/**
 * 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.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.jivesoftware.database.DbConnectionManager;
import org.jivesoftware.database.JiveID;
import org.jivesoftware.database.SequenceManager;
import org.jivesoftware.openfire.XMPPServer;
import org.jivesoftware.openfire.muc.MUCRole;
import org.jivesoftware.openfire.muc.MUCRoom;
import org.jivesoftware.openfire.plugin.MonitoringPlugin;
import org.jivesoftware.openfire.user.UserNameManager;
import org.jivesoftware.openfire.user.UserNotFoundException;
import org.jivesoftware.util.JiveGlobals;
import org.jivesoftware.util.LocaleUtils;
import org.jivesoftware.util.NotFoundException;
import org.jivesoftware.util.StringUtils;
import org.jivesoftware.util.cache.ExternalizableUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xmpp.packet.JID;

/**
 * Represents an IM conversation between two people. A conversation encompasses a series of messages sent back and forth. It may cover a single topic
 * or several. The start of a conversation occurs when the first message between two users is sent. It ends when either:
 * <ul>
 * <li>No messages are sent between the users for a certain period of time (default of 10 minutes). The default value can be overridden by setting the
 * Openfire property <tt>conversation.idleTime</tt>.</li>
 * <li>The total conversation time reaches a maximum value (default of 60 minutes). The default value can be overridden by setting the Openfire
 * property <tt>conversation.maxTime</tt>. When the max time has been reached and additional messages are sent between the users, a new conversation
 * will simply be started.</li>
 * </ul>
 * <p/>
 * Each conversation has a start time, date of the last message, and count of the messages in the conversation. Conversations are specially marked if
 * one of the participants is on an external server. If archiving is enabled, the actual messages in the conversation can be retrieved.
 * 
 * @author Matt Tucker
 */
@JiveID(50)
public class Conversation implements Externalizable {

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

	private static final String INSERT_CONVERSATION = "INSERT INTO ofConversation(conversationID, room, isExternal, startDate, "
			+ "lastActivity, messageCount) VALUES (?,?,?,?,?,0)";
	private static final String INSERT_PARTICIPANT = "INSERT INTO ofConParticipant(conversationID, joinedDate, bareJID, jidResource, nickname) "
			+ "VALUES (?,?,?,?,?)";
	private static final String LOAD_CONVERSATION = "SELECT room, isExternal, startDate, lastActivity, messageCount "
			+ "FROM ofConversation WHERE conversationID=?";
	private static final String LOAD_PARTICIPANTS = "SELECT bareJID, jidResource, nickname, joinedDate, leftDate FROM ofConParticipant "
			+ "WHERE conversationID=? ORDER BY joinedDate";
	private static final String LOAD_MESSAGES = "SELECT fromJID, fromJIDResource, toJID, toJIDResource, sentDate, body FROM ofMessageArchive WHERE conversationID=? "
			+ "ORDER BY sentDate";

	private transient ConversationManager conversationManager;

	private long conversationID = -1;
	private Map<String, UserParticipations> participants;
	private boolean external;
	private Date startDate;
	private Date lastActivity;
	private int messageCount;
	/**
	 * Room where the group conversion is taking place. For one-to-one chats there is no room so this variable will be null.
	 */
	private JID room;

	/**
	 * Do not use this constructor. It only exists for serialization purposes.
	 */
	public Conversation() {
	}

	/**
	 * Constructs a new one-to-one conversation.
	 * 
	 * @param conversationManager
	 *            the ConversationManager.
	 * @param users
	 *            the two participants in the conversation.
	 * @param external
	 *            true if the conversation includes a user on another server.
	 * @param startDate
	 *            the starting date of the conversation.
	 */
	public Conversation(ConversationManager conversationManager, Collection<JID> users, boolean external, Date startDate) {
		if (users.size() != 2) {
			throw new IllegalArgumentException("Illegal number of participants: " + users.size());
		}
		this.conversationManager = conversationManager;
		this.participants = new HashMap<String, UserParticipations>(2);
		// Ensure that we're use the full JID of each participant.
		for (JID user : users) {
			UserParticipations userParticipations = new UserParticipations(false);
			userParticipations.addParticipation(new ConversationParticipation(startDate));
			participants.put(user.toString(), userParticipations);
		}
		this.external = external;
		this.startDate = startDate;
		this.lastActivity = startDate;
		// If archiving is enabled, insert the conversation into the database.
		if (conversationManager.isMetadataArchivingEnabled()) {
			try {
				insertIntoDb();
			} catch (Exception e) {
				Log.error(e.getMessage(), e);
			}
		}
	}

