func createCertificateIdAndStoreinNSUserDefaults()

in IoT-Sample/Swift/IoTSampleSwift/ConnectionViewController.swift [189:235]
42 lines of code
3 McCabe index (conditional complexity)

    func createCertificateIdAndStoreinNSUserDefaults(onSuccess:  @escaping (String)->Void,
                                                     onFailure: @escaping (Error) -> Void) {
        let defaults = UserDefaults.standard
        // Now create and store the certificate ID in NSUserDefaults
        let csrDictionary = [ "commonName": CertificateSigningRequestCommonName,
                              "countryName": CertificateSigningRequestCountryName,
                              "organizationName": CertificateSigningRequestOrganizationName,
                              "organizationalUnitName": CertificateSigningRequestOrganizationalUnitName]
        
        self.iotManager.createKeysAndCertificate(fromCsr: csrDictionary) { (response) -> Void in
            guard let response = response else {
                DispatchQueue.main.async {
                    self.connectButton.isEnabled = true
                    self.activityIndicatorView.stopAnimating()
                    self.logTextView.text = "Unable to create keys and/or certificate, check values in Constants.swift"
                }
                onFailure(NSError(domain: "No response on iotManager.createKeysAndCertificate", code: -2, userInfo: nil))
                return
            }
            defaults.set(response.certificateId, forKey:"certificateId")
            defaults.set(response.certificateArn, forKey:"certificateArn")
            let certificateId = response.certificateId
            print("response: [\(String(describing: response))]")
            
            let attachPrincipalPolicyRequest = AWSIoTAttachPrincipalPolicyRequest()
            attachPrincipalPolicyRequest?.policyName = POLICY_NAME
            attachPrincipalPolicyRequest?.principal = response.certificateArn
            
            // Attach the policy to the certificate
            self.iot.attachPrincipalPolicy(attachPrincipalPolicyRequest!).continueWith (block: { (task) -> AnyObject? in
                if let error = task.error {
                    print("Failed: [\(error)]")
                    onFailure(error)
                } else  {
                    print("result: [\(String(describing: task.result))]")
                    DispatchQueue.main.asyncAfter(deadline: .now()+2, execute: {
                        if let certificateId = certificateId {
                            onSuccess(certificateId)
                        } else {
                            onFailure(NSError(domain: "Unable to generate certificate id", code: -1, userInfo: nil))
                        }
                    })
                }
                return nil
            })
        }
    }