Added room timeline screen with live events listening and back pagination. Rearranged project files.

ElementX/Sources/Screens/HomeScreen/HomeScreenCoordinator.swift

@@ -0,0 +1,103 @@
+//
+// 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
+import Combine
+import Kingfisher
+
+struct HomeScreenCoordinatorParameters {
+    let userSession: UserSession
+}
+
+enum HomeScreenCoordinatorResult {
+    case logout
+    case selectRoom(roomIdentifier: String)
+}
+
+final class HomeScreenCoordinator: Coordinator, Presentable {
+    
+    // MARK: - Properties
+    
+    // MARK: Private
+    
+    private let parameters: HomeScreenCoordinatorParameters
+    private let hostingController: UIViewController
+    private var viewModel: HomeScreenViewModelProtocol
+    
+    private var cancellables = Set<AnyCancellable>()
+    
+    // MARK: Public
+
+    // Must be used only internally
+    var childCoordinators: [Coordinator] = []
+    var completion: ((HomeScreenCoordinatorResult) -> Void)?
+    
+    // MARK: - Setup
+    
+    init(parameters: HomeScreenCoordinatorParameters, imageCache: Kingfisher.ImageCache) {
+        self.parameters = parameters
+        
+        let userDisplayName = self.parameters.userSession.userDisplayName ?? self.parameters.userSession.userIdentifier
+        viewModel = HomeScreenViewModel(userDisplayName: userDisplayName, imageCache: imageCache)
+        
+        let view = HomeScreen(context: viewModel.context)
+        hostingController = UIHostingController(rootView: view)
+        
+        viewModel.completion = { [weak self] result in
+            guard let self = self else { return }
+            
+            switch result {
+            case .logout:
+                self.completion?(.logout)
+            case .loadUserAvatar:
+                self.parameters.userSession.loadUserAvatar({ result in
+                    switch result {
+                    case .success(let avatar):
+                        self.viewModel.updateWithUserAvatar(avatar)
+                    default:
+                        break
+                    }
+                })
+            case .selectRoom(let roomIdentifier):
+                self.completion?(.selectRoom(roomIdentifier: roomIdentifier))
+            }
+        }
+        
+        parameters.userSession.callbacks.sink { [weak self] result in
+            switch result {
+            case .updatedRoomsList:
+                self?.updateRoomsList()
+            }
+        }.store(in: &cancellables)
+    }
+    
+    // MARK: - Public
+    func start() {
+        
+    }
+    
+    func toPresentable() -> UIViewController {
+        return self.hostingController
+    }
+    
+    // MARK: - Private
+    
+    func updateRoomsList() {
+        parameters.userSession.getRoomList { [weak self] rooms in
+            self?.viewModel.updateWithRoomList(rooms)
+        }
+    }
+}

ElementX/Sources/Screens/HomeScreen/HomeScreenModels.swift

@@ -0,0 +1,77 @@
+// 
+// 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
+import UIKit
+
+enum HomeScreenViewModelResult {
+    case logout
+    case loadUserAvatar
+    case selectRoom(roomIdentifier: String)
+}
+
+enum HomeScreenViewAction {
+    case logout
+    case loadUserAvatar
+    case loadRoomData(roomIdentifier: String)
+    case selectRoom(roomIdentifier: String)
+}
+
+struct HomeScreenViewState: BindableState {
+    let userDisplayName: String
+    var userAvatar: UIImage?
+    
+    var rooms: [HomeScreenRoom] = []
+    var isLoadingRooms: Bool = false
+    
+    var firstDirectRooms: [HomeScreenRoom] {
+        Array(rooms.filter { $0.isDirect }.prefix(5))
+    }
+    
+    var otherDirectRooms: [HomeScreenRoom] {
+        Array(rooms.filter { $0.isDirect }.dropFirst(5))
+    }
+    
+    var firstNondirectRooms: [HomeScreenRoom] {
+        Array(rooms.filter { !$0.isDirect }.prefix(5))
+    }
+    
+    var otherNondirectRooms: [HomeScreenRoom] {
+        Array(rooms.filter { !$0.isDirect }.dropFirst(5))
+    }
+}
+
+struct HomeScreenRoom: Identifiable {
+    let id: String
+    
+    var displayName: String?
+    
+    let topic: String?
+    let lastMessage: String?
+    
+    var avatar: UIImage?
+    
+    let isDirect: Bool
+    let isEncrypted: Bool
+}
+
+extension MutableCollection where Element == HomeScreenRoom {
+    mutating func updateEach(_ update: (inout Element) -> Void) {
+        for index in indices {
+            update(&self[index])
+        }
+    }
+}