	/**
	 * Constructs a new group chat conversation that is taking place in a room.
	 * 
	 * @param conversationManager
	 *            the ConversationManager.
	 * @param room
	 *            the JID of the room where the conversation is taking place.
	 * @param external
	 *            true if the conversation includes a user on another server.
	 * @param startDate
	 *            the starting date of the conversation.
	 */
	public Conversation(ConversationManager conversationManager, JID room, boolean external, Date startDate) {
		this.conversationManager = conversationManager;
		this.participants = new ConcurrentHashMap<String, UserParticipations>();
		// Add list of existing room occupants as participants of this conversation
		MUCRoom mucRoom = XMPPServer.getInstance().getMultiUserChatManager().getMultiUserChatService(room).getChatRoom(room.getNode());
		if (mucRoom != null) {
			for (MUCRole role : mucRoom.getOccupants()) {
				UserParticipations userParticipations = new UserParticipations(true);
				userParticipations.addParticipation(new ConversationParticipation(startDate, role.getNickname()));
				participants.put(role.getUserAddress().toString(), userParticipations);
			}
		}
		this.room = room;
		this.external = external;
		this.startDate = startDate;
		this.lastActivity = startDate;
		// If archiving is enabled, insert the conversation into the database.
		if (conversationManager.isMetadataArchivingEnabled()) {
			try {
				insertIntoDb();
			} catch (Exception e) {
				Log.error(e.getMessage(), e);
			}
		}
	}

	/**
	 * Loads a conversation from the database.
	 * 
	 * @param conversationManager
	 *            the conversation manager.
	 * @param conversationID
	 *            the ID of the conversation.
	 * @throws NotFoundException
	 *             if the conversation can't be loaded.
	 */
	public Conversation(ConversationManager conversationManager, long conversationID) throws NotFoundException {
		this.conversationManager = conversationManager;
		this.conversationID = conversationID;
		loadFromDb();
	}

	/**
	 * Returns the unique ID of the conversation. A unique ID is only meaningful when conversation archiving is enabled. Therefore, this method
	 * returns <tt>-1</tt> if archiving is not turned on.
	 * 
	 * @return the unique ID of the conversation, or <tt>-1</tt> if conversation archiving is not enabled.
	 */
	public long getConversationID() {
		return conversationID;
	}

	/**
	 * Returns the JID of the room where the group conversation took place. If the conversation was a one-to-one chat then a <tt>null</tt> value is
	 * returned.
	 * 
	 * @return the JID of room or null if this was a one-to-one chat.
	 */
	public JID getRoom() {
		return room;
	}

	/**
	 * Returns the conversation participants.
	 * 
	 * @return the two conversation participants. Returned JIDs are full JIDs.
	 */
	public Collection<JID> getParticipants() {
		List<JID> users = new ArrayList<JID>();
		for (String key : participants.keySet()) {
			users.add(new JID(key));
		}
		return users;
	}

	/**
	 * Returns the participations of the specified user (full JID) in this conversation. Each participation will hold the time when the user joined
	 * and left the conversation and the nickname if the room happened in a room.
	 * 
	 * @param user
	 *            the full JID of the user.
	 * @return the participations of the specified user (full JID) in this conversation.
	 */
	public Collection<ConversationParticipation> getParticipations(JID user) {
		UserParticipations userParticipations = participants.get(user.toString());
		if (userParticipations == null) {
			return Collections.emptyList();
		}
		return userParticipations.getParticipations();
	}

	/**
	 * Returns true if one of the conversation participants is on an external server.
	 * 
	 * @return true if one of the conversation participants is on an external server.
	 */
	public boolean isExternal() {
		return external;
	}

	/**
	 * Returns the starting timestamp of the conversation.
	 * 
	 * @return the start date.
	 */
	public Date getStartDate() {
		return startDate;
	}

	/**
	 * Returns the timestamp the last message was receieved.
	 * 
	 * @return the last activity.
	 */
	public Date getLastActivity() {
		return lastActivity;
	}

	/**
	 * Returns the number of messages that make up the conversation.
	 * 
	 * @return the message count.
	 */
	public int getMessageCount() {
		return messageCount;
	}

	/**
	 * Returns the archived messages in the conversation. If message archiving is not enabled, this method will always return an empty collection.
	 * This method will only return messages that have already been batch-archived to the database; in other words, it does not provide a real-time
	 * view of new messages.
	 * 
	 * @return the archived messages in the conversation.
	 */
	public List<ArchivedMessage> getMessages() {
		if (room == null && !conversationManager.isMessageArchivingEnabled()) {
			return Collections.emptyList();
		} else if (room != null && !conversationManager.isRoomArchivingEnabled()) {
			return Collections.emptyList();
		}

