function bp_members_invitations_complete_signup( $user_id, $user_login = '', $user_password = '', $user_email = '' ) {
	if ( ! $user_id ) {
		return;
	}

	// Check to see if this signup is the result of a valid invitation.
	$invite = bp_get_members_invitation_from_request();
	if ( ! $invite->id ) {
		return;
	}

	// Accept the invitation.
	$invites_class = new BP_Members_Invitation_Manager();
	$args          = array(
		'id' => $invite->id,
	);
	$invites_class->accept_invitation( $args );

	// User has already verified their email by responding to the invitation, so we can activate.
	$key = bp_get_user_meta( $user_id, 'activation_key', true );
	if ( $key ) {
		/**
		 * Filters the activation signup.
		 *
		 * @since 1.1.0
		 *
		 * @param bool|int $value Value returned by activation.
		 *                        Integer on success, boolean on failure.
		 */
		$user = apply_filters( 'bp_core_activate_account', bp_core_activate_signup( $key ) );

		// If there were errors, add a message and redirect.
		if ( ! empty( $user->errors ) ) {
			bp_core_add_message( $user->get_error_message(), 'error' );
			bp_core_redirect( trailingslashit( bp_get_root_domain() . '/' . $bp->pages->activate->slug ) );
		}

		bp_core_add_message( __( 'Your account is now active!', 'buddypress' ) );
		bp_core_redirect( add_query_arg( 'activated', '1', bp_get_activation_page() ) );
	}
}