/*
    * ====================================================================
    * 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 java.io.IOException;
  import java.net.SocketAddress;
  import java.nio.ByteBuffer;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.atomic.AtomicReference;
  
  import javax.net.ssl.SSLSession;
  
  import org.apache.hc.core5.annotation.Internal;
  import org.apache.hc.core5.concurrent.FutureCallback;
  import org.apache.hc.core5.http.ConnectionClosedException;
  import org.apache.hc.core5.http.EndpointDetails;
  import org.apache.hc.core5.http.HttpVersion;
  import org.apache.hc.core5.http.ProtocolVersion;
  import org.apache.hc.core5.http.impl.nio.HttpConnectionEventHandler;
  import org.apache.hc.core5.http.nio.command.CommandSupport;
  import org.apache.hc.core5.http2.ssl.ApplicationProtocol;
  import org.apache.hc.core5.io.CloseMode;
  import org.apache.hc.core5.io.SocketTimeoutExceptionFactory;
  import org.apache.hc.core5.reactor.IOSession;
  import org.apache.hc.core5.reactor.ProtocolIOSession;
  import org.apache.hc.core5.reactor.ssl.TlsDetails;
  import org.apache.hc.core5.util.Args;
  import org.apache.hc.core5.util.TextUtils;
  import org.apache.hc.core5.util.Timeout;
  
  /**
   * @since 5.2
   */
  @Internal
  public class HttpProtocolNegotiator implements HttpConnectionEventHandler {
  
      private final ProtocolIOSession ioSession;
      private final FutureCallback<ProtocolIOSession> resultCallback;
      private final AtomicBoolean completed;
      private final AtomicReference<ProtocolVersion> negotiatedProtocolRef;
  
      public HttpProtocolNegotiator(
              final ProtocolIOSession ioSession,
              final FutureCallback<ProtocolIOSession> resultCallback) {
          this.ioSession = Args.notNull(ioSession, "I/O session");
          this.resultCallback = resultCallback;
          this.completed = new AtomicBoolean();
          this.negotiatedProtocolRef = new AtomicReference<>();
      }
  
      void startProtocol(final HttpVersion httpVersion) {
          ioSession.switchProtocol(
                  httpVersion == HttpVersion.HTTP_2 ? ApplicationProtocol.HTTP_2.id : ApplicationProtocol.HTTP_1_1.id,
                  resultCallback);
          negotiatedProtocolRef.set(httpVersion);
      }
  
      @Override
      public void connected(final IOSession session) throws IOException {
          final HttpVersion httpVersion;
          final TlsDetails tlsDetails = ioSession.getTlsDetails();
          if (tlsDetails != null) {
              final String appProtocol = tlsDetails.getApplicationProtocol();
              if (TextUtils.isEmpty(appProtocol)) {
                  httpVersion = HttpVersion.HTTP_1_1;
              } else if (appProtocol.equals(ApplicationProtocol.HTTP_1_1.id)) {
                  httpVersion = HttpVersion.HTTP_1_1;
              } else if (appProtocol.equals(ApplicationProtocol.HTTP_2.id)) {
                  httpVersion = HttpVersion.HTTP_2;
              } else {
                  throw new ProtocolNegotiationException("Unsupported application protocol: " + appProtocol);
              }
          } else {
              httpVersion = HttpVersion.HTTP_1_1;
         }
         startProtocol(httpVersion);
     }
     @Override
     public void inputReady(final IOSession session, final ByteBuffer src) throws IOException  {
         throw new ProtocolNegotiationException("Unexpected input");
     }
 
     @Override
     public void outputReady(final IOSession session) throws IOException {
         throw new ProtocolNegotiationException("Unexpected output");
     }
 
     @Override
     public void timeout(final IOSession session, final Timeout timeout) {
         exception(session, SocketTimeoutExceptionFactory.create(timeout));
     }
 
     @Override
     public void exception(final IOSession session, final Exception cause) {
         try {
             session.close(CloseMode.IMMEDIATE);
             CommandSupport.failCommands(session, cause);
         } catch (final Exception ex) {
             if (completed.compareAndSet(false, true) && resultCallback != null) {
                 resultCallback.failed(ex);
             }
         }
     }
 
     @Override
     public void disconnected(final IOSession session) {
         try {
             CommandSupport.cancelCommands(session);
         } finally {
             if (completed.compareAndSet(false, true) && resultCallback != null) {
                 resultCallback.failed(new ConnectionClosedException());
             }
         }
     }
 
     @Override
     public SSLSession getSSLSession() {
         final TlsDetails tlsDetails = ioSession.getTlsDetails();
         return tlsDetails != null ? tlsDetails.getSSLSession() : null;
     }
 
     @Override
     public EndpointDetails getEndpointDetails() {
         return null;
     }
 
     @Override
     public void setSocketTimeout(final Timeout timeout) {
         ioSession.setSocketTimeout(timeout);
     }
 
     @Override
     public Timeout getSocketTimeout() {
         return ioSession.getSocketTimeout();
     }
 
     @Override
     public ProtocolVersion getProtocolVersion() {
         return negotiatedProtocolRef.get();
     }
 
     @Override
     public SocketAddress getRemoteAddress() {
         return ioSession.getRemoteAddress();
     }
 
     @Override
     public SocketAddress getLocalAddress() {
         return ioSession.getLocalAddress();
     }
 
     @Override
     public boolean isOpen() {
         return ioSession.isOpen();
     }
 
     @Override
     public void close() throws IOException {
         ioSession.close();
     }
 
     @Override
     public void close(final CloseMode closeMode) {
         ioSession.close(closeMode);
     }
 
     @Override
     public String toString() {
         return getClass().getName();
     }
 
 }