Make LinkNewDeviceScreen fall back to the App Lock PIN code when there's no passcode. (#5794)

* Fall back to the AppLock PIN code when there's no passcode.

* Add extra tests on the LinkNewDeviceFlowCoordinator.

* Misc tweaks for clarification.

* Regenerate snapshots.

ElementX/Sources/Screens/AppLock/AppLockScreen/AppLockScreenCoordinator.swift

@@ -12,6 +12,8 @@ import SwiftUI
 struct AppLockScreenCoordinatorParameters {
     /// The service used to unlock the app.
     let appLockService: AppLockServiceProtocol
+    /// The context in which the screen is being shown.
+    var mode: AppLockScreenMode = .appUnlock
 }
 
 enum AppLockScreenCoordinatorAction {
@@ -19,6 +21,8 @@ enum AppLockScreenCoordinatorAction {
     case appUnlocked
     /// The user failed to unlock the app (or forgot their PIN).
     case forceLogout
+    /// The user cancelled device owner verification. Only sent in the `.verifyDeviceOwner` mode.
+    case cancelVerifyDeviceOwner
 }
 
 final class AppLockScreenCoordinator: CoordinatorProtocol {
@@ -31,7 +35,7 @@ final class AppLockScreenCoordinator: CoordinatorProtocol {
     }
     
     init(parameters: AppLockScreenCoordinatorParameters) {
-        viewModel = AppLockScreenViewModel(appLockService: parameters.appLockService)
+        viewModel = AppLockScreenViewModel(appLockService: parameters.appLockService, mode: parameters.mode)
     }
     
     func start() {
@@ -44,6 +48,8 @@ final class AppLockScreenCoordinator: CoordinatorProtocol {
                 self.actionsSubject.send(.appUnlocked)
             case .forceLogout:
                 self.actionsSubject.send(.forceLogout)
+            case .cancelVerifyDeviceOwner:
+                self.actionsSubject.send(.cancelVerifyDeviceOwner)
             }
         }
         .store(in: &cancellables)

ElementX/Sources/Screens/AppLock/AppLockScreen/AppLockScreenModels.swift

@@ -13,9 +13,21 @@ enum AppLockScreenViewModelAction {
     case appUnlocked
     /// The user failed to unlock the app (or forgot their PIN).
     case forceLogout
+    /// The user cancelled device owner verification. Only sent in the `.verifyDeviceOwner` mode.
+    case cancelVerifyDeviceOwner
+}
+
+enum AppLockScreenMode {
+    /// Unlocking the app on launch/foregrounding.
+    case appUnlock
+    /// Verifying that the user is the device owner to gate a sensitive action.
+    case verifyDeviceOwner
 }
 
 struct AppLockScreenViewState: BindableState {
+    /// The context in which the screen is being shown.
+    var mode: AppLockScreenMode = .appUnlock
+    
     /// The number of attempts allowed to unlock the app.
     let maximumAttempts = 3
     
@@ -64,4 +76,6 @@ enum AppLockScreenViewAction {
     case clearPINCode
     /// The user didn't heed the warnings and can't remember their PIN.
     case forgotPIN
+    /// The user cancelled device owner verification.
+    case cancelVerifyDeviceOwner
 }

ElementX/Sources/Screens/AppLock/AppLockScreen/AppLockScreenViewModel.swift

@@ -19,10 +19,10 @@ class AppLockScreenViewModel: AppLockScreenViewModelType, AppLockScreenViewModel
         actionsSubject.eraseToAnyPublisher()
     }
     
-    init(appLockService: AppLockServiceProtocol) {
+    init(appLockService: AppLockServiceProtocol, mode: AppLockScreenMode = .appUnlock) {
         self.appLockService = appLockService
         
-        super.init(initialViewState: AppLockScreenViewState(bindings: .init()))
+        super.init(initialViewState: AppLockScreenViewState(mode: mode, bindings: .init()))
         
         appLockService.numberOfPINAttempts
             .weakAssign(to: \.state.numberOfPINAttempts, on: self)
@@ -51,6 +51,8 @@ class AppLockScreenViewModel: AppLockScreenViewModelType, AppLockScreenViewModel
             state.bindings.pinCode = ""
         case .forgotPIN:
             handleForgotPIN()
+        case .cancelVerifyDeviceOwner:
+            actionsSubject.send(.cancelVerifyDeviceOwner)
         }
     }
     

