const express = require('express');
const router  = express.Router();
const billing  = require('../services/billing');
const yukassa  = require('../services/yukassa');
const { query } = require('../config/db');

function uid(req) { return req.headers['x-user-id'] ? parseInt(req.headers['x-user-id']) : null; }

// GET /api/billing/balance — баланс + план текущего юзера
router.get('/balance', async (req, res) => {
  const userId = uid(req);
  if (!userId) return res.status(401).json({ error: 'x-user-id required' });
  try {
    await billing.ensureBalance(userId);
    const bal = await billing.getBalance(userId);
    res.json(bal);
  } catch (err) { res.status(500).json({ error: err.message }); }
});

// GET /api/billing/transactions — история транзакций
router.get('/transactions', async (req, res) => {
  const userId = uid(req);
  if (!userId) return res.status(401).json({ error: 'x-user-id required' });
  const limit  = Math.min(parseInt(req.query.limit  || 50), 200);
  const offset = parseInt(req.query.offset || 0);
  try {
    const txs = await billing.getTransactions(userId, { limit, offset });
    const { rows: [{ total }] } = await query(
      'SELECT count(*)::int as total FROM user_transactions WHERE user_id=$1', [userId]
    );
    res.json({ transactions: txs, total, limit, offset });
  } catch (err) { res.status(500).json({ error: err.message }); }
});

// GET /api/billing/plans — все тарифы (публичный)
router.get('/plans', async (req, res) => {
  try {
    const { rows } = await query(
      'SELECT * FROM plans WHERE is_active=true ORDER BY sort_order'
    );
    const { rows: costs } = await query('SELECT * FROM credit_costs ORDER BY operation');
    res.json({ plans: rows, costs });
  } catch (err) { res.status(500).json({ error: err.message }); }
});

// POST /api/billing/admin/credit — начислить кредиты вручную (только admin)
router.post('/admin/credit', async (req, res) => {
  const adminId = uid(req);
  if (!adminId) return res.status(401).json({ error: 'x-user-id required' });
  const { rows: [admin] } = await query('SELECT is_admin FROM users WHERE id=$1', [adminId]);
  if (!admin?.is_admin) return res.status(403).json({ error: 'Forbidden' });

  const { user_id, amount, description = 'Ручное начисление от администратора' } = req.body;
  if (!user_id || !amount) return res.status(400).json({ error: 'user_id и amount обязательны' });
  try {
    const result = await billing.credit(user_id, amount, 'bonus', description, { by_admin: adminId });
    res.json(result);
  } catch (err) { res.status(500).json({ error: err.message }); }
});

// GET /api/billing/admin/users — балансы всех пользователей (только admin)
router.get('/admin/users', async (req, res) => {
  const adminId = uid(req);
  if (!adminId) return res.status(401).json({ error: 'x-user-id required' });
  const { rows: [admin] } = await query('SELECT is_admin FROM users WHERE id=$1', [adminId]);
  if (!admin?.is_admin) return res.status(403).json({ error: 'Forbidden' });
  try {
    const { rows } = await query(`
      SELECT u.id, u.email, u.name,
             ub.credits, ub.reset_at,
             p.name as plan_name, p.code as plan_code, p.price_rub
      FROM users u
      LEFT JOIN user_balance ub ON ub.user_id = u.id
      LEFT JOIN user_subscriptions us ON us.user_id = u.id
        AND us.status='active' AND (us.expires_at IS NULL OR us.expires_at > NOW())
      LEFT JOIN plans p ON p.id = us.plan_id
      ORDER BY u.created_at DESC
    `);
    res.json(rows);
  } catch (err) { res.status(500).json({ error: err.message }); }
});

module.exports = router;

// POST /api/billing/checkout — создать платёж ЮKassa
router.post('/checkout', async (req, res) => {
  const userId = uid(req);
  if (!userId) return res.status(401).json({ error: 'x-user-id required' });
  const { plan_code } = req.body;
  if (!plan_code) return res.status(400).json({ error: 'plan_code required' });
  try {
    const { rows: [user] } = await query('SELECT email FROM users WHERE id=$1', [userId]);
    const result = await yukassa.createPayment({ userId, planCode: plan_code, userEmail: user?.email });
    res.json(result);
  } catch (err) {
    console.error('[billing] checkout:', err.message);
    res.status(500).json({ error: err.message });
  }
});

// POST /api/billing/webhook — вебхук ЮKassa (без auth, проверка по IP/подписи)
router.post('/webhook', express.json({ type: '*/*' }), async (req, res) => {
  try {
    const result = await yukassa.handleWebhook(req.body);
    res.json({ ok: true, ...result });
  } catch (err) {
    console.error('[billing] webhook error:', err.message);
    res.status(500).json({ error: err.message });
  }
});

// POST /api/billing/monthly-reset — ежемесячный сброс кредитов (вызывается cron)
router.post('/monthly-reset', async (req, res) => {
  try {
    const processed = await billing.processMonthlyResets();
    console.log(`[Billing] monthly reset: ${processed} users processed`);
    res.json({ ok: true, processed });
  } catch (err) {
    console.error('[Billing] monthly-reset error:', err.message);
    res.status(500).json({ error: err.message });
  }
});