hugo/gen_vor.php

<?php
// read vor.txt and generate vor.md, inserting dates if missing
// Helper function for next Tuesday calculation depending on PHP version
function getTuesday($ts) {
    // This is for PHP >= 8.1 as the old strftime will be deprecated by then, so use datefmt_format_object if we are running on PHP beyond version 7
    if (intval(explode(".", phpversion())[0]) >= 7) {
        $date_time = new DateTime();
        $date_time->setTimestamp(strtotime('fourth tuesday of this month', $ts));
        $tuesday = datefmt_format_object($date_time, 'cccc, d.M.yyyy ', 'de_DE.utf8');
    } else {
        $tuesday = strftime('%A, %d.%m.%Y ', strtotime('fourth tuesday of this month', $ts));
    }
    return $tuesday;
}

date_default_timezone_set("CET");
setlocale(LC_TIME, 'de_DE.utf8');
$file_txt = 'vor.txt';
$file_md = 'vor.md';
$fil = file($file_txt, FILE_IGNORE_NEW_LINES);
// Insert header
$arr = ['| | |  |', '|:------|:------|:------|'];
$first_day = new DateTime('first day of this month');
$ts = $first_day->getTimeStamp();
$first_wedn = new DateTime('first wednesday of this month');
$number = 'fourth';
// Treat March differently
if ($first_wedn->format('md') == '0301') {
    $number = 'fifth';
}
$tues_ts = strtotime($number . ' tuesday of this month', $ts);
$tues_date = (new DateTime())->setTimeStamp($tues_ts);

const JUST_DATE = 'Ymd';

// Are we past the fourth Tuesday of this month? 
if ((new DateTime())->getTimeStamp() >= $tues_ts && $first_day->format(JUST_DATE) != $first_wedn->format(JUST_DATE) && $tues_date->format('md') != '0322') {
    $ts = strtotime('+1 month', $ts);
    /*
      var_dump($tues_date->format('md'));
    var_dump($first_day);
    var_dump($first_wedn);
    var_dump($ts);
    */
} 

foreach ($fil as $line) {
    // Skip empty lines
    if (strlen($line)) {
        // Remove empty fields too
        $fields = array_filter(explode('|', $line));
        // Get next Tuesday independent of PHP version
        $tuesday = getTuesday($ts);
        if (count($fields) == 2) {
            // Date missing, insert
            array_unshift($fields, $tuesday);
        }
        $ts = strtotime('+1 month', $ts);
        $li = implode('|', $fields);
        // Insert leading and trailing spaces if required
        if ($li[0] != ' ') {
            $li = ' ' . $li;
        }
        if (substr($li, -1) != ' ') {
            $li = $li . ' ';
        }
        array_push($arr, '|' . $li . '|');    
    }
}
file_put_contents($file_md, implode(PHP_EOL, $arr) . PHP_EOL);
?>