#40: Add server selection screen from EI.

ElementX/Sources/Screens/Authentication/ServerSelection/MockServerSelectionScreenState.swift

@@ -0,0 +1,44 @@
+//
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import SwiftUI
+
+enum MockServerSelectionScreenState: CaseIterable {
+    case matrix
+    case emptyAddress
+    case invalidAddress
+    case nonModal
+    
+    /// Generate the view struct for the screen state.
+    @MainActor var viewModel: ServerSelectionViewModel {
+        switch self {
+        case .matrix:
+            return ServerSelectionViewModel(homeserverAddress: "https://matrix.org",
+                                            hasModalPresentation: true)
+        case .emptyAddress:
+            return ServerSelectionViewModel(homeserverAddress: "",
+                                            hasModalPresentation: true)
+        case .invalidAddress:
+            let viewModel = ServerSelectionViewModel(homeserverAddress: "thisisbad",
+                                                     hasModalPresentation: true)
+            viewModel.displayError(.footerMessage(ElementL10n.unknownError))
+            return viewModel
+        case .nonModal:
+            return ServerSelectionViewModel(homeserverAddress: "https://matrix.org",
+                                            hasModalPresentation: false)
+        }
+    }
+}

ElementX/Sources/Screens/Authentication/ServerSelection/ServerSelectionCoordinator.swift

@@ -0,0 +1,110 @@
+//
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import SwiftUI
+
+struct ServerSelectionCoordinatorParameters {
+    /// The homeserver to be shown initially.
+    let homeserver: LoginHomeserver
+    /// Whether the screen is presented modally or within a navigation stack.
+    let hasModalPresentation: Bool
+}
+
+enum ServerSelectionCoordinatorResult {
+    case selected(LoginHomeserver)
+    case dismiss
+}
+
+final class ServerSelectionCoordinator: Coordinator, Presentable {
+    
+    // MARK: - Properties
+    
+    // MARK: Private
+    
+    private let parameters: ServerSelectionCoordinatorParameters
+    private let serverSelectionHostingController: UIViewController
+    private var serverSelectionViewModel: ServerSelectionViewModelProtocol
+    
+    private var indicatorPresenter: UserIndicatorTypePresenterProtocol
+    private var loadingIndicator: UserIndicator?
+    
+    // MARK: Public
+
+    // Must be used only internally
+    var childCoordinators: [Coordinator] = []
+    var callback: (@MainActor (ServerSelectionCoordinatorResult) -> Void)?
+    
+    // MARK: - Setup
+    
+    init(parameters: ServerSelectionCoordinatorParameters) {
+        self.parameters = parameters
+        
+        let viewModel = ServerSelectionViewModel(homeserverAddress: parameters.homeserver.address,
+                                                 hasModalPresentation: parameters.hasModalPresentation)
+        let view = ServerSelectionScreen(context: viewModel.context)
+        serverSelectionViewModel = viewModel
+        serverSelectionHostingController = UIHostingController(rootView: view)
+        
+        indicatorPresenter = UserIndicatorTypePresenter(presentingViewController: serverSelectionHostingController)
+    }
+    
+    // MARK: - Public
+    
+    func start() {
+        MXLog.debug("[ServerSelectionCoordinator] did start.")
+        
+        serverSelectionViewModel.callback = { [weak self] result in
+            guard let self = self else { return }
+            MXLog.debug("[ServerSelectionCoordinator] ServerSelectionViewModel did complete with result: \(result).")
+            
+            switch result {
+            case .confirm(let homeserverAddress):
+                self.useHomeserver(homeserverAddress)
+            case .dismiss:
+                self.callback?(.dismiss)
+            }
+        }
+    }
+    
+    func toPresentable() -> UIViewController {
+        serverSelectionHostingController
+    }
+    
+    // MARK: - Private
+    
+    /// Show an activity indicator whilst loading.
+    /// - Parameters:
+    ///   - label: The label to show on the indicator.
+    ///   - isInteractionBlocking: Whether the indicator should block any user interaction.
+    private func startLoading(label: String = ElementL10n.loading, isInteractionBlocking: Bool = true) {
+        loadingIndicator = indicatorPresenter.present(.loading(label: label, isInteractionBlocking: isInteractionBlocking))
+    }
+    
+    /// Hide the currently displayed activity indicator.
+    private func stopLoading() {
+        loadingIndicator = nil
+    }
+    
+    /// Updates the login flow using the supplied homeserver address, or shows an error when this isn't possible.
+    private func useHomeserver(_ homeserverAddress: String) {
+        startLoading()
+        
+        let homeserverAddress = LoginHomeserver.sanitized(homeserverAddress)
+        
+        stopLoading()
+        callback?(.selected(LoginHomeserver(address: homeserverAddress)))
+    }
+}

