const express = require('express');
const crypto = require('crypto');
const { query } = require('../db');

const router = express.Router();

router.get('/', async (req, res) => {
  try {
    await query("DELETE FROM captchas WHERE created_at < NOW() - INTERVAL 5 MINUTE");
    const id = crypto.randomUUID();
    const ops = ['+', '-', '\u00d7'];
    const op = ops[Math.floor(Math.random() * ops.length)];
    let a, b;
    if (op === '\u00d7') { a = Math.floor(Math.random() * 9) + 1; b = Math.floor(Math.random() * 9) + 1; }
    else { a = Math.floor(Math.random() * 20) + 1; b = Math.floor(Math.random() * 10) + 1; if (op === '-' && a < b) [a, b] = [b, a]; }
    const answer = op === '+' ? a + b : op === '-' ? a - b : a * b;
    const question = `${a} ${op} ${b} = ?`;
    await query('INSERT INTO captchas(id, question, answer) VALUES (?,?,?)', [id, question, String(answer)]);
    res.json({ id, question });
  } catch (e) { res.status(500).json({ error: e.message }); }
});

async function verify(id, answer) {
  const rows = await query("SELECT * FROM captchas WHERE id = ? AND created_at > NOW() - INTERVAL 5 MINUTE", [id]);
  if (!rows.length) return false;
  await query('DELETE FROM captchas WHERE id = ?', [id]);
  return String(answer).trim() === rows[0].answer;
}

module.exports = router;
module.exports.verify = verify;