import express from 'express';
import bcrypt from 'bcrypt';
import { body, validationResult } from 'express-validator';
import crypto from 'crypto';
import pool from '../config/database.js';
import { authenticateToken, requireSuperAdmin } from '../middleware/auth.js';
import { sendDemoInviteMail } from '../lib/mail.js';
import { seedDemoTenant } from '../lib/seed.js';

const router = express.Router();
router.use(authenticateToken, requireSuperAdmin);

// GET /api/tenants
router.get('/', async (req, res) => {
  try {
    const [rows] = await pool.query(
      `SELECT t.*,
              (SELECT COUNT(*) FROM mitarbeiter WHERE tenant_id = t.id) AS user_count,
              (SELECT COUNT(*) FROM kunden WHERE tenant_id = t.id) AS kunden_count
       FROM tenants t
       ORDER BY t.erstellt_am DESC`
    );
    res.json(rows);
  } catch (e) {
    console.error('GET tenants:', e);
    res.status(500).json({ error: 'Serverfehler' });
  }
});

// GET /api/tenants/:id
router.get('/:id', async (req, res) => {
  try {
    const [rows] = await pool.query('SELECT * FROM tenants WHERE id = ?', [req.params.id]);
    if (rows.length === 0) return res.status(404).json({ error: 'Tenant nicht gefunden' });
    res.json(rows[0]);
  } catch (e) {
    res.status(500).json({ error: 'Serverfehler' });
  }
});

// POST /api/tenants  -> legt Demo-Tenant + Admin-User + Sample-Daten an, schickt Invite-Mail
// body: { name, kontakt_email, firma?, days? (default 30), seed? (default true) }
router.post('/', [
  body('name').notEmpty().trim(),
  body('kontakt_email').isEmail().normalizeEmail(),
  body('days').optional().isInt({ min: 1, max: 365 })
], async (req, res) => {
  const errors = validationResult(req);
  if (!errors.isEmpty()) return res.status(400).json({ errors: errors.array() });

  const { name, kontakt_email, firma, days = 30, seed = true } = req.body;
  const slug = (firma || name).toLowerCase()
    .replace(/[^a-z0-9]+/g, '-').replace(/^-|-$/g, '').slice(0, 50)
    + '-' + crypto.randomBytes(2).toString('hex');

  const conn = await pool.getConnection();
  try {
    await conn.beginTransaction();

    // tenant
    const tenantId = crypto.randomUUID();
    await conn.query(
      `INSERT INTO tenants (id, name, slug, kontakt_email, firma, typ, status, demo_expires_at, max_users)
       VALUES (?, ?, ?, ?, ?, 'demo', 'aktiv', DATE_ADD(NOW(), INTERVAL ? DAY), 5)`,
      [tenantId, name, slug, kontakt_email, firma || null, days]
    );

    // admin user
    const adminId = crypto.randomUUID();
    const plainPw = crypto.randomBytes(8).toString('base64url');
    const hash = await bcrypt.hash(plainPw, 10);
    await conn.query(
      `INSERT INTO mitarbeiter (id, tenant_id, email, password_hash, name, rolle, aktiv)
       VALUES (?, ?, ?, ?, ?, 'admin', 1)`,
      [adminId, tenantId, kontakt_email, hash, name]
    );

    if (seed) await seedDemoTenant(conn, tenantId);

    await conn.commit();

    // Mail asynchron - Fehler nicht blockend
    sendDemoInviteMail({
      to: kontakt_email, name, slug, password: plainPw,
      loginUrl: `https://pfandsystem.dockly.de/login?tenant=${slug}`,
      days
    }).catch(err => console.error('Mail-Fehler:', err.message));

    res.status(201).json({
      tenant_id: tenantId, slug,
      admin_email: kontakt_email,
      // Passwort wird ausnahmsweise im Response zurückgegeben, damit der SuperAdmin
      // es ggf. manuell weitergeben kann, falls die Mail nicht ankommt.
      admin_password_oneshot: plainPw,
      demo_expires_in_days: days
    });
  } catch (e) {
    await conn.rollback();
    console.error('Tenant-Anlage-Fehler:', e);
    res.status(500).json({ error: 'Fehler beim Anlegen des Tenants', detail: e.message });
  } finally {
    conn.release();
  }
});

// PATCH /api/tenants/:id  -> Demo verlaengern, Status ändern, Limits ändern
router.patch('/:id', async (req, res) => {
  const updates = [];
  const values = [];
  if (req.body.extend_days) {
    updates.push('demo_expires_at = DATE_ADD(COALESCE(demo_expires_at, NOW()), INTERVAL ? DAY)');
    values.push(parseInt(req.body.extend_days));
    updates.push("status = 'aktiv'");
  }
  if (req.body.status) { updates.push('status = ?'); values.push(req.body.status); }
  if (req.body.max_users) { updates.push('max_users = ?'); values.push(parseInt(req.body.max_users)); }
  if (req.body.typ) { updates.push('typ = ?'); values.push(req.body.typ); }
  if (updates.length === 0) return res.status(400).json({ error: 'Keine Änderungen' });
  values.push(req.params.id);
  try {
    await pool.query(`UPDATE tenants SET ${updates.join(', ')} WHERE id = ?`, values);
    const [rows] = await pool.query('SELECT * FROM tenants WHERE id = ?', [req.params.id]);
    res.json(rows[0]);
  } catch (e) {
    console.error('Tenant-Update:', e);
    res.status(500).json({ error: 'Serverfehler' });
  }
});

// DELETE /api/tenants/:id  -> Tenant inkl. aller Daten löschen (CASCADE)
router.delete('/:id', async (req, res) => {
  try {
    await pool.query('DELETE FROM tenants WHERE id = ?', [req.params.id]);
    res.json({ message: 'Tenant gelöscht' });
  } catch (e) {
    res.status(500).json({ error: 'Serverfehler' });
  }
});

export default router;