/*
 * 
 jFin, open source derivatives trade processing 
 *
 * 
 Copyright (C) 2005, 2006, 2007 Morgan Brown Consultancy Ltd. 
 *
 * 
 This file is part of jFin. 
 *
 * 
 jFin 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. 
 *
 * 
 jFin 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 jFin; if not, write to the Free Software Foundation, Inc., 51 Franklin
 * St, Fifth Floor, Boston, MA 02110-1301 USA. 
 */

package org.jfin.date.daycount.defaultimpl;

import java.util.Calendar;
import java.util.logging.Logger;

import org.jfin.date.daycount.DaycountCalculator;
import org.jfin.date.daycount.DaycountException;

/**
 * Based upon the implementation from QuantLib http://www.quantlib.org/
 *
 * If startCalendar and endCalendar are equal dates, returns zero.
 */
public class IT30360 extends DaycountCalculator
{

	private static Logger logger = Logger
			.getLogger("org.jfin.date.daycount.defaultimpl.IT30360");

	public double calculateDaycountFraction(Calendar startCalendar,
			Calendar endCalendar) throws DaycountException
	{

		if (startCalendar.after(endCalendar))
		{
			logger.fine("Dates are wrong way round so swap over");
			Calendar holdCalendar = startCalendar;
			startCalendar = endCalendar;
			endCalendar = holdCalendar;
		}

		if (startCalendar.equals(endCalendar))
		{
			logger.fine("Dates are the same so return zero");
			return 0.0d;
		}
		int dd1 = startCalendar.get(Calendar.DAY_OF_MONTH);
		int dd2 = endCalendar.get(Calendar.DAY_OF_MONTH);
		int mm1 = startCalendar.get(Calendar.MONTH);
		int mm2 = endCalendar.get(Calendar.MONTH);
		int yy1 = startCalendar.get(Calendar.YEAR);
		int yy2 = endCalendar.get(Calendar.YEAR);

		if (mm1 == 2 && dd1 > 27)
			dd1 = 30;
		if (mm2 == 2 && dd2 > 27)
			dd2 = 30;

		return ( yy2 - yy1 )
				+ ( ( 30 * ( mm2 - mm1 - 1 ) + Math.max(0, 30 - dd1) + Math
						.min(30, dd2) ) / 360.0d );
	}

	@Override
	public double calculateDaycountFraction(Calendar startCalendar,
			Calendar endCalendar, Calendar periodStartCalendar,
			Calendar periodEndCalendar) throws DaycountException
	{
		return calculateDaycountFraction(startCalendar, endCalendar);
	}
}