#!/usr/bin/env node
/**
 * sync-design-system.mjs
 *
 * Vendors this design system into a consumer's
 * playground/vendor/playground-design-system/ tree.
 *
 * Usage:
 *   node scripts/sync-design-system.mjs <consumer-name> --target <consumer-repo> [--source <dir>] [--force]
 *   node scripts/sync-design-system.mjs <consumer-name> --target <consumer-repo> --check
 *
 * Each consumer keeps its own pinned copy so it stays standalone.
 * MANIFEST.json records SHA-256 per file + source commit + sync date.
 * Drift detection refuses overwrite if a vendored file was modified
 * locally after sync; pass --force to overwrite anyway.
 *
 * Source boundary: only the files named in DELIVERED_FILES are vendored.
 * This repo's root holds the design system *and* the repo apparatus
 * (STATE.md, .git/, docs/, playground-examples/, LICENSE, SECURITY.md).
 * STATE.md is gitignored because this repo's remote is public; copying it
 * into a consumer would publish it. Walking the source tree, which is what
 * this script did while the system lived in its own directory inside the
 * marketplace monorepo, is therefore no longer safe.
 *
 * No npm dependencies. Node 16.7+.
 */

import { createHash } from 'node:crypto';
import { promises as fs } from 'node:fs';
import path from 'node:path';
import { execSync } from 'node:child_process';
import { fileURLToPath, pathToFileURL } from 'node:url';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const REPO_ROOT = path.resolve(__dirname, '..');
const SOURCE_LABEL = 'playground-design-system';
const GENERATED_HEADER = '/* Code generated by sync-design-system.mjs; DO NOT EDIT. */\n';

/**
 * The delivered system: exactly what a consumer vendors. Everything else in
 * this repo is apparatus and stays here.
 *
 * Adding a file to the design system means adding it here. Forgetting to is
 * caught by assertSourceBoundary() below rather than shipping silently, since
 * --check hashes a consumer's tree against its own MANIFEST and would stay
 * green forever on a file that was never copied.
 */
export const DELIVERED_FILES = [
  'CHANGELOG.md',
  'README.md',
  'base.css',
  'components-tier2.css',
  'components-tier3-supplement.css',
  'components-tier3.css',
  'components-tier4-project-view.css',
  'components.css',
  'fonts.css',
  'fonts/Inter-Bold.woff2',
  'fonts/Inter-Medium.woff2',
  'fonts/Inter-Regular.woff2',
  'fonts/Inter-SemiBold.woff2',
  'fonts/JetBrainsMono-Medium.woff2',
  'fonts/JetBrainsMono-Regular.woff2',
  'fonts/JetBrainsMono-SemiBold.woff2',
  'fonts/LICENSE-Inter.txt',
  'fonts/LICENSE-JetBrainsMono.txt',
  'fonts/LICENSE-SourceSerif4.md',
  'fonts/LICENSES.md',
  'fonts/SourceSerif4-Regular.woff2',
  'fonts/SourceSerif4-Semibold.woff2',
  'print.css',
  'schemas/finding.schema.json',
  'schemas/okr-set.schema.json',
  'schemas/ros-threat.schema.json',
  'tokens.css',
];

// Where an added design-system file would plausibly land. Scanned against the
// allowlist so an omission is loud. Deliberately narrow: root-level *.md and
// the repo apparatus are excluded by design, not by oversight.
const SCANNED_DIRS = ['fonts', 'schemas'];

function parseArgs(argv) {
  const args = { plugin: null, force: false, source: null, target: null, check: false };
  const rest = argv.slice(2);
  for (let i = 0; i < rest.length; i++) {
    const a = rest[i];
    if (a === '--force') args.force = true;
    else if (a === '--check') args.check = true;
    else if (a === '--source' || a === '--target') {
      const v = rest[++i];
      if (!v) throw new Error(`${a} requires a directory argument`);
      args[a === '--source' ? 'source' : 'target'] = v;
    } else if (a.startsWith('--source=')) args.source = a.slice('--source='.length);
    else if (a.startsWith('--target=')) args.target = a.slice('--target='.length);
    else if (a.startsWith('--')) {
      throw new Error(`Unknown flag: ${a}`);
    } else if (!args.plugin) {
      args.plugin = a;
    } else {
      throw new Error(`Unexpected positional arg: ${a}`);
    }
  }
  if (!args.plugin) {
    throw new Error('Missing consumer name. Usage: node scripts/sync-design-system.mjs <consumer-name> --target <consumer-repo> [--source <dir>] [--check] [--force]');
  }
  if (!args.target) {
    throw new Error('Missing --target. The marketplace no longer holds plugins/<name>, so the consumer repo root must be given explicitly.');
  }
  return args;
}

