/*
    * Copyright 2016 the original author or authors.
    *
    * Licensed 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.
   */
  package org.openehealth.ipf.platform.camel.ihe.mllp.core;
  
  
  import org.apache.camel.CamelException;
  import org.apache.camel.Exchange;
  import org.apache.camel.component.mina2.Mina2Consumer;
  import org.apache.mina.core.filterchain.IoFilterAdapter;
  import org.apache.mina.core.future.WriteFuture;
  import org.apache.mina.core.session.IoSession;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.net.ssl.SSLException;
  
  import static java.util.concurrent.TimeUnit.*;
  import static org.apache.camel.component.mina2.Mina2Constants.MINA_CLOSE_SESSION_WHEN_COMPLETE;
  import static org.apache.camel.component.mina2.Mina2PayloadHelper.getIn;
  import static org.apache.camel.component.mina2.Mina2PayloadHelper.getOut;
  
  /**
   * This {@link IoFilterAdapter} is used to catch all exceptions occurred inside the {@link MllpConsumer} filterChain,
   * before the message reaches the CamelRoute, and send appropriate response created by defined exceptionHandler
   * either over RouteBuilder exception handling using "consumer.bridgeErrorHandler=true" or directly by
   * "consumer.exceptionHandler=#myExceptionHandlerBean"
   *
   * @author Boris Stanojevic
   *
   */
  public class MllpExceptionIoFilter extends IoFilterAdapter {
  
      private static final Logger LOG = LoggerFactory.getLogger(MllpExceptionIoFilter.class);
  
      private final Mina2Consumer mina2Consumer;
  
      public MllpExceptionIoFilter(Mina2Consumer mina2Consumer) {
          this.mina2Consumer = mina2Consumer;
      }
  
      @Override
      public void exceptionCaught(NextFilter nextFilter, IoSession session, Throwable cause) throws Exception {
          if (!session.isClosing()) {
              if (sendResponse(cause)) {
                  Exception exception = new CamelException(cause.getMessage());
                  Exchange exchange = createExchange(exception);
                  mina2Consumer.getExceptionHandler().handleException("", exchange, exception);
                  sendResponse(session, exchange);
              } else {
                  session.closeNow();
                  nextFilter.sessionClosed(session);
              }
          }
      }
  
      private void sendResponse(IoSession session, Exchange exchange) {
          boolean disconnect = mina2Consumer.getEndpoint().getConfiguration().isDisconnect();
          Object response = exchange.hasOut()? getOut(mina2Consumer.getEndpoint(), exchange):
                                               getIn(mina2Consumer.getEndpoint(), exchange);
          if (response != null) {
              WriteFuture future = session.write(response);
              LOG.trace("Waiting for write to complete for body: {} using session: {}", response, session);
              if (!future.awaitUninterruptibly(10, SECONDS)) {
                  LOG.warn("Cannot write body: " + response + " using session: " + session);
              }
          } else {
              LOG.debug("Writing no response");
              disconnect = Boolean.TRUE;
          }
  
          // should session be closed after complete?
          Boolean close = (Boolean)session.getAttribute(MINA_CLOSE_SESSION_WHEN_COMPLETE);
          if (close != null) {
              disconnect = close;
          }
          if (disconnect) {
              LOG.debug("Closing session when complete at address: {}", mina2Consumer.getAcceptor().getLocalAddress());
              session.closeNow();
          }
      }
  
      private Exchange createExchange(Throwable cause){
          Exchange exchange = mina2Consumer.getEndpoint().createExchange();
          exchange.setException(cause);
          return exchange;
      }
 
     private boolean sendResponse(Throwable cause){
         return !(cause instanceof SSLException);
     }
 }