xref: /webtrees/app/Date/JulianDate.php (revision ee551e0b6d330340f2c6e961359bd855b89571fb) 
1<?php
2
3/**
4 * webtrees: online genealogy
5 * Copyright (C) 2023 webtrees development team
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <https://www.gnu.org/licenses/>.
16 */
17
18declare(strict_types=1);
19
20namespace Fisharebest\Webtrees\Date;
21
22use Fisharebest\ExtCalendar\JulianCalendar;
23use Fisharebest\Webtrees\I18N;
24
25/**
26 * Definitions for proleptic Julian dates.
27 */
28class JulianDate extends AbstractGregorianJulianDate
29{
30    // GEDCOM calendar escape
31    public const ESCAPE = '@#DJULIAN@';
32
33    // For dates recorded in new-style/old-style format, e.g. 2 FEB 1743/44
34    private bool $new_old_style = false;
35
36    /**
37     * Create a date from either:
38     * a Julian day number
39     * day/month/year strings from a GEDCOM date
40     * another CalendarDate object
41     *
42     * @param array<string>|int|AbstractCalendarDate $date
43     */
44    public function __construct($date)
45    {
46        $this->calendar = new JulianCalendar();
47        parent::__construct($date);
48    }
49
50    /**
51     * Most years are 1 more than the previous, but not always (e.g. 1BC->1AD)
52     *
53     * @param int $year
54     *
55     * @return int
56     */
57    protected function nextYear(int $year): int
58    {
59        if ($year === -1) {
60            return 1;
61        }
62
63        return $year + 1;
64    }
65
66    /**
67     * Process new-style/old-style years and years BC
68     *
69     * @param string $year
70     *
71     * @return int
72     */
73    protected function extractYear(string $year): int
74    {
75        if (preg_match('/^(\d\d\d\d)\/\d{1,4}$/', $year, $match)) {
76            // Assume the first year is correct
77            $this->new_old_style = true;
78
79            return (int) $match[1] + 1;
80        }
81
82        if (preg_match('/^(\d+) B\.C\.$/', $year, $match)) {
83            return -(int) $match[1];
84        }
85
86        return (int) $year;
87    }
88
89    /**
90     * Generate the %Y format for a date.
91     *
92     * @return string
93     */
94    protected function formatLongYear(): string
95    {
96        if ($this->year < 0) {
97            return /*  I18N: BCE=Before the Common Era, for Julian years < 0. See https://en.wikipedia.org/wiki/Common_Era */
98                I18N::translate('%s&nbsp;BCE', I18N::digits(-$this->year));
99        }
100
101        if ($this->new_old_style) {
102            return I18N::translate('%s&nbsp;CE', I18N::digits(sprintf('%d/%02d', $this->year - 1, $this->year % 100)));
103        }
104
105        /* I18N: CE=Common Era, for Julian years > 0. See https://en.wikipedia.org/wiki/Common_Era */
106        return I18N::translate('%s&nbsp;CE', I18N::digits($this->year));
107    }
108
109    /**
110     * Generate the %E format for a date.
111     *
112     * @return string
113     */
114    protected function formatGedcomYear(): string
115    {
116        if ($this->year < 0) {
117            return sprintf('%04d B.C.', -$this->year);
118        }
119
120        if ($this->new_old_style) {
121            return sprintf('%04d/%02d', $this->year - 1, $this->year % 100);
122        }
123
124        return sprintf('%04d', $this->year);
125    }
126}
127