MBL-1368: Fetch PaymentMethod to display Stripe Link in pledge flow

Kickstarter-iOS/Features/PledgePaymentMethods/Controller/PledgePaymentMethodsViewController.swift

@@ -167,7 +167,7 @@ final class PledgePaymentMethodsViewController: UIViewController {
         strongSelf.paymentSheetFlowController?.presentPaymentOptions(from: strongSelf) { [weak self] in
           guard let strongSelf = self else { return }
 
-          strongSelf.confirmPaymentResult(with: data.clientSecret)
+          strongSelf.confirmPaymentResult(with: data)
         }
         strongSelf.viewModel.inputs.stripePaymentSheetDidAppear()
       }
@@ -190,7 +190,7 @@ final class PledgePaymentMethodsViewController: UIViewController {
     }
   }
 
-  private func confirmPaymentResult(with clientSecret: String) {
+  private func confirmPaymentResult(with data: PaymentSheetSetupData) {
     guard self.paymentSheetFlowController?.paymentOption != nil else {
       self.viewModel.inputs.shouldCancelPaymentSheetAppearance(state: true)
 
@@ -207,12 +207,11 @@ final class PledgePaymentMethodsViewController: UIViewController {
 
       switch paymentResult {
       case .completed:
-        let paymentDisplayData = PaymentSheetPaymentOptionsDisplayData(
-          image: existingPaymentOption.image,
-          label: existingPaymentOption.label
+        strongSelf.didConfirmAddedPaymentOption(
+          paymentOption: existingPaymentOption,
+          forClientSecret: data.clientSecret,
+          forPaymentSheetType: data.paymentSheetType
         )
-        strongSelf.viewModel.inputs
-          .paymentSheetDidAdd(newCard: paymentDisplayData, clientSecret: clientSecret)
       case .canceled:
         // User cancelled intentionally so do nothing.
         break
@@ -223,6 +222,98 @@ final class PledgePaymentMethodsViewController: UIViewController {
     }
   }
 
+  private func didConfirmAddedPaymentOption(
+    paymentOption: PaymentSheet.FlowController.PaymentOptionDisplayData,
+    forClientSecret clientSecret: String,
+    forPaymentSheetType paymentSheetType: PledgePaymentSheetType
+  ) {
+    // Stripe also defines this constant, but it's defined internally to the Stripe SDK :(
+    let linkIdentifier = "link"
+
+    // For regular payment types, continue with the display information they gave us
+    if paymentOption.paymentMethodType != linkIdentifier {
+      let paymentDisplayData = PaymentSheetPaymentOptionsDisplayData(
+        image: paymentOption.image,
+        label: paymentOption.label
+      )
+
+      self.viewModel.inputs.paymentSheetDidAdd(newCard: paymentDisplayData, clientSecret: clientSecret)
+      return
+    }
+
+    // For link payment types, fetch the underlying payment method so we can get at the card type and label
+
+    switch paymentSheetType {
+    case .setupIntent:
+      STPAPIClient.shared
+        .retrieveSetupIntent(
+          withClientSecret: clientSecret,
+          expand: ["payment_method"]
+        ) { [weak self] intent, _ in
+          guard let strongSelf = self else { return }
+          guard let paymentDisplayData = strongSelf.paymentDisplayData(forLink: intent?.paymentMethod)
+          else { return }
+          strongSelf.viewModel.inputs.paymentSheetDidAdd(
+            newCard: paymentDisplayData,
+            clientSecret: clientSecret
+          )
+        }
+
+    case .paymentIntent:
+      STPAPIClient.shared
+        .retrievePaymentIntent(
+          withClientSecret: clientSecret,
+          expand: ["payment_method"]
+        ) { [weak self] intent, _ in
+          guard let strongSelf = self else { return }
+          guard let paymentDisplayData = strongSelf.paymentDisplayData(forLink: intent?.paymentMethod)
+          else { return }
+          strongSelf.viewModel.inputs.paymentSheetDidAdd(
+            newCard: paymentDisplayData,
+            clientSecret: clientSecret
+          )
+        }
+    }
+  }
+
+  private func paymentDisplayData(forLink optionalPaymentMethod: STPPaymentMethod?)
+    -> PaymentSheetPaymentOptionsDisplayData? {
+    guard let paymentMethod = optionalPaymentMethod else {
+      return nil
+    }
+
+    let formattedLabel = self.formatLinkLabel(paymentMethod.label)
+    return PaymentSheetPaymentOptionsDisplayData(
+      image: paymentMethod.image,
+      label: formattedLabel ?? paymentMethod.label
+    )
+  }
+
+  private func formatLinkLabel(_ label: String) -> String? {
+    // Link gives us a label like "Visa 1234"; reformat it to match our UI
+    do {
+      let regex = try NSRegularExpression(pattern: "\\d{4}")
+      let matches = regex.matches(
+        in: label,
+        range: NSRange(location: 0, length: label.count)
+      )
+
+      guard let match = matches.first else {
+        return nil
+      }
+
+      guard let range = Range(match.range, in: label) else {
+        return nil
+      }
+
+      let lastFour = label[range]
+      return "•••• \(lastFour)"
+
+    } catch {
+      return nil
+    }
+  }
+
   private func updateAddNewPaymentMethodButtonLoading(state: Bool) {
     self.dataSource.updateAddNewPaymentCardLoad(state: state)