require('dotenv').config();

const path = require('path');
const fs = require('fs');
const crypto = require('crypto');
const express = require('express');
const multer = require('multer');

const auth = require('./lib/auth');
const { readContent, writeContent, readTheme, writeTheme, PROJECT_DIR } = require('./lib/content-store');
const { validateContent, validateTheme } = require('./lib/validate');
const schema = require('./lib/schema');
const { runBuild } = require('./lib/build');

const PORT = process.env.PORT || 4321;
const UPLOAD_DIR = process.env.UPLOAD_DIR || path.join(PROJECT_DIR, 'public', 'uploads');
const ALLOWED_IMAGE_TYPES = {
  'image/jpeg': '.jpg',
  'image/png': '.png',
  'image/webp': '.webp',
  'image/svg+xml': '.svg',
};
const MAX_UPLOAD_BYTES = 8 * 1024 * 1024;

if (!auth.hasConfiguredUsers() || !process.env.SESSION_SECRET) {
  console.error(
    'Mindestens ein Benutzer (ADMIN_USERNAME/ADMIN_PASSWORD_HASH) und SESSION_SECRET müssen gesetzt sein (siehe admin/.env.example).'
  );
  process.exit(1);
}

fs.mkdirSync(UPLOAD_DIR, { recursive: true });

const app = express();
app.set('trust proxy', 1);
app.disable('x-powered-by');

app.use((req, res, next) => {
  res.setHeader('X-Frame-Options', 'DENY');
  res.setHeader('X-Content-Type-Options', 'nosniff');
  res.setHeader('Referrer-Policy', 'same-origin');
  next();
});

app.use(express.json({ limit: '2mb' }));

// --- Login ---

function renderLoginPage({ csrfToken, error, locked }) {
  return `<!doctype html>
<html lang="de">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<meta name="robots" content="noindex, nofollow" />
<title>Anmelden · larpaso Admin</title>
<style>
  body { font-family: system-ui, sans-serif; background: #14110f; color: #f2ede4; display: flex; min-height: 100vh; align-items: center; justify-content: center; margin: 0; }
  form { background: #1f1a16; padding: 2.5rem; border-radius: 12px; width: min(360px, 90vw); box-shadow: 0 10px 30px rgba(0,0,0,0.4); }
  h1 { font-size: 1.25rem; margin: 0 0 1.5rem; }
  label { display: block; font-size: 0.85rem; margin-bottom: 0.3rem; color: #c9a876; }
  input { width: 100%; box-sizing: border-box; padding: 0.6rem 0.75rem; margin-bottom: 1rem; border-radius: 6px; border: 1px solid #3a332c; background: #14110f; color: #f2ede4; }
  button { width: 100%; padding: 0.7rem; border-radius: 6px; border: none; background: #c9a876; color: #14110f; font-weight: 600; cursor: pointer; }
  .error { background: #4a1f1f; color: #f2b8b8; padding: 0.6rem 0.75rem; border-radius: 6px; margin-bottom: 1rem; font-size: 0.85rem; }
</style>
</head>
<body>
  <form method="POST" action="/admin/login">
    <h1>larpaso · Admin-Bereich</h1>
    ${error ? `<div class="error">${error}</div>` : ''}
    <label for="username">Benutzername</label>
    <input type="text" id="username" name="username" autocomplete="username" required ${locked ? 'disabled' : ''} />
    <label for="password">Passwort</label>
    <input type="password" id="password" name="password" autocomplete="current-password" required ${locked ? 'disabled' : ''} />
    <input type="hidden" name="csrf" value="${csrfToken}" />
    <button type="submit" ${locked ? 'disabled' : ''}>Anmelden</button>
  </form>
</body>
</html>`;
}

app.get('/admin/login', (req, res) => {
  const cookies = auth.getCookies(req);
  if (auth.isValidSession(cookies[auth.SESSION_COOKIE])) {
    return res.redirect('/admin');
  }
  const csrfToken = auth.issueCsrfToken(res);
  const locked = auth.isLockedOut(req);
  res.send(
    renderLoginPage({
      csrfToken,
      locked,
      error: locked ? 'Zu viele Fehlversuche. Bitte in 15 Minuten erneut versuchen.' : null,
    })
  );
});