// The consumer (vendor target) repo root. The vendored tree goes below it at
// playground/vendor/playground-design-system/.
function resolvePluginDir(args) {
  return path.resolve(args.target);
}

async function sha256(filePath) {
  const buf = await fs.readFile(filePath);
  return createHash('sha256').update(buf).digest('hex');
}

async function walk(dir, base = dir) {
  const entries = await fs.readdir(dir, { withFileTypes: true });
  const out = [];
  for (const e of entries) {
    const full = path.join(dir, e.name);
    if (e.isDirectory()) {
      out.push(...(await walk(full, base)));
    } else if (e.isFile()) {
      out.push(path.relative(base, full));
    }
  }
  return out;
}

async function readJsonIfExists(p) {
  try {
    return JSON.parse(await fs.readFile(p, 'utf8'));
  } catch (e) {
    if (e.code === 'ENOENT') return null;
    throw e;
  }
}

/**
 * Both directions of the boundary: every delivered file must exist in the
 * source, and no design-system file may exist in the source without being
 * delivered.
 */
async function assertSourceBoundary(sourceDir) {
  const delivered = new Set(DELIVERED_FILES);

  const missing = [];
  for (const rel of DELIVERED_FILES) {
    try {
      await fs.access(path.join(sourceDir, rel));
    } catch {
      missing.push(rel);
    }
  }
  if (missing.length) {
    throw new Error(
      `Source is missing ${missing.length} delivered file(s):\n` +
      missing.map(f => `  - ${f}`).join('\n'),
    );
  }

  const candidates = [];
  for (const e of await fs.readdir(sourceDir, { withFileTypes: true })) {
    if (e.isFile() && e.name.endsWith('.css')) candidates.push(e.name);
  }
  for (const dir of SCANNED_DIRS) {
    const full = path.join(sourceDir, dir);
    try {
      for (const rel of await walk(full)) candidates.push(path.join(dir, rel));
    } catch (e) {
      if (e.code !== 'ENOENT') throw e;
    }
  }

  const unlisted = candidates.filter(rel => !delivered.has(rel)).sort();
  if (unlisted.length) {
    throw new Error(
      `Source holds ${unlisted.length} design-system file(s) the allowlist does not name:\n` +
      unlisted.map(f => `  - ${f}`).join('\n') +
      '\nAdd them to DELIVERED_FILES, or move them out of the delivered tree.',
    );
  }
}

async function copyDelivered(sourceDir, targetDir) {
  for (const rel of DELIVERED_FILES) {
    const dest = path.join(targetDir, rel);
    await fs.mkdir(path.dirname(dest), { recursive: true });
    await fs.copyFile(path.join(sourceDir, rel), dest);
  }
}

async function detectDrift(targetDir, prevManifest) {
  if (!prevManifest || !prevManifest.files) return [];
  const drifted = [];
  for (const [rel, prevHash] of Object.entries(prevManifest.files)) {
    const tgt = path.join(targetDir, rel);
    try {
      const cur = await sha256(tgt);
      if (cur !== prevHash) drifted.push(rel);
    } catch (e) {
      if (e.code === 'ENOENT') drifted.push(`${rel} (missing)`);
      else throw e;
    }
  }
  return drifted;
}

async function injectGeneratedHeader(targetDir, files) {
  for (const rel of files) {
    if (!rel.endsWith('.css')) continue;
    const p = path.join(targetDir, rel);
    const content = await fs.readFile(p, 'utf8');
    if (content.startsWith(GENERATED_HEADER)) continue;
    await fs.writeFile(p, GENERATED_HEADER + content, 'utf8');
  }
}

async function buildManifest(targetDir, files, sourceCommit, sourceLabel) {
  const fileHashes = {};
  for (const rel of files.sort()) {
    fileHashes[rel] = await sha256(path.join(targetDir, rel));
  }
  return {
    generated_by: 'scripts/sync-design-system.mjs',
    do_not_edit: true,
    source: sourceLabel,
    source_commit: sourceCommit,
    sync_date: new Date().toISOString(),
    file_count: files.length,
    files: fileHashes,
  };
}

function getCurrentCommit(cwd) {
  try {
    return execSync('git rev-parse HEAD', {
      cwd: cwd || REPO_ROOT,
      encoding: 'utf8',
    }).trim();
  } catch {
    return 'unknown';
  }
}

