#!/usr/bin/env node
/* 极简静态文件服务器（官网预览用，替代沙箱内不可用的 python3 -m http.server） */
const http = require('http');
const fs = require('fs');
const path = require('path');

const ROOT = path.join(__dirname, '..', 'exp');
const PORT = Number(process.argv[2]) || 8898;

const MIME = {
  html: 'text/html; charset=utf-8', js: 'text/javascript', mjs: 'text/javascript',
  css: 'text/css', json: 'application/json; charset=utf-8', png: 'image/png',
  jpg: 'image/jpeg', jpeg: 'image/jpeg', gif: 'image/gif', svg: 'image/svg+xml',
  webp: 'image/webp', woff: 'font/woff', woff2: 'font/woff2', ttf: 'font/ttf',
  pdf: 'application/pdf', docx: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
  txt: 'text/plain; charset=utf-8', md: 'text/plain; charset=utf-8', ico: 'image/x-icon',
  mp4: 'video/mp4', webm: 'video/webm',
};

http.createServer((req, res) => {
  try {
    let p = decodeURIComponent(new URL(req.url, 'http://x').pathname);
    if (p.endsWith('/')) p += 'index.html';
    const file = path.normalize(path.join(ROOT, p));
    if (!file.startsWith(ROOT)) { res.writeHead(403); return res.end(); }
    fs.readFile(file, (err, data) => {
      if (err) { res.writeHead(404); return res.end('not found'); }
      const ext = path.extname(file).slice(1).toLowerCase();
      res.writeHead(200, { 'Content-Type': MIME[ext] || 'application/octet-stream' });
      res.end(data);
    });
  } catch (e) { res.writeHead(500); res.end(String(e)); }
}).listen(PORT, '127.0.0.1', () => console.log(`preview: http://127.0.0.1:${PORT}/ (root: ${ROOT})`));