ElementX/Sources/Screens/HomeScreen/HomeScreenViewModel.swift

@@ -0,0 +1,181 @@
+//
+// 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
+import Combine
+import Kingfisher
+
+@available(iOS 14, *)
+typealias HomeScreenViewModelType = StateStoreViewModel<HomeScreenViewState,
+                                                        Never,
+                                                        HomeScreenViewAction>
+@available(iOS 14, *)
+class HomeScreenViewModel: HomeScreenViewModelType, HomeScreenViewModelProtocol {
+    
+    private var roomUpdateListeners = Set<AnyCancellable>()
+    private var roomList: [RoomProxyProtocol]? {
+        didSet {
+            self.state.isLoadingRooms = (roomList == nil)
+        }
+    }
+    
+    private let imageCache: ImageCache
+
+    var completion: ((HomeScreenViewModelResult) -> Void)?
+    
+    // MARK: - Setup
+    
+    init(userDisplayName: String, imageCache: Kingfisher.ImageCache) {
+        self.imageCache = imageCache
+        super.init(initialViewState: HomeScreenViewState(userDisplayName: userDisplayName, isLoadingRooms: true))
+    }
+    
+    // MARK: - Public
+    
+    override func process(viewAction: HomeScreenViewAction) {
+        switch viewAction {
+        case .logout:
+            self.completion?(.logout)
+        case .loadRoomData(let roomIdentifier):
+            self.loadAvatarForRoomWithIdentifier(roomIdentifier)
+            self.loadRoomDisplayNameForRoomWithIdentifier(roomIdentifier)
+        case .loadUserAvatar:
+            self.completion?(.loadUserAvatar)
+        case .selectRoom(let roomIdentifier):
+            self.completion?(.selectRoom(roomIdentifier: roomIdentifier))
+        }
+    }
+    
+    func updateWithRoomList(_ roomList: [RoomProxyProtocol]) {
+        
+        roomUpdateListeners.removeAll()
+        
+        self.roomList = roomList
+        
+        roomList.forEach({ roomProxy  in
+            roomProxy.paginateBackwards(start: 0, finish: 1)
+            roomProxy.startLiveEventListener()
+            roomProxy.callbacks.sink { [weak self] callback in
+                switch callback {
+                case .updatedLastMessage:
+                    self?.updateRoomForProxy(roomProxy)
+                default:
+                    break
+                }
+            }
+            .store(in: &roomUpdateListeners)
+        })
+        
+        state.rooms = roomList.map { roomProxy in
+            roomFromProxy(roomProxy)
+        }
+    }
+    
+    func updateWithUserAvatar(_ avatar: UIImage?) {
+        self.state.userAvatar = avatar
+    }
+    
+    // MARK: - Private
+    
+    private func loadAvatarForRoomWithIdentifier(_ roomIdentifier: String) {
+        guard let room = roomList?.filter({ $0.id == roomIdentifier }).first,
+              let cacheKey = room.avatarURL?.path else {
+                  return
+              }
+        
+        if imageCache.isCached(forKey: cacheKey) {
+            imageCache.retrieveImage(forKey: cacheKey) { [weak self] result in
+                guard let self = self else { return }
+                switch result {
+                case .success(let value):
+                    self.updateAvatar(value.image, forRoomWithIdentifier: roomIdentifier)
+                case .failure(let error):
+                    MXLog.error("Failed retrieving avatar from cache with error: \(error)")
+                }
+            }
+            
+            return
+        }
+        
+        room.loadAvatar { [weak self] result in
+            guard let self = self else { return }
+            
+            switch result {
+            case .success(let avatar):
+                guard let avatar = avatar else {
+                    return
+                }
+                
+                self.imageCache.store(avatar, forKey: cacheKey)
+                self.updateAvatar(avatar, forRoomWithIdentifier: roomIdentifier)
+            default:
+                break
+            }
+        }
+    }
+    
+    private func loadRoomDisplayNameForRoomWithIdentifier(_ roomIdentifier: String) {
+        guard let room = roomList?.filter({ $0.id == roomIdentifier }).first else {
+            return
+        }
+        
+        room.loadDisplayName { [weak self] result in
+            guard let self = self else { return }
+            
+            switch result {
+            case .success(let displayName):
+                self.updateDisplayName(displayName, forRoomWithIdentifier: roomIdentifier)
+            default:
+                break
+            }
+        }
+    }
+    
+    private func updateDisplayName(_ displayName: String, forRoomWithIdentifier roomIdentifier: String) {
+        guard let index = self.state.rooms.firstIndex(where: { $0.id == roomIdentifier }) else {
+            return
+        }
+        
+        self.state.rooms[index].displayName = displayName
+    }
+    
+    private func updateAvatar(_ avatar: UIImage?, forRoomWithIdentifier roomIdentifier: String) {
+        guard let index = self.state.rooms.firstIndex(where: { $0.id == roomIdentifier }) else {
+            return
+        }
+        
+        self.state.rooms[index].avatar = avatar
+    }
+    
+    private func updateRoomForProxy(_ roomProxy: RoomProxyProtocol) {
+        state.rooms.updateEach { room in
+            if room.id != roomProxy.id {
+                return
+            }
+            
+            room = roomFromProxy(roomProxy)
+        }
+    }
+    
+    private func roomFromProxy(_ roomProxy: RoomProxyProtocol) -> HomeScreenRoom {
+        HomeScreenRoom(id: roomProxy.id,
+                       displayName: roomProxy.name,
+                       topic: roomProxy.topic,
+                       lastMessage: roomProxy.lastMessage,
+                       isDirect: roomProxy.isDirect,
+                       isEncrypted: roomProxy.isEncrypted)
+    }
+}

ElementX/Sources/Screens/HomeScreen/HomeScreenViewModelProtocol.swift

@@ -0,0 +1,28 @@
+// 
+// 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
+import UIKit
+
+protocol HomeScreenViewModelProtocol {
+    var completion: ((HomeScreenViewModelResult) -> Void)? { get set }
+    
+    var context: HomeScreenViewModelType.Context { get }
+    
+    func updateWithRoomList(_ roomList: [RoomProxyProtocol])
+    
+    func updateWithUserAvatar(_ avatar: UIImage?)
+}

ElementX/Sources/Screens/HomeScreen/Test/UI/HomeScreenUITests.swift

@@ -0,0 +1,17 @@
+//
+// 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 XCTest

ElementX/Sources/Screens/HomeScreen/Test/Unit/HomeScreenViewModelTests.swift

@@ -0,0 +1,29 @@
+// 
+// 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 XCTest
+
+@testable import ElementX
+
+class HomeScreenViewModelTests: XCTestCase {
+    override func setUpWithError() throws {
+
+    }
+
+    func testInitialState() {
+
+    }
+}

