/*
    * ====================================================================
    * 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.impl.nio;
  
  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.function.Callback;
  import org.apache.hc.core5.http.URIScheme;
  import org.apache.hc.core5.http.impl.nio.ClientHttp1IOEventHandler;
  import org.apache.hc.core5.http.impl.nio.ClientHttp1StreamDuplexerFactory;
  import org.apache.hc.core5.http.impl.nio.HttpConnectionEventHandler;
  import org.apache.hc.core5.http.nio.ssl.TlsStrategy;
  import org.apache.hc.core5.http2.HttpVersionPolicy;
  import org.apache.hc.core5.http2.ssl.ApplicationProtocol;
  import org.apache.hc.core5.reactor.EndpointParameters;
  import org.apache.hc.core5.reactor.IOEventHandlerFactory;
  import org.apache.hc.core5.reactor.ProtocolIOSession;
  import org.apache.hc.core5.util.Args;
  import org.apache.hc.core5.util.Timeout;
  
  /**
   * Client I/O event starter that prepares I/O sessions for an initial protocol handshake.
   * This class may return a different {@link org.apache.hc.core5.reactor.IOEventHandler}
   * implementation based on the current HTTP version policy.
   *
   * @since 5.1
   */
  @Contract(threading = ThreadingBehavior.IMMUTABLE_CONDITIONAL)
  @Internal
  public class ClientHttpProtocolNegotiationStarter implements IOEventHandlerFactory {
  
      private final ClientHttp1StreamDuplexerFactory http1StreamHandlerFactory;
      private final ClientH2StreamMultiplexerFactory http2StreamHandlerFactory;
      private final HttpVersionPolicy versionPolicy;
      private final TlsStrategy tlsStrategy;
      private final Timeout handshakeTimeout;
      private final Callback<Exception> exceptionCallback;
  
      public ClientHttpProtocolNegotiationStarter(
              final ClientHttp1StreamDuplexerFactory http1StreamHandlerFactory,
              final ClientH2StreamMultiplexerFactory http2StreamHandlerFactory,
              final HttpVersionPolicy versionPolicy,
              final TlsStrategy tlsStrategy,
              final Timeout handshakeTimeout,
              final Callback<Exception> exceptionCallback) {
          this.http1StreamHandlerFactory = Args.notNull(http1StreamHandlerFactory, "HTTP/1.1 stream handler factory");
          this.http2StreamHandlerFactory = Args.notNull(http2StreamHandlerFactory, "HTTP/2 stream handler factory");
          this.versionPolicy = versionPolicy != null ? versionPolicy : HttpVersionPolicy.NEGOTIATE;
          this.tlsStrategy = tlsStrategy;
          this.handshakeTimeout = handshakeTimeout;
          this.exceptionCallback = exceptionCallback;
      }
  
      @Override
      public HttpConnectionEventHandler createHandler(final ProtocolIOSession ioSession, final Object attachment) {
          HttpVersionPolicy endpointPolicy = versionPolicy;
          if (attachment instanceof EndpointParameters) {
              final EndpointParameters params = (EndpointParameters) attachment;
              if (tlsStrategy != null && URIScheme.HTTPS.same(params.getScheme())) {
                  tlsStrategy.upgrade(ioSession, params, params.getAttachment(), handshakeTimeout, null);
              }
              if (params.getAttachment() instanceof HttpVersionPolicy) {
                  endpointPolicy = (HttpVersionPolicy) params.getAttachment();
              }
          }
  
          ioSession.registerProtocol(ApplicationProtocol.HTTP_1_1.id, new ClientHttp1UpgradeHandler(http1StreamHandlerFactory));
          ioSession.registerProtocol(ApplicationProtocol.HTTP_2.id, new ClientH2UpgradeHandler(http2StreamHandlerFactory, exceptionCallback));
  
          switch (endpointPolicy) {
              case FORCE_HTTP_2:
                  return new ClientH2PrefaceHandler(ioSession, http2StreamHandlerFactory, false, exceptionCallback);
              case FORCE_HTTP_1:
                 return new ClientHttp1IOEventHandler(http1StreamHandlerFactory.create(ioSession));
             default:
                 return new HttpProtocolNegotiator(ioSession, null);
         }
     }
 
 }