Add chat example

RiotSwiftUI/Modules/Template/TemplateAdvancedRoomsExample/TemplateRoomList/ViewModel/TemplateRoomListViewModel.swift

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+// 
+// 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
+    
+@available(iOS 14.0, *)
+class TemplateRoomListViewModel: ObservableObject, TemplateRoomListViewModelProtocol {
+    
+    // MARK: - Properties
+    
+    // MARK: Private
+    private let templateRoomListService: TemplateRoomListServiceProtocol
+    private var cancellables = Set<AnyCancellable>()
+    
+    // MARK: Public
+    @Published private(set) var viewState: TemplateRoomListViewState
+    
+    var completion: ((TemplateRoomListViewModelResult) -> Void)?
+    
+    // MARK: - Setup
+    init(templateRoomListService: TemplateRoomListServiceProtocol, initialState: TemplateRoomListViewState? = nil) {
+        self.templateRoomListService = templateRoomListService
+        self.viewState = initialState ?? Self.defaultState(templateRoomListService: templateRoomListService)
+        
+        templateRoomListService.roomsSubject
+            .map(TemplateRoomListStateAction.updateRooms)
+            .receive(on: DispatchQueue.main)
+            .sink(receiveValue: { [weak self] action in
+                self?.dispatch(action:action)
+            })
+            .store(in: &cancellables)
+    }
+    
+    private static func defaultState(templateRoomListService: TemplateRoomListServiceProtocol) -> TemplateRoomListViewState {
+        return TemplateRoomListViewState(rooms: templateRoomListService.roomsSubject.value)
+    }
+    
+    // MARK: - Public
+    func process(viewAction: TemplateRoomListViewAction) {
+        switch viewAction {
+        case .cancel:
+            cancel()
+        case .done:
+            done()
+        }
+    }
+    
+    // MARK: - Private
+    /**
+     Send state actions to mutate the state.
+     */
+    private func dispatch(action: TemplateRoomListStateAction) {
+        Self.reducer(state: &self.viewState, action: action)
+    }
+    
+    /**
+     A redux style reducer, all modifications to state happen here. Receives a state and a state action and produces a new state.
+     */
+    private static func reducer(state: inout TemplateRoomListViewState, action: TemplateRoomListStateAction) {
+        switch action {
+        case .updateRooms(let rooms):
+            state.rooms = rooms
+        }
+        UILog.debug("[TemplateRoomListViewModel] reducer with action \(action) produced state: \(state)")
+    }
+    
+    private func done() {
+        completion?(.done)
+    }
+    
+    private func cancel() {
+        completion?(.cancel)
+    }
+}

RiotSwiftUI/Modules/Template/TemplateAdvancedRoomsExample/TemplateRoomList/ViewModel/TemplateRoomListViewModelProtocol.swift

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+// 
+// 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 TemplateRoomListViewModelProtocol {
+    var completion: ((TemplateRoomListViewModelResult) -> Void)? { get set }
+}