fix: Hide back button in Klarna vc if no stack

Author: henry-cooper-primer

Sources/PrimerSDK/Classes/Extensions & Utilities/UINavigationController+Extensions.swift

@@ -7,6 +7,9 @@
 import UIKit
 
 extension UINavigationController {
+    
+    var canPop: Bool { viewControllers.count > 1 }
+    
     func pushViewController(viewController: UIViewController, animated: Bool, completion: (() -> Void)?) {
         pushViewController(viewController, animated: animated)
 

Sources/PrimerSDK/Classes/User Interface/Klarna Categories Sheet/PrimerKlarnaCategoriesViewController.swift

@@ -171,7 +171,7 @@ extension PrimerKlarnaCategoriesViewController: PrimerHeadlessErrorableDelegate,
             switch step {
             case .paymentSessionCreated(let clientToken, let paymentCategories):
                 DispatchQueue.main.async { [weak self] in
-                    guard let self = self else { return }
+                    guard let self else { return }
 
                     // If only one payment category is available, skip the selection and continue with the only option
                     if paymentCategories.count == 1, let onlyPaymentCategory = paymentCategories.first {
@@ -187,7 +187,11 @@ extension PrimerKlarnaCategoriesViewController: PrimerHeadlessErrorableDelegate,
 
                     hideLoader()
                     self.clientToken = clientToken
-                    klarnaCategoriesVM.updatePaymentCategories(paymentCategories)
+                    klarnaCategoriesVM
+                        .updatePaymentCategories(
+                            paymentCategories,
+                            showBackButton: navigationController?.canPop ?? false
+                        )
                 }
 
             case .paymentSessionFinalizationRequired:

Sources/PrimerSDK/Classes/User Interface/Klarna Categories Sheet/PrimerKlarnaCategoriesViewModel.swift

@@ -15,8 +15,11 @@ final class PrimerKlarnaCategoriesViewModel: ObservableObject {
     @Published var isAuthorizing: Bool = false
     @Published var shouldDisableKlarnaViews: Bool = false
 
-    func updatePaymentCategories(_ paymentCategories: [KlarnaPaymentCategory]) {
+    func updatePaymentCategories(
+        _ paymentCategories: [KlarnaPaymentCategory],
+        showBackButton: Bool
+    ) {
         self.paymentCategories = paymentCategories
-        self.showBackButton = true
+        self.showBackButton = showBackButton
     }
 }