server.js

const express = require('express');
const path = require('path');
const fs = require('fs');
const compression = require('compression');
require('dotenv').config();

const app = express();
const PORT = process.env.PORT || 3000;
const BASE_URL = process.env.BASE_URL || 'https://sua-url.vercel.app';

// Simple in-memory cache for HTML pages (LRU-like with max size)
const cache = new Map();
const MAX_CACHE_ITEMS = 20;
function getFromCache(key) {
  return cache.get(key);
}
function setToCache(key, value) {
  if (cache.has(key)) {
    cache.delete(key);
  }
  cache.set(key, value);
  if (cache.size > MAX_CACHE_ITEMS) {
    // Evict the oldest inserted
    const firstKey = cache.keys().next().value;
    cache.delete(firstKey);
  }
}

app.use(compression());

// Serve static assets with long-term caching
app.use('/assets', express.static(path.join(__dirname, 'assets'), {
  etag: true,
  maxAge: '1d',
  setHeaders: (res, filePath) => {
    if (/\.(svg|png|jpg|jpeg|gif|css|js)$/i.test(filePath)) {
      res.setHeader('Cache-Control', 'public, max-age=86400, immutable');
    }
  }
}));

// Serve src folder for CSS, JSON, etc.
app.use('/src', express.static(path.join(__dirname, 'src')));

app.get('/', (req, res) => {
  const index = path.join(__dirname, 'src', 'pages', 'index.html');
  if (fs.existsSync(index)) {
    res.setHeader('Content-Type', 'text/html; charset=utf-8');
    return res.sendFile(index);
  }
  return res.redirect('/roadmap');
});

app.get('/roadmap', (req, res) => {
  const roadmap = path.join(__dirname, 'src', 'pages', 'roadmap.html');
  if (fs.existsSync(roadmap)) {
    res.setHeader('Content-Type', 'text/html; charset=utf-8');
    return res.sendFile(roadmap);
  }
  return res.redirect('/');
});

app.get(['/ferramentas', '/tools'], (req, res) => {
  const tools = path.join(__dirname, 'src', 'pages', 'tools.html');
  if (fs.existsSync(tools)) {
    res.setHeader('Content-Type', 'text/html; charset=utf-8');
    return res.sendFile(tools);
  }
  return res.redirect('/');
});

app.get('/infografico/:id', (req, res) => {
  const id = req.params.id;
  if (!/^\d+$/.test(id)) {
    return res.status(400).send('ID inválido');
  }
  let file = path.join(__dirname, 'src', 'pages', `${id}.page.html`);
  if (!fs.existsSync(file)) {
    file = path.join(__dirname, `${id}.page.html`);
  }

  try {
    let html = getFromCache(file);
    if (!html) {
      if (!fs.existsSync(file)) {
        return res.status(404).send('Infográfico não encontrado');
      }
      html = fs.readFileSync(file, 'utf-8');
      setToCache(file, html);
    }
    res.setHeader('Content-Type', 'text/html; charset=utf-8');
    res.setHeader('Cache-Control', 'public, max-age=300'); // cache de página por 5 min
    return res.send(html);
  } catch (err) {
    console.error('Erro ao servir página:', err);
    return res.status(500).send('Erro interno do servidor');
  }
});

// Sitemap XML para SEO
app.get('/sitemap.xml', (req, res) => {
  const sitemapPath = path.join(__dirname, 'sitemap.xml');
  if (fs.existsSync(sitemapPath)) {
    let sitemap = fs.readFileSync(sitemapPath, 'utf-8');
    // Substitui a URL base se necessário
    if (BASE_URL !== 'https://example.com') {
      sitemap = sitemap.replace(/https:\/\/example\.com/g, BASE_URL);
    }
    res.setHeader('Content-Type', 'application/xml; charset=utf-8');
    res.setHeader('Cache-Control', 'public, max-age=3600'); // cache por 1 hora
    return res.send(sitemap);
  }
  return res.status(404).send('Sitemap não encontrado');
});

// Robots.txt para SEO
app.get('/robots.txt', (req, res) => {
  const robotsTxt = `User-agent: *
Allow: /
Disallow: /node_modules/
Disallow: /package.json
Disallow: /package-lock.json

Sitemap: ${BASE_URL}/sitemap.xml
`;
  res.setHeader('Content-Type', 'text/plain; charset=utf-8');
  res.setHeader('Cache-Control', 'public, max-age=86400'); // cache por 1 dia
  return res.send(robotsTxt);
});

app.listen(PORT, () => {
  console.log(`Servidor iniciado em http://localhost:${PORT}`);
  console.log(`URL base configurada: ${BASE_URL}`);
  console.log(`Sitemap disponível em: ${BASE_URL}/sitemap.xml`);
});