ElementX/Sources/Screens/HomeScreen/View/HomeScreen.swift

@@ -0,0 +1,170 @@
+// 
+// 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
+import Kingfisher
+
+struct HomeScreen: View {
+    
+    @ObservedObject var context: HomeScreenViewModel.Context
+    
+    // MARK: Views
+    
+    var body: some View {
+        NavigationView {
+            VStack(spacing: 16.0) {
+                if context.viewState.isLoadingRooms {
+                    VStack {
+                        Text("Loading rooms")
+                        ProgressView()
+                    }
+                } else {
+                    List {
+                        Section("People") {
+                            ForEach(context.viewState.firstDirectRooms) { room in
+                                RoomCell(room: room, context: context)
+                            }
+                            
+                            let other = context.viewState.otherDirectRooms
+                            
+                            if other.count > 0 {
+                                DisclosureGroup("See more") {
+                                    ForEach(other) { room in
+                                        RoomCell(room: room, context: context)
+                                    }
+                                }
+                            }
+                        }
+                        
+                        Section("Rooms") {
+                            ForEach(context.viewState.firstNondirectRooms) { room in
+                                RoomCell(room: room, context: context)
+                            }
+                            
+                            let other = context.viewState.otherNondirectRooms
+                            
+                            if other.count > 0 {
+                                DisclosureGroup("See more") {
+                                    ForEach(other) { room in
+                                        RoomCell(room: room, context: context)
+                                    }
+                                }
+                            }
+                        }
+                    }
+                    .listStyle(.plain)
+                }
+                
+                Spacer()
+            }
+            .ignoresSafeArea(.all, edges: .bottom)
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .navigationBarLeading) {
+                    HStack {
+                        if let avatar = context.viewState.userAvatar {
+                            Image(uiImage: avatar)
+                                .resizable()
+                                .scaledToFill()
+                                .frame(width: 40, height: 40, alignment: .center)
+                                .mask(Circle())
+                        } else {
+                            let _ = context.send(viewAction: .loadUserAvatar)
+                        }
+                        Text("Hello, \(context.viewState.userDisplayName)!")
+                            .font(.subheadline)
+                            .fontWeight(.bold)
+                    }
+                }
+                ToolbarItem(placement: .navigationBarTrailing) {
+                    Button("Logout") {
+                        context.send(viewAction: .logout)
+                    }
+                }
+            }
+        }
+        .navigationViewStyle(StackNavigationViewStyle())
+    }
+}
+
+struct RoomCell: View {
+    
+    let room: HomeScreenRoom
+    let context: HomeScreenViewModel.Context
+    
+    var body: some View {
+        Button {
+            context.send(viewAction: .selectRoom(roomIdentifier: room.id))
+        } label: {
+            HStack(spacing: 16.0) {
+                if let avatar = room.avatar {
+                    Image(uiImage: avatar)
+                        .resizable()
+                        .scaledToFill()
+                        .frame(width: 40, height: 40)
+                        .mask(Circle())
+                } else {
+                    let _ = context.send(viewAction: .loadRoomData(roomIdentifier: room.id))
+                    Image(systemName: "person.3")
+                        .frame(width: 40, height: 40)
+                }
+                
+                VStack(alignment: .leading, spacing: 4.0) {
+                    Text(roomName(room))
+                        .font(.headline)
+                        .fontWeight(.regular)
+                    
+                    if let roomTopic = room.topic, roomTopic.count > 0 {
+                        Text(roomTopic)
+                            .font(.footnote)
+                            .fontWeight(.bold)
+                            .lineLimit(1)
+                    }
+                    
+                    if let lastMessage = room.lastMessage {
+                        Text(lastMessage)
+                            .font(.footnote)
+                            .fontWeight(.medium)
+                            .lineLimit(1)
+                    }
+                }
+            }
+            .frame(minHeight: 60.0)
+        }
+    }
+    
+    private func roomName(_ room: HomeScreenRoom) -> String {
+        room.displayName ?? room.id + (room.isEncrypted ? "🛡": "")
+    }
+}
+
+// MARK: - Previews
+
+struct HomeScreen_Previews: PreviewProvider {
+    static var previews: some View {
+        let viewModel = HomeScreenViewModel(userDisplayName: "Johnny Appleseed", imageCache: ImageCache.default)
+        
+        let rooms = [MockRoomProxy(displayName: "Alfa"),
+                     MockRoomProxy(displayName: "Beta"),
+                     MockRoomProxy(displayName: "Omega")]
+        
+        viewModel.updateWithRoomList(rooms)
+        
+        viewModel.updateWithUserAvatar(UIImage(systemName: "person.fill.questionmark"))
+        
+        return HomeScreen(context: viewModel.context)
+    }
+}

ElementX/Sources/Screens/LoginScreen/LoginScreenCoordinator.swift

@@ -0,0 +1,65 @@
+//
+// 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 LoginScreenCoordinatorParameters {
+    
+}
+
+final class LoginScreenCoordinator: Coordinator, Presentable {
+    
+    // MARK: - Properties
+    
+    // MARK: Private
+    
+    private let parameters: LoginScreenCoordinatorParameters
+    private let loginScreenHostingController: UIViewController
+    private var loginScreenViewModel: LoginScreenViewModelProtocol
+    
+    // MARK: Public
+
+    // Must be used only internally
+    var childCoordinators: [Coordinator] = []
+    var completion: ((LoginScreenViewModelResult) -> Void)?
+    
+    // MARK: - Setup
+    
+    init(parameters: LoginScreenCoordinatorParameters) {
+        self.parameters = parameters
+        
+        loginScreenViewModel = LoginScreenViewModel()
+        let view = LoginScreen(context: loginScreenViewModel.context)
+        
+        loginScreenHostingController = UIHostingController(rootView: view)
+        loginScreenHostingController.isModalInPresentation = true
+        
+        loginScreenViewModel.completion = { [weak self] result in
+            MXLog.debug("[LoginScreenCoordinator] LoginScreenViewModel did complete.")
+            guard let self = self else { return }
+            self.completion?(result)
+        }
+    }
+    
+    // MARK: - Public
+    func start() {
+        
+    }
+    
+    func toPresentable() -> UIViewController {
+        return self.loginScreenHostingController
+    }
+}

