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

const uid = req => req.user.id;

// ── Ausgaben CRUD ──────────────────────────────────────────────────────────
router.get('/expenses', authenticate, (req, res) => {
  const { from, to } = req.query;
  let q = 'SELECT * FROM expenses WHERE user_id=?';
  const p = [uid(req)];
  if (from) { q += ' AND date>=?'; p.push(from); }
  if (to)   { q += ' AND date<=?'; p.push(to); }
  q += ' ORDER BY date DESC, id DESC';
  res.json(db.prepare(q).all(...p));
});

router.post('/expenses', authenticate, (req, res) => {
  const { date, category, description, amount } = req.body;
  if (!date || !description || !amount) return res.status(400).json({ error: 'Fehlende Felder' });
  const r = db.prepare('INSERT INTO expenses (user_id,date,category,description,amount) VALUES (?,?,?,?,?)')
    .run(uid(req), date, category||'Sonstiges', description, parseFloat(amount));
  res.json(db.prepare('SELECT * FROM expenses WHERE id=?').get(r.lastInsertRowid));
});

router.delete('/expenses/:id', authenticate, (req, res) => {
  const e = db.prepare('SELECT id FROM expenses WHERE id=? AND user_id=?').get(req.params.id, uid(req));
  if (!e) return res.status(404).json({ error: 'Nicht gefunden' });
  db.prepare('DELETE FROM expenses WHERE id=?').run(e.id);
  res.json({ ok: true });
});

// ── Statistik-Daten ────────────────────────────────────────────────────────
router.get('/overview', authenticate, (req, res) => {
  const { from, to } = req.query;
  const u = uid(req);

  let oq = `SELECT o.*,
    COALESCE(o.custom_price,
      (SELECT SUM(oi.custom_price * oi.stueckzahl) FROM order_items oi WHERE oi.order_id=o.id AND oi.custom_price IS NOT NULL)
    ) as revenue,
    (SELECT COALESCE(SUM(COALESCE(c.preis_freundschaft, oi.preis_freundschaft, 0) * oi.stueckzahl),0)
     FROM order_items oi LEFT JOIN calculations c ON c.id=oi.calculation_id WHERE oi.order_id=o.id) as base_cost
    FROM orders o WHERE o.user_id=?`;
  const op = [u];
  if (from) { oq += ' AND DATE(o.created_at)>=?'; op.push(from); }
  if (to)   { oq += ' AND DATE(o.created_at)<=?'; op.push(to); }
  oq += ' ORDER BY o.created_at DESC';
  const orders = db.prepare(oq).all(...op);

  const paidOrders = orders.filter(o => !!o.bezahlt);
  const openOrders = orders.filter(o => !o.bezahlt && o.status !== 'warteliste');

  const totalRevenue  = paidOrders.reduce((s,o) => s + (o.revenue || 0), 0);
  const openRevenue   = openOrders.reduce((s,o) => s + (o.revenue || 0), 0);
  const totalBaseCost = paidOrders.reduce((s,o) => s + (o.base_cost || 0), 0);
  const totalProfit   = totalRevenue - totalBaseCost;

  let eq = 'SELECT * FROM expenses WHERE user_id=?';
  const ep = [u];
  if (from) { eq += ' AND date>=?'; ep.push(from); }
  if (to)   { eq += ' AND date<=?'; ep.push(to); }
  const expenses = db.prepare(eq + ' ORDER BY date DESC').all(...ep);
  const totalExpenses = expenses.reduce((s,e) => s + e.amount, 0);
  const netProfit = totalProfit - totalExpenses;

  const byStatus = { warteliste:0, in_arbeit:0, fertig:0, bezahlt:0, abgeschlossen:0 };
  for (const o of orders) {
    if (!!o.bezahlt && !!o.abgeholt) byStatus.abgeschlossen++;
    else if (!!o.bezahlt)            byStatus.bezahlt++;
    else if (o.status in byStatus)   byStatus[o.status]++;
  }

  const byCategory = {};
  for (const e of expenses) {
    byCategory[e.category] = (byCategory[e.category] || 0) + e.amount;
  }

  // Monatliche Daten
  const monthlyRev = db.prepare(`
    SELECT strftime('%Y-%m', created_at) as month,
      SUM(CASE WHEN bezahlt=1 THEN COALESCE(custom_price,0) ELSE 0 END) as revenue,
      COUNT(*) as orders
    FROM orders WHERE user_id=? GROUP BY month ORDER BY month
  `).all(u);

  const monthlyExp = db.prepare(`
    SELECT strftime('%Y-%m', date) as month, SUM(amount) as expenses
    FROM expenses WHERE user_id=? GROUP BY month ORDER BY month
  `).all(u);

  const monthlyMap = {};
  for (const m of monthlyRev) monthlyMap[m.month] = { month:m.month, revenue:m.revenue||0, orders:m.orders||0, expenses:0 };
  for (const m of monthlyExp) {
    if (monthlyMap[m.month]) monthlyMap[m.month].expenses = m.expenses||0;
    else monthlyMap[m.month] = { month:m.month, revenue:0, orders:0, expenses:m.expenses||0 };
  }
  const monthlyData = Object.values(monthlyMap).sort((a,b)=>a.month.localeCompare(b.month)).slice(-12);

  let cum = 0;
  const cumulativeData = monthlyData.map(m => {
    cum += (m.revenue||0) - (m.expenses||0);
    return { month: m.month, value: Math.round(cum*100)/100 };
  });

  res.json({
    totalRevenue, openRevenue, totalBaseCost, totalProfit,
    totalExpenses, netProfit, totalOrders: orders.length,
    byStatus, byCategory, monthlyData, cumulativeData,
    expenses: expenses.slice(0,100),
    recentOrders: orders.slice(0,30),
  });
});

module.exports = router;