		List<ArchivedMessage> messages = new ArrayList<ArchivedMessage>();
		Connection con = null;
		PreparedStatement pstmt = null;
		ResultSet rs = null;
		try {
			con = DbConnectionManager.getConnection();
			pstmt = con.prepareStatement(LOAD_MESSAGES);
			pstmt.setLong(1, getConversationID());
			rs = pstmt.executeQuery();
			while (rs.next()) {
				JID fromJID = new JID(rs.getString(1));
				String fromJIDResource = rs.getString(2);
				if (fromJIDResource != null && !"".equals(fromJIDResource)) {
					fromJID = new JID(rs.getString(1) + "/" + fromJIDResource);
				}
				JID toJID = new JID(rs.getString(3));
				String toJIDResource = rs.getString(4);
				if (toJIDResource != null && !"".equals(toJIDResource)) {
					toJID = new JID(rs.getString(3) + "/" + toJIDResource);
				}
				Date date = new Date(rs.getLong(5));
				String body = DbConnectionManager.getLargeTextField(rs, 6);
				messages.add(new ArchivedMessage(conversationID, fromJID, toJID, date, body, false));
			}
		} catch (SQLException sqle) {
			Log.error(sqle.getMessage(), sqle);
		} finally {
			DbConnectionManager.closeConnection(rs, pstmt, con);
		}
		// Add messages of users joining or leaving the group chat conversation
		if (room != null) {
			for (Map.Entry<String, UserParticipations> entry : participants.entrySet()) {
				JID user = new JID(entry.getKey());
				boolean anonymous = false;
				String name;
				try {
					name = UserNameManager.getUserName(user);
				} catch (UserNotFoundException e) {
					name = user.toBareJID();
					anonymous = true;
				}
				for (ConversationParticipation participation : entry.getValue().getParticipations()) {
					if (participation.getJoined() == null) {
						Log.warn("Found muc participant with no join date in conversation: " + conversationID);
						continue;
					}
					JID jid = new JID(room + "/" + participation.getNickname());
					String joinBody;
					String leftBody;
					if (anonymous) {
						joinBody = LocaleUtils.getLocalizedString("muc.conversation.joined.anonymous", MonitoringConstants.NAME,
								Arrays.asList(participation.getNickname()));
						leftBody = LocaleUtils.getLocalizedString("muc.conversation.left.anonymous", MonitoringConstants.NAME,
								Arrays.asList(participation.getNickname()));
					} else {
						joinBody = LocaleUtils.getLocalizedString("muc.conversation.joined", MonitoringConstants.NAME,
								Arrays.asList(participation.getNickname(), name));
						leftBody = LocaleUtils.getLocalizedString("muc.conversation.left", MonitoringConstants.NAME,
								Arrays.asList(participation.getNickname(), name));
					}
					messages.add(new ArchivedMessage(conversationID, user, jid, participation.getJoined(), joinBody, true));
					if (participation.getLeft() != null) {
						messages.add(new ArchivedMessage(conversationID, user, jid, participation.getLeft(), leftBody, true));
					}
				}
			}
			// Sort messages by sent date
			Collections.sort(messages, new Comparator<ArchivedMessage>() {
				public int compare(ArchivedMessage o1, ArchivedMessage o2) {
					return o1.getSentDate().compareTo(o2.getSentDate());
				}
			});
		}
		return messages;
	}

	@Override
	public String toString() {
		StringBuilder buf = new StringBuilder();
		buf.append("Conversation [").append(conversationID).append("]");
		if (room != null) {
			buf.append(" in room").append(room);
		}
		buf.append(" between ").append(participants);
		buf.append(". started ").append(JiveGlobals.formatDateTime(startDate));
		buf.append(", last active ").append(JiveGlobals.formatDateTime(lastActivity));
		buf.append(". Total messages: ").append(messageCount);
		return buf.toString();
	}