ElementX/Sources/Screens/LoginScreen/LoginScreenModels.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 Foundation
+
+enum LoginScreenViewModelResult {
+    case login((username: String, password: String))
+}
+
+enum LoginScreenViewAction {
+    case login
+}
+
+struct LoginScreenViewState: BindableState {
+    var bindings: LoginScreenViewStateBindings
+}
+
+struct LoginScreenViewStateBindings {
+    var username: String
+    var password: String
+}
+
+struct LoginScreenErrorAlertInfo: Identifiable {
+    enum AlertType {
+        case genericFailure
+    }
+    
+    let id: AlertType
+    let title: String
+    let subtitle: String
+}

ElementX/Sources/Screens/LoginScreen/LoginScreenViewModel.swift

@@ -0,0 +1,49 @@
+//
+// 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
+
+@available(iOS 14, *)
+typealias LoginScreenViewModelType = StateStoreViewModel<LoginScreenViewState,
+                                                         Never,
+                                                         LoginScreenViewAction>
+@available(iOS 14, *)
+class LoginScreenViewModel: LoginScreenViewModelType, LoginScreenViewModelProtocol {
+
+    // MARK: - Properties
+
+    // MARK: Private
+
+    // MARK: Public
+
+    var completion: ((LoginScreenViewModelResult) -> Void)?
+
+    // MARK: - Setup
+
+    init() {
+        super.init(initialViewState: LoginScreenViewState(bindings: LoginScreenViewStateBindings(username: "",
+                                                                                                 password: "")))
+    }
+
+    // MARK: - Public
+
+    override func process(viewAction: LoginScreenViewAction) {
+        switch viewAction {
+        case .login:
+            completion?(.login((username: context.username, password: context.password)))
+        }
+    }
+}

ElementX/Sources/Screens/LoginScreen/LoginScreenViewModelProtocol.swift

@@ -0,0 +1,24 @@
+// 
+// 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
+
+protocol LoginScreenViewModelProtocol {
+    
+    var completion: ((LoginScreenViewModelResult) -> Void)? { get set }
+    @available(iOS 14, *)
+    var context: LoginScreenViewModelType.Context { get }
+}

ElementX/Sources/Screens/LoginScreen/Test/UI/LoginScreenUITests.swift

@@ -0,0 +1,17 @@
+//
+// 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 XCTest

ElementX/Sources/Screens/LoginScreen/Test/Unit/LoginScreenViewModelTests.swift

@@ -0,0 +1,30 @@
+// 
+// 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 XCTest
+
+@testable import ElementX
+
+class LoginScreenViewModelTests: XCTestCase {
+    
+    override func setUpWithError() throws {
+        
+    }
+
+    func testInitialState() {
+        
+    }
+}

ElementX/Sources/Screens/LoginScreen/View/LoginScreen.swift

@@ -0,0 +1,57 @@
+// 
+// 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 LoginScreen: View {
+    
+    @ObservedObject var context: LoginScreenViewModel.Context
+    
+    var body: some View {
+        NavigationView {
+            VStack {
+                TextField("Username", text: $context.username)
+                    .textFieldStyle(.roundedBorder)
+                    .disableAutocorrection(true)
+                    .autocapitalization(.none)
+                SecureField("Password", text: $context.password)
+                    .textFieldStyle(.roundedBorder)
+                
+                Button("Login") {
+                    context.send(viewAction: .login)
+                }
+                .buttonStyle(.borderedProminent)
+                .padding(.horizontal, 50)
+            }
+            .padding(.horizontal, 8.0)
+            .navigationTitle("Login")
+            .navigationBarTitleDisplayMode(.inline)
+            .onSubmit {
+                context.send(viewAction: .login)
+            }
+        }
+        .navigationViewStyle(StackNavigationViewStyle())
+    }
+}
+
+// MARK: - Previews
+
+struct LoginScreen_Previews: PreviewProvider {
+    static var previews: some View {
+        let viewModel = LoginScreenViewModel()
+        LoginScreen(context: viewModel.context)
+    }
+}

ElementX/Sources/Screens/RoomScreen/RoomScreenCoordinator.swift

@@ -0,0 +1,67 @@
+//
+// 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 RoomScreenCoordinatorParameters {
+    let roomProxy: RoomProxyProtocol
+}
+
+final class RoomScreenCoordinator: Coordinator, Presentable {
+    
+    // MARK: - Properties
+    
+    // MARK: Private
+    
+    private let parameters: RoomScreenCoordinatorParameters
+    private let roomScreenHostingController: UIViewController
+    private var roomScreenViewModel: RoomScreenViewModelProtocol
+    
+    // MARK: Public
+
+    // Must be used only internally
+    var childCoordinators: [Coordinator] = []
+    var completion: ((RoomScreenViewModelResult) -> Void)?
+    
+    // MARK: - Setup
+    
+    @available(iOS 14.0, *)
+    init(parameters: RoomScreenCoordinatorParameters) {
+        self.parameters = parameters
+        
+        let timelineProvider = RoomTimelineProvider(roomProxy: parameters.roomProxy)
+        let timelineController = RoomTimelineController(timelineProvider: timelineProvider)
+        
+        let viewModel = RoomScreenViewModel(roomProxy: parameters.roomProxy, timelineController: timelineController)
+        let view = RoomScreen(context: viewModel.context)
+        roomScreenViewModel = viewModel
+        roomScreenHostingController = UIHostingController(rootView: view)
+    }
+    
+    // MARK: - Public
+    func start() {
+        MXLog.debug("[RoomScreenCoordinator] did start.")
+        roomScreenViewModel.completion = { [weak self] result in
+            MXLog.debug("[RoomScreenCoordinator] RoomScreenViewModel did complete with result: \(result).")
+            guard let self = self else { return }
+            self.completion?(result)
+        }
+    }
+    
+    func toPresentable() -> UIViewController {
+        return self.roomScreenHostingController
+    }
+}

