*/
	private function process_customer( \WP_REST_Request $request ) {
		try {
			if ( $this->should_create_customer_account( $request ) ) {
				$customer_id = $this->create_customer_account(
					$request['billing_address']['email'],
					$request['billing_address']['first_name'],
					$request['billing_address']['last_name']
				);
				// Log the customer in.
				wc_set_customer_auth_cookie( $customer_id );

				// Associate customer with the order.
				$this->order->set_customer_id( $customer_id );
				$this->order->save();
			}
		} catch ( \Exception $error ) {
			switch ( $error->getMessage() ) {
				case 'registration-error-invalid-email':
					throw new RouteException(
						'registration-error-invalid-email',
						__( 'Please provide a valid email address.', 'woocommerce' ),
						400
					);
				case 'registration-error-email-exists':
					throw new RouteException(
						'registration-error-email-exists',
						__( 'An account is already registered with your email address. Please log in before proceeding.', 'woocommerce' ),
						400
					);
			}
		}

		// Persist customer address data to account.
		$this->order_controller->sync_customer_data_with_order( $this->order );
	}

	/**
	 * Check request options and store (shop) config to determine if a user account should be created as part of order
	 * processing.
	 *
	 * @param \WP_REST_Request $request The current request object being handled.
	 * @return boolean True if a new user account should be created.
	 */
	private function should_create_customer_account( \WP_REST_Request $request ) {
		if ( is_user_logged_in() ) {
			return false;
		}

		// Return false if registration is not enabled for the store.
		if ( false === filter_var( wc()->checkout()->is_registration_enabled(), FILTER_VALIDATE_BOOLEAN ) ) {
			return false;
		}

		// Return true if the store requires an account for all purchases. Note - checkbox is not displayed to shopper in this case.
		if ( true === filter_var( wc()->checkout()->is_registration_required(), FILTER_VALIDATE_BOOLEAN ) ) {
			return true;
		}

		// Create an account if requested via the endpoint.
		if ( true === filter_var( $request['create_account'], FILTER_VALIDATE_BOOLEAN ) ) {
			// User has requested an account as part of checkout processing.
			return true;
		}

		return false;
	}

	/**
	 * Create a new account for a customer.
	 *
	 * The account is created with a generated username. The customer is sent
	 * an email notifying them about the account and containing a link to set
	 * their (initial) password.
	 *
	 * Intended as a replacement for wc_create_new_customer in WC core.
	 *
	 * @throws \Exception If an error is encountered when creating the user account.
	 *
	 * @param string $user_email The email address to use for the new account.
	 * @param string $first_name The first name to use for the new account.
	 * @param string $last_name  The last name to use for the new account.
	 *
	 * @return int User id if successful
	 */
	private function create_customer_account( $user_email, $first_name, $last_name ) {
		if ( empty( $user_email ) || ! is_email( $user_email ) ) {
			throw new \Exception( 'registration-error-invalid-email' );
		}

		if ( email_exists( $user_email ) ) {
			throw new \Exception( 'registration-error-email-exists' );
		}

		$username = wc_create_new_customer_username( $user_email );

		// Handle password creation.
		$password           = wp_generate_password();
		$password_generated = true;

		// Use WP_Error to handle registration errors.
		$errors = new \WP_Error();

		/**
		 * Fires before a customer account is registered.
		 *
		 * This hook fires before customer accounts are created and passes the form data (username, email) and an array
		 * of errors.
		 *
		 * This could be used to add extra validation logic and append errors to the array.
		 *
		 * @internal Matches filter name in WooCommerce core.
		 *
		 * @param string $username Customer username.
		 * @param string $user_email Customer email address.
		 * @param \WP_Error $errors Error object.
		 */
		do_action( 'woocommerce_register_post', $username, $user_email, $errors );

		/**
		 * Filters registration errors before a customer account is registered.
		 *
		 * This hook filters registration errors. This can be used to manipulate the array of errors before
		 * they are displayed.
		 *
		 * @internal Matches filter name in WooCommerce core.
		 *
		 * @param \WP_Error $errors Error object.
		 * @param string $username Customer username.
		 * @param string $user_email Customer email address.
		 * @return \WP_Error
		 */
		$errors = apply_filters( 'woocommerce_registration_errors', $errors, $username, $user_email );

		if ( is_wp_error( $errors ) && $errors->get_error_code() ) {
			throw new \Exception( $errors->get_error_code() );
		}

		/**
		 * Filters customer data before a customer account is registered.
		 *
		 * This hook filters customer data. It allows user data to be changed, for example, username, password, email,
		 * first name, last name, and role.
		 *
		 * @param array $customer_data An array of customer (user) data.
		 * @return array
		 */
		$new_customer_data = apply_filters(
			'woocommerce_new_customer_data',
			array(
				'user_login' => $username,
				'user_pass'  => $password,
				'user_email' => $user_email,
				'first_name' => $first_name,
				'last_name'  => $last_name,
				'role'       => 'customer',
				'source'     => 'store-api,',
			)
		);

		$customer_id = wp_insert_user( $new_customer_data );

		if ( is_wp_error( $customer_id ) ) {
			throw $this->map_create_account_error( $customer_id );
		}

