/*

	TUIO Java backend - part of the reacTIVision project

	http://reactivision.sourceforge.net/

	Copyright (c) 2005-2009 Martin Kaltenbrunner <mkalten@iua.upf.edu>

    This program 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.

    This program 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 this program; if not, write to the Free Software

    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

package TUIO;

/**

 * The TuioTime class is a simple structure that is used to reprent the time that has elapsed since the session start.

 * The time is internally represented as seconds and fractions of microseconds which should be more than sufficient for gesture related timing requirements.

 * Therefore at the beginning of a typical TUIO session the static method initSession() will set the reference time for the session. 

 * Another important static method getSessionTime will return a TuioTime object representing the time elapsed since the session start.

 * The class also provides various addtional convience method, which allow some simple time arithmetics.

 *

 * @author Martin Kaltenbrunner

 * @version 1.4

 */ 

public class TuioTime {

	/**

	 * the time since session start in seconds  

	 */ 

	private long seconds = 0;

	/**

	 * time fraction in microseconds  

	 */ 

	private long  micro_seconds = 0;

	/**

	 * the session start time in seconds

	 */ 

	private static long start_seconds = 0;

	/**

	 * start time fraction in microseconds

	 */ 

	private static long start_micro_seconds = 0;

	/**

	 * The default constructor takes no arguments and sets   

	 * the Seconds and Microseconds attributes of the newly created TuioTime both to zero.

	 */

	public TuioTime () {

		this.seconds = 0;

		this.micro_seconds = 0;

	}

	/**

	 * This constructor takes the provided time represented in total Milliseconds 

	 * and assigs this value to the newly created TuioTime.

	 *

	 * @param  msec  the total time in Millseconds

	 */

	public TuioTime (long msec) {

		this.seconds = msec/1000;

		this.micro_seconds = 1000*(msec%1000);

	}

	/**

	 * This constructor takes the provided time represented in Seconds and Microseconds   

	 * and assigs these value to the newly created TuioTime.

	 *

	 * @param  sec  the total time in seconds

	 * @param  usec	the microseconds time component

	 */	

	public TuioTime (long sec, long usec) {

		this.seconds = sec;

		this.micro_seconds = usec;

	}

	/**

	 * This constructor takes the provided TuioTime   

	 * and assigs its Seconds and Microseconds values to the newly created TuioTime.

	 *

	 * @param  ttime  the TuioTime used to copy

	 */	

	public TuioTime (TuioTime ttime) {

		this.seconds = ttime.getSeconds();

		this.micro_seconds = ttime.getMicroseconds();

	}

	/**

	 * Sums the provided time value represented in total Microseconds to this TuioTime.

	 *

	 * @param  us	the total time to add in Microseconds

	 * @return the sum of this TuioTime with the provided argument in microseconds

	*/	

	public TuioTime add(long us) {

		long sec = seconds + us/1000000;

		long usec = micro_seconds + us%1000000;

		return new TuioTime(sec,usec);

	}

	/**

	 * Sums the provided TuioTime to the private Seconds and Microseconds attributes.  

	 *

	 * @param  ttime	the TuioTime to add

	 * @return the sum of this TuioTime with the provided TuioTime argument

	 */

	public TuioTime add(TuioTime ttime) {

		long sec = seconds + ttime.getSeconds();

		long usec = micro_seconds + ttime.getMicroseconds();

		sec += usec/1000000;

		usec = usec%1000000;

		return new TuioTime(sec,usec);

	}

	/**

	 * Subtracts the provided time represented in Microseconds from the private Seconds and Microseconds attributes.

	 *

	 * @param  us	the total time to subtract in Microseconds

	 * @return the subtraction result of this TuioTime minus the provided time in Microseconds

	 */		

	public TuioTime subtract(long us) {

		long sec = seconds - us/1000000;

		long usec = micro_seconds - us%1000000;

		if (usec<0) {

			usec += 1000000;

			sec--;

		}			

		return new TuioTime(sec,usec);

	}

	/**

	 * Subtracts the provided TuioTime from the private Seconds and Microseconds attributes.

	 *

	 * @param  ttime	the TuioTime to subtract

	 * @return the subtraction result of this TuioTime minus the provided TuioTime

	 */	

	public TuioTime subtract(TuioTime ttime) {

		long sec = seconds - ttime.getSeconds();

		long usec = micro_seconds - ttime.getMicroseconds();

		if (usec<0) {

			usec += 1000000;

			sec--;

		}

		return new TuioTime(sec,usec);

	}

	/**

	 * Takes a TuioTime argument and compares the provided TuioTime to the private Seconds and Microseconds attributes.

	 *

	 * @param  ttime	the TuioTime to compare

	 * @return true if the two TuioTime have equal Seconds and Microseconds attributes

	 */	

	public boolean equals(TuioTime ttime) {

		if ((seconds==ttime.getSeconds()) && (micro_seconds==ttime.getMicroseconds())) return true;

		else return false;

	}

	/**

	 * Resets the seconds and micro_seconds attributes to zero.

	 */

	public void reset() {

		seconds = 0;

		micro_seconds = 0;

	}

	/**

	 * Returns the TuioTime Seconds component.

	 * @return the TuioTime Seconds component

	 */	

	public long getSeconds() {

		return seconds;

	}

	/**

	 * Returns the TuioTime Microseconds component.

	 * @return the TuioTime Microseconds component

	 */	

	public long getMicroseconds() {

		return micro_seconds;

	}

	/**

	 * Returns the total TuioTime in Milliseconds.

	 * @return the total TuioTime in Milliseconds

	 */	

	public long getTotalMilliseconds() {

		return seconds*1000+micro_seconds/1000;

	}

	/**

	 * This static method globally resets the TUIO session time.

	 */		

	public static void initSession() {

		TuioTime startTime = getSystemTime();

		start_seconds = startTime.getSeconds();

		start_micro_seconds = startTime.getMicroseconds();

	}

	/**

	 * Returns the present TuioTime representing the time since session start.

	 * @return the present TuioTime representing the time since session start

	 */	

	public static TuioTime getSessionTime() {

		TuioTime sessionTime = getSystemTime().subtract(getStartTime());

		return sessionTime;

	}

	/**

	 * Returns the absolut TuioTime representing the session start.

	 * @return the absolut TuioTime representing the session start

	 */	

	public static TuioTime getStartTime() {

		return new TuioTime(start_seconds,start_micro_seconds);

	}

	/**

	 * Returns the absolut TuioTime representing the current system time.

	 * @return the absolut TuioTime representing the current system time

	 */	

	public static TuioTime getSystemTime() {

		long usec = System.nanoTime()/1000;

		return new TuioTime(usec/1000000,usec%1000000);

	}

}