ElementX/Sources/Screens/RoomScreen/RoomScreenModels.swift

@@ -0,0 +1,50 @@
+// 
+// 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
+
+enum RoomScreenViewModelResult {
+
+}
+
+enum RoomScreenViewAction {
+    case loadPreviousPage
+}
+
+private var dateFormatter: DateFormatter = {
+    let dateFormatter = DateFormatter()
+    dateFormatter.dateStyle = .short
+    dateFormatter.timeStyle = .short
+    return dateFormatter
+}()
+
+struct RoomScreenMessage: Identifiable, Equatable {
+    
+    let id: String
+    let sender: String
+    let text: String
+    let originServerTs: Date
+    
+    var timestamp: String {
+        dateFormatter.string(from: originServerTs)
+    }
+}
+
+struct RoomScreenViewState: BindableState {
+    var roomTitle: String?
+    var isLoading: Bool = false
+    var messages: [RoomScreenMessage] = []
+}

ElementX/Sources/Screens/RoomScreen/RoomScreenViewModel.swift

@@ -0,0 +1,74 @@
+//
+// 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
+
+@available(iOS 14, *)
+typealias RoomScreenViewModelType = StateStoreViewModel<RoomScreenViewState,
+                                                                  Never,
+                                                                  RoomScreenViewAction>
+@available(iOS 14, *)
+class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol {
+    
+    private struct Constants {
+        static let backPaginationPageSize: UInt = 20
+    }
+
+    private let roomProxy: RoomProxyProtocol
+    private let timelineController: RoomTimelineControllerProtocol
+
+    var completion: ((RoomScreenViewModelResult) -> Void)?
+
+    // MARK: - Setup
+
+    init(roomProxy: RoomProxyProtocol, timelineController: RoomTimelineControllerProtocol) {
+        self.roomProxy = roomProxy
+        self.timelineController = timelineController
+        
+        super.init(initialViewState: RoomScreenViewState())
+        
+        state.messages = buildRoomScreenMessages(timelineController.timelineItems)
+        
+        timelineController.callbacks.sink { [weak self] callback in
+            guard let self = self else { return }
+            
+            switch callback {
+            case .updatedTimelineItems:
+                self.state.messages = self.buildRoomScreenMessages(timelineController.timelineItems)
+            }
+        }.store(in: &cancellables)
+        
+        timelineController.paginateBackwards(Constants.backPaginationPageSize)
+    }
+
+    // MARK: - Public
+
+    override func process(viewAction: RoomScreenViewAction) {
+        switch viewAction {
+        case .loadPreviousPage:
+            timelineController.paginateBackwards(Constants.backPaginationPageSize)
+        }
+    }
+    
+    // MARK: - Private
+    
+    private func buildRoomScreenMessages(_ timelineItems: [RoomTimelineItemProtocol]) -> [RoomScreenMessage] {
+        timelineItems.map { RoomScreenMessage(id: $0.id,
+                                              sender: $0.senderDisplayName,
+                                              text: $0.text,
+                                              originServerTs: $0.originServerTs) }
+    }
+}

ElementX/Sources/Screens/RoomScreen/RoomScreenViewModelProtocol.swift

@@ -0,0 +1,24 @@
+// 
+// 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
+
+protocol RoomScreenViewModelProtocol {
+    
+    var completion: ((RoomScreenViewModelResult) -> Void)? { get set }
+    @available(iOS 14, *)
+    var context: RoomScreenViewModelType.Context { get }
+}

ElementX/Sources/Screens/RoomScreen/Test/UI/RoomScreenUITests.swift

@@ -0,0 +1,17 @@
+//
+// 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 XCTest

ElementX/Sources/Screens/RoomScreen/Test/Unit/RoomScreenViewModelTests.swift

@@ -0,0 +1,21 @@
+// 
+// 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 XCTest
+
+class RoomScreenViewModelTests: XCTestCase {
+    
+}

