const express = require('express');
const router  = express.Router();
const db      = require('../config/database');
const { requireAdmin } = require('../middleware/auth');

// GET /admin/contracts
router.get('/', requireAdmin, async (req, res) => {
  try {
    // Verträge nach Kategorie
    const [byCategory] = await db.query(`
      SELECT 
        c.name as category_name,
        COUNT(m.id)                                              as total,
        SUM(CASE WHEN m.status='active'   THEN 1 ELSE 0 END)   as active,
        SUM(CASE WHEN m.status='paused'   THEN 1 ELSE 0 END)   as paused,
        SUM(CASE WHEN m.status='inactive' THEN 1 ELSE 0 END)   as inactive,
        SUM(COALESCE(m.agreed_price, t.price_monthly))          as monthly_revenue
      FROM memberships m
      JOIN tariffs t    ON m.tariff_id    = t.id
      LEFT JOIN categories c ON t.category_id = c.id
      GROUP BY c.id, c.name
      ORDER BY total DESC
    `);

    // Verträge nach Tarif
    const [byTariff] = await db.query(`
      SELECT 
        t.name as tariff_name, t.price_monthly, t.duration_months, t.active as tariff_active,
        COUNT(m.id)                                              as total,
        SUM(CASE WHEN m.status='active'   THEN 1 ELSE 0 END)   as active,
        SUM(COALESCE(m.agreed_price, t.price_monthly))          as monthly_revenue
      FROM memberships m
      JOIN tariffs t ON m.tariff_id = t.id
      GROUP BY t.id, t.name, t.price_monthly, t.duration_months, t.active
      ORDER BY active DESC, total DESC
    `);

    // Gesamtübersicht
    const [totals] = await db.query(`
      SELECT
        COUNT(*)                                               as total,
        SUM(CASE WHEN status='active'   THEN 1 ELSE 0 END)   as active,
        SUM(CASE WHEN status='paused'   THEN 1 ELSE 0 END)   as paused,
        SUM(CASE WHEN status='inactive' THEN 1 ELSE 0 END)   as inactive,
        SUM(CASE WHEN is_minor=1        THEN 1 ELSE 0 END)   as minors,
        SUM(COALESCE(agreed_price, 0))                        as total_monthly
      FROM memberships
    `);

    // Auslaufende Verträge – 3 Monate
    const [expiring] = await db.query(`
      SELECT m.*, t.name as tariff_name, t.price_monthly,
             COALESCE(m.agreed_price, t.price_monthly) as agreed_price
      FROM memberships m
      JOIN tariffs t ON m.tariff_id = t.id
      WHERE m.status = 'active'
        AND m.effective_end BETWEEN CURDATE() AND DATE_ADD(CURDATE(), INTERVAL 3 MONTH)
      ORDER BY m.effective_end ASC
    `);

    // Alle aktiven Tarife für Dropdown
    const [tariffs] = await db.query('SELECT * FROM tariffs WHERE active=1 ORDER BY name ASC');

    res.render('admin/contracts', {
      admin: req.session.adminUser,
      byCategory, byTariff,
      totals: totals[0],
      expiring, tariffs,
      success: req.query.success || null,
      error:   req.query.error   || null
    });
  } catch (err) {
    console.error(err);
    res.redirect('/admin?error=Fehler+in+Vertragsübersicht:+' + encodeURIComponent(err.message));
  }
});

module.exports = router;