/*
 * Copyright (C) 2005 Luca Veltri - University of Parma - Italy
 * 
 * This file is part of MjSip (http://www.mjsip.org)
 * 
 * MjSip is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * MjSip is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with MjSip; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * Author(s):
 * Luca Veltri (luca.veltri@unipr.it)
 */

package org.zoolu.sip.transaction;

import org.zoolu.tools.Timer;
import org.zoolu.sip.provider.*;
import org.zoolu.sip.message.*;
import org.zoolu.tools.LogLevel;

/**
 * Generic server transaction as defined in RFC 3261 (Section 17.2.2). A
 * TransactionServer is responsable to create a new SIP transaction that starts
 * with a request message received by the SipProvider and ends sending a final
 * response.<BR>
 * The changes of the internal status and the received messages are fired to the
 * TransactionListener passed to the TransactionServer object.<BR>
 * When costructing a new TransactionServer, the transaction type is passed as
 * String parameter to the costructor (e.g. "CANCEL", "BYE", etc..)
 */

public class TransactionServer extends Transaction {
	/**
	 * the TransactionServerListener that captures the events fired by the
	 * TransactionServer
	 */
	TransactionServerListener transaction_listener;

	/** last response message */
	Message response;

	/** clearing timeout ("Timer J" in RFC 3261) */
	Timer clearing_to;

	/** Costructs a new TransactionServer. */
	protected TransactionServer(SipProvider sip_provider) {
		super(sip_provider);
		transaction_listener = null;
		response = null;
	}

	/** Creates a new TransactionServer of type <i>method</i>. */
	public TransactionServer(SipProvider sip_provider, String method,
			TransactionServerListener listener) {
		super(sip_provider);
		init(listener, new TransactionIdentifier(method), null);
	}

	/** Creates a new TransactionServer for the already received request <i>req</i>. */
	public TransactionServer(SipProvider provider, Message req,
			TransactionServerListener listener) {
		super(provider);
		request = new Message(req);
		init(listener, request.getTransactionId(), request.getConnectionId());

		printLog("start", LogLevel.LOW);
		changeStatus(STATE_TRYING);
		sip_provider.addSipProviderListener(transaction_id, this);
	}

	/** Initializes timeouts and listener. */
	void init(TransactionServerListener listener,
			TransactionIdentifier transaction_id,
			ConnectionIdentifier connection_id) {
		this.transaction_listener = listener;
		this.transaction_id = transaction_id;
		this.connection_id = connection_id;
		this.response = null;
		clearing_to = new Timer(SipStack.transaction_timeout, "Clearing", this);
		printLog("id: " + String.valueOf(transaction_id), LogLevel.HIGH);
		printLog("created", LogLevel.HIGH);
	}

	/** Starts the TransactionServer. */
	public void listen() {
		if (statusIs(STATE_IDLE)) {
			printLog("start", LogLevel.LOW);
			changeStatus(STATE_WAITING);
			sip_provider.addSipProviderListener(transaction_id, this);
		}
	}

	/** Sends a response message */
	public void respondWith(Message resp) {
		response = resp;
		if (statusIs(STATE_TRYING) || statusIs(STATE_PROCEEDING)) {
			sip_provider.sendMessage(response, connection_id);
			int code = response.getStatusLine().getCode();
			if (code >= 100 && code < 200 && statusIs(STATE_TRYING)) {
				changeStatus(STATE_PROCEEDING);
			}
			if (code >= 200 && code < 700) {
				changeStatus(STATE_COMPLETED);
				if (connection_id == null)
					clearing_to.start();
				else {
					printLog("clearing_to=0 for reliable transport",
							LogLevel.LOW);
					onTimeout(clearing_to);
				}
			}
		}
	}

	/**
	 * Method derived from interface SipListener. It's fired from the
	 * SipProvider when a new message is received for to the present
	 * TransactionServer.
	 */
	public void onReceivedMessage(SipProvider provider, Message msg) {
		if (msg.isRequest()) {
			if (statusIs(STATE_WAITING)) {
				request = new Message(msg);
				connection_id = msg.getConnectionId();
				sip_provider.removeSipProviderListener(transaction_id);
				transaction_id = request.getTransactionId();
				sip_provider.addSipProviderListener(transaction_id, this);
				changeStatus(STATE_TRYING);
				if (transaction_listener != null)
					transaction_listener.onTransRequest(this, msg);
				return;
			}
			if (statusIs(STATE_PROCEEDING) || statusIs(STATE_COMPLETED)) { // retransmission
				// of
				// the
				// last
				// response
				printLog("response retransmission", LogLevel.LOW);
				sip_provider.sendMessage(response, connection_id);
				return;
			}
		}
	}

	/**
	 * Method derived from interface TimerListener. It's fired from an active
	 * Timer.
	 */
	public void onTimeout(Timer to) {
		try {
			if (to.equals(clearing_to)) {
				printLog("Clearing timeout expired", LogLevel.HIGH);
				sip_provider.removeSipProviderListener(transaction_id);
				changeStatus(STATE_TERMINATED);
				transaction_listener = null;
				// clearing_to=null;
			}
		} catch (Exception e) {
			printException(e, LogLevel.HIGH);
		}
	}

	/** Terminates the transaction. */
	public void terminate() {
		if (!statusIs(STATE_TERMINATED)) {
			clearing_to.halt();
			sip_provider.removeSipProviderListener(transaction_id);
			changeStatus(STATE_TERMINATED);
			transaction_listener = null;
			// clearing_to=null;
		}
	}

	// **************************** Logs ****************************/

	/** Adds a new string to the default Log */
	protected void printLog(String str, int level) {
		if (log != null)
			log.println("TransactionServer#" + transaction_sqn + ": " + str,
					level + SipStack.LOG_LEVEL_TRANSACTION);
	}

}