ElementX/Sources/Screens/AppLock/AppLockScreen/View/AppLockScreen.swift

@@ -54,6 +54,19 @@ struct AppLockScreen: View {
                 .animation(.elementDefault, value: context.viewState.forcedLogoutIndicator)
         }
         .alert(item: $context.alertInfo)
+        .toolbar { toolbar }
+    }
+    
+    @ToolbarContentBuilder
+    var toolbar: some ToolbarContent {
+        if context.viewState.mode == .verifyDeviceOwner {
+            ToolbarItem(placement: .cancellationAction) {
+                ToolbarButton(role: .cancel) {
+                    context.send(viewAction: .cancelVerifyDeviceOwner)
+                }
+                .accessibilityIdentifier(A11yIdentifiers.appLockScreen.cancel)
+            }
+        }
     }
     
     var header: some View {
@@ -114,10 +127,17 @@ struct AppLockScreen: View {
 
 struct AppLockScreen_Previews: PreviewProvider, TestablePreview {
     static let viewModel = AppLockScreenViewModel(appLockService: AppLockServiceMock.mock())
+    static let verifyViewModel = AppLockScreenViewModel(appLockService: AppLockServiceMock.mock(), mode: .verifyDeviceOwner)
     
     static var previews: some View {
         ElementNavigationStack {
             AppLockScreen(context: viewModel.context)
         }
+        .previewDisplayName("Unlock")
+        
+        ElementNavigationStack {
+            AppLockScreen(context: verifyViewModel.context)
+        }
+        .previewDisplayName("Verify")
     }
 }

ElementX/Sources/Screens/LinkNewDeviceScreen/LinkNewDeviceScreenCoordinator.swift

@@ -11,6 +11,7 @@ import SwiftUI
 enum LinkNewDeviceScreenCoordinatorAction {
     case linkMobileDevice(LinkNewDeviceService.LinkMobileProgressPublisher)
     case linkDesktopComputer
+    case verifyWithAppLockPIN(CheckedContinuation<Bool, Never>)
     case dismiss
 }
 
@@ -47,6 +48,8 @@ final class LinkNewDeviceScreenCoordinator: CoordinatorProtocol {
                 actionsSubject.send(.linkMobileDevice(progressPublisher))
             case .linkDesktopComputer:
                 actionsSubject.send(.linkDesktopComputer)
+            case .verifyWithAppLockPIN(let continuation):
+                actionsSubject.send(.verifyWithAppLockPIN(continuation))
             case .dismiss:
                 actionsSubject.send(.dismiss)
             }

ElementX/Sources/Screens/LinkNewDeviceScreen/LinkNewDeviceScreenModels.swift

@@ -10,6 +10,7 @@ import Foundation
 enum LinkNewDeviceScreenViewModelAction {
     case linkMobileDevice(LinkNewDeviceService.LinkMobileProgressPublisher)
     case linkDesktopComputer
+    case verifyWithAppLockPIN(CheckedContinuation<Bool, Never>)
     case dismiss
 }
 

ElementX/Sources/Screens/LinkNewDeviceScreen/LinkNewDeviceScreenViewModel.swift

@@ -72,8 +72,10 @@ class LinkNewDeviceScreenViewModel: LinkNewDeviceScreenViewModelType, LinkNewDev
         case .verified, .unavailable:
             break
         case .appLockPINRequired:
-            // Follow-up PR: present the App Lock PIN screen to verify the device owner.
-            return
+            guard await verifyWithAppLockPIN() else {
+                state.mode = .readyToLink(.idle)
+                return
+            }
         case .cancelled, .unverified:
             state.mode = .readyToLink(.idle)
             return
@@ -92,6 +94,13 @@ class LinkNewDeviceScreenViewModel: LinkNewDeviceScreenViewModelType, LinkNewDev
         }
     }
     
+    /// Asks the coordinator to verify the device owner with the App Lock PIN, suspending until it has a result.
+    private func verifyWithAppLockPIN() async -> Bool {
+        await withCheckedContinuation { continuation in
+            actionsSubject.send(.verifyWithAppLockPIN(continuation))
+        }
+    }
+    
     private func linkMobileDevice() async {
         state.mode = .readyToLink(.generatingCode)