export interface SpawnOptions {
  /** Current working directory. */
  cwd?: string
  /** Environment variables. set to `null` to clear the process env. */
  env?: Record<string, string>
  /**
   * Character encoding for stdout/stderr
   *
   * @since 2.0.0
   *  */
  encoding?: string
}

export interface InternalSpawnOptions extends SpawnOptions {
  sidecar?: boolean
}

export type IOPayload = string | Uint8Array

export interface ChildProcess<O extends IOPayload> {
  /** Exit code of the process. `null` if the process was terminated by a signal on Unix. */
  code: number | null
  /** If the process was terminated by a signal, represents that signal. */
  signal: number | null
  /** The data that the process wrote to `stdout`. */
  stdout: O
  /** The data that the process wrote to `stderr`. */
  stderr: O
}

/**
 * Payload for the `Terminated` command event.
 */
export interface TerminatedPayload {
  /** Exit code of the process. `null` if the process was terminated by a signal on Unix. */
  code: number | null
  /** If the process was terminated by a signal, represents that signal. */
  signal: number | null
}

export interface CommandEvents {
  close: TerminatedPayload
  error: string
}

/**
 * Describes the event message received from the command.
 */
interface Event<T, V> {
  event: T
  payload: V
}

/** Events emitted by the child process. */
export type CommandEvent<O extends IOPayload> =
  | Event<'Stdout', O>
  | Event<'Stderr', O>
  | Event<'Terminated', TerminatedPayload>
  | Event<'Error', string>

export interface OutputEvents<O extends IOPayload> {
  data: O
}