/*
    * 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 java.util.List;
  
  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.MqttUnsubscribeMessage;
  import net.anyflow.lannister.AbnormalDisconnectEventArgs;
  import net.anyflow.lannister.plugin.DisconnectEventListener;
  import net.anyflow.lannister.plugin.Plugins;
  import net.anyflow.lannister.plugin.UnsubscribeEventArgs;
  import net.anyflow.lannister.plugin.UnsubscribeEventListener;
  import net.anyflow.lannister.session.Session;
  import net.anyflow.lannister.topic.TopicSubscriber;
  import net.anyflow.lannister.topic.TopicSubscription;
  
  @Sharable
  public class UnsubscribeReceiver extends SimpleChannelInboundHandler<MqttUnsubscribeMessage> {
  	private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(UnsubscribeReceiver.class);
  	public static final UnsubscribeReceiver INSTANCE = new UnsubscribeReceiver();
  
  	@Override
  	protected void channelRead0(ChannelHandlerContext ctx, MqttUnsubscribeMessage msg) throws Exception {
  		logger.debug("packet incoming [message={}]", msg.toString());
  
  		Session session = Session.NEXUS.get(ctx.channel().id());
  		if (session == null) {
  			logger.error("None exist session message [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());
  
  		List<String> topicFilters = msg.payload().topics();
  
  		if (topicFilters == null || topicFilters.isEmpty()) {
  			session.dispose(true); // [MQTT-4.8.0-1]
  			return;
  		}
  
  		topicFilters.stream().forEach(tf -> {
  			TopicSubscription.NEXUS.removeByKey(tf, session.clientId());
  			TopicSubscriber.NEXUS.removeByTopicFilter(session.clientId(), tf);
  		});
  
  		Plugins.INSTANCE.get(UnsubscribeEventListener.class).unsubscribed(new UnsubscribeEventArgs() {
  			@Override
  			public String clientId() {
  				return session.clientId();
  			}
  
  			@Override
  			public List<String> topicFilters() {
  				return topicFilters;
  			}
  		});
  
  		session.send(MqttMessageFactory.unsuback(msg.variableHeader().messageId()), null); // [MQTT-2.3.1-7],[MQTT-3.10.4-4],[MQTT-3.10.4-5]
  	}
  }