In the file classes/Category.php, copy the function GetProducts and change the name to getAvailableProducts or so.
then add to the its SQL WHERE part something like this:
WHERE product_shop.`id_shop` = ‘.(int)$context->shop->id.’
AND cp.`id_category` = ‘.(int)$this->id
.($active ? ‘ AND product_shop.`active` = 1’ : ”)
.’ AND stock.quantity > 0 ‘
.($front ? ‘ AND product_shop.`visibility` IN („both”, „catalog”)’ : ”)
.($id_supplier ? ‘ AND p.id_supplier = ‘.(int)$id_supplier : ”)
.’ GROUP BY product_shop.id_product’;
Save the file and use the new function to get the products with available quantity
