/*
 * Copyright (C) 2008 Jive Software. All rights reserved.
 *
 * 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.jivesoftware.openfire.archive;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.TimerTask;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.CopyOnWriteArraySet;

import org.dom4j.Element;
import org.jivesoftware.database.DbConnectionManager;
import org.jivesoftware.openfire.XMPPServer;
import org.jivesoftware.openfire.XMPPServerInfo;
import org.jivesoftware.openfire.archive.cluster.GetConversationCountTask;
import org.jivesoftware.openfire.archive.cluster.GetConversationTask;
import org.jivesoftware.openfire.archive.cluster.GetConversationsTask;
import org.jivesoftware.openfire.cluster.ClusterManager;
import org.jivesoftware.openfire.component.ComponentEventListener;
import org.jivesoftware.openfire.component.InternalComponentManager;
import org.jivesoftware.openfire.plugin.MonitoringPlugin;
import org.jivesoftware.openfire.reporting.util.TaskEngine;
import org.jivesoftware.openfire.stats.Statistic;
import org.jivesoftware.openfire.stats.StatisticsManager;
import org.jivesoftware.util.JiveConstants;
import org.jivesoftware.util.JiveGlobals;
import org.jivesoftware.util.LocaleUtils;
import org.jivesoftware.util.NotFoundException;
import org.jivesoftware.util.PropertyEventDispatcher;
import org.jivesoftware.util.PropertyEventListener;
import org.jivesoftware.util.StringUtils;
import org.jivesoftware.util.cache.CacheFactory;
import org.picocontainer.Startable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xmpp.packet.IQ;
import org.xmpp.packet.JID;
import org.xmpp.packet.Message;

/**
 * Manages all conversations in the system. Optionally, conversations (messages plus meta-data) can be archived to the database. Archiving of
 * conversation data is enabled by default, but can be disabled by setting "conversation.metadataArchiving" to <tt>false</tt>. Archiving of messages
 * in a conversation is disabled by default, but can be enabled by setting "conversation.messageArchiving" to <tt>true</tt>.
 * <p>
 *
 * When running in a cluster only the senior cluster member will keep track of the active conversations. Other cluster nodes will forward conversation
 * events that occurred in the local node to the senior cluster member. If the senior cluster member goes down then current conversations will be
 * terminated and if users keep sending messages between them then new conversations will be created.
 *
 * @author Matt Tucker
 */
public class ConversationManager implements Startable, ComponentEventListener{

	private static final Logger Log = LoggerFactory.getLogger(ConversationManager.class);

	private static final String UPDATE_CONVERSATION = "UPDATE ofConversation SET lastActivity=?, messageCount=? WHERE conversationID=?";
	private static final String UPDATE_PARTICIPANT = "UPDATE ofConParticipant SET leftDate=? WHERE conversationID=? AND bareJID=? AND jidResource=? AND joinedDate=?";
	private static final String INSERT_MESSAGE = "INSERT INTO ofMessageArchive(messageID, conversationID, fromJID, fromJIDResource, toJID, toJIDResource, sentDate, body, stanza) "
			+ "VALUES (?,?,?,?,?,?,?,?,?)";
	private static final String CONVERSATION_COUNT = "SELECT COUNT(*) FROM ofConversation";
	private static final String MESSAGE_COUNT = "SELECT COUNT(*) FROM ofMessageArchive";
	private static final String DELETE_CONVERSATION_1 = "DELETE FROM ofMessageArchive WHERE conversationID=?";
	private static final String DELETE_CONVERSATION_2 = "DELETE FROM ofConParticipant WHERE conversationID=?";
	private static final String DELETE_CONVERSATION_3 = "DELETE FROM ofConversation WHERE conversationID=?";

	private static final int DEFAULT_IDLE_TIME = 10;
	private static final int DEFAULT_MAX_TIME = 60;
	public static final int DEFAULT_MAX_TIME_DEBUG = 30;

	public static final int DEFAULT_MAX_RETRIEVABLE = 0;
	private static final int DEFAULT_MAX_AGE = 0;

	public static final String CONVERSATIONS_KEY = "conversations";

	private ConversationEventsQueue conversationEventsQueue;
	private TaskEngine taskEngine;

	private Map<String, Conversation> conversations = new ConcurrentHashMap<String, Conversation>();
	private boolean metadataArchivingEnabled;
	/**
	 * Flag that indicates if messages of one-to-one chats should be archived.
	 */
	private boolean messageArchivingEnabled;
	/**
	 * Flag that indicates if messages of group chats (in MUC rooms) should be archived.
	 */
	private boolean roomArchivingEnabled;
	private boolean roomArchivingStanzasEnabled;
	/**
	 * List of room names to archive. When list is empty then all rooms are archived (if roomArchivingEnabled is enabled).
	 */
	private Collection<String> roomsArchived;
	private long idleTime;
	private long maxTime;
	private long maxAge;
	private long maxRetrievable;
	private PropertyEventListener propertyListener;

	private Queue<Conversation> conversationQueue;
	private Queue<ArchivedMessage> messageQueue;
	/**
	 * Queue of participants that joined or left a conversation. This queue is processed by the ArchivingTask.
	 */
	private Queue<RoomParticipant> participantQueue;

	private boolean archivingRunning = false;

	private TimerTask archiveTask;
	private TimerTask cleanupTask;

	private TimerTask maxAgeTask;

	private Collection<ConversationListener> conversationListeners;

