WordPress - create unique username by provided email

username-by-email.php

<?php 

function create_unique_user_name_by_email ($email) {
  $email_name = explode( '@', $email );

  if ( ! get_user_by( 'login', $email_name[0] ) ) {
    $username = $email_name[0];
  } else {
    $username = uniqid( $email_name[0], false );
  }
}