PHP & MySQL Order checker script

We need a small script that allows users to login with their username & password of our joomla website and which then automatically checks if the user made an order on our webshop of a specific product_id. The product id(s) to check for, will be parsed into the url used to access the script on our website. For example the url: https://www.ourwebsite.com/thescript&id20 In which id20 is the webshop product with the id #20 Attached to this project page, you'll find an more detailed overview of what we need the script to do. Please do read it and let us know with your reply if you got questions about it.