'use strict';

// 静态前端：精确路径白名单（新增 public 文件需在 STATIC_MAP 登记）+ /assets/ 单段文件

const fs = require('fs');
const path = require('path');

const STATIC_MAP = {
  '/': ['index.html', 'text/html; charset=utf-8'],
  '/index.html': ['index.html', 'text/html; charset=utf-8'],
  '/app.js': ['app.js', 'application/javascript; charset=utf-8'],
  '/crawl.js': ['crawl.js', 'application/javascript; charset=utf-8'],
  '/gen.js': ['gen.js', 'application/javascript; charset=utf-8'],
  '/history.js': ['history.js', 'application/javascript; charset=utf-8'],
  '/tasks.js': ['tasks.js', 'application/javascript; charset=utf-8'],
  '/analysis-templates.js': ['analysis-templates.js', 'application/javascript; charset=utf-8'],
  '/reports.js': ['reports.js', 'application/javascript; charset=utf-8'],
  '/lake.js': ['lake.js', 'application/javascript; charset=utf-8'],
  '/ops.js': ['ops.js', 'application/javascript; charset=utf-8'],
  '/schools.js': ['schools.js', 'application/javascript; charset=utf-8'],
  '/multi-select.js': ['multi-select.js', 'application/javascript; charset=utf-8'],
  '/cockpit.js': ['cockpit.js', 'application/javascript; charset=utf-8'],
  '/vendor/china-map.json': ['vendor/china-map.json', 'application/json; charset=utf-8'],
  '/vendor/cn-universities.json': ['vendor/cn-universities.json', 'application/json; charset=utf-8'],
  '/vendor/cn-cities.json': ['vendor/cn-cities.json', 'application/json; charset=utf-8'],
  '/ask.js': ['ask.js', 'application/javascript; charset=utf-8'],
  '/vendor/echarts.min.js': ['vendor/echarts.min.js', 'application/javascript; charset=utf-8'],
  '/style.css': ['style.css', 'text/css; charset=utf-8'],
};

const STATIC_TYPES = {
  '.png': 'image/png', '.jpg': 'image/jpeg', '.svg': 'image/svg+xml',
  '.ico': 'image/x-icon', '.css': 'text/css', '.js': 'application/javascript',
};

function serveStatic(publicDir, pathname, res) {
  const entry = STATIC_MAP[pathname];
  if (entry) {
    const full = path.join(publicDir, entry[0]);
    fs.readFile(full, (err, data) => {
      if (err) { res.writeHead(404); return res.end('Not found'); }
      res.writeHead(200, { 'Content-Type': entry[1], 'Cache-Control': 'no-cache' });
      res.end(data);
    });
    return;
  }
  if (pathname.startsWith('/assets/')) {
    const rel = pathname.replace('/assets/', '');
    if (rel.includes('..') || rel.includes('/')) { res.writeHead(403); return res.end('Forbidden'); }
    const full = path.join(publicDir, 'assets', rel);
    if (!fs.existsSync(full) || !fs.statSync(full).isFile()) { res.writeHead(404); return res.end('Not found'); }
    const ext = path.extname(full).toLowerCase();
    res.writeHead(200, { 'Content-Type': STATIC_TYPES[ext] || 'application/octet-stream', 'Cache-Control': 'no-cache' });
    fs.createReadStream(full).pipe(res);
    return;
  }
  res.writeHead(404);
  res.end('Not found');
}

function register(app, ctx) {
  app.fallback((pathname, res) => serveStatic(ctx.PUBLIC_DIR, pathname, res));
}

module.exports = { register };