Method addItem

public function addItem($id = 0, $catid = 0)
{
    if ($id > 0) {
        $app = Factory::getApplication();
        $count = count($this->items);
        if ($count > 2) {
            $message = Text::_('COM_PHOCACART_ONLY_THREE_PRODUCTS_CAN_BE_LISTED_IN_COMPARISON_LIST');
            $app->enqueueMessage($message, 'error');
            return false;
        }
        if (isset($this->items[$id]) && (int) $this->items[$id] > 0) {
            $message = Text::_('COM_PHOCACART_PRODUCT_INCLUDED_IN_COMPARISON_LIST');
            $app->enqueueMessage($message, 'error');
            return false;
        } else {
            $this->items[$id]['id'] = $id;
            $this->items[$id]['catid'] = $catid;
            $session = Factory::getSession();
            $session->set('compare', $this->items, 'phocaCart');
        }
        return true;
    }
    return false;
}