Best approach to define models on a flutter firebase application - firebase

Question

First let me give you a little bit of context. I'm currently working on a Flutter app using firebase. This is the first app that I make using firebase as a backend for flutter. So, I'm looking for recommendations of which would be the best approach.
First, I have the next model which I use to register a new user into my app.
class user {
String userName;
String firstName;
String lastName;
String password;
String email;
}
My doubt comes when I make the process, so my user can sign up into my app. I want to retrieve my user's ID (document id) from firebase.
Because my app bases on interactions between users. So, when user A sends a request to user B, user B muss be able to see that request, so I need a way to store those request between users on a collection and I plan to use the ID of my users to store those relations between users.
So, would you recommend me to create two separate models like the next two?
One for a new user that just signed in, and another one for a user which signs up.
class newUser {
String userName;
String firstName;
String lastName;
String password;
String email;
}
class registeredUser {
String userID;
}
Or create just a single model like this? And when the user logs in, just store his/her userID (I don't use the other fields in most of my application screens, just when the user wants to change his/her profile.)
class user {
String userID;
String userName;
String firstName;
String lastName;
String password;
String email;
}
I ask this question, because I want to create a maintainable and scalable app.
So, what would you recommend me? Or do you have any other suggestion?

Answer 1

I suggest you use only one model for the user
class User {
String uid;
String userName;
String firstName;
String lastName;
String email;
}
P.S notice the capitalized class name, that's the dart way.
Using the above model would ensure that you don't store plaintext password in firestore which improves the overall data security of your app.