/*
    * ====================================================================
    * 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.http2.ssl;
  
  import javax.net.ssl.SSLEngine;
  import javax.net.ssl.SSLParameters;
  
  import org.apache.hc.core5.http.ssl.TLS;
  import org.apache.hc.core5.http.ssl.TlsCiphers;
  import org.apache.hc.core5.http2.HttpVersionPolicy;
  import org.apache.hc.core5.net.NamedEndpoint;
  import org.apache.hc.core5.reactor.ssl.SSLSessionInitializer;
  import org.apache.hc.core5.util.ReflectionUtils;
  
  /**
   * HTTP/2 TLS support methods
   *
   * @since 5.0
   */
  public final class H2TlsSupport {
  
      public static void setEnableRetransmissions(final SSLParameters sslParameters, final boolean value) {
          ReflectionUtils.callSetter(sslParameters, "EnableRetransmissions", Boolean.TYPE, value);
      }
  
      public static void setApplicationProtocols(final SSLParameters sslParameters, final String[] values) {
          ReflectionUtils.callSetter(sslParameters, "ApplicationProtocols", String[].class, values);
      }
  
      public static String[] selectApplicationProtocols(final Object attachment) {
          final HttpVersionPolicyttp2/HttpVersionPolicy.html#HttpVersionPolicy">HttpVersionPolicy versionPolicy = attachment instanceof HttpVersionPolicy ?
                  (HttpVersionPolicy) attachment : HttpVersionPolicy.NEGOTIATE;
          switch (versionPolicy) {
              case FORCE_HTTP_1:
                  return new String[] { ApplicationProtocol.HTTP_1_1.id };
              case FORCE_HTTP_2:
                  return new String[] { ApplicationProtocol.HTTP_2.id };
              default:
                  return new String[] { ApplicationProtocol.HTTP_2.id, ApplicationProtocol.HTTP_1_1.id };
          }
      }
  
      public static SSLSessionInitializer enforceRequirements(
              final Object attachment,
              final SSLSessionInitializer initializer) {
          return new SSLSessionInitializer() {
  
              @Override
              public void initialize(final NamedEndpoint endpoint, final SSLEngine sslEngine) {
                  final SSLParameters sslParameters = sslEngine.getSSLParameters();
                  sslParameters.setProtocols(TLS.excludeWeak(sslParameters.getProtocols()));
                  sslParameters.setCipherSuites(TlsCiphers.excludeH2Blacklisted(sslParameters.getCipherSuites()));
                  setEnableRetransmissions(sslParameters, false);
                  setApplicationProtocols(sslParameters, selectApplicationProtocols(attachment));
                  sslEngine.setSSLParameters(sslParameters);
                  if (initializer != null) {
                      initializer.initialize(endpoint, sslEngine);
                  }
              }
  
          };
      }
  
  }