/**
 * admin.js — admin-only API routes.
 * Монтируется на /api/admin
 */
const express = require('express');
const router  = express.Router();
const { query } = require('../config/db');

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

async function requireAdmin(req, res) {
  const adminId = uid(req);
  if (!adminId) { res.status(401).json({ error: 'x-user-id required' }); return null; }
  const { rows: [u] } = await query('SELECT is_admin FROM users WHERE id=$1', [adminId]);
  if (!u?.is_admin) { res.status(403).json({ error: 'Forbidden' }); return null; }
  return adminId;
}

// GET /api/admin/dashboard
router.get('/dashboard', async (req, res) => {
  if (!await requireAdmin(req, res)) return;
  try {
    const [users, channels, posts, drafts, revenue, ai, regs] = await Promise.all([
      query(`SELECT count(*)::int as total,
        count(*) FILTER (WHERE created_at > NOW()-INTERVAL '7 days')::int as new_7d,
        count(*) FILTER (WHERE created_at > NOW()-INTERVAL '30 days')::int as new_30d
        FROM users`),
      query(`SELECT platform, count(*)::int as cnt FROM channels WHERE is_active=true GROUP BY platform`),
      query(`SELECT count(*)::int as total,
        count(*) FILTER (WHERE published_at > NOW()-INTERVAL '24 hours')::int as today,
        count(*) FILTER (WHERE published_at > NOW()-INTERVAL '7 days')::int as week
        FROM scheduled_posts WHERE status='sent'`),
      query(`SELECT count(*)::int as pending FROM post_drafts WHERE status='pending'`),
      query(`SELECT coalesce(sum(amount_rub),0)::int as total_rub,
        count(*) FILTER (WHERE status='succeeded')::int as paid_count,
        coalesce(sum(amount_rub) FILTER (WHERE created_at > NOW()-INTERVAL '30 days'),0)::int as month_rub
        FROM payment_orders WHERE status='succeeded'`),
      query(`SELECT coalesce(sum(cost_rub),0)::numeric(10,2) as month_rub,
        count(*)::int as calls,
        count(*) FILTER (WHERE NOT succeeded)::int as errors
        FROM ai_usage WHERE created_at > NOW()-INTERVAL '30 days'`),
      query(`SELECT date_trunc('day', created_at)::date as day, count(*)::int as cnt
        FROM users WHERE created_at > NOW()-INTERVAL '14 days'
        GROUP BY 1 ORDER BY 1`),
    ]);
    res.json({
      users:   users.rows[0],
      channels: channels.rows,
      posts:   posts.rows[0],
      drafts:  drafts.rows[0],
      revenue: revenue.rows[0],
      ai:      { ...ai.rows[0], cost_rub: parseFloat(ai.rows[0].month_rub) },
      registrations_14d: regs.rows,
    });
  } catch (err) { res.status(500).json({ error: err.message }); }
});

// GET /api/admin/users — балансы всех пользователей
router.get('/users', async (req, res) => {
  if (!await requireAdmin(req, res)) return;
  try {
    const { rows } = await query(`
      SELECT u.id, u.email, u.name, u.created_at,
             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 }); }
});

// POST /api/admin/credit — начислить кредиты
router.post('/credit', async (req, res) => {
  if (!await requireAdmin(req, res)) return;
  const { user_id, amount, description = 'Ручное начисление' } = req.body;
  if (!user_id || !amount) return res.status(400).json({ error: 'user_id и amount обязательны' });
  try {
    const billing = require('../services/billing');
    const result = await billing.credit(user_id, amount, 'bonus', description, { by_admin: uid(req) });
    res.json(result);
  } catch (err) { res.status(500).json({ error: err.message }); }
});

// PATCH /api/admin/plans/:id
router.patch('/plans/:id', async (req, res) => {
  if (!await requireAdmin(req, res)) return;
  const { price_rub, credits_month, channels_max, name } = req.body;
  try {
    const sets = []; const vals = [];
    if (price_rub    !== undefined) sets.push(`price_rub=$${vals.push(price_rub)}`);
    if (credits_month!== undefined) sets.push(`credits_month=$${vals.push(credits_month)}`);
    if (channels_max !== undefined) sets.push(`channels_max=$${vals.push(channels_max)}`);
    if (name         !== undefined) sets.push(`name=$${vals.push(name)}`);
    if (!sets.length) return res.status(400).json({ error: 'nothing to update' });
    vals.push(req.params.id);
    const { rows: [plan] } = await query(`UPDATE plans SET ${sets.join(',')} WHERE id=$${vals.length} RETURNING *`, vals);
    res.json(plan);
  } catch (err) { res.status(500).json({ error: err.message }); }
});

