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/FlowCoordinators/AppLockFlowCoordinator.swift

@@ -242,6 +242,8 @@ class AppLockFlowCoordinator: CoordinatorProtocol {
                 stateMachine.tryEvent(.didUnlockWithPIN)
             case .forceLogout:
                 stateMachine.tryEvent(.forceLogout)
+            case .cancelVerifyDeviceOwner:
+                fatalError("Cancelling is not allowed when unlocking the app.")
             }
         }
         .store(in: &cancellables)

ElementX/Sources/FlowCoordinators/LinkNewDeviceFlowCoordinator.swift

@@ -10,6 +10,8 @@ import Foundation
 
 enum LinkNewDeviceFlowCoordinatorAction {
     case requestOAuthAuthorisation(URL, OAuthAccountSettingsPresenter.Continuation)
+    /// The user failed to remember their App Lock PIN.
+    case forceLogout
     case dismiss
 }
 
@@ -58,6 +60,8 @@ class LinkNewDeviceFlowCoordinator: FlowCoordinatorProtocol {
                     presentQRCodeScreen(mode: .linkMobile(progressPublisher, flowParameters.userSession.clientProxy))
                 case .linkDesktopComputer:
                     presentQRCodeScreen(mode: .linkDesktop(flowParameters.userSession.clientProxy.linkNewDeviceService()))
+                case .verifyWithAppLockPIN(let continuation):
+                    presentAppLockScreen(continuation: continuation)
                 case .dismiss:
                     actionsSubject.send(.dismiss)
                 }
@@ -67,6 +71,33 @@ class LinkNewDeviceFlowCoordinator: FlowCoordinatorProtocol {
         navigationStackCoordinator.setRootCoordinator(coordinator)
     }
     
+    private func presentAppLockScreen(continuation: CheckedContinuation<Bool, Never>) {
+        // We can use the AppLockScreen as a fallback here. It might seem weird but in the end it only calls
+        // AppLockService.unlock which is a no-op when the app is already unlocked.
+        let stackCoordinator = NavigationStackCoordinator()
+        let coordinator = AppLockScreenCoordinator(parameters: .init(appLockService: appLockService, mode: .verifyDeviceOwner))
+        
+        coordinator.actions
+            .sink { [weak self] action in
+                guard let self else { return }
+                
+                switch action {
+                case .appUnlocked:
+                    continuation.resume(returning: true)
+                    navigationStackCoordinator.setFullScreenCoverCoordinator(nil)
+                case .cancelVerifyDeviceOwner:
+                    continuation.resume(returning: false)
+                    navigationStackCoordinator.setFullScreenCoverCoordinator(nil)
+                case .forceLogout:
+                    actionsSubject.send(.forceLogout)
+                }
+            }
+            .store(in: &cancellables)
+        
+        stackCoordinator.setRootCoordinator(coordinator)
+        navigationStackCoordinator.setFullScreenCoverCoordinator(stackCoordinator)
+    }
+    
     private func presentQRCodeScreen(mode: QRCodeLoginScreenMode) {
         let coordinator = QRCodeLoginScreenCoordinator(parameters: .init(mode: mode,
                                                                          canSignInManually: false, // No need to worry about this when linking a device.

ElementX/Sources/FlowCoordinators/SettingsFlowCoordinator.swift

@@ -192,6 +192,8 @@ class SettingsFlowCoordinator: FlowCoordinatorProtocol {
                     navigationStackCoordinator.setSheetCoordinator(nil)
                 case .requestOAuthAuthorisation(let url, let continuation):
                     presentAccountManagementURL(url, continuation: continuation)
+                case .forceLogout:
+                    actionsSubject.send(.forceLogout)
                 }
             }
             .store(in: &cancellables)