const fs = require('fs');
const path = require('path');

const LOCK_FILE = path.join(__dirname, '../data/login_locks.json');

const DEFAULT_CONFIG = {
  maxAttempts: 3,
  lockDuration: 10 * 60 * 1000
};

function ensureDataDir() {
  const dataDir = path.join(__dirname, '../data');
  if (!fs.existsSync(dataDir)) {
    fs.mkdirSync(dataDir, { recursive: true });
  }
}

function loadLocks() {
  ensureDataDir();
  try {
    if (fs.existsSync(LOCK_FILE)) {
      const data = fs.readFileSync(LOCK_FILE, 'utf8');
      return JSON.parse(data);
    }
  } catch (e) {
    console.error('Error loading login locks:', e);
  }
  return { users: {}, config: DEFAULT_CONFIG };
}

function saveLocks(locks) {
  ensureDataDir();
  try {
    fs.writeFileSync(LOCK_FILE, JSON.stringify(locks, null, 2));
  } catch (e) {
    console.error('Error saving login locks:', e);
  }
}

function getLockStatus(username) {
  const locks = loadLocks();
  const userLock = locks.users[username];
  
  if (!userLock) {
    return { locked: false, attempts: 0 };
  }
  
  const now = Date.now();
  if (userLock.lockedUntil && now < userLock.lockedUntil) {
    const remainingMs = userLock.lockedUntil - now;
    return {
      locked: true,
      attempts: userLock.attempts,
      lockedUntil: userLock.lockedUntil,
      remainingMs: remainingMs
    };
  }
  
  if (userLock.lockedUntil && now >= userLock.lockedUntil) {
    const newLocks = loadLocks();
    delete newLocks.users[username];
    saveLocks(newLocks);
    return { locked: false, attempts: 0 };
  }
  
  return { locked: false, attempts: userLock.attempts || 0 };
}

function recordFailedAttempt(username) {
  const locks = loadLocks();
  const now = Date.now();
  
  if (!locks.users[username]) {
    locks.users[username] = { attempts: 0 };
  }
  
  const userLock = locks.users[username];
  
  if (userLock.lockedUntil && now >= userLock.lockedUntil) {
    userLock.attempts = 0;
    userLock.lockedUntil = null;
  }
  
  userLock.attempts = (userLock.attempts || 0) + 1;
  userLock.lastAttempt = now;
  
  const maxAttempts = locks.config?.maxAttempts || DEFAULT_CONFIG.maxAttempts;
  const lockDuration = locks.config?.lockDuration || DEFAULT_CONFIG.lockDuration;
  
  if (userLock.attempts >= maxAttempts) {
    userLock.lockedUntil = now + lockDuration;
  }
  
  saveLocks(locks);
  
  return getLockStatus(username);
}

function clearLock(username) {
  const locks = loadLocks();
  delete locks.users[username];
  saveLocks(locks);
}

function getConfig() {
  const locks = loadLocks();
  return locks.config || DEFAULT_CONFIG;
}

function updateConfig(newConfig) {
  const locks = loadLocks();
  locks.config = { ...DEFAULT_CONFIG, ...newConfig };
  saveLocks(locks);
}

module.exports = {
  getLockStatus,
  recordFailedAttempt,
  clearLock,
  getConfig,
  updateConfig
};