// PATCH /api/admin/credit-costs/:operation
router.patch('/credit-costs/:operation', async (req, res) => {
  if (!await requireAdmin(req, res)) return;
  const { credits } = req.body;
  try {
    await query('UPDATE credit_costs SET credits=$1 WHERE operation=$2', [credits, req.params.operation]);
    res.json({ ok: true, operation: req.params.operation, credits });
  } catch (err) { res.status(500).json({ error: err.message }); }
});

module.exports = router;

// GET /api/admin/users/:id — детальная информация о пользователе
router.get('/users/:id', async (req, res) => {
  if (!await requireAdmin(req, res)) return;
  try {
    const [user, channels, balance, txs, sub] = await Promise.all([
      query(`SELECT id, email, name, is_admin, is_blocked, created_at FROM users WHERE id=$1`, [req.params.id]),
      query(`SELECT id, name, platform, is_active, tg_username, created_at FROM channels WHERE user_id=$1 ORDER BY created_at DESC`, [req.params.id]),
      query(`SELECT ub.credits, ub.reset_at, p.name as plan_name, p.code as plan_code, p.price_rub
        FROM user_balance ub
        LEFT JOIN user_subscriptions us ON us.user_id=ub.user_id AND us.status='active'
        LEFT JOIN plans p ON p.id=us.plan_id
        WHERE ub.user_id=$1`, [req.params.id]),
      query(`SELECT * FROM user_transactions WHERE user_id=$1 ORDER BY created_at DESC LIMIT 20`, [req.params.id]),
      query(`SELECT us.*, p.name as plan_name, p.code as plan_code FROM user_subscriptions us
        JOIN plans p ON p.id=us.plan_id WHERE us.user_id=$1 AND us.status='active' LIMIT 1`, [req.params.id]),
    ]);
    if (!user.rows.length) return res.status(404).json({ error: 'User not found' });
    res.json({
      user: user.rows[0],
      channels: channels.rows,
      balance: balance.rows[0] || null,
      transactions: txs.rows,
      subscription: sub.rows[0] || null,
    });
  } catch (err) { res.status(500).json({ error: err.message }); }
});

// PATCH /api/admin/users/:id — обновить пользователя (block/unblock, план)
router.patch('/users/:id', async (req, res) => {
  if (!await requireAdmin(req, res)) return;
  const { is_blocked, plan_code, name } = req.body;
  try {
    if (is_blocked !== undefined) {
      await query('UPDATE users SET is_blocked=$1 WHERE id=$2', [is_blocked, req.params.id]);
    }
    if (name !== undefined) {
      await query('UPDATE users SET name=$1 WHERE id=$2', [name, req.params.id]);
    }
    if (plan_code !== undefined) {
      // Смена плана вручную
      const { rows: [plan] } = await query('SELECT * FROM plans WHERE code=$1', [plan_code]);
      if (!plan) return res.status(400).json({ error: `Plan ${plan_code} not found` });
      await query("UPDATE user_subscriptions SET status='cancelled' WHERE user_id=$1 AND status='active'", [req.params.id]);
      const expires = new Date(Date.now() + 32*24*60*60*1000);
      await query(`INSERT INTO user_subscriptions (user_id, plan_id, status, expires_at)
        VALUES ($1,$2,'active',$3)`, [req.params.id, plan.id, expires]);
      // Начисляем кредиты по новому плану
      if (plan.credits_month > 0) {
        await query('UPDATE user_balance SET credits=$1, reset_at=$2 WHERE user_id=$3',
          [plan.credits_month, expires, req.params.id]);
        await query(`INSERT INTO user_transactions (user_id, type, amount, balance_after, description)
          VALUES ($1,'plan_credit',$2,$2,$3)`,
          [req.params.id, plan.credits_month, `Ручная смена плана на ${plan.name}`]);
      }
    }
    res.json({ ok: true });
  } catch (err) { res.status(500).json({ error: err.message }); }
});