在ios swift中使用云firestore进行电话身份验证?

在我的应用程序中,我使用电话身份验证进行登录,并将用户登录的用户电话号码和uid存储在数据库中。当使用现有用户电话号码登录时,它会创建具有相同uid和电话号码的新文档id,您可以查看图像1和3。

这是我用来登录的代码,如果用户存在,意味着它应该检查并导航到主控制器,否则请签署用户详细信息控制器。

     @IBAction func loginbtn(_ sender: UIButton) {

    let defaults = UserDefaults.standard
    let credential: PhoneAuthCredential = PhoneAuthProvider.provider().credential(withVerificationID: defaults.string(forKey: "authVID")!,
                                                                                  verificationCode: otpText.text!)
    Auth.auth().signIn(with: credential)
    {
        (user, error) in
        if error != nil
        {
            print("error: \(String(describing: error?.localizedDescription))")
        }
        else if user != nil
        {


            print("Phone number: \(String(describing: user?.phoneNumber))")
            let userInfo = user?.providerData[0]
            print("Provider ID: \(String(describing: userInfo?.providerID))")

            let currentUser = Auth.auth().currentUser?.uid
            var ref: DocumentReference? = nil


            ref = self.db.collection("Users").addDocument(data: [
                                    "phoneNumber"   : user?.phoneNumber as Any,
                                    "UID"           : user?.uid as Any

                                ]) { err in
                                    if let err = err {

                                        print("Error adding document: \(err)")

                                    } else {

                                        print("Document added with ID: \(ref!.documentID)")

                                    }
                                }

            let storyboard = UIStoryboard(name: "Main", bundle: nil)
            let controller = storyboard.instantiateViewController(withIdentifier: "HomeViewController")
            self.present(controller, animated: true, completion: nil)


        } else {




            }


        }

    }

有谁能帮我摆脱这一切,我几乎在挣扎过去的一天!!!