func showLogin()

in Example/AmazonFreeRTOSDemo/AmazonFreeRTOSDemo/DevicesViewController.swift [77:125]
34 lines of code
5 McCabe index (conditional complexity)

    func showLogin() {
        AWSMobileClient.default().initialize { userState, error in

            // initialize error

            if let error = error {
                DispatchQueue.main.async {
                    Alertift.alert(title: NSLocalizedString("Error", comment: String()), message: error.localizedDescription)
                        .action(.default(NSLocalizedString("OK", comment: String())))
                        .show(on: self)
                }
                return
            }

            // process userState

            guard let navigationController = self.navigationController, let userState = userState else {
                return
            }

            switch userState {

            case .signedIn:
                self.attachPrincipalPolicy()

            case .signedOut:

                let signInUIOptions = SignInUIOptions(canCancel: false, logoImage: #imageLiteral(resourceName: "common_logo"), backgroundColor: UIColor(named: "teal_color"))
                AWSMobileClient.default().showSignIn(navigationController: navigationController, signInUIOptions: signInUIOptions) { _, error in

                    // signin error

                    if let error = error {
                        DispatchQueue.main.async {
                            Alertift.alert(title: NSLocalizedString("Error", comment: String()), message: error.localizedDescription)
                                .action(.default(NSLocalizedString("OK", comment: String())))
                                .show(on: self)
                        }
                        return
                    }

                    self.attachPrincipalPolicy()
                }

            default:
                AWSMobileClient.default().signOut()
            }
        }
    }