Add a discount through a parameter in the URL

I installed pro discount and i was wondering if there was any way to add a coupon automatically with a parameter in the URL.

For example with this URL
https://mywebsite.com/invoice/confirm?invoice_key=9999&;app_discount_code=MYCODEHERE
i want to be able to see the invoice with the discount already added to my invoice.

We want to do a newsletter campaign with a link to the invoice with the code in it. We want people to have the least actions to do to fasten the sales.

Thanks