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

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)
+    }
+}