Handle invalid PIN input in the settings flow. (#1972)

ElementX/Sources/Screens/AppLock/AppLockSetupPINScreen/AppLockSetupPINScreenCoordinator.swift

@@ -27,10 +27,12 @@ struct AppLockSetupPINScreenCoordinatorParameters {
 }
 
 enum AppLockSetupPINScreenCoordinatorAction {
-    /// The user cancelled PIN entry.
-    case cancel
     /// The user succeeded PIN entry.
     case complete
+    /// The user cancelled PIN entry.
+    case cancel
+    /// The user failed to remember their PIN to unlock.
+    case forceLogout
 }
 
 final class AppLockSetupPINScreenCoordinator: CoordinatorProtocol {
@@ -62,6 +64,8 @@ final class AppLockSetupPINScreenCoordinator: CoordinatorProtocol {
                 actionsSubject.send(.complete)
             case .cancel:
                 actionsSubject.send(.cancel)
+            case .forceLogout:
+                actionsSubject.send(.forceLogout)
             }
         }
         .store(in: &cancellables)

ElementX/Sources/Screens/AppLock/AppLockSetupPINScreen/AppLockSetupPINScreenModels.swift

@@ -21,6 +21,8 @@ enum AppLockSetupPINScreenViewModelAction {
     case complete
     /// The user cancelled PIN entry.
     case cancel
+    /// The user failed to remember their PIN to unlock.
+    case forceLogout
 }
 
 enum AppLockSetupPINScreenMode {
@@ -33,10 +35,19 @@ enum AppLockSetupPINScreenMode {
 }
 
 struct AppLockSetupPINScreenViewState: BindableState {
+    /// The number of attempts allowed to enter the PIN.
+    let maximumAttempts = 3
+    
     /// The current mode that the screen is in.
     var mode: AppLockSetupPINScreenMode
     /// Whether the screen is mandatory or can be cancelled.
     let isMandatory: Bool
+    /// The number of attempts the user has made in the `confirm` mode.
+    var numberOfConfirmAttempts = 0
+    /// The number of attempts the user has made in the `unlock` mode.
+    var numberOfUnlockAttempts = 0
+    /// The user failed to unlock the app (or forgot their PIN) and the log out is in progress.
+    var isLoggingOut = false
     
     var title: String {
         switch mode {
@@ -46,10 +57,14 @@ struct AppLockSetupPINScreenViewState: BindableState {
         }
     }
     
-    var subtitle: String? {
-        switch mode {
-        case .create, .confirm: return L10n.screenAppLockSetupPinContext(InfoPlistReader.main.bundleDisplayName)
-        case .unlock: return nil
+    /// Whether the subtitle is in a warning state or not.
+    var isSubtitleWarning: Bool { mode == .unlock && numberOfUnlockAttempts > 0 }
+    var subtitle: String {
+        guard mode == .unlock else { return L10n.screenAppLockSetupPinContext(InfoPlistReader.main.bundleDisplayName) }
+        if !isSubtitleWarning {
+            return L10n.screenAppLockSubtitle(maximumAttempts)
+        } else {
+            return L10n.screenAppLockSubtitleWrongPin(maximumAttempts - numberOfUnlockAttempts)
         }
     }
     
@@ -68,6 +83,8 @@ enum AppLockSetupPINScreenAlertType {
     case pinMismatch
     /// An error occurred setting the PIN code in the App Lock service.
     case failedToSetPIN
+    /// The user failed to unlock the app (or forgot their PIN).
+    case forceLogout
 }
 
 enum AppLockSetupPINScreenViewAction {

ElementX/Sources/Screens/AppLock/AppLockSetupPINScreen/AppLockSetupPINScreenViewModel.swift

@@ -32,7 +32,12 @@ class AppLockSetupPINScreenViewModel: AppLockSetupPINScreenViewModelType, AppLoc
 
     init(initialMode: AppLockSetupPINScreenMode, isMandatory: Bool, appLockService: AppLockServiceProtocol) {
         self.appLockService = appLockService
+        
         super.init(initialViewState: AppLockSetupPINScreenViewState(mode: initialMode, isMandatory: isMandatory, bindings: .init(pinCode: "")))
+        
+        appLockService.numberOfPINAttempts
+            .weakAssign(to: \.state.numberOfUnlockAttempts, on: self)
+            .store(in: &cancellables)
     }
     
     // MARK: - Public
@@ -74,6 +79,7 @@ class AppLockSetupPINScreenViewModel: AppLockSetupPINScreenViewModelType, AppLoc
         newPIN = pinCode
         state.mode = .confirm
         state.bindings.pinCode = ""
+        state.numberOfConfirmAttempts = 0
     }
     
     /// Handles a PIN input from the confirm mode. Stores the pin if it matches.
@@ -102,9 +108,10 @@ class AppLockSetupPINScreenViewModel: AppLockSetupPINScreenViewModelType, AppLoc
     /// Handles a PIN input for the unlock mode.
     private func unlock() {
         guard appLockService.unlock(with: state.bindings.pinCode) else {
-            // show an error
-            // https://www.figma.com/file/0MMNu7cTOzLOlWb7ctTkv3?node-id=13067:107631&mode=dev#591068578
             state.bindings.pinCode = ""
+            if state.numberOfUnlockAttempts >= state.maximumAttempts {
+                handleError(.forceLogout)
+            }
             return
         }
         
