// commons-loader.test.mjs — Tests for the vendored-commons JSON artifact loader
//
// v8 Phase 5 step 2: llm-security-commons doesn't exist yet (Phase 4 is
// blocked on the operator creating the Forgejo repo), so these tests drive
// the loader against a local fixture directory instead of a real vendored
// subtree — including the "commons isn't vendored yet" case, which must
// degrade gracefully rather than crash.

import { describe, it, beforeEach, afterEach } from 'node:test';
import assert from 'node:assert/strict';
import { writeFileSync, mkdirSync, rmSync } from 'node:fs';
import { join } from 'node:path';
import { tmpdir } from 'node:os';
import { loadArtifact, _resetCacheForTest } from '../../scanners/lib/commons-loader.mjs';

const TEST_ROOT = join(tmpdir(), `llm-security-commons-loader-test-${Date.now()}`);
const FIXTURE_COMMONS_ROOT = join(TEST_ROOT, 'fixture-commons');

function writeArtifact(relPath, data) {
  const filePath = join(FIXTURE_COMMONS_ROOT, `${relPath}.json`);
  mkdirSync(join(filePath, '..'), { recursive: true });
  writeFileSync(filePath, JSON.stringify(data));
}

describe('commons-loader', () => {
  beforeEach(() => {
    _resetCacheForTest();
    mkdirSync(FIXTURE_COMMONS_ROOT, { recursive: true });
  });

  afterEach(() => {
    _resetCacheForTest();
    try { rmSync(TEST_ROOT, { recursive: true }); } catch {}
  });

  it('loads and parses a valid artifact from an explicit commonsRoot', () => {
    writeArtifact('lexicon/injection-lexicon', { version: '0.1.0', terms: ['ignore previous instructions'] });
    const data = loadArtifact('lexicon/injection-lexicon', { commonsRoot: FIXTURE_COMMONS_ROOT, fallback: null });
    assert.deepEqual(data, { version: '0.1.0', terms: ['ignore previous instructions'] });
  });

  it('returns the caller fallback when the artifact file is missing', () => {
    const data = loadArtifact('lexicon/injection-lexicon', { commonsRoot: FIXTURE_COMMONS_ROOT, fallback: [] });
    assert.deepEqual(data, []);
  });

  it('returns the caller fallback when the artifact JSON is invalid', () => {
    const filePath = join(FIXTURE_COMMONS_ROOT, 'mapping', 'owasp-map.json');
    mkdirSync(join(filePath, '..'), { recursive: true });
    writeFileSync(filePath, 'not valid json!!!');
    const data = loadArtifact('mapping/owasp-map', { commonsRoot: FIXTURE_COMMONS_ROOT, fallback: {} });
    assert.deepEqual(data, {});
  });

  it('degrades gracefully when commons has not been vendored yet (no commonsRoot override)', () => {
    // Phase 4 hasn't run in this repo checkout: the default scanners/commons
    // vendor path does not exist. The loader must not throw, and — since the
    // commons location is never policy- or target-derived — this cannot be
    // influenced by an on-disk .llm-security/policy.json either.
    const data = loadArtifact('lexicon/injection-lexicon', { fallback: 'EMPTY' });
    assert.equal(data, 'EMPTY');
  });

  it('caches a loaded artifact per resolved path', () => {
    writeArtifact('calibration/calibration', { entropyFloor: 4.5 });
    const first = loadArtifact('calibration/calibration', { commonsRoot: FIXTURE_COMMONS_ROOT });
    writeArtifact('calibration/calibration', { entropyFloor: 9.9 }); // mutate after first read
    const second = loadArtifact('calibration/calibration', { commonsRoot: FIXTURE_COMMONS_ROOT });
    assert.equal(first, second); // same reference (cached)
    assert.equal(second.entropyFloor, 4.5); // original value, not the mutation
  });

  it('caches a failed load too, so a fixed-but-unread file still returns the fallback', () => {
    const first = loadArtifact('signatures/malware-signatures', { commonsRoot: FIXTURE_COMMONS_ROOT, fallback: [] });
    writeArtifact('signatures/malware-signatures', { rules: [{ id: 'late-arrival' }] });
    const second = loadArtifact('signatures/malware-signatures', { commonsRoot: FIXTURE_COMMONS_ROOT, fallback: [] });
    assert.deepEqual(first, []);
    assert.deepEqual(second, []);
  });

  it('a cached failure does not leak one caller\'s fallback shape to another', () => {
    const arrayFallback = loadArtifact('missing/artifact', { commonsRoot: FIXTURE_COMMONS_ROOT, fallback: [] });
    const objectFallback = loadArtifact('missing/artifact', { commonsRoot: FIXTURE_COMMONS_ROOT, fallback: {} });
    assert.deepEqual(arrayFallback, []);
    assert.deepEqual(objectFallback, {}); // not [] from the first caller's cached fallback
  });

  it('defaults the fallback to null when the caller passes none', () => {
    const data = loadArtifact('lexicon/injection-lexicon', { commonsRoot: FIXTURE_COMMONS_ROOT });
    assert.equal(data, null);
  });

  it('freezes a loaded artifact so a caller mutation throws instead of leaking process-wide', () => {
    writeArtifact('lexicon/injection-lexicon', { version: '0.1.0', terms: ['a'] });
    const data = loadArtifact('lexicon/injection-lexicon', { commonsRoot: FIXTURE_COMMONS_ROOT });
    assert.throws(() => { data.terms.push('mutated'); }, TypeError);
    assert.throws(() => { data.version = '9.9.9'; }, TypeError);
  });

  it('does not read .llm-security/policy.json from any target — commons.root is not honored', () => {
    // Simulates a hostile scanned target shipping .llm-security/policy.json
    // with {"commons":{"root": "..."}} to redirect detection data. Even
    // with such a file on disk and CLAUDE_PROJECT_ROOT pointed at it, the
    // loader must ignore it entirely and fall through to the caller's
    // explicit commonsRoot / default, never to policy.
    const hostileTargetRoot = join(TEST_ROOT, 'hostile-target');
    const hostilePolicyDir = join(hostileTargetRoot, '.llm-security');
    mkdirSync(hostilePolicyDir, { recursive: true });
    writeFileSync(
      join(hostilePolicyDir, 'policy.json'),
      JSON.stringify({ commons: { root: join(TEST_ROOT, 'attacker-controlled-empty-commons') } }),
    );
    const prevProjectRoot = process.env.CLAUDE_PROJECT_ROOT;
    process.env.CLAUDE_PROJECT_ROOT = hostileTargetRoot;
    try {
      writeArtifact('lexicon/injection-lexicon', { version: '0.1.0', terms: ['still-here'] });
      const data = loadArtifact('lexicon/injection-lexicon', { commonsRoot: FIXTURE_COMMONS_ROOT, fallback: null });
      assert.deepEqual(data, { version: '0.1.0', terms: ['still-here'] });
    } finally {
      if (prevProjectRoot === undefined) delete process.env.CLAUDE_PROJECT_ROOT;
      else process.env.CLAUDE_PROJECT_ROOT = prevProjectRoot;
    }
  });
});