	/**
	 * Keeps the address of those components that provide the gateway service.
	 */
	private List<String> gateways;
	private XMPPServerInfo serverInfo;

	public ConversationManager(TaskEngine taskEngine) {
		this.taskEngine = taskEngine;
		this.gateways = new CopyOnWriteArrayList<String>();
		this.serverInfo = XMPPServer.getInstance().getServerInfo();
		this.conversationEventsQueue = new ConversationEventsQueue(this, taskEngine);
	}

	public void start() {
		metadataArchivingEnabled = JiveGlobals.getBooleanProperty("conversation.metadataArchiving", true);
		messageArchivingEnabled = JiveGlobals.getBooleanProperty("conversation.messageArchiving", false);
		if (messageArchivingEnabled && !metadataArchivingEnabled) {
			Log.warn("Metadata archiving must be enabled when message archiving is enabled. Overriding setting.");
			metadataArchivingEnabled = true;
		}
		roomArchivingEnabled = JiveGlobals.getBooleanProperty("conversation.roomArchiving", false);
		roomArchivingStanzasEnabled = JiveGlobals.getBooleanProperty("conversation.roomArchivingStanzas", false);
		roomsArchived = StringUtils.stringToCollection(JiveGlobals.getProperty("conversation.roomsArchived", ""));
		if (roomArchivingEnabled && !metadataArchivingEnabled) {
			Log.warn("Metadata archiving must be enabled when room archiving is enabled. Overriding setting.");
			metadataArchivingEnabled = true;
		}
		idleTime = JiveGlobals.getIntProperty("conversation.idleTime", DEFAULT_IDLE_TIME) * JiveConstants.MINUTE;
		maxTime = JiveGlobals.getIntProperty("conversation.maxTime", DEFAULT_MAX_TIME) * JiveConstants.MINUTE;

		maxAge = JiveGlobals.getIntProperty("conversation.maxAge", DEFAULT_MAX_AGE) * JiveConstants.DAY;
		maxRetrievable = JiveGlobals.getIntProperty("conversation.maxRetrievable", DEFAULT_MAX_RETRIEVABLE) * JiveConstants.DAY;

		// Listen for any changes to the conversation properties.
		propertyListener = new ConversationPropertyListener();
		PropertyEventDispatcher.addListener(propertyListener);

		conversationQueue = new ConcurrentLinkedQueue<Conversation>();
		messageQueue = new ConcurrentLinkedQueue<ArchivedMessage>();
		participantQueue = new ConcurrentLinkedQueue<RoomParticipant>();

		conversationListeners = new CopyOnWriteArraySet<ConversationListener>();

		// Schedule a task to do conversation archiving.
		archiveTask = new TimerTask() {
			@Override
			public void run() {
				new ArchivingTask().run();
			}
		};
		taskEngine.scheduleAtFixedRate(archiveTask, JiveConstants.MINUTE, JiveConstants.MINUTE);

		if (JiveGlobals.getProperty("conversation.maxTimeDebug") != null) {
			Log.info("Monitoring plugin max time value deleted. Must be left over from stalled userCreation plugin run.");
			JiveGlobals.deleteProperty("conversation.maxTimeDebug");
		}
		
		// Schedule a task to do conversation cleanup.
		cleanupTask = new TimerTask() {
			@Override
			public void run() {
				for (String key : conversations.keySet()) {
					Conversation conversation = conversations.get(key);
					long now = System.currentTimeMillis();
					if ((now - conversation.getLastActivity().getTime() > idleTime) || (now - conversation.getStartDate().getTime() > maxTime)) {
						removeConversation(key, conversation, new Date(now));
					}
				}
			}
		};
		taskEngine.scheduleAtFixedRate(cleanupTask, JiveConstants.MINUTE * 5, JiveConstants.MINUTE * 5);

		// Schedule a task to do conversation purging.
		maxAgeTask = new TimerTask() {
			@Override
			public void run() {
				if (maxAge > 0) {
					// Delete conversations older than maxAge days
					Connection con = null;
					PreparedStatement pstmt1 = null;
					PreparedStatement pstmt2 = null;
					PreparedStatement pstmt3 = null;
					try {
						con = DbConnectionManager.getConnection();
						pstmt1 = con.prepareStatement(DELETE_CONVERSATION_1);
						pstmt2 = con.prepareStatement(DELETE_CONVERSATION_2);
						pstmt3 = con.prepareStatement(DELETE_CONVERSATION_3);
						Date now = new Date();
						Date maxAgeDate = new Date(now.getTime() - maxAge);
						ArchiveSearch search = new ArchiveSearch();
						search.setDateRangeMax(maxAgeDate);
						MonitoringPlugin plugin = (MonitoringPlugin) XMPPServer.getInstance().getPluginManager().getPlugin(MonitoringConstants.NAME);
						ArchiveSearcher archiveSearcher = (ArchiveSearcher) plugin.getModule(ArchiveSearcher.class);
						Collection<Conversation> conversations = archiveSearcher.search(search);
						int conversationDeleted = 0;
						for (Conversation conversation : conversations) {
							Log.debug("Deleting: " + conversation.getConversationID() + " with date: " + conversation.getStartDate()
									+ " older than: " + maxAgeDate);
							pstmt1.setLong(1, conversation.getConversationID());
							pstmt1.execute();
							pstmt2.setLong(1, conversation.getConversationID());
							pstmt2.execute();
							pstmt3.setLong(1, conversation.getConversationID());
							pstmt3.execute();
							conversationDeleted++;
						}
						if (conversationDeleted > 0) {
							Log.info("Deleted " + conversationDeleted + " conversations with date older than: " + maxAgeDate);
						}
					} catch (Exception e) {
						Log.error(e.getMessage(), e);
					} finally {
						DbConnectionManager.closeConnection(pstmt1, con);
						DbConnectionManager.closeConnection(pstmt2, con);
						DbConnectionManager.closeConnection(pstmt3, con);
					}
				}
			}
		};
		taskEngine.scheduleAtFixedRate(maxAgeTask, JiveConstants.MINUTE, JiveConstants.MINUTE);

