<?php
  /**************************************************************************\
  * eGroupWare - holidaycalc_JP                                              *
  * http://www.egroupware.org                                              *
  * Based on Yoshihiro Kamimura <your@itheart.com>                           *
  *          http://www.itheart.com                                          *
  * --------------------------------------------                             *
  *  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.                                              *
  \**************************************************************************/

  /* $Id$ */

	class holidaycalc
	{
		function calculate_date($holiday, &$holidays, $year)
		{
			static	$cached_month;
			static	$cached_day;
			static	$cached_observance_rule;

			if ($holiday['day'] == 0 && $holiday['dow'] != 0 && $holiday['occurence'] != 0)
			{
				$dow = $GLOBALS['phpgw']->datetime->day_of_week($year, $holiday['month'], 1);
				$dayshift = (($holiday['dow'] + 7) - $dow) % 7;
				$day = ($holiday['occurence'] - 1) * 7 + $dayshift + 1;

				// Happy monday law.
				if ($holiday['month'] == 1)
				{
					if ($year < 2000)
					{
						$day = 15;
					}
				}
				elseif ($holiday['month'] == 7)
				{
					if ($year < 2003)
					{
						$day = 20;
					}
				}
				elseif ($holiday['month'] == 9)
				{
					if ($year < 2003)
					{
						$day = 15;
					}
				}
				elseif ($holiday['month'] == 10)
				{
					if ($year < 2000)
					{
						$day = 10;
					}
				}
			}
			elseif ($holiday['day'] == 0 && $holiday['dow'] == 0 && $holiday['occurence'] == 0)
			{
				// For the next generation.
				// over 2151, please set $factor...
				if ($holiday['month'] == 3)
				{
					// for Vernal Equinox
					if ($year >= 1980 && $year <= 2099)
					{
						$factor = 20.8431;
					}
					elseif ($year >= 2100 && $year <= 2150)
					{
						$factor = 21.851;
					}
				}
				elseif ($holiday['month'] == 9)
				{
					// for Autumnal Equinox
					if ($year >= 1980 && $year <= 2099)
					{
						$factor = 23.2488;
					}
					elseif ($year >= 2100 && $year <= 2150)
					{
						$factor = 24.2488;
					}
				}

				$day = (int)($factor + 0.242194 * ($year - 1980)
					- (int)(($year - 1980) / 4));
			}
			else
			{
				// normal holiday
				$day = $holiday['day'];
			}

			if ($year >= 1985 && $holiday['month'] == $cached_month && $day == $cached_day + 2 && $cached_observance_rule == True && $holiday['observance_rule'] == True)
			{
				$pdow = $GLOBALS['phpgw']->datetime->day_of_week($year,$holiday['month'],$day-1);
				if ($pdow != 0)
				{
					$addcnt = count($holidays) + 1;
					$holidays[$addcnt]['locale'] = $holiday['locale'];
					if ($pdow == 1)
					{
						$holidays[$addcnt]['name'] = lang('overlap holiday');
					}
					else
					{
						$holidays[$addcnt]['name'] = lang('people holiday');
					}
					$holidays[$addcnt]['day'] = $day - 1;
					$holidays[$addcnt]['month'] = $holiday['month'];
					$holidays[$addcnt]['occurence'] = 0;
					$holidays[$addcnt]['dow'] = 0;
					$holidays[$addcnt]['date'] = mktime(0,0,0,$holiday['month'],$day-1,$year);
					$holidays[$addcnt]['observance_rule'] = 0;
				}
			}

			$cached_month = $holiday['month'];
			$cached_day = $day;
			$cached_observance_rule = $holiday['observance_rule'];

			if ($year >= 1985 && $holiday['month'] == 5 && $day == 3)
			{
				;
			}
			elseif ($holiday['observance_rule'] == True)
			{
				$dow = $GLOBALS['phpgw']->datetime->day_of_week($year,$holiday['month'],$day);
				// This now calulates Observed holidays and creates a new entry for them.
				if($dow == 0)
				{
					$addcnt = count($holidays) + 1;
					$holidays[$addcnt]['locale'] = $holiday['locale'];
					$holidays[$addcnt]['name'] = lang('overlap holiday');
					$holidays[$addcnt]['day'] = $day + 1;
					$holidays[$addcnt]['month'] = $holiday['month'];
					$holidays[$addcnt]['occurence'] = $holiday['occurence'];
					$holidays[$addcnt]['dow'] = $holiday['dow'];
					$holidays[$addcnt]['date'] = mktime(0,0,0,$holiday['month'],$day+1,$year);
					$holidays[$addcnt]['observance_rule'] = 0;
				}
			}

			$date = mktime(0,0,0,$holiday['month'],$day,$year);

			return $date;
		}
	}
?>