/*
    * ====================================================================
    * 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.http.URIScheme;
  import org.apache.hc.core5.http.impl.nio.HttpConnectionEventHandler;
  import org.apache.hc.core5.http.impl.nio.ServerHttp1IOEventHandler;
  import org.apache.hc.core5.http.impl.nio.ServerHttp1StreamDuplexerFactory;
  import org.apache.hc.core5.http.nio.ssl.TlsStrategy;
  import org.apache.hc.core5.http2.HttpVersionPolicy;
  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.Asserts;
  import org.apache.hc.core5.util.Timeout;
  
  /**
   * Server 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 ServerHttpProtocolNegotiationStarter implements IOEventHandlerFactory {
  
      private final ServerHttp1StreamDuplexerFactory http1StreamHandlerFactory;
      private final ServerH2StreamMultiplexerFactory http2StreamHandlerFactory;
      private final HttpVersionPolicy versionPolicy;
      private final TlsStrategy tlsStrategy;
      private final Timeout handshakeTimeout;
  
      public ServerHttpProtocolNegotiationStarter(
              final ServerHttp1StreamDuplexerFactory http1StreamHandlerFactory,
              final ServerH2StreamMultiplexerFactory http2StreamHandlerFactory,
              final HttpVersionPolicy versionPolicy,
              final TlsStrategy tlsStrategy,
              final Timeout handshakeTimeout) {
          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;
      }
  
      @Override
      public HttpConnectionEventHandler createHandler(final ProtocolIOSession ioSession, final Object attachment) {
          HttpVersionPolicy endpointPolicy = versionPolicy;
          URIScheme uriScheme = URIScheme.HTTP;
          if (attachment instanceof EndpointParameters) {
              final EndpointParameters params = (EndpointParameters) attachment;
              if (URIScheme.HTTPS.same(params.getScheme())) {
                  Asserts.notNull(tlsStrategy, "TLS strategy");
                  uriScheme = URIScheme.HTTPS;
                  tlsStrategy.upgrade(
                          ioSession,
                          null,
                          ioSession.getLocalAddress(),
                          ioSession.getRemoteAddress(),
                          params.getAttachment(),
                          handshakeTimeout);
              }
              if (params.getAttachment() instanceof HttpVersionPolicy) {
                  endpointPolicy = (HttpVersionPolicy) params.getAttachment();
              }
          }
          switch (endpointPolicy) {
              case FORCE_HTTP_2:
                  return new H2OnlyServerHttpProtocolNegotiator(ioSession, http2StreamHandlerFactory);
             case FORCE_HTTP_1:
                 return new ServerHttp1IOEventHandler(http1StreamHandlerFactory.create(uriScheme.id, ioSession));
             default:
                 return new ServerHttpProtocolNegotiator(ioSession, http1StreamHandlerFactory, http2StreamHandlerFactory, HttpVersionPolicy.NEGOTIATE);
         }
     }
 
 }