceived(
             final HttpResponse response) throws IOException, HttpException {
         if (this.log.isDebugEnabled()) {
             this.log.debug("[exchange: " + getId() + "] Response received " + response.getStatusLine());
         }
         this.localContext.setAttribute(HttpCoreContext.HTTP_RESPONSE, response);
         this.httpProcessor.process(response, this.localContext);
 
         setCurrentResponse(response);
 
         this.responseConsumer.responseReceived(response);
     }
 
     @Override
     public void consumeContent(
             final ContentDecoder decoder, final IOControl ioControl) throws IOException {
         if (this.log.isDebugEnabled()) {
             this.log.debug("[exchange: " + getId() + "] Consume content");
         }
         this.responseConsumer.consumeContent(decoder, ioControl);
         if (!decoder.isCompleted() && this.responseConsumer.isDone()) {
             markConnectionNonReusable();
             try {
                 markCompleted();
                 releaseConnection();
                 this.resultFuture.cancel();
             } finally {
                 close();
             }
         }
     }
 
     @Override
     public void responseCompleted() throws IOException, HttpException {
         manageConnectionPersistence();
         this.responseConsumer.responseCompleted(this.localContext);
         if (this.log.isDebugEnabled()) {
             this.log.debug("[exchange: " + getId() + "] Response processed");
         }
         try {
             markCompleted();
             releaseConnection();
             final T result = this.responseConsumer.getResult();
             final Exception ex = this.responseConsumer.getException();
             if (ex == null) {
                 this.resultFuture.completed(result);
             } else {
                 this.resultFuture.failed(ex);
             }
         } finally {
             close();
         }
     }
 
     @Override
     public void inputTerminated() {
         close();
     }
 
     public void abortConnection() {
         discardConnection();
     }
 
 }