type t
@module external process: t = "process"
@send external exit: (t, unit) => unit = "exit"
type exitCode = | @as(0) Success | @as(1) Failure
@send external exitWithCode: (t, exitCode) => unit = "exit"

module Util = {
  @unboxed
  type depth = Int(int) | @as(null) Null
  @unboxed
  type compact = Bool(bool) | Int(int)
  @unboxed
  type sorted = Bool(bool) | Fn((string, string) => int)
  @unboxed
  type getters = | @as(true) True | @as(false) False | @as("get") Get | @as("set") Set

  @unbox
  type inspectOptions = {
    showHidden?: bool,
    depth?: depth,
    colors?: bool,
    customInspect?: bool,
    showProxy?: bool,
    maxArrayLength?: int,
    maxStringLength?: int,
    breakLength?: int,
    @as("compact") compact?: compact,
    sorted?: sorted,
    getters?: string,
    numericSeparator?: bool,
  }

  @module("util") external inspect: ('a, inspectOptions) => string = "inspect"

  let inspectObj = a => inspect(a, {showHidden: false, depth: Null, colors: true})
}

module Path = {
  type t

  @module("path") @variadic
  external resolve: array<string> => t = "resolve"

  @module("path") external join: (t, string) => t = "join"

  external toString: t => string = "%identity"

  external __dirname: t = "__dirname"
}

module Fs = {
  type writeFileOptions = {
    mode?: int,
    // flag?: Flag.t,
    encoding?: string,
  }

  module Promises = {
    @module("fs") @scope("promises")
    external writeFile: (
      ~filepath: Path.t,
      ~content: string,
      ~options: writeFileOptions=?,
    ) => promise<unit> = "writeFile"

    @module("fs") @scope("promises")
    external appendFile: (
      ~filepath: Path.t,
      ~content: string,
      ~options: writeFileOptions=?,
    ) => Js.Promise.t<unit> = "appendFile"

    @module("fs") @scope("promises")
    external access: Path.t => Js.Promise.t<unit> = "access"

    type encoding = | @as("utf8") Utf8

    @module("fs") @scope("promises")
    external readFile: (~filepath: Path.t, ~encoding: encoding) => promise<string> = "readFile"
  }
}