ElementX/Sources/Screens/Authentication/ServerSelection/ServerSelectionModels.swift

@@ -0,0 +1,78 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+// MARK: View model
+
+enum ServerSelectionViewModelResult {
+    /// The user would like to use the homeserver at the given address.
+    case confirm(homeserverAddress: String)
+    /// Dismiss the view without using the entered address.
+    case dismiss
+}
+
+// MARK: View
+
+struct ServerSelectionViewState: BindableState {
+    /// View state that can be bound to from SwiftUI.
+    var bindings: ServerSelectionBindings
+    /// An error message to be shown in the text field footer.
+    var footerErrorMessage: String?
+    /// Whether the screen is presented modally or within a navigation stack.
+    var hasModalPresentation: Bool
+    
+    /// The message to show in the text field footer.
+    var footerMessage: String {
+        footerErrorMessage ?? ElementL10n.serverSelectionServerFooter
+    }
+    
+    /// The title shown on the confirm button.
+    var buttonTitle: String {
+        hasModalPresentation ? ElementL10n.actionConfirm : ElementL10n.actionNext
+    }
+    
+    /// The text field is showing an error.
+    var isShowingFooterError: Bool {
+        footerErrorMessage != nil
+    }
+    
+    /// Whether it is possible to continue when tapping the confirmation button.
+    var hasValidationError: Bool {
+        bindings.homeserverAddress.isEmpty || isShowingFooterError
+    }
+}
+
+struct ServerSelectionBindings {
+    /// The homeserver address input by the user.
+    var homeserverAddress: String
+    /// Information describing the currently displayed alert.
+    var alertInfo: AlertInfo<ServerSelectionErrorType>?
+}
+
+enum ServerSelectionViewAction {
+    /// The user would like to use the homeserver at the input address.
+    case confirm
+    /// Dismiss the view without using the entered address.
+    case dismiss
+    /// Clear any errors shown in the text field footer.
+    case clearFooterError
+}
+
+enum ServerSelectionErrorType: Hashable {
+    /// An error message to be shown in the text field footer.
+    case footerMessage(String)
+}

ElementX/Sources/Screens/Authentication/ServerSelection/ServerSelectionViewModel.swift

@@ -0,0 +1,68 @@
+//
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import SwiftUI
+
+typealias ServerSelectionViewModelType = StateStoreViewModel<ServerSelectionViewState, ServerSelectionViewAction>
+
+class ServerSelectionViewModel: ServerSelectionViewModelType, ServerSelectionViewModelProtocol {
+
+    // MARK: - Properties
+
+    // MARK: Private
+
+    // MARK: Public
+
+    var callback: (@MainActor (ServerSelectionViewModelResult) -> Void)?
+
+    // MARK: - Setup
+
+    init(homeserverAddress: String, hasModalPresentation: Bool) {
+        let bindings = ServerSelectionBindings(homeserverAddress: homeserverAddress)
+        super.init(initialViewState: ServerSelectionViewState(bindings: bindings,
+                                                              hasModalPresentation: hasModalPresentation))
+    }
+
+    // MARK: - Public
+
+    override func process(viewAction: ServerSelectionViewAction) async {
+        switch viewAction {
+        case .confirm:
+            callback?(.confirm(homeserverAddress: state.bindings.homeserverAddress))
+        case .dismiss:
+            callback?(.dismiss)
+        case .clearFooterError:
+            clearFooterError()
+        }
+    }
+    
+    func displayError(_ type: ServerSelectionErrorType) {
+        switch type {
+        case .footerMessage(let message):
+            withAnimation {
+                state.footerErrorMessage = message
+            }
+        }
+    }
+    
+    // MARK: - Private
+    
+    /// Clear any errors shown in the text field footer.
+    private func clearFooterError() {
+        guard state.footerErrorMessage != nil else { return }
+        withAnimation { state.footerErrorMessage = nil }
+    }
+}

