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('\n===== Smart Home Automation System =====');
    print('1. Turn Lights On/Off');
    print('2. Set Thermostat Temperature');
    print('3. Arm/Disarm Security System');
    print('4. View System Status');
    print('5. Exit');
    stdout.write('Enter your choice: ');
    String? choice = stdin.readLineSync();

    if (choice == '5') {
      print('Exiting Smart Home System. Goodbye!');
      break;
    }

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

      case '2':
        stdout.write('Enter new temperature ($minTemp - $maxTemp): ');
        String? input = stdin.readLineSync();
        int? newTemp = int.tryParse(input ?? '');
        if (newTemp != null && newTemp >= minTemp && newTemp <= maxTemp) {
          temperature = newTemp;
          print('Temperature set to $temperature°C.');
        } else {
          print('Invalid temperature! Please enter between $minTemp and $maxTemp.');
        }
        break;

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

      case '4':
        String lightsStatus = lightsOn ? "ON" : "OFF";
        String securityStatus = securityArmed ? "ARMED" : "DISARMED";

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

        print('\n--- System Status ---');
        print('Lights: $lightsStatus');
        print('Thermostat: $temperature°C ${dayMessage.isNotEmpty ? "($dayMessage)" : ""}');
        print('Security System: ${securityStatus.toUpperCase()}');
        break;

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