Custom Auth using AWS Cognito, Swift - swift

Question

I am trying to use AWS Cognito for password less signin/signup using mobile number.
Signin/Signup steps:
User submits only mobile number
After receiving the passcode via sms, the user submits that to signin/signup.
To achieve the above, as there is no example code for mobile number only Signin, I am trying to amend the standard sign up (email, password) code shown in this aws sdk github example.
Can someone please advice what changes are to be made to achieve signin via mobile number only (no e-mail or username).
import Foundation
import AWSCognitoIdentityProvider
class SignUpViewController: UIViewController {
var pool: AWSCognitoIdentityUserPool?
var sentTo: String?
#IBOutlet weak var username: UITextField!
#IBOutlet weak var password: UITextField!
#IBOutlet weak var phone: UITextField!
#IBOutlet weak var email: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
self.pool = AWSCognitoIdentityUserPool.init(forKey: AWSCognitoUserPoolsSignInProviderKey)
}
override func viewWillAppear(_ animated: Bool) {
self.navigationController?.setNavigationBarHidden(false, animated: false)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let signUpConfirmationViewController = segue.destination as? ConfirmSignUpViewController {
signUpConfirmationViewController.sentTo = self.sentTo
signUpConfirmationViewController.user = self.pool?.getUser(self.username.text!)
}
}
#IBAction func signUp(_ sender: AnyObject) {
guard let userNameValue = self.username.text, !userNameValue.isEmpty,
let passwordValue = self.password.text, !passwordValue.isEmpty else {
let alertController = UIAlertController(title: "Missing Required Fields",
message: "Username / Password are required for registration.",
preferredStyle: .alert)
let okAction = UIAlertAction(title: "Ok", style: .default, handler: nil)
alertController.addAction(okAction)
self.present(alertController, animated: true, completion: nil)
return
}
var attributes = [AWSCognitoIdentityUserAttributeType]()
if let phoneValue = self.phone.text, !phoneValue.isEmpty {
let phone = AWSCognitoIdentityUserAttributeType()
phone?.name = "phone_number"
phone?.value = phoneValue
attributes.append(phone!)
}
if let emailValue = self.email.text, !emailValue.isEmpty {
let email = AWSCognitoIdentityUserAttributeType()
email?.name = "email"
email?.value = emailValue
attributes.append(email!)
}
//sign up the user
self.pool?.signUp(userNameValue, password: passwordValue, userAttributes: attributes, validationData: nil).continueWith {[weak self] (task) -> Any? in
guard let strongSelf = self else { return nil }
DispatchQueue.main.async(execute: {
if let error = task.error as? NSError {
let alertController = UIAlertController(title: error.userInfo["__type"] as? String,
message: error.userInfo["message"] as? String,
preferredStyle: .alert)
let retryAction = UIAlertAction(title: "Retry", style: .default, handler: nil)
alertController.addAction(retryAction)
self?.present(alertController, animated: true, completion: nil)
} else if let result = task.result {
// handle the case where user has to confirm his identity via email / SMS
if (result.user.confirmedStatus != AWSCognitoIdentityUserStatus.confirmed) {
strongSelf.sentTo = result.codeDeliveryDetails?.destination
strongSelf.performSegue(withIdentifier: "confirmSignUpSegue", sender:sender)
} else {
let _ = strongSelf.navigationController?.popToRootViewController(animated: true)
}
}
})
return nil
}
}
}