		// Set account flag to remind customer to update generated password.
		update_user_option( $customer_id, 'default_password_nag', true, true );

		/**
		 * Fires after a customer account has been registered.
		 *
		 * This hook fires after customer accounts are created and passes the customer data.
		 *
		 * @internal Matches filter name in WooCommerce core.
		 *
		 * @param integer $customer_id New customer (user) ID.
		 * @param array $new_customer_data Array of customer (user) data.
		 * @param string $password_generated The generated password for the account.
		 */
		do_action( 'woocommerce_created_customer', $customer_id, $new_customer_data, $password_generated );

		return $customer_id;
	}

	/**
	 * Convert an account creation error to an exception.
	 *
	 * @param \WP_Error $error An error object.
	 * @return \Exception.
	 */
	private function map_create_account_error( \WP_Error $error ) {
		switch ( $error->get_error_code() ) {
			// WordPress core error codes.
			case 'empty_username':
			case 'invalid_username':
			case 'empty_email':
			case 'invalid_email':
			case 'email_exists':
			case 'registerfail':
				return new \Exception( 'woocommerce_rest_checkout_create_account_failure' );
		}
		return new \Exception( 'woocommerce_rest_checkout_create_account_failure' );
	}
}
accepted_args   Optional. The number of arguments the function accepts. Default 1.
	 */
	protected static function add_filter( string $hook_name, $callback, int $priority = 10, int $accepted_args = 1 ): void {
		self::process_callback_before_hooking( $callback );
		add_filter( $hook_name, $callback, $priority, $accepted_args );
	}

	/**
	 * Do the required processing to a callback before invoking the WordPress 'add_action' or 'add_filter' function.
	 *
	 * @param callable $callback The callback to process.
	 * @return void
	 */
	protected static function process_callback_before_hooking( $callback ): void {
		if ( ! is_array( $callback ) || count( $callback ) < 2 ) {
			return;
		}

		$first_item = $callback[0];
		if ( __CLASS__ === $first_item ) {
			static::mark_static_method_as_accessible( $callback[1] );
		} elseif ( is_object( $first_item ) && get_class( $first_item ) === __CLASS__ ) {
			$first_item->mark_method_as_accessible( $callback[1] );
		}
	}

	/**
	 * Register a private or protected instance method of this class as externally accessible.
	 *
	 * @param string $method_name Method name.
	 * @return bool True if the method has been marked as externally accessible, false if the method doesn't exist.
	 */
	protected function mark_method_as_accessible( string $method_name ): bool {
		// Note that an "is_callable" check would be useless here:
		// "is_callable" always returns true if the class implements __call.
		if ( method_exists( $this, $method_name ) ) {
			$this->_accessible_private_methods[ $method_name ] = $method_name;
			return true;
		}

		return false;
	}

	/**
	 * Register a private or protected static method of this class as externally accessible.
	 *
	 * @param string $method_name Method name.
	 * @return bool True if the method has been marked as externally accessible, false if the method doesn't exist.
	 */
	protected static function mark_static_method_as_accessible( string $method_name ): bool {
		if ( method_exists( __CLASS__, $method_name ) ) {
			static::$_accessible_static_private_methods[ $method_name ] = $method_name;
			return true;
		}

		return false;
	}

	/**
	 * Undefined/inaccessible instance method call handler.
	 *
	 * @param string $name Called method name.
	 * @param array  $arguments Called method arguments.
	 * @return mixed
	 * @throws \Error The called instance method doesn't exist or is private/protected and not marked as externally accessible.
	 */
	public function __call( $name, $arguments ) {
		if ( isset( $this->_accessible_private_methods[ $name ] ) ) {
			return call_user_func_array( array( $this, $name ), $arguments );
		} elseif ( is_callable( array( 'parent', '__call' ) ) ) {
			return parent::__call( $name, $arguments );
		} elseif ( method_exists( $this, $name ) ) {
			throw new \Error( 'Call to private method ' . get_class( $this ) . '::' . $name );
		} else {
			throw new \Error( 'Call to undefined method ' . get_class( $this ) . '::' . $name );
		}
	}

	/**
	 * Undefined/inaccessible static method call handler.
	 *
	 * @param string $name Called method name.
	 * @param array  $arguments Called method arguments.
	 * @return mixed
	 * @throws \Error The called static method doesn't exist or is private/protected and not marked as externally accessible.
	 */
	public static function __callStatic( $name, $arguments ) {
		if ( isset( static::$_accessible_static_private_methods[ $name ] ) ) {
			return call_user_func_array( array( __CLASS__, $name ), $arguments );
		} elseif ( is_callable( array( 'parent', '__callStatic' ) ) ) {
			return parent::__callStatic( $name, $arguments );
		} elseif ( 'add_action' === $name || 'add_filter' === $name ) {
			$proper_method_name = 'add_static_' . substr( $name, 4 );
			throw new \Error( __CLASS__ . '::' . $name . " can't be called statically, did you mean '$proper_method_name'?" );
		} elseif ( method_exists( __CLASS__, $name ) ) {
			throw new \Error( 'Call to private method ' . __CLASS__ . '::' . $name );
		} else {
			throw new \Error( 'Call to undefined method ' . __CLASS__ . '::' . $name );
		}
	}
}