/*
    * ====================================================================
    * 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.protocol;
  
  import java.io.IOException;
  
  import org.apache.hc.client5.http.config.RequestConfig;
  import org.apache.hc.core5.annotation.Contract;
  import org.apache.hc.core5.annotation.ThreadingBehavior;
  import org.apache.hc.core5.http.EntityDetails;
  import org.apache.hc.core5.http.HttpException;
  import org.apache.hc.core5.http.HttpHeaders;
  import org.apache.hc.core5.http.HttpRequest;
  import org.apache.hc.core5.http.HttpRequestInterceptor;
  import org.apache.hc.core5.http.Method;
  import org.apache.hc.core5.http.ProtocolVersion;
  import org.apache.hc.core5.http.protocol.HttpContext;
  import org.apache.hc.core5.util.Args;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * @since 5.4
   */
  @Contract(threading = ThreadingBehavior.STATELESS)
  public final class RequestUpgrade implements HttpRequestInterceptor {
  
      private static final Logger LOG = LoggerFactory.getLogger(RequestUpgrade.class);
  
      public RequestUpgrade() {
      }
  
      @Override
      public void process(
              final HttpRequest request,
              final EntityDetails entity,
              final HttpContext context) throws HttpException, IOException {
          Args.notNull(request, "HTTP request");
          Args.notNull(context, "HTTP context");
  
          final HttpClientContext clientContext = HttpClientContext.cast(context);
          final RequestConfig requestConfig = clientContext.getRequestConfigOrDefault();
          if (requestConfig.isProtocolUpgradeEnabled()) {
              final ProtocolVersion version = request.getVersion() != null ? request.getVersion() : clientContext.getProtocolVersion();
              if (!request.containsHeader(HttpHeaders.UPGRADE) &&
                      !request.containsHeader(HttpHeaders.CONNECTION) &&
                      version.getMajor() == 1 && version.getMinor() >= 1) {
                  if (LOG.isDebugEnabled()) {
                      LOG.debug("Connection is upgradable: protocol version = {}", version);
                  }
                  final String method = request.getMethod();
                  if ((Method.OPTIONS.isSame(method) || Method.HEAD.isSame(method) || Method.GET.isSame(method)) &&
                          clientContext.getSSLSession() == null) {
                      LOG.debug("Connection is upgradable to TLS: method = {}", method);
                      request.addHeader(HttpHeaders.UPGRADE, "TLS/1.2");
                      request.addHeader(HttpHeaders.CONNECTION, HttpHeaders.UPGRADE);
                  }
              }
          }
      }
  
  }