// Static server for the built site behind the demos.githubnext.com gateway.
// The gateway strips the /iamnbutler/stylize prefix before forwarding and sends it as X-Forwarded-Prefix.
import { createReadStream, statSync } from 'node:fs';
import { createServer } from 'node:http';
import { extname, join, normalize, resolve } from 'node:path';

const ROOT = resolve(process.env.SITE_DIR ?? 'site');
const PORT = Number(process.env.PORT ?? 3214);
const TYPES = {
  '.html': 'text/html; charset=utf-8',
  '.js': 'text/javascript; charset=utf-8',
  '.mjs': 'text/javascript; charset=utf-8',
  '.css': 'text/css; charset=utf-8',
  '.json': 'application/json; charset=utf-8',
  '.svg': 'image/svg+xml',
  '.png': 'image/png',
  '.jpg': 'image/jpeg',
  '.webp': 'image/webp',
  '.woff2': 'font/woff2',
};

function stat(path) {
  try { return statSync(path); } catch { return null; }
}

createServer((req, res) => {
  const url = new URL(req.url, 'http://x');
  if (url.pathname === '/healthz') return res.end('ok');
  if (req.method !== 'GET' && req.method !== 'HEAD') return res.writeHead(405).end();

  const path = normalize(decodeURIComponent(url.pathname));
  let file = join(ROOT, path);
  if (!file.startsWith(ROOT)) return res.writeHead(404).end();

  let info = stat(file);
  if (info?.isDirectory()) {
    // Directions load ../content/posts.json, so directory URLs need the trailing slash.
    if (!path.endsWith('/')) {
      const prefix = (req.headers['x-forwarded-prefix'] ?? '').replace(/\/$/, '');
      return res.writeHead(301, { location: `${prefix}${path}/${url.search}` }).end();
    }
    file = join(file, 'index.html');
    info = stat(file);
  }
  if (!info?.isFile()) return res.writeHead(404, { 'content-type': 'text/plain' }).end('not found');

  res.writeHead(200, {
    'content-type': TYPES[extname(file)] ?? 'application/octet-stream',
    'content-length': info.size,
    'cache-control': 'private, no-cache',
  });
  if (req.method === 'HEAD') return res.end();
  createReadStream(file).pipe(res);
}).listen(PORT, '0.0.0.0', () => console.log(`serving ${ROOT} on :${PORT}`));