/*
    * Copyright 2016 The Lannister Project
    * 
    * 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 net.anyflow.lannister.packetreceiver;
  
  import java.util.Date;
  
  import io.netty.channel.ChannelFutureListener;
  import io.netty.channel.ChannelHandler.Sharable;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.SimpleChannelInboundHandler;
  import io.netty.handler.codec.mqtt.MqttMessage;
  import io.netty.handler.codec.mqtt.MqttMessageIdVariableHeader;
  import net.anyflow.lannister.AbnormalDisconnectEventArgs;
  import net.anyflow.lannister.plugin.DisconnectEventListener;
  import net.anyflow.lannister.plugin.Plugins;
  import net.anyflow.lannister.session.Session;
  
  @Sharable
  public class GenericReceiver extends SimpleChannelInboundHandler<MqttMessage> {
  	private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(GenericReceiver.class);
  	public static final GenericReceiver INSTANCE = new GenericReceiver();
  
  	@Override
  	protected void channelRead0(ChannelHandlerContext ctx, MqttMessage msg) throws Exception {
  		if (!msg.decoderResult().isSuccess()) {
  			logger.error("decoding MQTT message failed : {}", msg.decoderResult().cause().getMessage());
  
  			Session session = Session.NEXUS.get(ctx.channel().id());
  			if (session != null) {
  				session.dispose(true); // [MQTT-4.8.0-1]
  			}
  			else {
  				ctx.channel().writeAndFlush(msg).addListener(f -> {
  					logger.debug("packet outgoing [{}]", msg);
  
  					ctx.channel().disconnect().addListener(ChannelFutureListener.CLOSE).addListener(fs -> // [MQTT-3.2.2-5]
  					Plugins.INSTANCE.get(DisconnectEventListener.class)
  							.disconnected(new AbnormalDisconnectEventArgs()));
  				});
  			}
  			return;
  		}
  		else {
  			logger.debug("packet incoming [message={}]", msg.toString());
  
  			Session session = Session.NEXUS.get(ctx.channel().id());
  			if (session == null) {
  				logger.error("None exist session message : {}", msg.toString());
  
  				ctx.channel().disconnect().addListener(ChannelFutureListener.CLOSE).addListener(fs -> // [MQTT-4.8.0-1]
  				Plugins.INSTANCE.get(DisconnectEventListener.class).disconnected(new AbnormalDisconnectEventArgs()));
  				return;
  			}
  
  			session.setLastIncomingTime(new Date());
  
  			switch (msg.fixedHeader().messageType()) {
  			case DISCONNECT:
  				DisconnectReceiver.SHARED.handle(ctx, session);
  				return;
  
  			case PINGREQ:
  				PingReqReceiver.SHARED.handle(ctx, session);
  				return;
  
  			case PUBREC:
  				PubRecReceiver.SHARED.handle(ctx, session,
  						((MqttMessageIdVariableHeader) msg.variableHeader()).messageId());
  				return;
  
  			case PUBREL:
  				PubRelReceiver.SHARED.handle(ctx, session,
  						((MqttMessageIdVariableHeader) msg.variableHeader()).messageId());
  				return;
  
  			case PUBCOMP:
  				PubCompReceiver.SHARED.handle(ctx, session,
  						((MqttMessageIdVariableHeader) msg.variableHeader()).messageId());
  				return;
  
  			default:
  				session.dispose(true); // [MQTT-4.8.0-1]
  				return;
  			}
  		}
 	}
 
 	@Override
 	public void channelInactive(ChannelHandlerContext ctx) throws Exception {
 		Session session = Session.NEXUS.get(ctx.channel().id());
 		if (session == null) {
 			logger.debug("session does not exist : [channelId={}]", ctx.channel().id());
 			return;
 		}
 		else {
 			session.dispose(true); // abnormal disconnection without DISCONNECT
 									// [MQTT-4.8.0-1]
 		}
 	}
 
 	@Override
 	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
 		logger.error(cause.getMessage(), cause);
 
 		Session session = Session.NEXUS.get(ctx.channel().id());
 		if (session != null) {
 			session.dispose(true);
 		}
 		else {
 			ctx.channel().disconnect().addListener(ChannelFutureListener.CLOSE).addListener(fs -> // [MQTT-3.2.2-5]
 			Plugins.INSTANCE.get(DisconnectEventListener.class).disconnected(new AbnormalDisconnectEventArgs()));
 		}
 	}
 }