		// Register a statistic.
		Statistic conversationStat = new Statistic() {

			public String getName() {
				return LocaleUtils.getLocalizedString("stat.conversation.name", MonitoringConstants.NAME);
			}

			public Type getStatType() {
				return Type.count;
			}

			public String getDescription() {
				return LocaleUtils.getLocalizedString("stat.conversation.desc", MonitoringConstants.NAME);
			}

			public String getUnits() {
				return LocaleUtils.getLocalizedString("stat.conversation.units", MonitoringConstants.NAME);
			}

			public double sample() {
				return getConversationCount();
			}

			public boolean isPartialSample() {
				return false;
			}
		};
		StatisticsManager.getInstance().addStatistic(CONVERSATIONS_KEY, conversationStat);
		InternalComponentManager.getInstance().addListener(this);
	}

	public void stop() {
		archiveTask.cancel();
		archiveTask = null;
		cleanupTask.cancel();
		cleanupTask = null;

		// Remove the statistics.
		StatisticsManager.getInstance().removeStatistic(CONVERSATIONS_KEY);

		PropertyEventDispatcher.removeListener(propertyListener);
		propertyListener = null;
		conversations.clear();
		conversations = null;

		// Archive anything remaining in the queue before quitting.
		new ArchivingTask().run();

		conversationQueue.clear();
		conversationQueue = null;

		messageQueue.clear();
		messageQueue = null;

		conversationListeners.clear();
		conversationListeners = null;

		serverInfo = null;
		InternalComponentManager.getInstance().removeListener(this);
	}

	/**
	 * Returns true if metadata archiving is enabled. Conversation meta-data includes the participants, start date, last activity, and the count of
	 * messages sent. When archiving is enabled, all meta-data is written to the database.
	 *
	 * @return true if metadata archiving is enabled.
	 */
	public boolean isMetadataArchivingEnabled() {
		return metadataArchivingEnabled;
	}

	/**
	 * Sets whether metadata archiving is enabled. Conversation meta-data includes the participants, start date, last activity, and the count of
	 * messages sent. When archiving is enabled, all meta-data is written to the database.
	 *
	 * @param enabled
	 *            true if archiving should be enabled.
	 */
	public void setMetadataArchivingEnabled(boolean enabled) {
		this.metadataArchivingEnabled = enabled;
		JiveGlobals.setProperty("conversation.metadataArchiving", Boolean.toString(enabled));
	}

	/**
	 * Returns true if one-to-one chats or group chats messages are being archived.
	 *
	 * @return true if one-to-one chats or group chats messages are being archived.
	 */
	public boolean isArchivingEnabled() {
		return isMessageArchivingEnabled() || isRoomArchivingEnabled();
	}

	/**
	 * Returns true if message archiving is enabled for one-to-one chats. When enabled, all messages in one-to-one conversations are stored in the
	 * database. Note: it's not possible for meta-data archiving to be disabled when message archiving is enabled; enabling message archiving
	 * automatically enables meta-data archiving.
	 *
	 * @return true if message archiving is enabled.
	 */
	public boolean isMessageArchivingEnabled() {
		return messageArchivingEnabled;
	}

	/**
	 * Sets whether message archiving is enabled. When enabled, all messages in conversations are stored in the database. Note: it's not possible for
	 * meta-data archiving to be disabled when message archiving is enabled; enabling message archiving automatically enables meta-data archiving.
	 *
	 * @param enabled
	 *            true if message should be enabled.
	 */
	public void setMessageArchivingEnabled(boolean enabled) {
		this.messageArchivingEnabled = enabled;
		JiveGlobals.setProperty("conversation.messageArchiving", Boolean.toString(enabled));
		// Force metadata archiving enabled.
		if (enabled) {
			this.metadataArchivingEnabled = true;
		}
	}

	/**
	 * Returns true if message archiving is enabled for group chats. When enabled, all messages in group conversations are stored in the database
	 * unless a list of rooms was specified in {@link #getRoomsArchived()} . Note: it's not possible for meta-data archiving to be disabled when room
	 * archiving is enabled; enabling room archiving automatically enables meta-data archiving.
	 *
	 * @return true if room archiving is enabled.
	 */
	public boolean isRoomArchivingEnabled() {
		return roomArchivingEnabled;
	}


	public boolean isRoomArchivingStanzasEnabled() {
		return roomArchivingStanzasEnabled;
	}

	/**
	 * Sets whether message archiving is enabled for group chats. When enabled, all messages in group conversations are stored in the database unless
	 * a list of rooms was specified in {@link #getRoomsArchived()} . Note: it's not possible for meta-data archiving to be disabled when room
	 * archiving is enabled; enabling room archiving automatically enables meta-data archiving.
	 *
	 * @param enabled
	 *            if room archiving is enabled.
	 */
	public void setRoomArchivingEnabled(boolean enabled) {
		this.roomArchivingEnabled = enabled;
		JiveGlobals.setProperty("conversation.roomArchiving", Boolean.toString(enabled));
		// Force metadata archiving enabled.
		if (enabled) {
			this.metadataArchivingEnabled = true;
		}
	}
	
	public void setRoomArchivingStanzasEnabled(boolean enabled) {
		this.roomArchivingStanzasEnabled = enabled;
		JiveGlobals.setProperty("conversation.roomArchivingStanzas", Boolean.toString(enabled));
		// Force metadata archiving enabled.
	}
	/**
	 * Returns list of room names whose messages will be archived. When room archiving is enabled and this list is empty then messages of all local
	 * rooms will be archived. However, when name of rooms are defined in this list then only messages of those rooms will be archived.
	 *
	 * @return list of local room names whose messages will be archived.
	 */
	public Collection<String> getRoomsArchived() {
		return roomsArchived;
	}

