#!/usr/bin/env node
'use strict';

/**
 * lint-regression-test-names.cjs — ban NEW top-level bug-NNNN test files.
 *
 * ## Why
 *
 * The 2026-06 CI audit found 244 one-off `tests/bug-NNNN-*.test.cjs` files —
 * ~38% of the suite. `node --test` spawns one child process per FILE, so file
 * count (not test count) is the unit of CI overhead, and it is worst on the
 * Windows lanes where every spawn is Defender-scanned. Each regression test
 * belongs in the owning module's main test file as a regression case (e.g. a
 * `describe('regressions')` block in `tests/<module>.test.cjs`), where it
 * costs zero additional processes.
 *
 * ## What this enforces
 *
 * Identity ratchet (scripts/lib/allowlist-ratchet.cjs) over basenames matching
 * /^bug-\d+.*\.test\.cjs$/ in tests/:
 *   - A NEW bug-* file (not in the allowlist) fails: fold the regression into
 *     the owning module's test file instead.
 *   - A REMOVED bug-* file with a stale allowlist entry also fails: prune the
 *     entry from scripts/lint-regression-test-names.allowlist.json so the
 *     baseline only ever shrinks.
 *
 * See docs/TESTING-SUITES.md ("Regression tests") for the placement policy.
 */

const fs = require('fs');
const path = require('path');
const { assertWithinAllowlist } = require('./lib/allowlist-ratchet.cjs');
const { ExitError, runMain } = require('./lib/cli-exit.cjs');

const ROOT = path.join(__dirname, '..');
// Env overrides exist for the lint's own tests only (sandbox fixture dirs).
const TESTS_DIR = process.env.GSD_LINT_REGRESSION_TESTS_DIR || path.join(ROOT, 'tests');
const ALLOWLIST_PATH =
  process.env.GSD_LINT_REGRESSION_ALLOWLIST ||
  path.join(__dirname, 'lint-regression-test-names.allowlist.json');

const BUG_FILE_RE = /^bug-\d+.*\.test\.cjs$/;

function main() {
  const current = fs
    .readdirSync(TESTS_DIR)
    .filter(f => BUG_FILE_RE.test(f))
    .sort();
  const known = JSON.parse(fs.readFileSync(ALLOWLIST_PATH, 'utf8'));

  const failures = [];
  const { novel } = assertWithinAllowlist({
    label: 'regression-test-names',
    current,
    known,
    fail: msg => failures.push(msg),
    pruneHint: 'edit scripts/lint-regression-test-names.allowlist.json',
  });

  if (failures.length > 0) {
    for (const msg of failures) console.error(msg);
    if (novel.length > 0) {
      console.error(
        '\nNew bug-NNNN test files are no longer accepted. Add the regression ' +
        "case to the owning module's test file (e.g. a describe('regressions') " +
        'block in tests/<module>.test.cjs) instead of creating a new file. ' +
        'See docs/TESTING-SUITES.md.'
      );
    }
    throw new ExitError(1);
  }

  console.log(
    `ok lint-regression-test-names: ${current.length} grandfathered bug-* file(s), no novel offenders`
  );
}

runMain(main);