export type Options = {
  /**
   * Include the provided PID in the list. Ignored if -1 is passed as PID.
   * @default false
   */
  root?: boolean;
};

export type AdvancedResult = {
  /**
   * PID of the parent.
   */
  ppid: number;
  /**
   * PID.
   */
  pid: number;
};

export type Result = number;

/**
 * Get the list of children pids of the given pid.
 * @param pid A PID. If -1 will return all the pids.
 * @param callback Called when the list is ready.
 */
declare function pidtree(
  pid: string | number,
  callback: (error: Error | undefined, result: Result[]) => void,
): void;

/**
 * Get the list of children pids of the given pid.
 * @param pid A PID. If -1 will return all the pids.
 * @param options Options object.
 * @param callback Called when the list is ready.
 */
declare function pidtree(
  pid: string | number,
  options: Options,
  callback: (error: Error | undefined, result: Result[]) => void,
): void;

/**
 * Get the list of children pids of the given pid.
 * @param pid A PID. If -1 will return all the pids.
 * @param options Options object.
 * @param callback Called when the list is ready.
 */
declare function pidtree(
  pid: string | number,
  options: Options & {advanced: true},
  callback: (error: Error | undefined, result: AdvancedResult[]) => void,
): void;

/**
 * Get the list of children pids of the given pid.
 * @param pid A PID. If -1 will return all the pids.
 * @param options Optional options object.
 * @returns A promise containing the list.
 */
declare function pidtree(
  pid: string | number,
  options?: Options,
): Promise<Result[]>;

/**
 * Get the list of children pids of the given pid.
 * @param pid A PID. If -1 will return all the pids.
 * @param options Options object.
 * @returns A promise containing the list.
 */
declare function pidtree(
  pid: string | number,
  options: Options & {advanced: true},
): Promise<AdvancedResult[]>;

export default pidtree;
export {pidtree};