app.post('/admin/login', express.urlencoded({ extended: false }), (req, res) => {
  if (auth.isLockedOut(req)) {
    const csrfToken = auth.issueCsrfToken(res);
    return res
      .status(429)
      .send(renderLoginPage({ csrfToken, locked: true, error: 'Zu viele Fehlversuche. Bitte in 15 Minuten erneut versuchen.' }));
  }

  if (!auth.verifyCsrfToken(req)) {
    const csrfToken = auth.issueCsrfToken(res);
    return res.status(403).send(renderLoginPage({ csrfToken, error: 'Sitzung abgelaufen, bitte erneut versuchen.' }));
  }

  const { username, password } = req.body;
  if (!auth.verifyPassword(username, password)) {
    auth.recordFailedLogin(req);
    const csrfToken = auth.issueCsrfToken(res);
    return res.status(401).send(renderLoginPage({ csrfToken, error: 'Benutzername oder Passwort falsch.' }));
  }

  auth.recordSuccessfulLogin(req);
  const token = auth.createSession();
  res.cookie(auth.SESSION_COOKIE, token, { ...auth.baseCookieOptions(), maxAge: 12 * 60 * 60 * 1000 });
  res.redirect('/admin');
});

app.post('/admin/logout', (req, res) => {
  const cookies = auth.getCookies(req);
  auth.destroySession(cookies[auth.SESSION_COOKIE]);
  res.clearCookie(auth.SESSION_COOKIE, auth.baseCookieOptions());
  res.redirect('/admin/login');
});

// --- Protected admin UI + API ---

app.get('/admin', auth.requireAuth, (req, res) => {
  res.sendFile(path.join(__dirname, 'public', 'index.html'));
});

app.get('/admin/api/schema', auth.requireAuth, (req, res) => {
  res.json(schema);
});

app.get('/admin/api/content', auth.requireAuth, (req, res) => {
  res.json(readContent());
});

app.put('/admin/api/content', auth.requireAuth, auth.requireAdminHeader, (req, res) => {
  const errors = validateContent(req.body);
  if (errors.length > 0) {
    return res.status(400).json({ error: 'Ungültige Daten.', details: errors });
  }
  try {
    writeContent(req.body);
    res.json({ ok: true });
  } catch (err) {
    res.status(500).json({ error: `Speichern fehlgeschlagen: ${err.message}` });
  }
});

app.get('/admin/api/theme', auth.requireAuth, (req, res) => {
  res.json(readTheme());
});

app.put('/admin/api/theme', auth.requireAuth, auth.requireAdminHeader, (req, res) => {
  const errors = validateTheme(req.body);
  if (errors.length > 0) {
    return res.status(400).json({ error: 'Ungültige Daten.', details: errors });
  }
  try {
    writeTheme(req.body);
    res.json({ ok: true });
  } catch (err) {
    res.status(500).json({ error: `Speichern fehlgeschlagen: ${err.message}` });
  }
});

const upload = multer({
  storage: multer.memoryStorage(),
  limits: { fileSize: MAX_UPLOAD_BYTES },
});

app.post('/admin/api/upload', auth.requireAuth, auth.requireAdminHeader, upload.single('file'), (req, res) => {
  if (!req.file) {
    return res.status(400).json({ error: 'Keine Datei erhalten.' });
  }
  const ext = ALLOWED_IMAGE_TYPES[req.file.mimetype];
  if (!ext) {
    return res.status(400).json({ error: 'Nur JPG, PNG, WebP oder SVG erlaubt.' });
  }
  const filename = `${Date.now()}-${crypto.randomBytes(6).toString('hex')}${ext}`;
  fs.writeFileSync(path.join(UPLOAD_DIR, filename), req.file.buffer);
  res.json({ url: `/uploads/${filename}` });
});

app.post('/admin/api/publish', auth.requireAuth, auth.requireAdminHeader, async (req, res) => {
  const result = await runBuild();
  const output = result.output.slice(-8000);
  if (!result.ok) {
    return res.status(500).json({ ok: false, error: result.error, output });
  }
  res.json({ ok: true, output });
});

// Static admin UI assets (index.html, app.js, style.css) — mounted after the
// API routes above so it never intercepts /admin/api/* requests.
app.use('/admin', auth.requireAuth, express.static(path.join(__dirname, 'public')));

app.listen(PORT, () => {
  console.log(`larpaso admin läuft auf Port ${PORT}`);
});