Check User Credentials at Launch (Sign In With Apple) with SwiftUI - swiftui

Question

I just implemented Sign In With Apple in my SwiftUI App using the examples I found on the web.
Works great but I have a very important question: Where should I do the Check if the user is validated or not?
I have a function checkUserAuth() that returns 3 states: undefined, signedOut and signedIn. Based on each one of those returns, I want to open a different View.
self.signInWithAppleManager.checkUserAuth { (authenticationState) in
switch authenticationState {
case .undefined:
print("AuthenticationState: .undefined")
case .signedOut:
print("AuthenticationState: .signedOut")
case .signedIn:
print("AuthenticationState: .signedIn")
}
}
If my function returns .undefined or .signedOut, I want to open the LoginView.swift. If the function returns .signIn, I want to open the MainView.swift.
Where should I make this Check?
Should I do that on the SceneDelegate.swift and show the right View or should a have a View responsible to make this validation and "navigate" to the right view?
Thanks I hope I could explain my problem.

Answer 1

My fast solution suggests to persist this state in some #Published var and check it in the needed view. It does not looks good, maybe better create checking functions somewhere else (like viewModel), but I think it will direct you to the right way:
import SwiftUI
import Combine
final class SingSingInWithAppleManager: ObservableObject {
#Published var userAuthState: UserAuthInAppleState
init() { // here you can check auth status
userAuthState = .undefined
}
func logIn() {
// here you're making login in and change status
userAuthState = .signedIn
}
}
enum UserAuthInAppleState {
case undefined
case signedOut
case signedIn
}
struct SingInWithAppleExample: View {
#EnvironmentObject var signInWithAppleManager: SingSingInWithAppleManager
var body: some View {
ZStack {
if signInWithAppleManager.userAuthState == .undefined {
Button(action:
{
self.signInWithAppleManager.logIn()
}) {
Text("Login in!")
}
} else {
Text("singed in!")
}
}
}
}
// MARK: how to make it with animation
struct SingInWithAppleExample: View {
#EnvironmentObject var signInWithAppleManager: SingSingInWithAppleManager
var body: some View {
ZStack {
Button(action:
{
withAnimation {
self.signInWithAppleManager.logIn()
}
}) {
Text("Login in!")
}
.opacity(signInWithAppleManager.userAuthState == .undefined ? 1 : 0)
Text("singed in!")
.opacity(signInWithAppleManager.userAuthState == .signedIn ? 1 : 0)
}
}
}
I think you should set this manager in the SceneDelegate func if it's the first thing you want to show. Here is PreviewProvider example:
struct SingInWithAppleExample_Previews: PreviewProvider {
static var previews: some View {
SingInWithAppleExample()
.environmentObject(SingSingInWithAppleManager()) // only add this line of code
}
}
P.S can you share "examples you found on the web" please, soon I'll need to implement it too