	/**
	 * Called when a new message for the conversation is received. Each time a new message is received, the last activity date will be updated and the
	 * message count incremented.
	 * 
	 * @param entity
	 *            JID of the entity that sent the message.
	 * @param date
	 *            the date the message was sent.
	 */
	synchronized void messageReceived(JID entity, Date date) {
		lastActivity = date;
		messageCount++;
	}

	synchronized void participantJoined(JID user, String nickname, long timestamp) {
		// Add the sender of the message as a participant of this conversation. If the sender
		// was already a participant then he/she will appear just once. Rooms are never considered
		// as participants
		UserParticipations userParticipations = participants.get(user.toString());
		if (userParticipations == null) {
			userParticipations = new UserParticipations(true);
			participants.put(user.toString(), userParticipations);
		} else {
			// Get last known participation and check that the user has finished it
			ConversationParticipation lastParticipation = userParticipations.getRecentParticipation();
			if (lastParticipation != null && lastParticipation.getLeft() == null) {
				Log.warn("Found user that never left a previous conversation: " + user);
				lastParticipation.participationEnded(new Date(timestamp));
				// Queue storeage of updated participation information
				conversationManager.queueParticipantLeft(this, user, lastParticipation);
			}
		}
		ConversationParticipation newParticipation = new ConversationParticipation(new Date(timestamp), nickname);
		// Add element to the beginning of the list
		userParticipations.addParticipation(newParticipation);
		// If archiving is enabled, insert the conversation into the database (if not persistent yet).
		if (conversationManager.isMetadataArchivingEnabled()) {
			try {
				if (conversationID == -1) {
					// Save new conversation to the database
					insertIntoDb();
				} else {
					// Store new participation information
					insertIntoDb(user, nickname, timestamp);
				}
			} catch (Exception e) {
				Log.error(e.getMessage(), e);
			}
		}
	}

	synchronized void participantLeft(JID user, long timestamp) {
		// Get the list of participations of the specified user
		UserParticipations userParticipations = participants.get(user.toString());
		if (userParticipations == null) {
			Log.warn("Found user that left a conversation but never started it: " + user);
		} else {
			// Get last known participation and check that the user has not finished it
			ConversationParticipation currentParticipation = userParticipations.getRecentParticipation();
			if (currentParticipation == null || currentParticipation.getLeft() != null) {
				Log.warn("Found user that left a conversation but never started it: " + user);
			} else {
				currentParticipation.participationEnded(new Date(timestamp));
				// Queue storeage of updated participation information
				conversationManager.queueParticipantLeft(this, user, currentParticipation);
			}
		}
	}

	/**
	 * Inserts a new conversation into the database.
	 * 
	 * @throws SQLException
	 *             if an error occurs inserting the conversation.
	 */
	private void insertIntoDb() throws SQLException {
		this.conversationID = SequenceManager.nextID(this);
		Connection con = null;
		boolean abortTransaction = false;
		try {
			con = DbConnectionManager.getTransactionConnection();
			PreparedStatement pstmt = con.prepareStatement(INSERT_CONVERSATION);
			pstmt.setLong(1, conversationID);
			pstmt.setString(2, room == null ? null : room.toString());
			pstmt.setInt(3, (external ? 1 : 0));
			pstmt.setLong(4, startDate.getTime());
			pstmt.setLong(5, lastActivity.getTime());
			pstmt.executeUpdate();
			pstmt.close();

			pstmt = con.prepareStatement(INSERT_PARTICIPANT);
			for (Map.Entry<String, UserParticipations> entry : participants.entrySet()) {
				JID user = new JID(entry.getKey());
				for (ConversationParticipation participation : entry.getValue().getParticipations()) {
					pstmt.setLong(1, conversationID);
					pstmt.setLong(2, participation.getJoined().getTime());
					pstmt.setString(3, user.toBareJID());
					pstmt.setString(4, user.getResource() == null ? "" : user.getResource());
					pstmt.setString(5, participation.getNickname());
					pstmt.executeUpdate();
				}
			}
			pstmt.close();
		} catch (SQLException sqle) {
			abortTransaction = true;
			throw sqle;
		} finally {
			DbConnectionManager.closeTransactionConnection(con, abortTransaction);
		}
	}

	/**
	 * Adds a new conversation participant into the database.
	 * 
	 * @param participant
	 *            the full JID of the participant.
	 * @param nickname
	 *            nickname of the user in the room.
	 * @param joined
	 *            timestamp when user joined the conversation.
	 * @throws SQLException
	 *             if an error occurs inserting the conversation.
	 */
	private void insertIntoDb(JID participant, String nickname, long joined) throws SQLException {
		Connection con = null;
		try {
			con = DbConnectionManager.getConnection();
			PreparedStatement pstmt = con.prepareStatement(INSERT_PARTICIPANT);
			pstmt.setLong(1, conversationID);
			pstmt.setLong(2, joined);
			pstmt.setString(3, participant.toBareJID());
			pstmt.setString(4, participant.getResource() == null ? "" : participant.getResource());
			pstmt.setString(5, nickname);
			pstmt.executeUpdate();
			pstmt.close();
		} catch (SQLException sqle) {
			throw sqle;
		} finally {
			DbConnectionManager.closeConnection(con);
		}
	}

