// lib/util/is-main.mjs
// Whether a module is the script node was started with, so a module can be both
// a library and a CLI: `if (isMain(import.meta.url)) { ... }`.
//
// Real paths on both sides. The older guard, import.meta.url === `file://${argv[1]}`,
// is false under a symlinked path (import.meta.url is the realpath) and under a
// path with a space (URL-encoded), and the CLI then exits 0 having done nothing
// (measured 2026-10-04). One helper instead of a copy per CLI (release review of
// 6.3.0, round 7: 31 copies of the fixed guard and 20 of the old one).

import { realpathSync } from 'node:fs';
import { fileURLToPath } from 'node:url';

/**
 * @param {string} url - the calling module's import.meta.url
 * @param {string|undefined} [argv1] - the started script (process.argv[1])
 * @returns {boolean}
 */
export function isMain(url, argv1 = process.argv[1]) {
  if (!argv1) return false;
  try {
    return realpathSync(argv1) === realpathSync(fileURLToPath(url));
  } catch {
    return false;
  }
}