Out Of Stock with no Stock

Hello guys

Im newbye in opencart, i like to have a extension or options, to put out of stock on some products.

I dont have stock, so.....what im thinking if exist or its possible develop, some feature like this.

On the product admin, a option to disable the add to cart and put out of stock image for example.

You can have the product visible, but with out of stock on button to add to cart, for example.

I dont have my stock working i dont know why, but i dont need for now, just understand if this "idea" is easy to develop or already exist?

Thanks
Merry Chispas for all

Not at my computer right now so I can't find it but search for "remove add to cart for out of stock". Free add on that replaces the add to cart button with "out of stock" text. There might be other options as well.