import { exec as execCb } from "node:child_process";
import { setTimeout } from "node:timers/promises";
import { promisify } from "node:util";

import { which } from "./which.mjs";

const exec = promisify(execCb);

/**
 * @param {string} file
 * @returns {Promise<void>}
 */
export async function waitLockUnlock(file) {
  if (!(await which("flock"))) throw new Error("flock is not installed");

  let locked = false;
  while (!locked) {
    try {
      await exec(`flock -ns "${file}" -c true`);
      await setTimeout(100);
    } catch {
      locked = true;
    }
  }

  while (locked) {
    try {
      await exec(`flock -ns "${file}" -c true`);
    } catch {
      await setTimeout(100);
      continue;
    }
    locked = false;
  }
}