import { access } from "node:fs/promises";
import { join } from "node:path";

export type PathExists = (path: string) => Promise<boolean>;

async function defaultPathExists(path: string): Promise<boolean> {
  try {
    await access(path);
    return true;
  } catch {
    return false;
  }
}

/** Resolve Readline's user configuration path without silently inventing one. */
export async function resolveUserInputrcPath(
  environment: Readonly<Record<string, string | undefined>> = process.env,
  homeDirectory = process.env.HOME,
  pathExists: PathExists = defaultPathExists,
): Promise<string | undefined> {
  const explicit = environment.INPUTRC;
  if (explicit !== undefined && explicit.length > 0)
    return (await pathExists(explicit)) ? explicit : undefined;
  if (homeDirectory === undefined || homeDirectory.length === 0)
    return undefined;
  const conventional = join(homeDirectory, ".inputrc");
  return (await pathExists(conventional)) ? conventional : undefined;
}