/*
    * 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.topic;
  
  import java.util.Collection;
  import java.util.List;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  import com.google.common.collect.Sets;
  import com.hazelcast.core.ITopic;
  
  import net.anyflow.lannister.cluster.ClusterDataFactory;
  import net.anyflow.lannister.cluster.Map;
  import net.anyflow.lannister.message.InboundMessageStatus;
  import net.anyflow.lannister.message.Message;
  import net.anyflow.lannister.message.OutboundMessageStatus;
  import net.anyflow.lannister.session.Sessions;
  
  public class Topics {
  	@SuppressWarnings("unused")
  	private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(Topics.class);
  
  	private final Map<String, Topic> topics;
  	private final ITopic<Notification> notifier;
  
  	protected Topics(Sessions sessions) {
  		this.topics = ClusterDataFactory.INSTANCE.createMap("topics");
  		this.notifier = ClusterDataFactory.INSTANCE.createTopic("publishNotifier");
  		this.notifier.addMessageListener(sessions);
  	}
  
  	public Set<String> keySet() {
  		return Sets.newHashSet(topics.keySet());
  	}
  
  	public ITopic<Notification> notifier() {
  		return notifier;
  	}
  
  	public Topic get(String name) {
  		return topics.get(name);
  	}
  
  	public enum ClientType {
  		SUBSCRIBER,
  		PUBLISHER
  	}
  
  	public Topic get(String clientId, int messageId, ClientType clientType) {
  		switch (clientType) {
  		case SUBSCRIBER:
  			return getFromSubscriber(clientId, messageId);
  
  		case PUBLISHER:
  			return getFromPublisher(clientId, messageId);
  
  		default:
  			throw new IllegalArgumentException();
  		}
  	}
  
  	private Topic getFromPublisher(String publisherId, int messageId) {
  		InboundMessageStatus status = InboundMessageStatus.NEXUS.getBy(messageId, publisherId);
  		if (status == null) { return null; }
  
  		return Topic.NEXUS.get(status.topicName());
  	}
  
  	private Topic getFromSubscriber(String subscriberId, int messageId) {
  		OutboundMessageStatus status = OutboundMessageStatus.NEXUS.getBy(messageId, subscriberId);
  		if (status == null) { return null; }
  
  		return Topic.NEXUS.get(status.topicName());
  	}
  
  	protected void persist(Topic topic) {
  		assert topic != null;
  
  		topics.put(topic.name(), topic);
  	}
  
  	public void insert(Topic topic) {
  		assert topic != null;
  
 		TopicSubscriber.NEXUS.updateByTopicName(topic.name());
 
 		// TODO should be added in case of no subscriber & no retained Message?
 		persist(topic);
 	}
 
 	public Topic remove(Topic topic) {
 		assert topic != null;
 
 		return topics.remove(topic.name());
 	}
 
 	public Topic prepare(Message message) {
 		Topic topic = get(message.topicName());
 		if (topic == null) {
 			topic = new Topic(message.topicName());
 			insert(topic);
 		}
 
 		return topic;
 	}
 
 	public List<Topic> matches(String topicFilter) {
 		return topics.keySet().stream().filter(topicName -> TopicMatcher.match(topicFilter, topicName))
 				.map(topicName -> topics.get(topicName)).collect(Collectors.toList());
 	}
 
 	public List<Topic> matches(Collection<String> topicFilters) {
 		return topics.keySet().stream()
 				.filter(topicName -> topicFilters.stream().filter(tf -> TopicMatcher.match(tf, topicName)).count() > 0)
 				.map(topicName -> topics.get(topicName)).collect(Collectors.toList());
 	}
 }