KeyVerification: Add new QR code confirmation screen.

Riot/Modules/KeyVerification/Common/ScanConfirmation/KeyVerificationScanConfirmationViewModel.swift

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+// File created from ScreenTemplate
+// $ createScreen.sh KeyVerification/Common/ScanConfirmation KeyVerificationScanConfirmation
+/*
+ Copyright 2020 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
+
+final class KeyVerificationScanConfirmationViewModel: KeyVerificationScanConfirmationViewModelType {
+    
+    // MARK: - Properties
+    
+    // MARK: Private
+
+    private let session: MXSession
+    private let transaction: MXQRCodeTransaction
+    private let codeScanning: KeyVerificationScanning
+    private let verificationKind: KeyVerificationKind
+    
+    private var isScanning: Bool {
+        if case .scannedOtherQRCode = self.codeScanning {
+            return true
+        }
+        return false
+    }
+    
+    // MARK: Public
+
+    weak var viewDelegate: KeyVerificationScanConfirmationViewModelViewDelegate?
+    weak var coordinatorDelegate: KeyVerificationScanConfirmationViewModelCoordinatorDelegate?
+    
+    // MARK: - Setup
+    
+    init(session: MXSession,
+         transaction: MXQRCodeTransaction,
+         codeScanning: KeyVerificationScanning,
+         verificationKind: KeyVerificationKind) {
+        self.session = session
+        self.transaction = transaction
+        self.codeScanning = codeScanning
+        self.verificationKind = verificationKind
+    }
+    
+    deinit {
+    }
+    
+    // MARK: - Public
+    
+    func process(viewAction: KeyVerificationScanConfirmationViewAction) {
+        switch viewAction {
+        case .loadData:
+            self.loadData()
+        case .acknowledgeOtherScannedMyCode(let otherHasScannedMyCode):
+            self.transaction.otherUserScannedMyQrCode(otherHasScannedMyCode)
+            if otherHasScannedMyCode == false {                self.coordinatorDelegate?.keyVerificationScanConfirmationViewModelDidCancel(self)
+            } else {
+                self.update(viewState: .loading)
+            }
+        case .cancel:
+            self.cancel()
+        }
+    }
+    
+    // MARK: - Private
+    
+    private func loadData() {
+        let otherUserId = self.transaction.otherUserId
+        let otherUser = self.session.user(withUserId: otherUserId)
+        let otherDisplayName = otherUser?.displayname ?? otherUserId
+        
+        let viewData = KeyVerificationScanConfirmationViewData(isScanning: self.isScanning, verificationKind: self.verificationKind, otherDisplayName: otherDisplayName)
+        self.update(viewState: .loaded(viewData))
+        
+        self.registerTransactionDidStateChangeNotification()
+        
+        if case .scannedOtherQRCode(let qrCodeData) = self.codeScanning {
+            self.transaction.userHasScannedOtherQrCodeData(qrCodeData)
+        }
+    }
+    
+    private func update(viewState: KeyVerificationScanConfirmationViewState) {
+        self.viewDelegate?.keyVerificationScanConfirmationViewModel(self, didUpdateViewState: viewState)
+    }
+    
+    private func cancel() {
+        self.transaction.cancel(with: MXTransactionCancelCode.user())
+        self.coordinatorDelegate?.keyVerificationScanConfirmationViewModelDidCancel(self)
+    }
+    
+    // MARK: - MXKeyVerificationTransactionDidChange
+    
+    private func registerTransactionDidStateChangeNotification() {
+        NotificationCenter.default.addObserver(self, selector: #selector(transactionDidStateChange(notification:)), name: .MXKeyVerificationTransactionDidChange, object: self.transaction)
+    }
+    
+    private func unregisterTransactionDidStateChangeNotification() {
+        NotificationCenter.default.removeObserver(self, name: .MXKeyVerificationTransactionDidChange, object: nil)
+    }
+    
+    @objc private func transactionDidStateChange(notification: Notification) {
+        guard let transaction = notification.object as? MXQRCodeTransaction else {
+            return
+        }
+
+        switch transaction.state {
+        case .verified:
+            self.unregisterTransactionDidStateChangeNotification()
+            self.coordinatorDelegate?.keyVerificationScanConfirmationViewModelDidComplete(self)
+        case .cancelled:
+            guard let reason = transaction.reasonCancelCode else {
+                return
+            }
+            self.unregisterTransactionDidStateChangeNotification()
+            self.update(viewState: .cancelled(reason))
+        case .cancelledByMe:
+            guard let reason = transaction.reasonCancelCode else {
+                return
+            }
+            self.unregisterTransactionDidStateChangeNotification()
+            self.update(viewState: .cancelledByMe(reason))
+        default:
+            break
+        }
+    }
+}