AuthenticatorViewModel.kt

class AuthenticatorViewModel(private val identityRepository: IdentityRepository) : ViewModel() {
    /**
     * Current user record, or null if the user is not logged in
     */
    val currentUser: LiveData<User?> = identityRepository.currentUser

    /**
     * Stored user name, or null if the user has never logged in
     */
    val storedUsername: LiveData<String?> = identityRepository.storedUsername

    /**
     * Initiate each flow in the authentication process
     */
    fun initiateSignin(handler: IdentityHandler) = identityRepository.initiateSignin(handler)
    fun initiateSignup(handler: IdentityHandler) = identityRepository.initiateSignup(handler)
    fun initiateForgotPassword(handler: IdentityHandler) = identityRepository.initiateForgotPassword(handler)

    /**
     * The sign-out process doesn't need to do anything other than complete as the
     * process should either fail or be successful, in which case the currentUser
     * will either update or not.
     */
    fun signOut() = identityRepository.initiateSignout { _, _, _ -> run { /* Do Nothing */ }}

    /**
     * Update the stored username
     */
    fun updateStoredUsername(username: String?) = identityRepository.updateStoredUsername(username)
}