Improve site creation error handling in the site assembly step

WordPress/Classes/ViewRelated/Site Creation/Final Assembly/SiteAssemblyWizardContent.swift

@@ -159,12 +159,17 @@ final class SiteAssemblyWizardContent: UIViewController {
             case .success(let domain):
                 self.contentView.siteName = domain
                 self.contentView.isFreeDomain = false
-            case .failure:
+                self.contentView.status = .succeeded
+            case .failure(let error):
                 self.contentView.isFreeDomain = true
-                // TODO: We should discuss how to handle domain purchasing errors
-                break
+                switch error {
+                case .unsupportedRedirect, .internal, .invalidInput, .other:
+                    self.installDomainCheckoutErrorStateViewController(domain: domain, site: site)
+                    self.contentView.status = .failed
+                case .canceled:
+                    self.contentView.status = .succeeded
+                }
             }
-            self.contentView.status = .succeeded
         }
     }
 
@@ -185,30 +190,63 @@ final class SiteAssemblyWizardContent: UIViewController {
     private func installErrorStateViewController(with type: ErrorStateViewType) {
         var configuration = ErrorStateViewConfiguration.configuration(type: type)
 
-        configuration.contactSupportActionHandler = { [weak self] in
+        configuration.retryActionHandler = { [weak self] in
             guard let self = self else {
                 return
             }
-            self.contactSupportTapped()
+            self.retryTapped()
         }
 
+        self.installErrorStateViewController(with: configuration)
+    }
+
+    private func installDomainCheckoutErrorStateViewController(domain: DomainSuggestion, site: Blog) {
+        var configuration = ErrorStateViewConfiguration.configuration(type: .domainCheckoutFailed)
+
         configuration.retryActionHandler = { [weak self] in
-            guard let self = self else {
+            guard let self else {
                 return
             }
-            self.retryTapped()
+            self.contentView.status = .inProgress
+            self.attemptDomainPurchasing(domain: domain, site: site)
         }
 
-        configuration.dismissalActionHandler = { [weak self] in
-            guard let self = self else {
-                return
+        self.installErrorStateViewController(with: configuration)
+    }
+
+    private func installErrorStateViewController(with configuration: ErrorStateViewConfiguration) {
+        var configuration = configuration
+
+        if configuration.contactSupportActionHandler == nil {
+            configuration.contactSupportActionHandler = { [weak self] in
+                guard let self = self else {
+                    return
+                }
+                self.contactSupportTapped()
             }
-            self.dismissTapped()
         }
 
+        if configuration.dismissalActionHandler == nil {
+            configuration.dismissalActionHandler = { [weak self] in
+                guard let self = self else {
+                    return
+                }
+                self.dismissTapped()
+            }
+        }
+
+        // Remove previous error state view controller
+        if let errorStateViewController {
+            errorStateViewController.willMove(toParent: nil)
+            errorStateViewController.view?.removeFromSuperview()
+            errorStateViewController.removeFromParent()
+            errorStateViewController.didMove(toParent: nil)
+        }
+
+        // Install new error state view controller
         let errorStateViewController = ErrorStateViewController(with: configuration)
 
-        contentView.errorStateView = errorStateViewController.view
+        self.contentView.errorStateView = errorStateViewController.view
 
         errorStateViewController.willMove(toParent: self)
         addChild(errorStateViewController)
@@ -223,9 +261,8 @@ final class SiteAssemblyWizardContent: UIViewController {
 private extension SiteAssemblyWizardContent {
     func contactSupportTapped() {
         // TODO : capture analytics event via #10335
-
         let supportVC = SupportTableViewController()
-        supportVC.showFromTabBar()
+        supportVC.show(from: self)
     }
 
     func dismissTapped(viaDone: Bool = false, completion: (() -> Void)? = nil) {

WordPress/Classes/ViewRelated/Site Creation/Shared/ErrorStates/ErrorStateViewConfiguration.swift

@@ -13,6 +13,7 @@ enum ErrorStateViewType {
     case general
     case networkUnreachable
     case siteLoading
+    case domainCheckoutFailed
 }
 
 // MARK: ErrorViewConfiguration
@@ -53,7 +54,7 @@ struct ErrorStateViewConfiguration {
 extension ErrorStateViewType {
     var localizedTitle: String {
         switch self {
-        case .general, .siteLoading:
+        case .general, .siteLoading, .domainCheckoutFailed:
             return NSLocalizedString("There was a problem",
                                      comment: "This primary message message is displayed if a user encounters a general error.")
         case .networkUnreachable:
@@ -69,6 +70,12 @@ extension ErrorStateViewType {
                                      comment: "This secondary message is displayed if a user encounters a general error.")
         case .networkUnreachable:
             return nil
+        case .domainCheckoutFailed:
+            return NSLocalizedString(
+                "site.creation.assembly.step.domain.checkout.error.subtitle",
+                value: "Your website has been created successfully, but we encountered an issue while preparing your custom domain for checkout. Please try again or contact support for assistance.",
+                comment: "The error message to show in the 'Site Creation > Assembly Step' when the domain checkout fails for unknown reasons."
+            )
         }
     }
 }

WordPress/Classes/ViewRelated/Support/SupportTableViewController.swift

@@ -71,6 +71,18 @@ class SupportTableViewController: UITableViewController {
         createUserActivity()
     }
 
+    func show(from presentingViewController: UIViewController) {
+        let navigationController = UINavigationController.init(rootViewController: self)
+
+        if WPDeviceIdentification.isiPad() {
+            navigationController.modalTransitionStyle = .crossDissolve
+            navigationController.modalPresentationStyle = .formSheet
+        }
+
+        presentingViewController.present(navigationController, animated: true)
+    }
+
+    // TODO: Refactor this method to use the general `show(from:)` method
     @objc func showFromTabBar() {
         let navigationController = UINavigationController.init(rootViewController: self)