import 'dart:io';

void main() {
  const int minTemp = 15;
  const int maxTemp = 30;

  bool lightsOn = false;
  int temperature = 20;
  bool securityArmed = false;

  while (true) {
    print('\nChoose an option:');
    print('1. Toggle lights');
    print('2. Set thermostat');
    print('3. Arm/Disarm security system');
    print('4. View system status');
    print('5. Exit');

    String? choice = stdin.readLineSync();

    switch (choice) {
      case '1':
        lightsOn = !lightsOn;
        print('Lights turned ${lightsOn ? "ON" : "OFF"}');
        break;

      case '2':
        int? newTemp;
        do {
          print('Enter temperature ($minTemp-$maxTemp):');
          String? tempInput = stdin.readLineSync();
          newTemp = int.tryParse(tempInput ?? '');
          if (newTemp == null || newTemp < minTemp || newTemp > maxTemp) {
            print('Invalid temperature. Try again.');
            newTemp = null;
          }
        } while (newTemp == null);
        temperature = newTemp;
        print('Temperature set to $temperature°C');
        break;

      case '3':
        securityArmed = !securityArmed;
        print('Security system ${securityArmed ? "ARMED" : "DISARMED"}');
        break;

      case '4':
        print('\n=== SYSTEM STATUS ===');
        print('Lights: ${lightsOn ? "ON" : "OFF"}');
        print('Temperature: $temperature°C');
        print('Security: ${securityArmed ? "ARMED" : "DISARMED"}');

        if (temperature % 3 == 0 && temperature % 5 == 0) {
          print('Perfect Day');
        } else if (temperature % 3 == 0) {
          print('Cool Day');
        } else if (temperature % 5 == 0) {
          print('Warm Day');
        }
        break;

      case '5':
        print('Exiting program...');
        return;

      default:
        print('Invalid choice. Try again.');
    }
  }
}