/*
    * ====================================================================
    * 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.client5.http.impl.classic;
  
  import java.io.IOException;
  import java.io.InterruptedIOException;
  
  import org.apache.hc.client5.http.HttpRequestRetryStrategy;
  import org.apache.hc.client5.http.HttpRoute;
  import org.apache.hc.client5.http.classic.ExecChain;
  import org.apache.hc.client5.http.classic.ExecChain.Scope;
  import org.apache.hc.client5.http.protocol.HttpClientContext;
  import org.apache.hc.client5.http.classic.ExecChainHandler;
  import org.apache.hc.core5.annotation.Contract;
  import org.apache.hc.core5.annotation.Internal;
  import org.apache.hc.core5.annotation.ThreadingBehavior;
  import org.apache.hc.core5.http.ClassicHttpRequest;
  import org.apache.hc.core5.http.ClassicHttpResponse;
  import org.apache.hc.core5.http.HttpEntity;
  import org.apache.hc.core5.http.HttpException;
  import org.apache.hc.core5.http.NoHttpResponseException;
  import org.apache.hc.core5.util.Args;
  import org.apache.hc.core5.util.TimeValue;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Request executor in the request execution chain that is responsible for
   * making a decision whether a request that failed due to an I/O exception
   * or received a specific response from the target server should
   * be re-executed.
   * <p>
   * Further responsibilities such as communication with the opposite
   * endpoint is delegated to the next executor in the request execution
   * chain.
   * </p>
   *
   * @since 5.0
   */
  @Contract(threading = ThreadingBehavior.STATELESS)
  @Internal
  public class HttpRequestRetryExec implements ExecChainHandler {
  
      private static final Logger LOG = LoggerFactory.getLogger(HttpRequestRetryExec.class);
  
      private final HttpRequestRetryStrategy retryStrategy;
  
      public HttpRequestRetryExec(
              final HttpRequestRetryStrategy retryStrategy) {
           Args.notNull(retryStrategy, "retryStrategy");
           this.retryStrategy = retryStrategy;
      }
  
      @Override
      public ClassicHttpResponse execute(
              final ClassicHttpRequest request,
              final Scope scope,
              final ExecChain chain) throws IOException, HttpException {
          Args.notNull(request, "request");
          Args.notNull(scope, "scope");
          final String exchangeId = scope.exchangeId;
          final HttpRoute route = scope.route;
          final HttpClientContext context = scope.clientContext;
          ClassicHttpRequest currentRequest = request;
  
          for (int execCount = 1;; execCount++) {
              final ClassicHttpResponse response;
              try {
                   response = chain.proceed(currentRequest, scope);
              } catch (final IOException ex) {
                  if (scope.execRuntime.isExecutionAborted()) {
                      throw new RequestFailedException("Request aborted");
                  }
                  final HttpEntity requestEntity = request.getEntity();
                  if (requestEntity != null && !requestEntity.isRepeatable()) {
                     if (LOG.isDebugEnabled()) {
                         LOG.debug("{}: cannot retry non-repeatable request", exchangeId);
                     }
                     throw ex;
                 }
                 if (retryStrategy.retryRequest(request, ex, execCount, context)) {
                     if (LOG.isDebugEnabled()) {
                         LOG.debug("{}: {}", exchangeId, ex.getMessage(), ex);
                     }
                     if (LOG.isInfoEnabled()) {
                         LOG.info("Recoverable I/O exception ({}) caught when processing request to {}",
                                 ex.getClass().getName(), route);
                     }
                     currentRequest = ClassicRequestCopier.INSTANCE.copy(scope.originalRequest);
                     continue;
                 } else {
                     if (ex instanceof NoHttpResponseException) {
                         final NoHttpResponseException updatedex = new NoHttpResponseException(
                                 route.getTargetHost().toHostString() + " failed to respond");
                         updatedex.setStackTrace(ex.getStackTrace());
                         throw updatedex;
                     }
                     throw ex;
                 }
             }
 
             try {
                 final HttpEntity entity = request.getEntity();
                 if (entity != null && !entity.isRepeatable()) {
                     if (LOG.isDebugEnabled()) {
                         LOG.debug("{}: cannot retry non-repeatable request", exchangeId);
                     }
                     return response;
                 }
                 if (retryStrategy.retryRequest(response, execCount, context)) {
                     response.close();
                     final TimeValue nextInterval =
                             retryStrategy.getRetryInterval(response, execCount, context);
                     if (TimeValue.isPositive(nextInterval)) {
                         try {
                             if (LOG.isDebugEnabled()) {
                                 LOG.debug("{}: wait for {}", exchangeId, nextInterval);
                             }
                             nextInterval.sleep();
                         } catch (final InterruptedException e) {
                             Thread.currentThread().interrupt();
                             throw new InterruptedIOException();
                         }
                     }
                     currentRequest = ClassicRequestCopier.INSTANCE.copy(scope.originalRequest);
                 } else {
                     return response;
                 }
             } catch (final RuntimeException ex) {
                 response.close();
                 throw ex;
             }
         }
     }
 
 }