	/**
	 * Sets list of room names whose messages will be archived. When room archiving is enabled and this list is empty then messages of all local rooms
	 * will be archived. However, when name of rooms are defined in this list then only messages of those rooms will be archived.
	 *
	 * @param roomsArchived
	 *            list of local room names whose messages will be archived.
	 */
	public void setRoomsArchived(Collection<String> roomsArchived) {
		this.roomsArchived = roomsArchived;
		JiveGlobals.setProperty("conversation.roomsArchived", StringUtils.collectionToString(roomsArchived));
	}

	/**
	 * Returns the number of minutes a conversation can be idle before it's ended.
	 *
	 * @return the conversation idle time.
	 */
	public int getIdleTime() {
		return (int) (idleTime / JiveConstants.MINUTE);
	}

	/**
	 * Sets the number of minutes a conversation can be idle before it's ended.
	 *
	 * @param idleTime
	 *            the max number of minutes a conversation can be idle before it's ended.
	 * @throws IllegalArgumentException
	 *             if idleTime is less than 1.
	 */
	public void setIdleTime(int idleTime) {
		if (idleTime < 1) {
			throw new IllegalArgumentException("Idle time less than 1 is not valid: " + idleTime);
		}
		JiveGlobals.setProperty("conversation.idleTime", Integer.toString(idleTime));
		this.idleTime = idleTime * JiveConstants.MINUTE;
	}

	/**
	 * Returns the maximum number of minutes a conversation can last before it's ended. Any additional messages between the participants in the chat
	 * will be associated with a new conversation.
	 *
	 * @return the maximum number of minutes a conversation can last.
	 */
	public int getMaxTime() {
		return (int) (maxTime / JiveConstants.MINUTE);
	}

	/**
	 * Sets the maximum number of minutes a conversation can last before it's ended. Any additional messages between the participants in the chat will
	 * be associated with a new conversation.
	 *
	 * @param maxTime
	 *            the maximum number of minutes a conversation can last.
	 * @throws IllegalArgumentException
	 *             if maxTime is less than 1.
	 */
	public void setMaxTime(int maxTime) {
		if (maxTime < 1) {
			throw new IllegalArgumentException("Max time less than 1 is not valid: " + maxTime);
		}
		JiveGlobals.setProperty("conversation.maxTime", Integer.toString(maxTime));
		this.maxTime = maxTime * JiveConstants.MINUTE;
	}

	public int getMaxAge() {
		return (int) (maxAge / JiveConstants.DAY);
	}

	public void setMaxAge(int maxAge) {
		if (maxAge < 0) {
			throw new IllegalArgumentException("Max age less than 0 is not valid: " + maxAge);
		}
		JiveGlobals.setProperty("conversation.maxAge", Integer.toString(maxAge));
		this.maxAge = maxAge * JiveConstants.DAY;
	}

	public int getMaxRetrievable() {
		return (int) (maxRetrievable / JiveConstants.DAY);
	}

	public void setMaxRetrievable(int maxRetrievable) {
		if (maxRetrievable < 0) {
			throw new IllegalArgumentException("Max retrievable less than 0 is not valid: " + maxRetrievable);
		}
		JiveGlobals.setProperty("conversation.maxRetrievable", Integer.toString(maxRetrievable));
		this.maxRetrievable = maxRetrievable * JiveConstants.DAY;
	}

	public ConversationEventsQueue getConversationEventsQueue() {
		return conversationEventsQueue;
	}

	/**
	 * Returns the count of active conversations.
	 *
	 * @return the count of active conversations.
	 */
	public int getConversationCount() {
		if (ClusterManager.isSeniorClusterMember()) {
			return conversations.size();
		}
		return (Integer) CacheFactory.doSynchronousClusterTask(new GetConversationCountTask(), ClusterManager.getSeniorClusterMember().toByteArray());
	}

	/**
	 * Returns a conversation by ID.
	 *
	 * @param conversationID
	 *            the ID of the conversation.
	 * @return the conversation.
	 * @throws NotFoundException
	 *             if the conversation could not be found.
	 */
	public Conversation getConversation(long conversationID) throws NotFoundException {
		if (ClusterManager.isSeniorClusterMember()) {
			// Search through the currently active conversations.
			for (Conversation conversation : conversations.values()) {
				if (conversation.getConversationID() == conversationID) {
					return conversation;
				}
			}
			// Otherwise, it might be an archived conversation, so attempt to load it.
			return new Conversation(this, conversationID);
		} else {
			// Get this info from the senior cluster member when running in a cluster
			Conversation conversation = (Conversation) CacheFactory.doSynchronousClusterTask(new GetConversationTask(conversationID), ClusterManager
					.getSeniorClusterMember().toByteArray());
			if (conversation == null) {
				throw new NotFoundException("Conversation not found: " + conversationID);
			}
			return conversation;
		}
	}

	/**
	 * Returns the set of active conversations.
	 *
	 * @return the active conversations.
	 */
	public Collection<Conversation> getConversations() {
		if (ClusterManager.isSeniorClusterMember()) {
			List<Conversation> conversationList = new ArrayList<Conversation>(conversations.values());
			// Sort the conversations by creation date.
			Collections.sort(conversationList, new Comparator<Conversation>() {
				public int compare(Conversation c1, Conversation c2) {
					return c1.getStartDate().compareTo(c2.getStartDate());
				}
			});
			return conversationList;
		} else {
			// Get this info from the senior cluster member when running in a cluster
			return (Collection<Conversation>) CacheFactory.doSynchronousClusterTask(new GetConversationsTask(), ClusterManager
					.getSeniorClusterMember().toByteArray());
		}
	}