ElementX/Sources/Screens/RoomScreen/View/RoomScreen.swift

@@ -0,0 +1,85 @@
+// 
+// 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 RoomScreen: View {
+    
+    let timelineBottomDividerIdentifier = "TimelineBottomDividerIdentifier"
+    
+    @ObservedObject var context: RoomScreenViewModel.Context
+    @State var backPaginationMessageIdentifier: String?
+    
+    var body: some View {
+        ScrollViewReader { reader in
+            List {
+                if backPaginationMessageIdentifier != nil {
+                    HStack {
+                        Spacer()
+                        ProgressView()
+                        Spacer()
+                    }
+                } else {
+                    Rectangle()
+                        .onAppear {
+                            let _ = MXLog.debug("Request load previous page")
+                            backPaginationMessageIdentifier = context.viewState.messages.first?.id
+                            context.send(viewAction: .loadPreviousPage)
+                        }
+                        .frame(height: 0.0)
+                }
+                ForEach(context.viewState.messages) { message in
+                    VStack(alignment: .leading) {
+                        HStack {
+                            Text(message.sender)
+                            Spacer()
+                            Text(message.timestamp)
+                        }
+                        .font(.footnote)
+                        Text(message.text)
+                    }
+                    .listRowSeparator(.hidden)
+                }
+                
+                Divider()
+                    .id(timelineBottomDividerIdentifier)
+                    .listRowSeparator(.hidden)
+            }
+            .listStyle(.plain)
+            .onAppear {
+                reader.scrollTo(timelineBottomDividerIdentifier, anchor: .bottom)
+            }
+            .onChange(of: context.viewState.messages) { _ in
+                if backPaginationMessageIdentifier != nil {
+                    self.backPaginationMessageIdentifier = nil
+                    return
+                }
+                
+                reader.scrollTo(timelineBottomDividerIdentifier, anchor: .bottom)
+            }
+        }
+    }
+}
+
+// MARK: - Previews
+
+struct RoomScreen_Previews: PreviewProvider {
+    static var previews: some View {
+        let viewModel = RoomScreenViewModel(roomProxy: MockRoomProxy(displayName: "Test"),
+                                            timelineController: MockRoomTimelineController())
+        RoomScreen(context: viewModel.context)
+    }
+}

ElementX/Sources/Screens/Splash/SplashViewController.swift

@@ -0,0 +1,12 @@
+//
+//  SplashViewController.swift
+//  ElementX
+//
+//  Created by Stefan Ceriu on 14.02.2022.
+//
+
+import UIKit
+
+class SplashViewController: UIViewController {
+    
+}

ElementX/Sources/Screens/Splash/SplashViewController.xib

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="19529" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES">
+    <device id="retina6_1" orientation="portrait" appearance="light"/>
+    <dependencies>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="19519"/>
+        <capability name="Safe area layout guides" minToolsVersion="9.0"/>
+        <capability name="System colors in document resources" minToolsVersion="11.0"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
+    </dependencies>
+    <objects>
+        <placeholder placeholderIdentifier="IBFilesOwner" id="-1" userLabel="File's Owner" customClass="SplashViewController" customModule="ElementX" customModuleProvider="target">
+            <connections>
+                <outlet property="view" destination="i5M-Pr-FkT" id="sfx-zR-JGt"/>
+            </connections>
+        </placeholder>
+        <placeholder placeholderIdentifier="IBFirstResponder" id="-2" customClass="UIResponder"/>
+        <view clearsContextBeforeDrawing="NO" contentMode="scaleToFill" id="i5M-Pr-FkT">
+            <rect key="frame" x="0.0" y="0.0" width="414" height="896"/>
+            <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+            <subviews>
+                <imageView clipsSubviews="YES" userInteractionEnabled="NO" contentMode="scaleAspectFit" horizontalHuggingPriority="251" verticalHuggingPriority="251" image="app-logo" translatesAutoresizingMaskIntoConstraints="NO" id="ue7-fB-5XS">
+                    <rect key="frame" x="87" y="328" width="240" height="240"/>
+                    <color key="tintColor" red="0.050980392156862744" green="0.74117647058823533" blue="0.54509803921568623" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                </imageView>
+            </subviews>
+            <viewLayoutGuide key="safeArea" id="fnl-2z-Ty3"/>
+            <color key="backgroundColor" systemColor="systemBackgroundColor"/>
+            <constraints>
+                <constraint firstItem="fnl-2z-Ty3" firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="ue7-fB-5XS" secondAttribute="bottom" constant="16" id="Cip-Sc-gaF"/>
+                <constraint firstItem="ue7-fB-5XS" firstAttribute="top" relation="greaterThanOrEqual" secondItem="fnl-2z-Ty3" secondAttribute="top" constant="16" id="Clt-cS-YAr"/>
+                <constraint firstItem="ue7-fB-5XS" firstAttribute="centerY" secondItem="i5M-Pr-FkT" secondAttribute="centerY" id="N3w-Jf-MRA"/>
+                <constraint firstItem="fnl-2z-Ty3" firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="ue7-fB-5XS" secondAttribute="trailing" constant="16" id="WfN-3K-kpr"/>
+                <constraint firstItem="ue7-fB-5XS" firstAttribute="centerX" secondItem="i5M-Pr-FkT" secondAttribute="centerX" id="ujr-SL-AyX"/>
+                <constraint firstItem="ue7-fB-5XS" firstAttribute="leading" relation="greaterThanOrEqual" secondItem="fnl-2z-Ty3" secondAttribute="leading" constant="16" id="yNl-Wu-AES"/>
+            </constraints>
+            <point key="canvasLocation" x="137.68115942028987" y="153.34821428571428"/>
+        </view>
+    </objects>
+    <resources>
+        <image name="app-logo" width="240" height="240"/>
+        <systemColor name="systemBackgroundColor">
+            <color white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+        </systemColor>
+    </resources>
+</document>

ElementX/Sources/Screens/Templates/SimpleScreenExample/Coordinator/TemplateSimpleScreenCoordinator.swift

