Auto-assign custom Group to new WooCommerce customers

auto-assign-customers.php

// When working with both WooCommerce and Groups plugins, I needed a way to auto-assign
// users with the Customer role to a specific group, separate from the default Registered group.

$AUTO_ASSIGNED_GROUP_NAME = 'General';
function my__edit_user_created_user( $user_id ) {

	$user  = get_userdata( $user_id );
	$roles = empty( $user->roles ) ? array() : $user->roles;
	if ( in_array( 'customer', $roles ) ) {

		$existing = my__get_users_groups( $user_id );
		if ( empty( $existing ) || count( $existing ) < 2 ) { // ignore if only Registered
			$default_group = Groups_Group::read_by_name( $AUTO_ASSIGNED_GROUP_NAME );
			if ( $default_group ) {
				$default_group_id = $default_group->group_id;
			}
			if ( $default_group_id ) {
				Groups_User_Group::create(
					array(
						'user_id'  => $user_id,
						'group_id' => $default_group_id
					)
				);
			}
		}
	}

}

function my__get_users_groups( $user_id ) {
	global $wpdb;
	$result = false;

	$user_group_table = _groups_get_tablename( 'user_group' );
	$user_groups      = $wpdb->get_row( $wpdb->prepare(
		"SELECT * FROM $user_group_table WHERE user_id = %d",
		Groups_Utility::id( $user_id )
	) );
	if ( $user_groups !== null ) {
		$result = $user_groups;
	}

	return $result;
}
add_action( 'edit_user_created_user', 'my__edit_user_created_user', 100, 1 );