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

/**
 * ACK server transaction should follow an INVITE server transaction within an
 * INVITE Dialog in a SIP UAC. The AckTransactionServer sends the final response
 * message and retransmits it several times until the method terminate() is
 * called or the trasaction timeout fires.
 */
public class AckTransactionServer extends Transaction {
	/**
	 * the TransactionServerListener that captures the events fired by the
	 * AckTransactionServer
	 */
	AckTransactionServerListener transaction_listener;

	/** last response message */
	Message response;

	/** retransmission timeout */
	Timer retransmission_to;
	/** transaction timeout */
	Timer transaction_to;

	/** Initializes timeouts and state */
	/**
	 * Creates a new AckTransactionServer. The AckTransactionServer starts
	 * sending a the <i>resp</i> message. It retransmits the resp several times
	 * if no ACK request is received.
	 */
	public AckTransactionServer(SipProvider sip_provider, Message resp,
			AckTransactionServerListener listener) {
		super(sip_provider);
		response = resp;
		init(listener, new TransactionIdentifier(SipMethods.ACK), null);
	}

	/**
	 * Creates a new AckTransactionServer. The AckTransactionServer starts
	 * sending the response message <i>resp</i> through the connection
	 * <i>conn_id</i>.
	 */
	public AckTransactionServer(SipProvider sip_provider,
			ConnectionIdentifier connection_id, Message resp,
			AckTransactionServerListener listener) {
		super(sip_provider);
		response = resp;
		init(listener, new TransactionIdentifier(SipMethods.ACK), connection_id);
	}

	/** Initializes timeouts and listener. */
	void init(AckTransactionServerListener listener,
			TransactionIdentifier transaction_id,
			ConnectionIdentifier connection_id) {
		this.transaction_listener = listener;
		this.transaction_id = transaction_id;
		this.connection_id = connection_id;
		transaction_to = new Timer(SipStack.transaction_timeout, "Transaction",
				this);
		retransmission_to = new Timer(SipStack.retransmission_timeout,
				"Retransmission", this);
		// (CHANGE-040905) now timeouts started in listen()
		// transaction_to.start();
		// if (connection_id==null) retransmission_to.start();
		printLog("id: " + String.valueOf(transaction_id), LogLevel.HIGH);
		printLog("created", LogLevel.HIGH);
	}

	/** Starts the AckTransactionServer. */
	public void respond() {
		printLog("start", LogLevel.LOW);
		changeStatus(STATE_PROCEEDING);
		// transaction_id=null; // it is not required since no
		// SipProviderListener is implemented
		// (CHANGE-040905) now timeouts started in listen()
		transaction_to.start();
		if (connection_id == null)
			retransmission_to.start();

		sip_provider.sendMessage(response, connection_id);
	}

	/**
	 * Method derived from interface TimerListener. It's fired from an active
	 * Timer.
	 */
	public void onTimeout(Timer to) {
		try {
			if (to.equals(retransmission_to) && statusIs(STATE_PROCEEDING)) {
				printLog("Retransmission timeout expired", LogLevel.HIGH);
				long timeout = 2 * retransmission_to.getTime();
				if (timeout > SipStack.max_retransmission_timeout)
					timeout = SipStack.max_retransmission_timeout;
				retransmission_to = new Timer(timeout, retransmission_to
						.getLabel(), this);
				retransmission_to.start();
				sip_provider.sendMessage(response, connection_id);
			}
			if (to.equals(transaction_to) && statusIs(STATE_PROCEEDING)) {
				printLog("Transaction timeout expired", LogLevel.HIGH);
				changeStatus(STATE_TERMINATED);
				if (transaction_listener != null)
					transaction_listener.onTransAckTimeout(this);
				// (CHANGE-040421) now it can free links to transaction_listener
				// and timers
				transaction_listener = null;
				// retransmission_to=null;
				// transaction_to=null;
			}
		} catch (Exception e) {
			printException(e, LogLevel.HIGH);
		}
	}

	/** Method used to drop an active transaction. */
	public void terminate() {
		retransmission_to.halt();
		transaction_to.halt();
		changeStatus(STATE_TERMINATED);
		// if (transaction_listener!=null)
		// transaction_listener.onAckSrvTerminated(this);
		// (CHANGE-040421) now it can free links to transaction_listener and
		// timers
		transaction_listener = null;
		// retransmission_to=null;
		// transaction_to=null;
	}

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

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

}