ElementX/Sources/Screens/Authentication/ServerSelection/ServerSelectionViewModelProtocol.swift

@@ -0,0 +1,27 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+@MainActor
+protocol ServerSelectionViewModelProtocol {
+    
+    var callback: (@MainActor (ServerSelectionViewModelResult) -> Void)? { get set }
+    var context: ServerSelectionViewModelType.Context { get }
+    
+    /// Displays an error to the user.
+    func displayError(_ type: ServerSelectionErrorType)
+}

ElementX/Sources/Screens/Authentication/ServerSelection/View/ServerSelectionScreen.swift

@@ -0,0 +1,123 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import SwiftUI
+
+struct ServerSelectionScreen: View {
+
+    // MARK: - Properties
+    
+    // MARK: Private
+    
+    @FocusState var isTextFieldFocused: Bool
+    
+    // MARK: Public
+    
+    @ObservedObject var context: ServerSelectionViewModel.Context
+    
+    // MARK: Views
+    
+    var body: some View {
+        ScrollView {
+            VStack(spacing: 0) {
+                header
+                    .padding(.top, UIConstants.topPaddingToNavigationBar)
+                    .padding(.bottom, 36)
+                
+                serverForm
+            }
+            .readableFrame()
+            .padding(.horizontal, 16)
+        }
+        .background(Color.element.background, ignoresSafeAreaEdges: .all)
+        .toolbar { toolbar }
+        .alert(item: $context.alertInfo) { $0.alert }
+    }
+    
+    /// The title, message and icon at the top of the screen.
+    var header: some View {
+        VStack(spacing: 8) {
+            AuthenticationIconImage(image: Asset.Images.serverSelectionIcon)
+                .padding(.bottom, 8)
+            
+            Text(ElementL10n.serverSelectionTitle)
+                .font(.element.title2B)
+                .multilineTextAlignment(.center)
+                .foregroundColor(.element.primaryContent)
+            
+            Text(ElementL10n.serverSelectionMessage)
+                .font(.element.body)
+                .multilineTextAlignment(.center)
+                .foregroundColor(.element.secondaryContent)
+        }
+    }
+    
+    /// The text field and confirm button where the user enters a server URL.
+    var serverForm: some View {
+        VStack(alignment: .leading, spacing: 12) {
+            TextField(ElementL10n.serverSelectionServerUrl, text: $context.homeserverAddress)
+                .focused($isTextFieldFocused)
+                .textFieldStyle(.elementInput(footerText: context.viewState.footerMessage,
+                                              isError: context.viewState.isShowingFooterError))
+                .keyboardType(.URL)
+                .autocapitalization(.none)
+                .disableAutocorrection(true)
+                .onChange(of: context.homeserverAddress) { _ in context.send(viewAction: .clearFooterError) }
+                .submitLabel(.done)
+                .onSubmit(submit)
+                .accessibilityIdentifier("addressTextField")
+            
+            Button(action: submit) {
+                Text(context.viewState.buttonTitle)
+            }
+            .buttonStyle(.elementAction(.xLarge))
+            .disabled(context.viewState.hasValidationError)
+            .accessibilityIdentifier("confirmButton")
+        }
+    }
+    
+    @ToolbarContentBuilder
+    var toolbar: some ToolbarContent {
+        ToolbarItem(placement: .cancellationAction) {
+            if context.viewState.hasModalPresentation {
+                Button { context.send(viewAction: .dismiss) } label: {
+                    Text(ElementL10n.actionCancel)
+                }
+                .accessibilityIdentifier("dismissButton")
+            }
+        }
+    }
+    
+    /// Sends the `confirm` view action so long as the text field input is valid.
+    func submit() {
+        guard !context.viewState.hasValidationError else { return }
+        context.send(viewAction: .confirm)
+    }
+}
+
+// MARK: - Previews
+
+struct ServerSelection_Previews: PreviewProvider {
+    static var previews: some View {
+        ForEach(MockServerSelectionScreenState.allCases, id: \.self) { state in
+            NavigationView {
+                ServerSelectionScreen(context: state.viewModel.context)
+                    .tint(.element.accent)
+            }
+            .navigationViewStyle(.stack)
+        }
+    }
+}