	private void loadFromDb() throws NotFoundException {
		Connection con = null;
		PreparedStatement pstmt = null;
		ResultSet rs = null;
		try {
			con = DbConnectionManager.getConnection();
			pstmt = con.prepareStatement(LOAD_CONVERSATION);
			pstmt.setLong(1, conversationID);
			rs = pstmt.executeQuery();
			if (!rs.next()) {
				throw new NotFoundException("Conversation not found: " + conversationID);
			}
			this.room = rs.getString(1) == null ? null : new JID(rs.getString(1));
			this.external = rs.getInt(2) == 1;
			this.startDate = new Date(rs.getLong(3));
			this.lastActivity = new Date(rs.getLong(4));
			this.messageCount = rs.getInt(5);
			rs.close();
			pstmt.close();

			this.participants = new ConcurrentHashMap<String, UserParticipations>();
			pstmt = con.prepareStatement(LOAD_PARTICIPANTS);
			pstmt.setLong(1, conversationID);
			rs = pstmt.executeQuery();
			while (rs.next()) {
				// Rebuild full JID of participant
				String baredJID = rs.getString(1);
				String resource = rs.getString(2);
				JID fullJID = new JID("".equals(resource) ? baredJID : baredJID + "/" + resource);
				// Rebuild joined and left time
				ConversationParticipation participation = new ConversationParticipation(new Date(rs.getLong(4)), rs.getString(3));
				if (rs.getLong(5) > 0) {
					participation.participationEnded(new Date(rs.getLong(5)));
				}
				// Store participation data
				UserParticipations userParticipations = participants.get(fullJID.toString());
				if (userParticipations == null) {
					userParticipations = new UserParticipations(room != null);
					participants.put(fullJID.toString(), userParticipations);
				}
				userParticipations.addParticipation(participation);
			}
		} catch (SQLException sqle) {
			Log.error(sqle.getMessage(), sqle);
		} finally {
			DbConnectionManager.closeConnection(rs, pstmt, con);
		}
	}

	/**
	 * Notification message inficating that conversation has finished so remaining participants should be marked that they left the conversation.
	 * 
	 * @param nowDate
	 *            the date when the conversation was finished
	 */
	void conversationEnded(Date nowDate) {
		for (Map.Entry<String, UserParticipations> entry : participants.entrySet()) {
			ConversationParticipation currentParticipation = entry.getValue().getRecentParticipation();
			if (currentParticipation.getLeft() == null) {
				currentParticipation.participationEnded(nowDate);
				// Queue storage of updated participation information
				conversationManager.queueParticipantLeft(this, new JID(entry.getKey()), currentParticipation);
			}
		}
	}

	public void writeExternal(ObjectOutput out) throws IOException {
		ExternalizableUtil.getInstance().writeLong(out, conversationID);
		ExternalizableUtil.getInstance().writeExternalizableMap(out, participants);
		ExternalizableUtil.getInstance().writeBoolean(out, external);
		ExternalizableUtil.getInstance().writeLong(out, startDate.getTime());
		ExternalizableUtil.getInstance().writeLong(out, lastActivity.getTime());
		ExternalizableUtil.getInstance().writeInt(out, messageCount);
		ExternalizableUtil.getInstance().writeBoolean(out, room != null);
		if (room != null) {
			ExternalizableUtil.getInstance().writeSerializable(out, room);
		}
	}

	public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
		MonitoringPlugin plugin = (MonitoringPlugin) XMPPServer.getInstance().getPluginManager().getPlugin(MonitoringConstants.NAME);
		conversationManager = (ConversationManager) plugin.getModule(ConversationManager.class);

		this.participants = new ConcurrentHashMap<String, UserParticipations>();

		conversationID = ExternalizableUtil.getInstance().readLong(in);
		ExternalizableUtil.getInstance().readExternalizableMap(in, participants, getClass().getClassLoader());
		external = ExternalizableUtil.getInstance().readBoolean(in);
		startDate = new Date(ExternalizableUtil.getInstance().readLong(in));
		lastActivity = new Date(ExternalizableUtil.getInstance().readLong(in));
		messageCount = ExternalizableUtil.getInstance().readInt(in);
		if (ExternalizableUtil.getInstance().readBoolean(in)) {
			room = (JID) ExternalizableUtil.getInstance().readSerializable(in);
		}
	}
}