// Urlaubsvergleich 2026 – Familie Heidrich
// Zero-dependency Node server: serves static page + voting API with file persistence.
const http = require('http');
const fs = require('fs');
const path = require('path');

const PORT = process.env.PORT || 80;
const PUBLIC = path.join(__dirname, 'public');

// Persistence: prefer mounted /data volume, fall back to local ./data
function pickDataDir() {
  const candidates = [process.env.DATA_DIR, '/data', path.join(__dirname, 'data')].filter(Boolean);
  for (const dir of candidates) {
    try { fs.mkdirSync(dir, { recursive: true }); fs.accessSync(dir, fs.constants.W_OK); return dir; }
    catch (e) { /* try next */ }
  }
  return __dirname;
}
const DATA_DIR = pickDataDir();
const DATA_FILE = path.join(DATA_DIR, 'votes.json');

const VOTERS = ['till', 'lea', 'astrid'];

function loadState() {
  try { return JSON.parse(fs.readFileSync(DATA_FILE, 'utf8')); }
  catch (e) { return { votes: {} }; }
}
function saveState(state) {
  try { fs.writeFileSync(DATA_FILE, JSON.stringify(state)); } catch (e) { console.error('save failed', e); }
}
let state = loadState();

// In-memory image cache for the proxy
const imgCache = new Map();
function hostAllowed(host) {
  return /(^|\.)urlaub\.check24\.de$/.test(host) || host === 'files.ahoi-schiff.de';
}

const MIME = { '.html': 'text/html; charset=utf-8', '.js': 'text/javascript; charset=utf-8',
  '.css': 'text/css; charset=utf-8', '.json': 'application/json', '.svg': 'image/svg+xml',
  '.png': 'image/png', '.jpg': 'image/jpeg', '.ico': 'image/x-icon', '.webmanifest': 'application/manifest+json' };

function sendJSON(res, code, obj) {
  const body = JSON.stringify(obj);
  res.writeHead(code, { 'Content-Type': 'application/json', 'Cache-Control': 'no-store' });
  res.end(body);
}

function readBody(req) {
  return new Promise((resolve) => {
    let b = ''; req.on('data', c => { b += c; if (b.length > 1e5) req.destroy(); });
    req.on('end', () => { try { resolve(JSON.parse(b || '{}')); } catch (e) { resolve({}); } });
  });
}

const server = http.createServer(async (req, res) => {
  const url = new URL(req.url, 'http://x');
  const p = url.pathname;

  // ---- API ----
  if (p === '/api/state' && req.method === 'GET') {
    return sendJSON(res, 200, { votes: state.votes, voters: VOTERS });
  }
  if (p === '/api/vote' && req.method === 'POST') {
    const { voter, option, stars } = await readBody(req);
    if (!VOTERS.includes(voter) || !option || typeof stars !== 'number' || stars < 0 || stars > 5) {
      return sendJSON(res, 400, { error: 'invalid' });
    }
    state.votes[voter] = state.votes[voter] || {};
    if (stars === 0) { delete state.votes[voter][option]; }
    else { state.votes[voter][option] = Math.round(stars); }
    saveState(state);
    return sendJSON(res, 200, { votes: state.votes, voters: VOTERS });
  }
  if (p === '/api/reset' && req.method === 'POST') {
    state = { votes: {} }; saveState(state);
    return sendJSON(res, 200, { votes: state.votes, voters: VOTERS });
  }
  if (p === '/health') { return sendJSON(res, 200, { ok: true }); }

  // ---- Image proxy (defeats hotlink/referrer protection, same-origin = always loads) ----
  if (p === '/img' && req.method === 'GET') {
    const u = url.searchParams.get('u');
    let host;
    try { host = new URL(u).host; } catch (e) { res.writeHead(400); return res.end('bad url'); }
    if (!hostAllowed(host)) { res.writeHead(403); return res.end('host not allowed'); }
    if (imgCache.has(u)) {
      const c = imgCache.get(u);
      res.writeHead(200, { 'Content-Type': c.type, 'Cache-Control': 'public, max-age=604800' });
      return res.end(c.buf);
    }
    try {
      const referer = host.endsWith('ahoi-schiff.de') ? 'https://www.ahoi-schiff.de/' : 'https://urlaub.check24.de/';
      const ac = new AbortController();
      const t = setTimeout(() => ac.abort(), 8000);
      const r = await fetch(u, { signal: ac.signal, headers: {
        'Referer': referer, 'User-Agent': 'Mozilla/5.0 (compatible; HeidrichReise/1.0)', 'Accept': 'image/*'
      }});
      clearTimeout(t);
      if (!r.ok) { res.writeHead(502); return res.end('upstream ' + r.status); }
      const type = r.headers.get('content-type') || 'image/jpeg';
      const buf = Buffer.from(await r.arrayBuffer());
      if (imgCache.size < 300) imgCache.set(u, { buf, type });
      res.writeHead(200, { 'Content-Type': type, 'Cache-Control': 'public, max-age=604800' });
      return res.end(buf);
    } catch (e) { res.writeHead(502); return res.end('proxy error'); }
  }

  // ---- Static ----
  let file = p === '/' ? '/index.html' : decodeURIComponent(p);
  const full = path.join(PUBLIC, path.normalize(file).replace(/^(\.\.[\/\\])+/, ''));
  if (!full.startsWith(PUBLIC)) { res.writeHead(403); return res.end('forbidden'); }
  fs.readFile(full, (err, data) => {
    if (err) {
      // SPA-ish fallback to index
      return fs.readFile(path.join(PUBLIC, 'index.html'), (e2, d2) => {
        if (e2) { res.writeHead(404); return res.end('not found'); }
        res.writeHead(200, { 'Content-Type': MIME['.html'] }); res.end(d2);
      });
    }
    const ext = path.extname(full).toLowerCase();
    res.writeHead(200, { 'Content-Type': MIME[ext] || 'application/octet-stream' });
    res.end(data);
  });
});

server.listen(PORT, () => console.log('Reise-Vergleich läuft auf Port ' + PORT + ' | Daten: ' + DATA_FILE));

// Prefetch all hotel/cruise images into the proxy cache so the first visit is instant.
(async () => {
  let list = [];
  try { list = JSON.parse(fs.readFileSync(path.join(__dirname, 'warm-urls.json'), 'utf8')); }
  catch (e) { return; }
  for (const u of list) {
    try {
      const host = new URL(u).host;
      if (!hostAllowed(host) || imgCache.has(u)) continue;
      const referer = host.endsWith('ahoi-schiff.de') ? 'https://www.ahoi-schiff.de/' : 'https://urlaub.check24.de/';
      const r = await fetch(u, { headers: { 'Referer': referer, 'User-Agent': 'Mozilla/5.0 (compatible; HeidrichReise/1.0)', 'Accept': 'image/*' } });
      if (r.ok) imgCache.set(u, { buf: Buffer.from(await r.arrayBuffer()), type: r.headers.get('content-type') || 'image/jpeg' });
    } catch (e) { /* skip */ }
  }
  console.log('Bild-Cache vorgewärmt:', imgCache.size + '/' + list.length);
})();