Connect acquiring ASSIST

Cafe site on a self-written engine on YII 2.
You must integrate with the ASSIST payment gateway https://www.belassist.by/
Integration documentation and a test payment server are available.

1) If "online card payment" is selected in the shopping cart, we redirect the user to the ASSIST gateway for payment.
2) After the payment is made, we return to the site, where we display a window that the order was successfully paid / issued or a window with an error and an offer to try to pay again.