// tests/kb-update/test-backfill-category.test.mjs
// TDD for the Category-backfill driver (R20). RX-OPS2 makes it importable (isMain
// guard + extracted run()/planCategoryBackfill) so its deterministic contract can be
// pinned without executing the corpus scan as an import side effect, and routes its
// writes through the crash-safe atomic writer. The pure, frozen contract:
//   - FOLDER_CATEGORY: the 5 operator-approved folder→category entries (2026-07-06).
//   - categoryForFile: immediate-parent-folder lookup; unknown folder → null.
//   - planCategoryBackfill: reads a corpus root, plans insert-only Category lines behind
//     the same one-line/byte-identical invariant as the sibling drivers; files that
//     already carry Category are idempotently skipped; unknown folders are unmatched
//     (never written).

import { test } from 'node:test';
import assert from 'node:assert/strict';
import { mkdtempSync, mkdirSync, rmSync, writeFileSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { join, dirname } from 'node:path';
import {
  FOLDER_CATEGORY,
  categoryForFile,
  planCategoryBackfill,
} from '../../scripts/kb-update/backfill-category.mjs';

function withTmp(fn) {
  const dir = mkdtempSync(join(tmpdir(), 'bcat-test-'));
  try {
    return fn(dir);
  } finally {
    rmSync(dir, { recursive: true, force: true });
  }
}

function writeFile(root, rel, content) {
  const path = join(root, rel);
  mkdirSync(dirname(path), { recursive: true });
  writeFileSync(path, content, 'utf8');
}

test('FOLDER_CATEGORY — frozen operator-approved taxonomy (5 folders, 2026-07-06)', () => {
  assert.deepEqual(FOLDER_CATEGORY, {
    architecture: 'Solution Architecture & Advisory',
    platforms: 'Microsoft AI Platforms',
    development: 'Microsoft AI Platforms',
    'responsible-ai': 'Responsible AI & Governance',
    'mlops-genaiops': 'MLOps & GenAIOps',
  });
});

test('categoryForFile — maps immediate-parent folder; unknown folder → null', () => {
  assert.equal(categoryForFile('skills/x/references/architecture/foo.md'), 'Solution Architecture & Advisory');
  assert.equal(categoryForFile('skills/x/references/mlops-genaiops/bar.md'), 'MLOps & GenAIOps');
  assert.equal(categoryForFile('skills/x/references/responsible-ai/baz.md'), 'Responsible AI & Governance');
  assert.equal(categoryForFile('skills/x/references/unknown-folder/qux.md'), null);
});

test('planCategoryBackfill — plans a Category-less file in a known folder (one line, right value)', () => {
  withTmp((root) => {
    writeFile(
      root,
      'skills/ms-ai-engineering/references/mlops-genaiops/x.md',
      '# X\n\n**Status:** Reference\n\n---\n\nBody.\n',
    );
    const { planned, unmatched } = planCategoryBackfill(root);
    assert.equal(unmatched.length, 0);
    assert.equal(planned.length, 1);
    assert.equal(planned[0].cat, 'MLOps & GenAIOps');
    // Insert-only invariant: exactly one extra line, the Category line.
    assert.match(planned[0].out, /^\*\*Category:\*\* MLOps & GenAIOps$/m);
  });
});

test('planCategoryBackfill — file already carrying Category is skipped (idempotent)', () => {
  withTmp((root) => {
    writeFile(
      root,
      'skills/ms-ai-engineering/references/mlops-genaiops/x.md',
      '# X\n\n**Category:** MLOps & GenAIOps\n**Status:** Reference\n\n---\n\nBody.\n',
    );
    const { planned, unmatched } = planCategoryBackfill(root);
    assert.equal(planned.length, 0);
    assert.equal(unmatched.length, 0);
  });
});

test('planCategoryBackfill — file in an unknown folder is unmatched, never planned for a write', () => {
  withTmp((root) => {
    writeFile(root, 'skills/ms-ai-x/references/mystery/x.md', '# X\n\n**Status:** Reference\n\n---\n\nBody.\n');
    const { planned, unmatched } = planCategoryBackfill(root);
    assert.equal(planned.length, 0);
    assert.equal(unmatched.length, 1);
    assert.match(unmatched[0], /mystery/);
  });
});