import { Option } from 'fp-ts/Option'
import { constructors, Union } from './utils'

type _ = never

export type index = number

export type Literal = Union<{
  String: string
  RegExp: RegExp
  Number: number
  Boolean: boolean
}>
export const Literal = constructors<Literal>()

export type Expr = Union<{
  Start: _
  End: _
  Optional: { expr: Expr }
  OneOrMore: { expr: Expr }
  MinMax: { expr: Expr, min: index, max: index }
  ZeroOrMore: { expr: Expr }
  AnyItem: _
  Or: { exprs: Expr[] }
  AnyString: _
  AnyNumber: _
  AnyBool: _
  Truthy: _
  Falsey: _
  Group: { exprs: Expr[] }
  PropertyMatch: { name: string; expr: Expr }
  Literal: Literal
  Sequence: { exprs: Expr[] }
}>
export const Expr = constructors<Expr>()

export type ListExpr = [Option<Expr>, Expr, Option<Expr>]