Swift 5 & Firebase: Creating a shared sign in and sign-out button - swift

Question

I thought I'd return to StackOverflow with another question because you guys helped me significantly with my last issue
Anyway, I currently have my authentication system setup so that the sign in and signup button are shared. I am looking to have firebase reference storage when an email is entered to have it checked against other accounts in the database. As of right now, a user can enter an email address for their account and then if they enter the wrong password it just sends them right to the sign up even though they currently have an account. This is a serious problem as it will cause confusion
I want it to work like so:
If the email address is taken, I want an alert to be displayed for the user says "Incorrect password"
If the email address is not taken, I want it to tell the user that they need to enter a password with at least 10 characters, 1 number, and 1 special character, which I have already figured out using
I only want it to segue to create a new user if the email is not taken and the password and email field meet the criteria fields that I have already set within my code. I just need help preventing it from switching to the create new user VC if the email is already taken, and I need to to say
func isValidPassword(_ email: String) -> Bool {
let emailRegEx = "##$%^&+=^.*(?=.{10,})(?=.*d)(?=.*[a-z])(?=.*[A-Z])(?=.*[##$%^&+=]).*$"
let emailPred = NSPredicate(format:"SELF MATCHES %#", emailRegEx)
return emailPred.evaluate(with: email)
}
Anyway, here is the code so far attached to the IBAction
if let email = emailField.text, let password = passwordField.text {
Auth.auth().signIn(withEmail: email, password: password, completion:
{ (user,error) in
if error == nil {
if let user = user {
self.userUid = user.user.uid
self.goToFeedVC()
}
} else {
self.goToCreateUserVC()
Here is a picture of the interface
I want it to be intuitive but I have been unable to code this myself so if anyone is able to help advise me on how to finish this block it would be incredibly appreciated

Answer 1

Firebase gives pretty detailed error responses for their Auth call:
So you can check to see what the error is inside of your call:
Below are the two error that they give (I only added the two scenarios that you mentioned)
Description: The password is invalid or the user does not have a password.
FIRAuthErrorUserInfoNameKey: ERROR_WRONG_PASSWORD
&
There is no user record corresponding to this identifier. The user may have been deleted.
FIRAuthErrorUserInfoNameKey: ERROR_USER_NOT_FOUND
Auth.auth().signIn(withEmail: email, password: password, completion:
{ (user,error) in
if error == nil {
if let user = user {
self.userUid = user.user.uid
self.goToFeedVC()
}
} else {
guard let error = error?.localizedDescription else { return } // but actually handle this
print(error)
if error == wrong password {
// show alert for email taken/wrong password
} else if error == user doesnt exists {
// self.goToCreateUserVC()
}
}
}
Just replace the if and else if conditions with the actual errors. I'd avoid comparing the strings and use the key/code in case the strings change in the future.
Official list of error codes can be found here
And if you print the full error instead of the error?.localizedDescription you'll get the full details, as can be seen here:
Optional(Error Domain=FIRAuthErrorDomain Code=17011 "There is no user record corresponding to this identifier. The user may have been deleted." UserInfo={NSLocalizedDescription=There is no user record corresponding to this identifier. The user may have been deleted., FIRAuthErrorUserInfoNameKey=ERROR_USER_NOT_FOUND})