Custom function for "CART"

I need cart function in my app but the problem is we are located in Turkey and Stripe is not supported in Turkey.
It would be great to have a custom payment processor or at least a custom triggger such as mailing the cart content or etc in glide when user clicks the “checkout” button.
Just because of I’m living in Turkey, I have to create a custom cart function which is not going to work well as it is natively in glide.