const fs = require('fs');
const path = require('path');
const config = require('./config');

const usersPath = path.join(__dirname, config.usersFile);
let users;

try {
  users = JSON.parse(fs.readFileSync(usersPath, 'utf-8'));
  console.log(`Loaded ${users.length} user(s) from ${config.usersFile}`);
} catch (err) {
  console.error(`Failed to load ${config.usersFile}:`, err.message);
  process.exit(1);
}

function authenticate(login, password) {
  const user = users.find(u => u.login === login && u.password === password);
  return user || null;
}

module.exports = { authenticate };