// --check: re-hash a consumer's vendored tree against its committed
// MANIFEST.json and exit non-zero on drift. No source needed — one command in
// a clean clone. Reads only; it never writes to the consumer.
async function runCheck(args) {
  const pluginDir = resolvePluginDir(args);
  const targetDir = path.join(pluginDir, 'playground', 'vendor', 'playground-design-system');
  const manifestPath = path.join(targetDir, 'MANIFEST.json');
  const manifest = await readJsonIfExists(manifestPath);
  if (!manifest) {
    console.error(`MANIFEST DRIFT: no MANIFEST.json at ${manifestPath}`);
    process.exit(2);
  }
  const drifted = await detectDrift(targetDir, manifest);
  if (drifted.length) {
    console.error(`MANIFEST DRIFT: ${drifted.length} vendored file(s) differ from MANIFEST.json:`);
    for (const f of drifted) console.error(`  - ${f}`);
    process.exit(2);
  }
  console.log(`MANIFEST OK (${manifest.file_count} files, source_commit ${manifest.source_commit})`);
}

async function main() {
  const args = parseArgs(process.argv);

  if (args.check) {
    await runCheck(args);
    return;
  }

  const pluginDir = resolvePluginDir(args);
  const sourceDir = args.source ? path.resolve(args.source) : REPO_ROOT;

  try {
    const stat = await fs.stat(pluginDir);
    if (!stat.isDirectory()) throw new Error('not a directory');
  } catch {
    throw new Error(`Consumer directory not found: ${pluginDir}`);
  }

  try {
    await fs.access(sourceDir);
  } catch {
    throw new Error(`Source directory missing: ${sourceDir}`);
  }

  await assertSourceBoundary(sourceDir);

  const targetDir = path.join(pluginDir, 'playground', 'vendor', 'playground-design-system');
  const manifestPath = path.join(targetDir, 'MANIFEST.json');

  const prevManifest = await readJsonIfExists(manifestPath);
  const drifted = await detectDrift(targetDir, prevManifest);
  if (drifted.length && !args.force) {
    console.error(`Refusing sync: ${drifted.length} vendored file(s) drifted from previous MANIFEST:`);
    for (const f of drifted) console.error(`  - ${f}`);
    console.error('Pass --force to overwrite local changes.');
    process.exit(2);
  }
  if (drifted.length && args.force) {
    console.warn(`--force: overwriting ${drifted.length} drifted file(s).`);
  }

  await fs.mkdir(path.dirname(targetDir), { recursive: true });
  await fs.rm(targetDir, { recursive: true, force: true });
  await fs.mkdir(targetDir, { recursive: true });
  await copyDelivered(sourceDir, targetDir);

  const files = await walk(targetDir);
  await injectGeneratedHeader(targetDir, files);

  const sourceCommit = getCurrentCommit(sourceDir);
  const finalFiles = await walk(targetDir);
  const manifest = await buildManifest(targetDir, finalFiles, sourceCommit, SOURCE_LABEL);
  await fs.writeFile(manifestPath, JSON.stringify(manifest, null, 2) + '\n', 'utf8');

  console.log(`Synced ${SOURCE_LABEL} → ${targetDir}`);
  console.log(`  Files: ${manifest.file_count + 1} (incl. MANIFEST.json)`);
  console.log(`  Source commit: ${sourceCommit}`);
  console.log(`  Sync date: ${manifest.sync_date}`);
}

// Importable: the tests read DELIVERED_FILES from here so the allowlist has
// exactly one definition.
if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
  main().catch(err => {
    console.error(`Error: ${err.message}`);
    process.exit(1);
  });
}