Gordon - Blacklist Saturday, Sunday & Mondays

functions.php

<?php

/**
 * @snippet       WooCommerce - Blacklist dates for Gordon Delivery
 * @author        Redlight Media AB / Christopher Hedqvist
 * @compatible    WooCommerce 4.9.0
 */
function redlight_gordon_blacklist_certain_days( $date_array ) {

  //På söndagar efter 23, hantera det som midnatt
  if(date('H') >= 23 && date('H') < 24 && date('N') == 7) {
    $lastSunday = date('Y-m-d',strtotime('last sunday',strtotime('tomorrow')));
  }else{
    $lastSunday = date('Y-m-d',strtotime('last sunday'));
  }

  $start = new DateTime($lastSunday);
  $end   = new DateTime(); // Current date time
  for ($i = 1; $i <= 20; $i++) {
        $date = new DateTime(date('Y-m-d', strtotime("+$i day")));
        $diff  = $start->diff($date);
        if ($diff->d > 17 ) {
            $date_array[] = $date->format('Y-m-d');
        }
    }
  return $date_array;
}
add_filter('redlight_gd_delivery_window_blacklist', 'redlight_gordon_blacklist_certain_days', 10 );