@@ -0,0 +1,64 @@
+//
+// 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 TemplateSimpleScreenCoordinatorParameters {
+    let promptType: TemplateSimpleScreenPromptType
+}
+
+final class TemplateSimpleScreenCoordinator: Coordinator, Presentable {
+    
+    // MARK: - Properties
+    
+    // MARK: Private
+    
+    private let parameters: TemplateSimpleScreenCoordinatorParameters
+    private let templateSimpleScreenHostingController: UIViewController
+    private var templateSimpleScreenViewModel: TemplateSimpleScreenViewModelProtocol
+    
+    // MARK: Public
+
+    // Must be used only internally
+    var childCoordinators: [Coordinator] = []
+    var completion: ((TemplateSimpleScreenViewModelResult) -> Void)?
+    
+    // MARK: - Setup
+    
+    @available(iOS 14.0, *)
+    init(parameters: TemplateSimpleScreenCoordinatorParameters) {
+        self.parameters = parameters
+        
+        let viewModel = TemplateSimpleScreenViewModel(promptType: parameters.promptType)
+        let view = TemplateSimpleScreen(viewModel: viewModel.context)
+        templateSimpleScreenViewModel = viewModel
+        templateSimpleScreenHostingController = VectorHostingController(rootView: view)
+    }
+    
+    // MARK: - Public
+    func start() {
+        MXLog.debug("[TemplateSimpleScreenCoordinator] did start.")
+        templateSimpleScreenViewModel.completion = { [weak self] result in
+            MXLog.debug("[TemplateSimpleScreenCoordinator] TemplateSimpleScreenViewModel did complete with result: \(result).")
+            guard let self = self else { return }
+            self.completion?(result)
+        }
+    }
+    
+    func toPresentable() -> UIViewController {
+        return self.templateSimpleScreenHostingController
+    }
+}

ElementX/Sources/Screens/Templates/SimpleScreenExample/MockTemplateSimpleScreenScreenState.swift

@@ -0,0 +1,57 @@
+// 
+// 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
+import SwiftUI
+
+/// Using an enum for the screen allows you define the different state cases with
+/// the relevant associated data for each case.
+@available(iOS 14.0, *)
+enum MockTemplateSimpleScreenScreenState: MockScreenState, CaseIterable {
+    // A case for each state you want to represent
+    // with specific, minimal associated data that will allow you
+    // mock that screen.
+    case promptType(TemplateSimpleScreenPromptType)
+    
+    /// The associated screen
+    var screenType: Any.Type {
+        TemplateSimpleScreen.self
+    }
+    
+    /// A list of screen state definitions
+    static var allCases: [MockTemplateSimpleScreenScreenState] {
+        // Each of the presence statuses
+        TemplateSimpleScreenPromptType.allCases.map(MockTemplateSimpleScreenScreenState.promptType)
+    }
+    
+    /// Generate the view struct for the screen state.
+    var screenView: ([Any], AnyView) {
+        let promptType: TemplateSimpleScreenPromptType
+        switch self {
+        case .promptType(let type):
+            promptType = type
+        }
+        let viewModel = TemplateSimpleScreenViewModel(promptType: promptType)
+        
+        // can simulate service and viewModel actions here if needs be.
+        
+        return (
+            [promptType, viewModel],
+            AnyView(TemplateSimpleScreen(viewModel: viewModel.context)
+                .addDependency(MockAvatarService.example))
+        )
+    }
+}

ElementX/Sources/Screens/Templates/SimpleScreenExample/TemplateSimpleScreenModels.swift

@@ -0,0 +1,67 @@
+// 
+// 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: - Coordinator
+
+enum TemplateSimpleScreenPromptType {
+    case regular
+    case upgrade
+}
+
+extension TemplateSimpleScreenPromptType: Identifiable, CaseIterable {
+    var id: Self { self }
+    
+    var title: String {
+        switch self {
+        case .regular:
+            return VectorL10n.roomCreationMakePublicPromptTitle
+        case .upgrade:
+            return VectorL10n.roomDetailsHistorySectionPromptTitle
+        }
+    }
+    
+    var image: ImageAsset {
+        switch self {
+        case .regular:
+            return Asset.Images.appSymbol
+        case .upgrade:
+            return Asset.Images.keyVerificationSuccessShield
+        }
+    }
+}
+
+// MARK: View model
+
+enum TemplateSimpleScreenViewModelResult {
+    case accept
+    case cancel
+}
+
+// MARK: View
+
+struct TemplateSimpleScreenViewState: BindableState {
+    var promptType: TemplateSimpleScreenPromptType
+    var count: Int
+}
+
+enum TemplateSimpleScreenViewAction {
+    case incrementCount
+    case decrementCount
+    case accept
+    case cancel
+}

ElementX/Sources/Screens/Templates/SimpleScreenExample/TemplateSimpleScreenViewModel.swift

@@ -0,0 +1,54 @@
+//
+// 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
+
+@available(iOS 14, *)
+typealias TemplateSimpleScreenViewModelType = StateStoreViewModel<TemplateSimpleScreenViewState,
+                                                                  Never,
+                                                                  TemplateSimpleScreenViewAction>
+@available(iOS 14, *)
+class TemplateSimpleScreenViewModel: TemplateSimpleScreenViewModelType, TemplateSimpleScreenViewModelProtocol {
+
+    // MARK: - Properties
+
+    // MARK: Private
+
+    // MARK: Public
+
+    var completion: ((TemplateSimpleScreenViewModelResult) -> Void)?
+
+    // MARK: - Setup
+
+    init(promptType: TemplateSimpleScreenPromptType, initialCount: Int = 0) {
+        super.init(initialViewState: TemplateSimpleScreenViewState(promptType: promptType, count: 0))
+    }
+
+    // MARK: - Public
+
+    override func process(viewAction: TemplateSimpleScreenViewAction) {
+        switch viewAction {
+        case .accept:
+            completion?(.accept)
+        case .cancel:
+            completion?(.cancel)
+        case .incrementCount:
+            state.count += 1
+        case .decrementCount:
+            state.count -= 1
+        }
+    }
+}

ElementX/Sources/Screens/Templates/SimpleScreenExample/TemplateSimpleScreenViewModelProtocol.swift

@@ -0,0 +1,24 @@
+// 
+// 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
+
+protocol TemplateSimpleScreenViewModelProtocol {
+    
+    var completion: ((TemplateSimpleScreenViewModelResult) -> Void)? { get set }
+    @available(iOS 14, *)
+    var context: TemplateSimpleScreenViewModelType.Context { get }
+}

