/*
    * ====================================================================
    * 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.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.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.Timeout;
  
  abstract class PrefaceHandlerBase implements HttpConnectionEventHandler {
  
      final ProtocolIOSession ioSession;
      private final AtomicReference<HttpConnectionEventHandler> protocolHandlerRef;
      private final FutureCallback<ProtocolIOSession> resultCallback;
      private final AtomicBoolean completed;
  
      PrefaceHandlerBase(
              final ProtocolIOSession ioSession,
              final FutureCallback<ProtocolIOSession> resultCallback) {
          this.ioSession = Args.notNull(ioSession, "I/O session");
          this.protocolHandlerRef = new AtomicReference<>();
          this.resultCallback = resultCallback;
          this.completed = new AtomicBoolean();
      }
  
      void startProtocol(final HttpConnectionEventHandler protocolHandler, final ByteBuffer data) throws IOException {
          protocolHandlerRef.set(protocolHandler);
          ioSession.upgrade(protocolHandler);
          protocolHandler.connected(ioSession);
          if (data != null && data.hasRemaining()) {
              protocolHandler.inputReady(ioSession, data);
          }
          if (completed.compareAndSet(false, true) && resultCallback != null) {
              resultCallback.completed(ioSession);
          }
      }
  
      @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) {
          final HttpConnectionEventHandler protocolHandler = protocolHandlerRef.get();
          try {
              session.close(CloseMode.IMMEDIATE);
              if (protocolHandler != null) {
                  protocolHandler.exception(session, cause);
              } else {
                  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) {
         final HttpConnectionEventHandler protocolHandler = protocolHandlerRef.getAndSet(null);
         try {
             if (protocolHandler != null) {
                 protocolHandler.disconnected(ioSession);
             } else {
                 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 HttpVersion.HTTP_2;
     }
 
     @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);
     }
 
 }