/*******************************************************************************
    * Copyright (c) 2007, 2014 Massimiliano Ziccardi
    *
    * 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 it.jnrpe.net;
  
  import io.netty.channel.ChannelFuture;
  import io.netty.channel.ChannelFutureListener;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelInboundHandlerAdapter;
  import io.netty.util.ReferenceCountUtil;
  import it.jnrpe.ReturnValue;
  import it.jnrpe.Status;
  import it.jnrpe.commands.CommandInvoker;
  import it.jnrpe.events.EventsUtil;
  import it.jnrpe.events.IJNRPEEventListener;
  import it.jnrpe.events.LogEvent;
  
  import java.util.Collection;
  
  import org.apache.commons.lang.StringUtils;
  
  /**
   * Receives and handles connections to the JNRPE server.
   * 
   * @author Massimiliano Ziccardi
   */
  public class JNRPEServerHandler extends ChannelInboundHandlerAdapter {
  
  	/**
  	 * The command invoker.
  	 */
  	private final CommandInvoker commandInvoker;
  
  	/**
  	 * The list of listener that will receive JNRPE events.
  	 */
  	private final Collection<IJNRPEEventListener> listeners;
  
  	/**
  	 * Constructor.
  	 * 
  	 * @param invoker
  	 *            the command invoker
  	 * @param eventListeners
  	 *            The list of listeners
  	 */
  	public JNRPEServerHandler(final CommandInvoker invoker,
  			final Collection<IJNRPEEventListener> eventListeners) {
  		this.commandInvoker = invoker;
  		this.listeners = eventListeners;
  	}
  
  	@Override
  	public final void channelRead(final ChannelHandlerContext ctx,
  			final Object msg) {
  		try {
  			JNRPERequest req = (JNRPERequest) msg;
  
  			ReturnValue ret = commandInvoker.invoke(req.getCommand(),
  					req.getArguments());
  
  			if (ret == null) {
  				String args = StringUtils.join(req.getArguments(), ',');
  
  				ret = new ReturnValue(Status.UNKNOWN, "Command ["
  						+ req.getCommand() + "] with args [" + args
  						+ "] returned null");
  			}
  
  			JNRPEResponse res = new JNRPEResponse();
  			res.setPacketVersion(PacketVersion.VERSION_2);
  
  			res.setResultCode(ret.getStatus().intValue());
  			res.setMessage(ret.getMessage());
  
  			ChannelFuture f = ctx.writeAndFlush(res);
  			f.addListener(ChannelFutureListener.CLOSE);
  		} finally {
  			ReferenceCountUtil.release(msg);
  		}
  	}
  
  	@Override
  	public final void exceptionCaught(final ChannelHandlerContext ctx,
  			final Throwable cause) {
  		EventsUtil.sendEvent(listeners, this, LogEvent.ERROR,
  				cause.getMessage(), cause);
 		ctx.close();
 	}
 }