automatically add time to date string if not exists

function getDate($dateStr)
{
    if (!preg_match('/(\d{4})-(\d{1,2})-(\d{1,2}) (\d{1,2}):(\d{1,2}):(\d{1,2})/', $datestr))
    {
        $datestr .= ' 00:00:00';
    }
    
    return date('Y-m-d H:i:s', strtotime($dateStr));
}