Method renderNavigation

public static function renderNavigation($vendorId, $ticketId, $unitId, $sectionId)
{
    // $ticketId is active ticket
    $tickets = self::getVendorTickets($vendorId, $unitId, $sectionId);
    $o = '<ul class="nav nav-tabs">';
    if (!empty($tickets)) {
        foreach ($tickets as $k => $v) {
            $active = '';
            if ((int) $v->ticket_id == (int) $ticketId) {
                $active = 'active';
            }
            $link = Route::_(PhocacartRoute::getPosRoute((int) $v->ticket_id, (int) $v->unit_id, (int) $v->section_id));
            $o .= '<li class="nav-item ' . $active . '">';
            $o .= '<a class="nav-link ' . $active . '" href="' . $link . '"> ' . (int) $v->ticket_id . ' </a>';
            $o .= '</li>';
        }
    } else {
        $link = Route::_(PhocacartRoute::getPosRoute());
        $o .= '<li class="nav-item active">';
        $o .= '<a class="nav-link active" href="' . $link . '"> 1 </a>';
        $o .= '</li>';
    }
    $o .= '</ul>';
    return $o;
}