import test from "node:test";
import assert from "node:assert/strict";
import {mkdtemp, rm} from "node:fs/promises";
import path from "node:path";
import os from "node:os";
import {spawn} from "node:child_process";
import {once} from "node:events";
import {withFileLock} from "../src/capability-language/file-lock.js";

test("authoring lock excludes concurrent mutations and survives owner death", async context => {
  const root = await mkdtemp(path.join(os.tmpdir(), "qx-lock-test-"));
  context.after(() => rm(root, {recursive: true, force: true}));
  const filename = path.join(root, "lock");
  await withFileLock(filename, async () => {
    await assert.rejects(withFileLock(filename, async () => assert.fail("concurrent mutation")), /Another authoring command/);
  });
  const module = new URL("../src/capability-language/file-lock.js", import.meta.url).href;
  const owner = spawn(process.execPath, ["--input-type=module", "-e",
    `import {withFileLock} from ${JSON.stringify(module)}; await withFileLock(${JSON.stringify(filename)}, async () => {process.stdout.write('ready'); await new Promise(() => {});});`],
    {stdio: ["ignore", "pipe", "pipe"]});
  context.after(() => owner.kill("SIGKILL"));
  await once(owner.stdout, "data");
  const exited = once(owner, "exit");
  owner.kill("SIGKILL");
  await exited;
  // EOF release happens in the helper; wait a bounded amount for scheduling.
  let acquired = false;
  for (let attempt = 0; attempt < 30 && !acquired; attempt++) {
    try { await withFileLock(filename, async () => {acquired = true;}); }
    catch (error) { if (!/Another authoring command/.test(String(error))) throw error; }
  }
  assert.equal(acquired, true);
});