import type { Args, Fn } from "../HKT";
import type { AssertStr, Eq } from "../helpers";

/**
 * Convert a boolean to a string.
 *
 * Sig: `(b: boolean) => string`
 */
export type ToStr<B extends boolean> = AssertStr<
  [B] extends [never] ? never
  : Eq<B, true> extends true ? "true"
  : Eq<B, false> extends true ? "false"
  : Eq<B, boolean> extends true ? "boolean"
  : string
>;

/**
 * [Fn] Convert a boolean to a string.
 *
 * Sig: `(b: boolean) => string`
 */
export default interface ToStrFn extends Fn<[boolean], string> {
  def: ([b]: Args<this>) => ToStr<typeof b>;
}