#!/usr/bin/env node

/**
 * Generates cli/engine/vendor/static-html-parsers.mjs
 * by bundling htmlparser2, css-select, css-tree, and domutils for skill/plugin installs.
 *
 * Run: node scripts/build-static-html-parsers.js
 * Check: node scripts/build-static-html-parsers.js --check
 */

import fs from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
import { build } from 'esbuild';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const ROOT = path.resolve(__dirname, '..');

const ENTRY = path.join(__dirname, 'lib/static-html-parsers.entry.mjs');
const OUT_DIR = path.join(ROOT, 'cli/engine/vendor');
const BUNDLE_NAME = 'static-html-parsers.mjs';
const LICENSES_NAME = 'static-html-parsers.LICENSES.txt';
const MAX_BUNDLE_BYTES = 256 * 1024;
const HEADER = `/**
 * GENERATED -- do not edit. Source: scripts/lib/static-html-parsers.entry.mjs
 * Rebuild: node scripts/build-static-html-parsers.js
 *
 * Bundles htmlparser2, css-select, css-tree, and domutils for skill/plugin installs.
 * Third-party licenses: see static-html-parsers.LICENSES.txt.
 */
`;

function packageRoots(inputs) {
  const roots = new Map();
  for (const input of Object.keys(inputs)) {
    const segments = input.replaceAll('\\', '/').split('/');
    const marker = segments.lastIndexOf('node_modules');
    if (marker < 0 || marker + 1 >= segments.length) continue;

    const nameParts = segments[marker + 1].startsWith('@')
      ? segments.slice(marker + 1, marker + 3)
      : segments.slice(marker + 1, marker + 2);
    const packageName = nameParts.join('/');
    const packageRoot = path.resolve(ROOT, ...segments.slice(0, marker + 1), ...nameParts);
    roots.set(packageRoot, packageName);
  }
  return [...roots]
    .map(([packageRoot, packageName]) => [packageName, packageRoot])
    .sort(([aName, aRoot], [bName, bRoot]) =>
      aName.localeCompare(bName) || aRoot.localeCompare(bRoot));
}

function buildLicenseFile(inputs) {
  const sections = packageRoots(inputs).map(([packageName, packageRoot]) => {
    const manifest = JSON.parse(fs.readFileSync(path.join(packageRoot, 'package.json'), 'utf8'));
    const licenseFile = fs.readdirSync(packageRoot)
      .filter((name) => /^licen[cs]e(?:\.|$)/i.test(name))
      .sort()[0];
    if (!licenseFile) throw new Error(`No license file found for bundled package ${packageName}`);

    const licenseText = fs.readFileSync(path.join(packageRoot, licenseFile), 'utf8')
      .replaceAll('\r\n', '\n')
      .replace(/[ \t]+$/gm, '')
      .trim();
    return [
      `Package: ${packageName}@${manifest.version}`,
      `License: ${manifest.license}`,
      '',
      licenseText,
    ].join('\n');
  });

  return [
    'Static HTML parser bundle: third-party licenses',
    'Generated by scripts/build-static-html-parsers.js. Do not edit.',
    '',
    sections.join('\n\n------------------------------------------------------------------------\n\n'),
    '',
  ].join('\n');
}

async function generate() {
  const result = await build({
    absWorkingDir: ROOT,
    bundle: true,
    entryPoints: [ENTRY],
    format: 'esm',
    legalComments: 'none',
    metafile: true,
    minify: true,
    platform: 'node',
    target: 'node22',
    write: false,
  });
  const bundle = HEADER + result.outputFiles[0].text;
  if (Buffer.byteLength(bundle) > MAX_BUNDLE_BYTES) {
    throw new Error(
      `${BUNDLE_NAME} is ${(Buffer.byteLength(bundle) / 1024).toFixed(1)} KB; ` +
      `the ${MAX_BUNDLE_BYTES / 1024} KB limit prevents provider-copy bloat`,
    );
  }
  return new Map([
    [BUNDLE_NAME, bundle],
    [LICENSES_NAME, buildLicenseFile(result.metafile.inputs)],
  ]);
}

function checkDirectoryArg() {
  const index = process.argv.indexOf('--check-dir');
  if (index < 0) return OUT_DIR;
  if (!process.argv.includes('--check') || !process.argv[index + 1]) {
    throw new Error('--check-dir requires --check and a directory path');
  }
  return path.resolve(process.argv[index + 1]);
}

const generated = await generate();
if (process.argv.includes('--check')) {
  const checkDir = checkDirectoryArg();
  for (const [name, fresh] of generated) {
    const committedPath = path.join(checkDir, name);
    const committed = fs.existsSync(committedPath) ? fs.readFileSync(committedPath, 'utf8') : null;
    if (fresh !== committed) {
      process.stderr.write(
        `${path.relative(ROOT, committedPath)} is stale. ` +
        'Run: node scripts/build-static-html-parsers.js\n',
      );
      process.exit(1);
    }
  }
  process.exit(0);
}

fs.mkdirSync(OUT_DIR, { recursive: true });
for (const [name, contents] of generated) {
  const output = path.join(OUT_DIR, name);
  fs.writeFileSync(output, contents);
  console.log(`Generated ${path.relative(ROOT, output)} (${(Buffer.byteLength(contents) / 1024).toFixed(1)} KB)`);
}