	/**
	 * Returns the total number of conversations that have been archived to the database. The archived conversation may only be the meta-data, or it
	 * might include messages as well if message archiving is turned on.
	 *
	 * @return the total number of archived conversations.
	 */
	public int getArchivedConversationCount() {
		int conversationCount = 0;
		Connection con = null;
		PreparedStatement pstmt = null;
		ResultSet rs = null;
		try {
			con = DbConnectionManager.getConnection();
			pstmt = con.prepareStatement(CONVERSATION_COUNT);
			rs = pstmt.executeQuery();
			if (rs.next()) {
				conversationCount = rs.getInt(1);
			}
		} catch (SQLException sqle) {
			Log.error(sqle.getMessage(), sqle);
		} finally {
			DbConnectionManager.closeConnection(rs, pstmt, con);
		}
		return conversationCount;
	}

	/**
	 * Returns the total number of messages that have been archived to the database.
	 *
	 * @return the total number of archived messages.
	 */
	public int getArchivedMessageCount() {
		int messageCount = 0;
		Connection con = null;
		PreparedStatement pstmt = null;
		ResultSet rs = null;
		try {
			con = DbConnectionManager.getConnection();
			pstmt = con.prepareStatement(MESSAGE_COUNT);
			rs = pstmt.executeQuery();
			if (rs.next()) {
				messageCount = rs.getInt(1);
			}
		} catch (SQLException sqle) {
			Log.error(sqle.getMessage(), sqle);
		} finally {
			DbConnectionManager.closeConnection(rs, pstmt, con);
		}
		return messageCount;
	}

	/**
	 * Adds a conversation listener, which will be notified of newly created conversations, conversations ending, and updates to conversations.
	 *
	 * @param listener
	 *            the conversation listener.
	 */
	public void addConversationListener(ConversationListener listener) {
		conversationListeners.add(listener);
	}

	/**
	 * Removes a conversation listener.
	 *
	 * @param listener
	 *            the conversation listener.
	 */
	public void removeConversationListener(ConversationListener listener) {
		conversationListeners.remove(listener);
	}

	/**
	 * Processes an incoming message of a one-to-one chat. The message will mapped to a conversation and then queued for storage if archiving is
	 * turned on.
	 *
	 * @param sender
	 *            sender of the message.
	 * @param receiver
	 *            receiver of the message.
	 * @param body
	 *            body of the message.
	 * @param stanza
	 * 			  String encoded message stanza
	 * @param date
	 *            date when the message was sent.
	 */
	void processMessage(JID sender, JID receiver, String body, String stanza, Date date) {
		String conversationKey = getConversationKey(sender, receiver);
		synchronized (conversationKey.intern()) {
			Conversation conversation = conversations.get(conversationKey);
			// Create a new conversation if necessary.
			if (conversation == null) {
				Collection<JID> participants = new ArrayList<JID>(2);
				participants.add(sender);
				participants.add(receiver);
				XMPPServer server = XMPPServer.getInstance();
				// Check to see if this is an external conversation; i.e. one of the participants
				// is on a different server. We can use XOR since we know that both JID's can't
				// be external.
				boolean external = isExternal(server, sender) ^ isExternal(server, receiver);
				// Make sure that the user joined the conversation before a message was received
				Date start = new Date(date.getTime() - 1);
				conversation = new Conversation(this, participants, external, start);
				conversations.put(conversationKey, conversation);
				// Notify listeners of the newly created conversation.
				for (ConversationListener listener : conversationListeners) {
					listener.conversationCreated(conversation);
				}
			}
			// Check to see if the current conversation exceeds either the max idle time
			// or max conversation time.
			else if ((date.getTime() - conversation.getLastActivity().getTime() > idleTime)
					|| (date.getTime() - conversation.getStartDate().getTime() > maxTime)) {
				removeConversation(conversationKey, conversation, conversation.getLastActivity());

				Collection<JID> participants = new ArrayList<JID>(2);
				participants.add(sender);
				participants.add(receiver);
				XMPPServer server = XMPPServer.getInstance();
				// Check to see if this is an external conversation; i.e. one of the participants
				// is on a different server. We can use XOR since we know that both JID's can't
				// be external.
				boolean external = isExternal(server, sender) ^ isExternal(server, receiver);
				// Make sure that the user joined the conversation before a message was received
				Date start = new Date(date.getTime() - 1);
				conversation = new Conversation(this, participants, external, start);
				conversations.put(conversationKey, conversation);
				// Notify listeners of the newly created conversation.
				for (ConversationListener listener : conversationListeners) {
					listener.conversationCreated(conversation);
				}
			}
			// Record the newly received message.
			conversation.messageReceived(sender, date);
			if (metadataArchivingEnabled) {
				conversationQueue.add(conversation);
			}
			if (messageArchivingEnabled) {
				if (body != null) {
					/* OF-677 - Workaround to prevent null messages being archived */
					messageQueue.add(new ArchivedMessage(conversation.getConversationID(), sender, receiver, date, body, stanza, false));
				}
			}
			// Notify listeners of the conversation update.
			for (ConversationListener listener : conversationListeners) {
				listener.conversationUpdated(conversation, date);
			}
		}
	}

