Change function to show date in days

Question

I have a functions that show upcoming event date like in month or in 4 weeks. I want to show every date in days. For example in 45 days, 38 days ago. My code is:

    function go_agotime($datetime, $full = false) {
    $now = new DateTime;
    $ago = new DateTime($datetime);
    $diff = $now->diff($ago);

    $diff->w = floor($diff->d / 7);
    $diff->d -= $diff->w * 7;

    $string = array(
        'y' => 'year',
        'm' => 'month',
        'w' => 'week',
        'd' => 'day',
        'h' => 'hour',
        'i' => 'minute',
        's' => 'second',
    );

    foreach ($string as $k => &$v) {
        if ($diff->$k) {
          //  $v = $diff->$k . ' ' . $v . ($diff->$k > 1 ? 's' : '');
            $v = $diff->$k . ' ' . topl($k, $diff->$k);

        } else {
            unset($string[$k]);
        }
    }

    if (!$full) $string = array_slice($string, 0, 1);
   // return $string ? implode(', ', $string) . ' ago' : 'Just now';
    if($ago > $now)
        return 'za ' . implode(', ', $string);

    return  $string ? 'Zakończone ' . implode(', ', $string) . ' temu' : 'Przed chwilą';
}