Engray/disable AddToCart BTTN after product added

-- HikaShop version -- : 2.3.4
-- Joomla version -- : 3.3.6
-- PHP version -- : 5.5.18

I have a long set of single unique products which are only one in stock and will never be again available once purchased.

I want that once a certain product is added to cart in a product listing its button goes gray / disabled so user can't click it again as it would make no sense.

But my button remains clickable.

Is there either a setting option or a cart.php trick to change this?

Doing it will require some code customization and Javascript skills, also note that you can also set the "Maximum quantity per order" option of your product to 1 so that your customer will only be able to add your product 1 time.