	/**
	 * Processes an incoming message sent to a room. The message will mapped to a conversation and then queued for storage if archiving is turned on.
	 *
	 * @param roomJID
	 *            the JID of the room where the group conversation is taking place.
	 * @param sender
	 *            the JID of the entity that sent the message.
	 * @param nickname
	 *            nickname of the user in the room when the message was sent.
	 * @param body
	 *            the message sent to the room.
	 * @param date
	 *            date when the message was sent.
	 */
	void processRoomMessage(JID roomJID, JID sender, String nickname, String body, String stanza, Date date) {
		String conversationKey = getRoomConversationKey(roomJID);
		synchronized (conversationKey.intern()) {
			Conversation conversation = conversations.get(conversationKey);
			// Create a new conversation if necessary.
			if (conversation == null) {
				// Make sure that the user joined the conversation before a message was received
				Date start = new Date(date.getTime() - 1);
				conversation = new Conversation(this, roomJID, false, start);
				conversations.put(conversationKey, conversation);
				// Notify listeners of the newly created conversation.
				for (ConversationListener listener : conversationListeners) {
					listener.conversationCreated(conversation);
				}
			}
			// Check to see if the current conversation exceeds either the max idle time
			// or max conversation time.
			else if ((date.getTime() - conversation.getLastActivity().getTime() > idleTime)
					|| (date.getTime() - conversation.getStartDate().getTime() > maxTime)) {
				removeConversation(conversationKey, conversation, conversation.getLastActivity());
				// Make sure that the user joined the conversation before a message was received
				Date start = new Date(date.getTime() - 1);
				conversation = new Conversation(this, roomJID, false, start);
				conversations.put(conversationKey, conversation);
				// Notify listeners of the newly created conversation.
				for (ConversationListener listener : conversationListeners) {
					listener.conversationCreated(conversation);
				}
			}
			// Record the newly received message.
			conversation.messageReceived(sender, date);
			if (metadataArchivingEnabled) {
				conversationQueue.add(conversation);
			}
			if (roomArchivingEnabled && (roomsArchived.isEmpty() || roomsArchived.contains(roomJID.getNode()))) {
				JID jid = new JID(roomJID + "/" + nickname);
				if (body != null) {
					/* OF-677 - Workaround to prevent null messages being archived */
					messageQueue.add(new ArchivedMessage(conversation.getConversationID(), sender, jid, date, body, roomArchivingStanzasEnabled ? stanza : "", false));
				}
			}
			// Notify listeners of the conversation update.
			for (ConversationListener listener : conversationListeners) {
				listener.conversationUpdated(conversation, date);
			}
		}
	}

	/**
	 * Notification message indicating that a user joined a groupchat conversation. If no groupchat conversation was taking place in the specified
	 * room then ignore this event.
	 * <p>
	 * <p/>
	 * Eventually, when a new conversation will start in the room and if this user is still in the room then the new conversation will detect this
	 * user and mark like if the user joined the converstion from the beginning.
	 *
	 * @param room
	 *            the room where the user joined.
	 * @param user
	 *            the user that joined the room.
	 * @param nickname
	 *            nickname of the user in the room.
	 * @param date
	 *            date when the user joined the group coversation.
	 */
	void joinedGroupConversation(JID room, JID user, String nickname, Date date) {
		Conversation conversation = getRoomConversation(room);
		if (conversation != null) {
			conversation.participantJoined(user, nickname, date.getTime());
		}
	}

	/**
	 * Notification message indicating that a user left a groupchat conversation. If no groupchat conversation was taking place in the specified room
	 * then ignore this event.
	 *
	 * @param room
	 *            the room where the user left.
	 * @param user
	 *            the user that left the room.
	 * @param date
	 *            date when the user left the group coversation.
	 */
	void leftGroupConversation(JID room, JID user, Date date) {
		Conversation conversation = getRoomConversation(room);
		if (conversation != null) {
			conversation.participantLeft(user, date.getTime());
		}
	}

	void roomConversationEnded(JID room, Date date) {
		Conversation conversation = getRoomConversation(room);
		if (conversation != null) {
			removeConversation(room.toString(), conversation, date);
		}
	}

	private void removeConversation(String key, Conversation conversation, Date date) {
		conversations.remove(key);
		// Notify conversation that it has ended
		conversation.conversationEnded(date);
		// Notify listeners of the conversation ending.
		for (ConversationListener listener : conversationListeners) {
			listener.conversationEnded(conversation);
		}
	}

	/**
	 * Returns the group conversation taking place in the specified room or <tt>null</tt> if none.
	 *
	 * @param room
	 *            JID of the room.
	 * @return the group conversation taking place in the specified room or null if none.
	 */
	private Conversation getRoomConversation(JID room) {
		String conversationKey = room.toString();
		return conversations.get(conversationKey);
	}

	private boolean isExternal(XMPPServer server, JID jid) {
		return !server.isLocal(jid) || gateways.contains(jid.getDomain());
	}

	/**
	 * Returns true if the specified message should be processed by the conversation manager. Only messages between two users, group chats, or
	 * gateways are processed.
	 *
	 * @param message
	 *            the message to analyze.
	 * @return true if the specified message should be processed by the conversation manager.
	 */
	boolean isConversation(Message message) {
		if (Message.Type.normal == message.getType() || Message.Type.chat == message.getType()) {
			// TODO: how should conversations with components on other servers be handled?
			return isConversationJID(message.getFrom()) && isConversationJID(message.getTo());
		}
		return false;
	}

	/**
	 * Returns true if the specified JID should be recorded in a conversation.
	 *
	 * @param jid
	 *            the JID.
	 * @return true if the JID should be recorded in a conversation.
	 */
	private boolean isConversationJID(JID jid) {
		// Ignore conversations when there is no jid
		if (jid == null) {
			return false;
		}
		XMPPServer server = XMPPServer.getInstance();
		if (jid.getNode() == null) {
			return false;
		}

