Create Sales Package Custom Module

[archit]

Hi,

 

I am creating a custom sales package module. When a custom joins a package he get discount if specific number of customer are reached for the product in that sales package.

 

In the product page when i create on custom button "JOIN", i need to check whether i am logged in the site or not...if not i need to redirect the user to login and again bring back the customer to that specific product.

 

Also when i click on the join button i want to call a function that set the cookie that customer has joined the package with checking of authentication.

 

But i dont want to modify the default prestashop code for it. So when i click on JOIN button how can i call a function that asks me to check for redirection.

 

Please i am still a learner in prestashop and not knowing much of it.

 

Thanks.