ElementX/Sources/Screens/Templates/SimpleScreenExample/Test/UI/TemplateSimpleScreenUITests.swift

@@ -0,0 +1,45 @@
+//
+// 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 XCTest
+import RiotSwiftUI
+
+@available(iOS 14.0, *)
+class TemplateSimpleScreenUITests: MockScreenTest {
+
+    override class var screenType: MockScreenState.Type {
+        return MockTemplateSimpleScreenScreenState.self
+    }
+
+    override class func createTest() -> MockScreenTest {
+        return TemplateSimpleScreenUITests(selector: #selector(verifyTemplateSimpleScreenScreen))
+    }
+
+    func verifyTemplateSimpleScreenScreen() throws {
+        guard let screenState = screenState as? MockTemplateSimpleScreenScreenState else { fatalError("no screen") }
+        switch screenState {
+        case .promptType(let promptType):
+            verifyTemplateSimpleScreenPromptType(promptType: promptType)
+        }
+    }
+    
+    func verifyTemplateSimpleScreenPromptType(promptType: TemplateSimpleScreenPromptType) {
+        let title = app.staticTexts["title"]
+        XCTAssert(title.exists)
+        XCTAssertEqual(title.label, promptType.title)
+    }
+
+}

ElementX/Sources/Screens/Templates/SimpleScreenExample/Test/Unit/TemplateSimpleScreenViewModelTests.swift

@@ -0,0 +1,49 @@
+// 
+// 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 XCTest
+
+@testable import RiotSwiftUI
+
+@available(iOS 14.0, *)
+class TemplateSimpleScreenViewModelTests: XCTestCase {
+    private enum Constants {
+        static let counterInitialValue = 0
+    }
+    
+    var viewModel: TemplateSimpleScreenViewModelProtocol!
+    var context: TemplateSimpleScreenViewModelType.Context!
+    
+    override func setUpWithError() throws {
+        viewModel = TemplateSimpleScreenViewModel(promptType: .regular, initialCount: Constants.counterInitialValue)
+        context = viewModel.context
+    }
+
+    func testInitialState() {
+        XCTAssertEqual(context.viewState.count, Constants.counterInitialValue)
+    }
+
+    func testCounter() throws {
+        context.send(viewAction: .incrementCount)
+        XCTAssertEqual(context.viewState.count, 1)
+        
+        context.send(viewAction: .incrementCount)
+        XCTAssertEqual(context.viewState.count, 2)
+        
+        context.send(viewAction: .decrementCount)
+        XCTAssertEqual(context.viewState.count, 1)
+    }
+}

ElementX/Sources/Screens/Templates/SimpleScreenExample/View/TemplateSimpleScreen.swift

@@ -0,0 +1,113 @@
+// 
+// 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
+
+@available(iOS 14.0, *)
+struct TemplateSimpleScreen: View {
+
+    // MARK: - Properties
+    
+    // MARK: Private
+    
+    @Environment(\.theme) private var theme
+    @Environment(\.horizontalSizeClass) private var horizontalSizeClass
+    
+    private var horizontalPadding: CGFloat {
+        horizontalSizeClass == .regular ? 50 : 16
+    }
+    
+    // MARK: Public
+    
+    @ObservedObject var viewModel: TemplateSimpleScreenViewModel.Context
+    
+    // MARK: Views
+    
+    var body: some View {
+        GeometryReader { geometry in
+            VStack {
+                ScrollView(showsIndicators: false) {
+                    mainContent
+                        .padding(.top, 50)
+                        .padding(.horizontal, horizontalPadding)
+                }
+                
+                buttons
+                    .padding(.horizontal, horizontalPadding)
+                    .padding(.bottom, geometry.safeAreaInsets.bottom > 0 ? 0 : 16)
+            }
+        }
+        .background(theme.colors.background.ignoresSafeArea())
+        .accentColor(theme.colors.accent)
+    }
+    
+    /// The main content of the view to be shown in a scroll view.
+    var mainContent: some View {
+        VStack(spacing: 36) {
+            Text(viewModel.viewState.promptType.title)
+                .font(theme.fonts.title1B)
+                .foregroundColor(theme.colors.primaryContent)
+                .accessibilityIdentifier("title")
+            
+            Image(viewModel.viewState.promptType.image.name)
+                .resizable()
+                .scaledToFit()
+                .frame(width: 100)
+                .foregroundColor(theme.colors.accent)
+            
+            HStack {
+                Text("Counter: \(viewModel.viewState.count)")
+                    .foregroundColor(theme.colors.primaryContent)
+                
+                Button("-") {
+                    viewModel.send(viewAction: .decrementCount)
+                }
+                
+                Button("+") {
+                    viewModel.send(viewAction: .incrementCount)
+                }
+            }
+            .font(theme.fonts.title3)
+        }
+    }
+    
+    /// The action buttons shown at the bottom of the view.
+    var buttons: some View {
+        VStack {
+            Button { viewModel.send(viewAction: .accept) } label: {
+                Text("Accept")
+                    .font(theme.fonts.bodySB)
+            }
+            .buttonStyle(PrimaryActionButtonStyle())
+            
+            Button { viewModel.send(viewAction: .cancel) } label: {
+                Text("Cancel")
+                    .font(theme.fonts.body)
+                    .padding(.vertical, 12)
+            }
+        }
+    }
+}
+
+// MARK: - Previews
+
+@available(iOS 14.0, *)
+struct TemplateSimpleScreen_Previews: PreviewProvider {
+    static let stateRenderer = MockTemplateSimpleScreenScreenState.stateRenderer
+    static var previews: some View {
+        stateRenderer.screenGroup()
+    }
+}