// 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';
import { _resetCacheForTest as _resetPolicyCacheForTest } from '../../scanners/lib/policy-loader.mjs';

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

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();
    _resetPolicyCacheForTest();
    mkdirSync(FIXTURE_COMMONS_ROOT, { recursive: true });
  });

  afterEach(() => {
    _resetCacheForTest();
    _resetPolicyCacheForTest();
    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 override, no policy)', () => {
    // Phase 4 hasn't run in this repo checkout: the default `shared/` vendor
    // path does not exist. The loader must not throw.
    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 cached 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('resolves commonsRoot from the commons.root policy value when no explicit override is given', () => {
    mkdirSync(POLICY_DIR, { recursive: true });
    writeFileSync(POLICY_FILE, JSON.stringify({ commons: { root: FIXTURE_COMMONS_ROOT } }));
    writeArtifact('codepoints/carriers', { zeroWidth: ['​'] });
    const data = loadArtifact('codepoints/carriers', { targetPath: TEST_ROOT, fallback: null });
    assert.deepEqual(data, { zeroWidth: ['​'] });
  });

  it('resolves a relative commons.root policy value against targetPath', () => {
    mkdirSync(POLICY_DIR, { recursive: true });
    writeFileSync(POLICY_FILE, JSON.stringify({ commons: { root: './fixture-commons' } }));
    writeArtifact('lexicon/injection-lexicon', { version: '0.1.0', terms: [] });
    const data = loadArtifact('lexicon/injection-lexicon', { targetPath: TEST_ROOT, fallback: null });
    assert.deepEqual(data, { version: '0.1.0', terms: [] });
  });

  it('an explicit commonsRoot option takes precedence over the commons.root policy value', () => {
    mkdirSync(POLICY_DIR, { recursive: true });
    writeFileSync(POLICY_FILE, JSON.stringify({ commons: { root: join(TEST_ROOT, 'does-not-exist') } }));
    writeArtifact('lexicon/injection-lexicon', { version: '0.1.0', terms: ['override-wins'] });
    const data = loadArtifact('lexicon/injection-lexicon', {
      targetPath: TEST_ROOT,
      commonsRoot: FIXTURE_COMMONS_ROOT,
      fallback: null,
    });
    assert.deepEqual(data, { version: '0.1.0', terms: ['override-wins'] });
  });

  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);
  });
});