		// Always accept local JIDs or JIDs related to gateways
		// (this filters our components, MUC, pubsub, etc. except gateways).
		if (server.isLocal(jid) || gateways.contains(jid.getDomain())) {
			return true;
		}

		// If not a local JID, always record it.
		if (!jid.getDomain().endsWith(serverInfo.getXMPPDomain())) {
			return true;
		}

		// Otherwise return false.
		return false;
	}

	/**
	 * Returns a unique key for a coversation between two JID's. The order of two JID parameters is irrelevant; the same key will be returned.
	 *
	 * @param jid1
	 *            the first JID.
	 * @param jid2
	 *            the second JID.
	 * @return a unique key.
	 */
	String getConversationKey(JID jid1, JID jid2) {
		StringBuilder builder = new StringBuilder();
		if (jid1.compareTo(jid2) < 0) {
			builder.append(jid1.toBareJID()).append("_").append(jid2.toBareJID());
		} else {
			builder.append(jid2.toBareJID()).append("_").append(jid1.toBareJID());
		}
		return builder.toString();
	}

	String getRoomConversationKey(JID roomJID) {
		return roomJID.toString();
	}

	public void componentInfoReceived(IQ iq) {
		// Check if the component is a gateway
		boolean gatewayFound = false;
		Element childElement = iq.getChildElement();
		for (Iterator<Element> it = childElement.elementIterator("identity"); it.hasNext();) {
			Element identity = it.next();
			if ("gateway".equals(identity.attributeValue("category"))) {
				gatewayFound = true;
			}
		}
		// If component is a gateway then keep track of the component
		if (gatewayFound) {
			gateways.add(iq.getFrom().getDomain());
		}
	}

	public void componentRegistered(JID componentJID) {
		// Do nothing
	}

	public void componentUnregistered(JID componentJID) {
		// Remove stored information about this component
		gateways.remove(componentJID.getDomain());
	}

	void queueParticipantLeft(Conversation conversation, JID user, ConversationParticipation participation) {
		RoomParticipant updatedParticipant = new RoomParticipant();
		updatedParticipant.conversationID = conversation.getConversationID();
		updatedParticipant.user = user;
		updatedParticipant.joined = participation.getJoined();
		updatedParticipant.left = participation.getLeft();
		participantQueue.add(updatedParticipant);
	}

	/**
	 * A task that persists conversation meta-data and messages to the database.
	 */
	private class ArchivingTask implements Runnable {

		public void run() {
			synchronized (this) {
				if (archivingRunning) {
					return;
				}
				archivingRunning = true;
			}
			if (!messageQueue.isEmpty() || !conversationQueue.isEmpty() || !participantQueue.isEmpty()) {
				Connection con = null;
				PreparedStatement pstmt = null;
				try {
					con = DbConnectionManager.getConnection();

					pstmt = con.prepareStatement(INSERT_MESSAGE);
					ArchivedMessage message;
					
					int msgCount = getArchivedMessageCount();
					
					int count = 0;
					while ((message = messageQueue.poll()) != null) {
						pstmt.setInt(1, ++msgCount);
						pstmt.setLong(2, message.getConversationID());
						pstmt.setString(3, message.getFromJID().toBareJID());
						pstmt.setString(4, message.getFromJID().getResource());
						pstmt.setString(5, message.getToJID().toBareJID());
						pstmt.setString(6, message.getToJID().getResource());
						pstmt.setLong(7, message.getSentDate().getTime());
						DbConnectionManager.setLargeTextField(pstmt, 8, message.getBody());
						DbConnectionManager.setLargeTextField(pstmt, 9, message.getStanza());
						if (DbConnectionManager.isBatchUpdatesSupported()) {
							pstmt.addBatch();
						} else {
							pstmt.execute();
						}
						count++;
						// Only batch up to 500 items at a time.
						if (count >= 500 && DbConnectionManager.isBatchUpdatesSupported()) {
							pstmt.executeBatch();
							count = 0;
						}
					}
					if (count > 0 && DbConnectionManager.isBatchUpdatesSupported()) {
						pstmt.executeBatch();
					}

					pstmt = con.prepareStatement(UPDATE_CONVERSATION);
					Conversation conversation;
					count = 0;
					while ((conversation = conversationQueue.poll()) != null) {
						pstmt.setLong(1, conversation.getLastActivity().getTime());
						pstmt.setInt(2, conversation.getMessageCount());
						pstmt.setLong(3, conversation.getConversationID());
						if (DbConnectionManager.isBatchUpdatesSupported()) {
							pstmt.addBatch();
						} else {
							pstmt.execute();
						}
						count++;
						// Only batch up to 500 items at a time.
						if (count >= 500 && DbConnectionManager.isBatchUpdatesSupported()) {
							pstmt.executeBatch();
							count = 0;
						}
					}
					if (count > 0 && DbConnectionManager.isBatchUpdatesSupported()) {
						pstmt.executeBatch();
					}

					pstmt = con.prepareStatement(UPDATE_PARTICIPANT);
					RoomParticipant particpiant;
					count = 0;
					while ((particpiant = participantQueue.poll()) != null) {
						pstmt.setLong(1, particpiant.left.getTime());
						pstmt.setLong(2, particpiant.conversationID);
						pstmt.setString(3, particpiant.user.toBareJID());
						pstmt.setString(4, particpiant.user.getResource() == null ? " " : particpiant.user.getResource());
						pstmt.setLong(5, particpiant.joined.getTime());
						if (DbConnectionManager.isBatchUpdatesSupported()) {
							pstmt.addBatch();
						} else {
							pstmt.execute();
						}
						count++;
						// Only batch up to 500 items at a time.
						if (count >= 500 && DbConnectionManager.isBatchUpdatesSupported()) {
							pstmt.executeBatch();
							count = 0;
						}
					}
					if (count > 0 && DbConnectionManager.isBatchUpdatesSupported()) {
						pstmt.executeBatch();
					}
				} catch (Exception e) {
					Log.error(e.getMessage(), e);
				} finally {
					DbConnectionManager.closeConnection(pstmt, con);
				}
			}
			// Set archiving running back to false.
			archivingRunning = false;
		}
	}

