// Copyright (c) 2018-present, Cruise LLC

// This source code is licensed under the Apache License, Version 2.0,
// found in the LICENSE file in the root directory of this source tree.
// You may not use this file except in compliance with the License.

// @flow

// A function that must be called with either an error or a value, but not both
export type Callback<T> = ((error: Error, value?: void) => void) & ((error: null, value: T) => void);

// Represents a timestamp based on the UNIX epoch (1970 Jan 1).
// See also: http://wiki.ros.org/roscpp/Overview/Time
export interface Time {
  // whole seconds
  sec: number;
  // additional nanoseconds past the sec value
  nsec: number;
}

export interface Filelike {
  read(offset: number, length: number, callback: Callback<Buffer>): void;
  size(): number;
}

export type RosMsgField = {|
  type: string,
  name: string,
  isComplex?: boolean,

  // For arrays
  isArray?: boolean,
  arrayLength?: ?number,

  // For constants
  isConstant?: boolean,
  value?: mixed,
|};

export type RosMsgDefinition = {|
  name?: string,
  definitions: RosMsgField[],
|};
export type NamedRosMsgDefinition = {|
  name: string,
  definitions: RosMsgField[],
|};