Create date time with weekday placeholder

date_create_from_format_with_w.php

<?php

/**
 * Create date time with weekday placeholder
 *
 * @param string $format
 * @param string $time
 * @param null|DateTime $timezone
 * @return bool|DateTime
 */
function date_create_from_format_with_w($format, $time, DateTime $timezone = null) {
    $datetime = DateTime::createFromFormat($format, $time, $timezone);

    // no need to continue there is no weekday
    if ($datetime) {
        return $datetime;
    }

    // if we there it means that either something is wrong or there is weekday placeholder
    // week id in format string
    $id    = 'w';
    // week format for date format
    $vDate = '?';

    // escape
    $dateString = str_replace($id, $vDate, $format);
    $datetime   = DateTime::createFromFormat($dateString, $time, $timezone);

    if (!$datetime) {
        return false;
    }

    $given   = str_split($time);
    $gened   = str_split($datetime->format($format));
    $weekDay = '';

    // difference will be the weekday
    foreach ($gened as $key => $char) {
        if ($char !== $given[$key]) {
            $weekDay .= $given[$key];
        }
    }

    if (isset($weekDay)) {
        $datetime->setDate(
            $datetime->format('Y'),
            $datetime->format('m'),
            $datetime->format('d') + $weekDay - $datetime->format('w')
        );
    }

    return $datetime;
}