iOS link two firebase account

Question

I'm trying to link two firebase accounts, usually the user would be logged in with social media or email or anonmus account and then a user would sign in with phone. I need to link these two accounts.

parent view

a function in the parent view would be called to sign up with phone number

class welcomeView: UIViewController, FUIAuthDelegate {

 //stores current user
 var previosUser = FIRUser()


 override func viewDidLoad() {
    super.viewDidLoad()
  if let user = Auth.auth().currentUser {
        previosUser = user 
    }else{
        Auth.auth().signInAnonymously() { (user, error) in

            if error != nil {
                //handle error
            }
            previosUser = user!
        }
    }

 }






 func signUpWithPhone(){ 
    let vc = signUpWithPhoneView()
    vc.authUI?.delegate = self
    vc.auth?.languageCode = "ar"
    self.present(vc, animated: true) 

  }


}

in the child view (signUpWithPhoneView) I present the FUIPhoneAuth

phoneProvider.signIn(withPresenting: self)

child view

import UIKit
import FirebaseAuthUI
import FirebasePhoneAuthUI

class signUpWithPhoneView: UIViewController {

 fileprivate(set) var authUI = FUIAuth.defaultAuthUI()
 var didload = false

 override func viewDidLoad() {
    super.viewDidLoad()
 }


 override func viewWillAppear(_ animated: Bool) {
    if !didload { // stops from looping 
        didload = !didload

        guard let authUI = self.authUI else {return}
        let phoneProvider = FUIPhoneAuth.init(authUI: authUI)
        self.authUI?.providers = [phoneProvider] 
     >> phoneProvider.signIn(withPresenting: self)

    }
 }


}

when the user signs in, the child view will be dismissed automatically and I have didSignInWith function that will be Called in the parents view. I need to link the previous user account and the user phone account

parent view

    func authUI(_ authUI: FUIAuth, didSignInWith user: FirebaseAuth.User?, error: Error?) {

    if let user = user{

        // link the the two accounts

    }else{

    }

}

I tried to link by using

        let provider = PhoneAuthProvider.provider(auth: authUI.auth!)
        let credential = PhoneAuthProvider.credential(provider)


        previosUser.link(with: credential, completion: { (user, error) in
            if error != nil {
                print("this is linking two acounts error : " , error)
            }
        })

but there was error in credential

in ...previosUser.link(with: *credential*, completion: ...

Cannot convert value of type '(String, String) -> PhoneAuthCredential' to expected 
argument type 'AuthCredential'

any help would be appreciated thanks

Answer 1

You are getting the provider with authUI.auth and then not using it to get the credential and you are currently using the static reference of the instance method credential .

The instance method itself takes two strings and returns an AuthCredential which is why you're seeing (String, String) -> AuthCredential . You must create the credential using a verification ID and code that you must collect from the user.

guard let auth = authUI.auth else { return }

let provider = PhoneAuthProvider.provider(auth: auth)
let credential = provider.credential(
   withVerificationID: "XXXXXXXXXXXX", 
   verificationCode: "XXXXXX"
)

// ...