MESSENGER-5271 crosssigning - add alert and better strings, only show button when usable

Riot/Modules/KeyVerification/Device/SelfVerifyWait/KeyVerificationSelfVerifyWaitViewModel.swift

@@ -83,6 +83,18 @@ final class KeyVerificationSelfVerifyWaitViewModel: KeyVerificationSelfVerifyWai
         }
     }
     
+    // bwi: only show corsssigning button when there is more than one device in your account
+    func checkCrosssigningDevices() {
+        self.session.matrixRestClient.devices { [weak self] response in
+            switch response {
+            case .success(let devices):
+                self?.update(viewState: .crosssigningPossible(devices.count > 1))
+            case .failure:
+                break
+            }
+        }
+    }
+    
     // MARK: - Private
     
     private func loadData() {
@@ -258,6 +270,8 @@ final class KeyVerificationSelfVerifyWaitViewModel: KeyVerificationSelfVerifyWai
         }
         
         if keyVerificationRequest.state == MXKeyVerificationRequestStateReady {
+            self.update(viewState: .verificationAccepted)
+            
             self.unregisterKeyVerificationRequestChangeNotification()
             self.coordinatorDelegate?.keyVerificationSelfVerifyWaitViewModel(self,
                                                                              didAcceptKeyVerificationRequest: keyVerificationRequest)