@@ -119,12 +126,29 @@ class AppLockSetupPINScreenViewModel: AppLockSetupPINScreenViewModelType, AppLoc
                                              message: L10n.screenAppLockSetupPinBlacklistedDialogContent,
                                              primaryButton: .init(title: L10n.actionOk) { self.state.bindings.pinCode = "" })
         case .pinMismatch:
+            state.numberOfConfirmAttempts += 1
             state.bindings.alertInfo = .init(id: error,
                                              title: L10n.screenAppLockSetupPinMismatchDialogTitle,
                                              message: L10n.screenAppLockSetupPinMismatchDialogContent,
-                                             primaryButton: .init(title: L10n.actionTryAgain) { self.state.bindings.pinCode = "" })
+                                             primaryButton: .init(title: L10n.actionTryAgain) { self.restartCreateIfNeeded() })
         case .failedToSetPIN:
             state.bindings.alertInfo = .init(id: error)
+        case .forceLogout:
+            state.isLoggingOut = true // Disable the screen before showing the alert.
+            state.bindings.alertInfo = .init(id: error,
+                                             title: L10n.screenAppLockSignoutAlertTitle,
+                                             message: L10n.screenAppLockSignoutAlertMessage,
+                                             primaryButton: .init(title: L10n.actionOk) { self.actionsSubject.send(.forceLogout) })
+        }
+    }
+    
+    private func restartCreateIfNeeded() {
+        state.bindings.pinCode = ""
+        
+        if state.numberOfConfirmAttempts >= state.maximumAttempts {
+            newPIN = ""
+            state.mode = .create
+            state.numberOfConfirmAttempts = 0
         }
     }
 }

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

@@ -23,9 +23,21 @@ struct AppLockSetupPINScreen: View {
     
     @FocusState private var textFieldFocus
     
+    var stackSpacing: CGFloat {
+        context.viewState.mode == .unlock ? 36 : 40
+    }
+    
+    var subtitleColor: Color {
+        context.viewState.isSubtitleWarning ? .compound.textCriticalPrimary : .compound.textSecondary
+    }
+    
+    var interactiveDismissDisabled: Bool {
+        context.viewState.isMandatory || context.viewState.isLoggingOut
+    }
+    
     var body: some View {
         ScrollView {
-            VStack(spacing: 48) {
+            VStack(spacing: stackSpacing) {
                 header
                 
                 PINTextField(pinCode: $context.pinCode,
@@ -44,7 +56,8 @@ struct AppLockSetupPINScreen: View {
         .toolbar { toolbar }
         .toolbar(.visible, for: .navigationBar)
         .navigationBarBackButtonHidden()
-        .interactiveDismissDisabled(context.viewState.isMandatory)
+        .interactiveDismissDisabled(interactiveDismissDisabled)
+        .disabled(context.viewState.isLoggingOut)
         .alert(item: $context.alertInfo)
         .onAppear { textFieldFocus = true }
     }
@@ -60,12 +73,10 @@ struct AppLockSetupPINScreen: View {
                 .multilineTextAlignment(.center)
                 .foregroundColor(.compound.textPrimary)
             
-            if let subtitle = context.viewState.subtitle {
-                Text(subtitle)
-                    .font(.compound.bodyMD)
-                    .multilineTextAlignment(.center)
-                    .foregroundColor(.compound.textSecondary)
-            }
+            Text(context.viewState.subtitle)
+                .font(.compound.bodyMD)
+                .multilineTextAlignment(.center)
+                .foregroundColor(subtitleColor)
         }
     }
     
@@ -84,8 +95,9 @@ struct AppLockSetupPINScreen: View {
 // MARK: - Previews
 
 struct AppLockSetupPINScreen_Previews: PreviewProvider, TestablePreview {
-    static let service = AppLockService(keychainController: KeychainControllerMock(),
-                                        appSettings: ServiceLocator.shared.settings)
+    static let service = AppLockServiceMock.mock()
+    static let failedService = AppLockServiceMock.mock(numberOfPINAttempts: 1)
+    
     static let createViewModel = AppLockSetupPINScreenViewModel(initialMode: .create,
                                                                 isMandatory: false,
                                                                 appLockService: service)
@@ -95,6 +107,9 @@ struct AppLockSetupPINScreen_Previews: PreviewProvider, TestablePreview {
     static let unlockViewModel = AppLockSetupPINScreenViewModel(initialMode: .unlock,
                                                                 isMandatory: false,
                                                                 appLockService: service)
+    static let unlockFailedViewModel = AppLockSetupPINScreenViewModel(initialMode: .unlock,
+                                                                      isMandatory: false,
+                                                                      appLockService: failedService)
     
     static var previews: some View {
         NavigationStack {
@@ -111,5 +126,10 @@ struct AppLockSetupPINScreen_Previews: PreviewProvider, TestablePreview {
             AppLockSetupPINScreen(context: unlockViewModel.context)
         }
         .previewDisplayName("Unlock")
+        
+        NavigationStack {
+            AppLockSetupPINScreen(context: unlockFailedViewModel.context)
+        }
+        .previewDisplayName("Unlock Failed")
     }
 }