import { existsSync, readdirSync, readFileSync, statSync } from 'node:fs';
import { gzipSync } from 'node:zlib';
import { basename, join, resolve } from 'node:path';

const root = resolve(process.cwd());
const dist = resolve(root, 'dist');
const assets = join(dist, 'assets');
const budgets = {
  initialJsGzip: 350 * 1024,
  initialCssGzip: 30 * 1024,
  fontsBytes: 2 * 1024 * 1024,
  moduleMediaBytes: 1 * 1024 * 1024,
};

function readAsset(relativePath) {
  return readFileSync(join(dist, relativePath));
}

function gzipBytes(bytes) {
  return gzipSync(bytes, { level: 9 }).byteLength;
}

function formatBytes(bytes) {
  return `${(bytes / 1024).toFixed(1)} KiB`;
}

if (!existsSync(join(dist, 'index.html')) || !existsSync(assets)) {
  console.error('性能预算检查需要先运行 pnpm run build:vite。');
  process.exit(1);
}

const html = readFileSync(join(dist, 'index.html'), 'utf8');
const initialJs = [...html.matchAll(/<script[^>]+src="\.\/([^\"]+\.js)"/g)]
  .map((match) => match[1])
  .reduce((total, relativePath) => total + gzipBytes(readAsset(relativePath)), 0);
const initialCss = [...html.matchAll(/<link[^>]+href="\.\/([^\"]+\.css)"/g)]
  .map((match) => match[1])
  .reduce((total, relativePath) => total + gzipBytes(readAsset(relativePath)), 0);
const assetNames = readdirSync(assets);
const fontBytes = assetNames
  .filter((name) => /\.(woff2?|otf|ttf)$/i.test(name))
  .reduce((total, name) => total + statSync(join(assets, name)).size, 0);
const moduleMediaBytes = assetNames
  .filter((name) => /^module-.*\.(avif|webp|png|jpe?g)$/i.test(name))
  .reduce((total, name) => total + statSync(join(assets, name)).size, 0);

const metrics = { initialJsGzip: initialJs, initialCssGzip: initialCss, fontsBytes: fontBytes, moduleMediaBytes };
console.log(JSON.stringify({ metrics, budgets }, null, 2));

const failures = Object.entries(budgets)
  .filter(([key, budget]) => metrics[key] > budget)
  .map(([key, budget]) => `${key} ${formatBytes(metrics[key])} > ${formatBytes(budget)}`);
if (failures.length > 0) {
  console.error(`性能预算超标：${failures.join('; ')}`);
  process.exit(1);
}