import type { Int } from ".";
import type { ParsingError } from "../../Error";
import type { Args, Call1, Fn } from "../../HKT";
import type { Every } from "../../List/Every";
import type { Err, Ok, Result } from "../../Result";
import type IsDigitFn from "../../Str/IsDigit";
import type { Str$$Show } from "../../Str/Show";
import type { ToChars } from "../../Str/ToChars";
import type { Assert } from "../../helpers";
import type { Abs } from "../Abs";

/**
 * Parse a string to an {@link Int}.
 *
 * Sig: `(s: string) => Result<Int, ParsingError>`
 */
export type FromStr<S extends string> = Assert<
  Result<Int, ParsingError>,
  string extends S ? Result<Int, ParsingError>
  : S extends `${infer N extends number}` ?
    Every<IsDigitFn, ToChars<`${Abs<N>}`>> extends true ?
      Ok<N>
    : Err<ParsingError<`${Call1<Str$$Show["Show"], S>} is not a valid integer`>>
  : Err<ParsingError<`${Call1<Str$$Show["Show"], S>} is not a valid integer`>>
>;

/**
 * [Fn] Parse a string to an {@link Int}.
 *
 * Sig: `(s: string) => Result<Int, ParsingError>`
 */
export default interface FromStrFn extends Fn<[string], Result<Int, ParsingError>> {
  def: ([s]: Args<this>) => FromStr<typeof s>;
}