xref: /webtrees/app/Date/JulianDate.php (revision bbb76c12bd7338ebbb054916678efe20cb71ce1f)

<?php
/**
 * webtrees: online genealogy
 * Copyright (C) 2018 webtrees development team
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */
namespace Fisharebest\Webtrees\Date;

use Fisharebest\ExtCalendar\JulianCalendar;
use Fisharebest\Webtrees\I18N;

/**
 * Definitions for the Julian Proleptic calendar
 * (Proleptic means we extend it backwards, prior to its introduction in 46BC)
 */
class JulianDate extends CalendarDate
{
    /** @var bool True for dates recorded in new-style/old-style format, e.g. 2 FEB 1743/44 */
    private $new_old_style = false;

    /**
     * Create a date from either:
     * a Julian day number
     * day/month/year strings from a GEDCOM date
     * another CalendarDate object
     *
     * @param array|int|CalendarDate $date
     */
    public function __construct($date)
    {
        $this->calendar = new JulianCalendar;
        parent::__construct($date);
    }

    /**
     * Most years are 1 more than the previous, but not always (e.g. 1BC->1AD)
     *
     * @param int $year
     *
     * @return int
     */
    protected function nextYear($year)
    {
        if ($year == -1) {
            return 1;
        } else {
            return $year + 1;
        }
    }

    /**
     * Process new-style/old-style years and years BC
     *
     * @param string $year
     *
     * @return int
     */
    protected function extractYear($year)
    {
        if (preg_match('/^(\d\d\d\d)\/\d{1,4}$/', $year, $match)) {
            // Assume the first year is correct
            $this->new_old_style = true;

            return $match[1] + 1;
        } elseif (preg_match('/^(\d+) B\.C\.$/', $year, $match)) {
            return -$match[1];
        } else {
            return (int)$year;
        }
    }

    /**
     * Generate the %Y format for a date.
     *
     * @return string
     */
    protected function formatLongYear()
    {
        if ($this->y < 0) {
            return /*  I18N: BCE=Before the Common Era, for Julian years < 0. See http://en.wikipedia.org/wiki/Common_Era */
                I18N::translate('%s&nbsp;BCE', I18N::digits(-$this->y));
        } else {
            if ($this->new_old_style) {
                return I18N::translate('%s&nbsp;CE', I18N::digits(sprintf('%d/%02d', $this->y - 1, $this->y % 100)));
            } else {
                /* I18N: CE=Common Era, for Julian years > 0. See http://en.wikipedia.org/wiki/Common_Era */
                return I18N::translate('%s&nbsp;CE', I18N::digits($this->y));
            }
        }
    }

    /**
     * Generate the %E format for a date.
     *
     * @return string
     */
    protected function formatGedcomYear()
    {
        if ($this->y < 0) {
            return sprintf('%04d B.C.', -$this->y);
        } else {
            if ($this->new_old_style) {
                return sprintf('%04d/%02d', $this->y - 1, $this->y % 100);
            } else {
                return sprintf('%04d', $this->y);
            }
        }
    }
}