Hi,
I'm Prestashop expert for over 7 years in PHP5, HTML5, MYSQL, CSS 2/3 (Bootstrap), Smarty, JS (Jquery, Angular), ajax and web development in general.
You can see my previous successful Prestashop projects on my profile.
I Propose to add the php in the product controller since we cannot add php to tpl files.
I'm available to discuss more the project and begin the work.
Cordially.