Apple Pay and Subscription

[kekko7072]

Hey I saw from stripe documentation that I can use Apple Pay to create payment method and then create subscription but I don't have any idea on how to make it. At the moment my code works using card and creating the payment method, then I register the subscription. I think I just need to change the payment method process but don't know where to start.

DART FRONT END CODE

 Future<void> _handlePayPress({required BuildContext context}) async {
    if (_card == null) {
      return;
    }
    try {
      //1. Start loading
      setState(() {
        enableButton = false;
        loadingPayment = true;
        loadingPaymentDone = false;
      });

      // 2. Create setup intent on backend **IT CALLS CREATE CUSTOMER BACKEND FUNCTION**
      final clientSecret = await PaymentService()
          .createCustomer(user: widget.user, userData: widget.userData);

      //3. Gather customer billing information
      final billingDetails = stripe.BillingDetails(
        name: cardHolderName,
        email: widget.userData.profileUser.email,
        phone: '${widget.user.phoneNumber}',
      );

      //4. Confirm setup intent
      final setupIntentResult = await stripe.Stripe.instance.confirmSetupIntent(
        clientSecret,
        stripe.PaymentMethodParams.card(
            paymentMethodData: stripe.PaymentMethodData(
              billingDetails: billingDetails,
            ),
            options: const stripe.PaymentMethodOptions(
              setupFutureUsage: stripe.PaymentIntentsFutureUsage.OffSession,
            )),
      );

      debugPrint('Setup Intent created: $setupIntentResult');

   
      await Future.delayed(const Duration(seconds: 1)).whenComplete(() {
        if (widget.dismissible) {
          Navigator.of(context).pop();
        } else if (widget.onCompleted != null) {
          widget.onCompleted!();
        }
      });
    } catch (error, stack) {
      //5. Show message error
      stripe.StripeException? detectedError = error as stripe.StripeException;
      EasyLoading.showToast(
        detectedError.error.localizedMessage ??
            'Errore nella registrazione della carta',
        toastPosition: EasyLoadingToastPosition.center,
        maskType: EasyLoadingMaskType.clear,
        dismissOnTap: true,
        duration: const Duration(seconds: 5),
      );
    
    }
  }

TYPESCRIPT BACKEND CODE FOR CREATE CUSTOMER

import * as functions from "firebase-functions";
import { stripe, userCollection } from "../constants";

exports.request = functions.https.onCall(async (req, context) => {
 const {
   email = req.email,
   name = req.fullName,
   phoneNumber = req.phoneNumber,
   payment_method_types = ["card"],
 }: {
  
   email: string;
   name: string;
   phoneNumber: string;
   payment_method_types: string[];
 } = req;

 const customer =  await stripe.customers.create({
         email: email,
         description: context.auth?.uid,
         name: name,
         phone: phoneNumber,
       });

 const setupIntent = await stripe.setupIntents.create({
   customer: customer.id,
   payment_method_types,
   usage: "off_session",
 });
 
   return { clientSecret: setupIntent.client_secret };
});

NOTE: I'm already using Apple Pay thanks the Payment Sheet so I've just configured merchant id and other stuff.