/*
 * 
 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.ArrayList;
import java.util.Calendar;
import java.util.List;
import java.util.logging.Logger;

import org.jfin.date.Period;
import org.jfin.date.ScheduleGenerator;
import org.jfin.date.daycount.DaycountCalculator;
import org.jfin.date.daycount.DaycountException;
import org.jfin.date.util.ISDADateFormat;

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

public class ISDAActualActual extends DaycountCalculator
{

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

	/**
	 * Calculates the ISDA Actual actual day count fraction
	 * between two dates.
	 */
	public double calculateDaycountFraction(Calendar startCalendar,
			Calendar endCalendar) throws DaycountException
	{
		logger.finer("Calculating daycount fraction for "
				+ ISDADateFormat.format(startCalendar) + " - "
				+ ISDADateFormat.format(endCalendar));

		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 0.0;
		}

		double fraction = 0;
		List subPeriods = getPeriods(startCalendar,endCalendar);

		int[] numerators = getNumerators(subPeriods);
		int[] denominators = getDenominators(subPeriods);

		for(int i=0;i getPeriods(Calendar startCalendar, Calendar endCalendar) {
		Calendar hold = ScheduleGenerator.copyAndReset(startCalendar);
		Calendar end = ScheduleGenerator.copyAndReset(endCalendar);

		List periods = new ArrayList();


		while(hold.get(Calendar.YEAR) subPeriods) {

		int[] numerators = new int[subPeriods.size()];

		for(int i=0;i subPeriods) {

		int[] denominators = new int[subPeriods.size()];

		for(int i=0;i