	/**
	 * A PropertyEventListener that tracks updates to Jive properties that are related to conversation tracking and archiving.
	 */
	private class ConversationPropertyListener implements PropertyEventListener {

		public void propertySet(String property, Map<String, Object> params) {
			if (property.equals("conversation.metadataArchiving")) {
				String value = (String) params.get("value");
				metadataArchivingEnabled = Boolean.valueOf(value);
			} else if (property.equals("conversation.messageArchiving")) {
				String value = (String) params.get("value");
				messageArchivingEnabled = Boolean.valueOf(value);
				// Force metadata archiving enabled on if message archiving on.
				if (messageArchivingEnabled) {
					metadataArchivingEnabled = true;
				}
			} else if (property.equals("conversation.roomArchiving")) {
				String value = (String) params.get("value");
				roomArchivingEnabled = Boolean.valueOf(value);
				// Force metadata archiving enabled on if message archiving on.
				if (roomArchivingEnabled) {
					metadataArchivingEnabled = true;
				}
			} else if( property.equals( "conversation.roomArchivingStanzas" ) ) {
				String value = (String) params.get( "value" );
				roomArchivingStanzasEnabled = Boolean.valueOf( value );
			} else if (property.equals("conversation.roomsArchived")) {
				String value = (String) params.get("value");
				roomsArchived = StringUtils.stringToCollection(value);
			} else if (property.equals("conversation.idleTime")) {
				String value = (String) params.get("value");
				try {
					idleTime = Integer.parseInt(value) * JiveConstants.MINUTE;
				} catch (Exception e) {
					Log.error(e.getMessage(), e);
					idleTime = DEFAULT_IDLE_TIME * JiveConstants.MINUTE;
				}
			} else if (property.equals("conversation.maxTime")) {
				String value = (String) params.get("value");
				try {
					maxTime = Integer.parseInt(value) * JiveConstants.MINUTE;
				} catch (Exception e) {
					Log.error(e.getMessage(), e);
					maxTime = DEFAULT_MAX_TIME * JiveConstants.MINUTE;
				}
			} else if (property.equals("conversation.maxRetrievable")) {
				String value = (String) params.get("value");
				try {
					maxRetrievable = Integer.parseInt(value) * JiveConstants.DAY;
				} catch (Exception e) {
					Log.error(e.getMessage(), e);
					maxRetrievable = DEFAULT_MAX_RETRIEVABLE * JiveConstants.DAY;
				}
			} else if (property.equals("conversation.maxAge")) {
				String value = (String) params.get("value");
				try {
					maxAge = Integer.parseInt(value) * JiveConstants.DAY;
				} catch (Exception e) {
					Log.error(e.getMessage(), e);
					maxAge = DEFAULT_MAX_AGE * JiveConstants.DAY;
				}
			} else if (property.equals("conversation.maxTimeDebug")) {
				String value = (String) params.get("value");
				try {
					Log.info("Monitoring plugin max time overridden (as used by userCreation plugin)");
					maxTime = Integer.parseInt(value);
				} catch (Exception e) {
					Log.error(e.getMessage(), e);
					Log.info("Monitoring plugin max time reset back to " + DEFAULT_MAX_TIME + " minutes");
					maxTime = DEFAULT_MAX_TIME * JiveConstants.MINUTE;
				}
			}
		}

		public void propertyDeleted(String property, Map<String, Object> params) {
			if (property.equals("conversation.metadataArchiving")) {
				metadataArchivingEnabled = true;
			} else if (property.equals("conversation.messageArchiving")) {
				messageArchivingEnabled = false;
			} else if (property.equals("conversation.roomArchiving")) {
				roomArchivingEnabled = false;
			} else if (property.equals("conversation.roomArchivingStanzas")) {
				roomArchivingStanzasEnabled = false;
			} else if (property.equals("conversation.roomsArchived")) {
				roomsArchived = Collections.emptyList();
			} else if (property.equals("conversation.idleTime")) {
				idleTime = DEFAULT_IDLE_TIME * JiveConstants.MINUTE;
			} else if (property.equals("conversation.maxTime")) {
				maxTime = DEFAULT_MAX_TIME * JiveConstants.MINUTE;
			} else if (property.equals("conversation.maxAge")) {
				maxAge = DEFAULT_MAX_AGE * JiveConstants.DAY;
			} else if (property.equals("conversation.maxRetrievable")) {
				maxRetrievable = DEFAULT_MAX_RETRIEVABLE * JiveConstants.DAY;
			}  else if (property.equals("conversation.maxTimeDebug")) {
				Log.info("Monitoring plugin max time reset back to " + DEFAULT_MAX_TIME + " minutes");
				maxTime = DEFAULT_MAX_TIME * JiveConstants.MINUTE;
			}
		}

		public void xmlPropertySet(String property, Map<String, Object> params) {
			// Ignore.
		}

		public void xmlPropertyDeleted(String property, Map<String, Object> params) {
			// Ignore.
		}
	}

	private static class RoomParticipant {
		private long conversationID = -1;
		private JID user;
		private Date joined;
		private Date left;
	}
}
