import 'dart:io';

void main() {
  bool lightsOn = false;
  double thermostatTemp = 20.0;
  bool securityArmed = false;

  const minTemp = 15.0;
  const maxTemp = 30.0;

  print('Welcome to the Smart Home System!');

  while (true) {
    print('\nPlease choose an action:');
    print('1. Toggle lights');
    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();

    switch (choice) {
      case '1':
        lightsOn = !lightsOn;
        print('Lights are now ${lightsOn ? "ON" : "OFF"}.');
        break;
      case '2':
        stdout.write('Set thermostat temperature (${minTemp}°C - ${maxTemp}°C): ');
        String? tempInput = stdin.readLineSync();
        if (tempInput != null) {
          double? newTemp = double.tryParse(tempInput);
          if (newTemp != null && newTemp >= minTemp && newTemp <= maxTemp) {
            thermostatTemp = newTemp;
            print('Thermostat set to ${thermostatTemp}°C.');
          } else {
            print('Invalid temperature. Please enter a value between $minTemp and $maxTemp.');
          }
        }
        break;
      case '3':
        securityArmed = !securityArmed;
        print('Security system is now ${securityArmed ? "ARMED" : "DISARMED"}.');
        break;
      case '4':
        print('\nSystem Status:');
        print('- Lights: ${lightsOn ? "ON" : "OFF"}');
        
        String tempMessage = '- Thermostat: ${thermostatTemp}°C';
        if (thermostatTemp % 15 == 0) { // Multiple of both 3 and 5
            tempMessage += ' - Perfect Day';
        } else if (thermostatTemp % 3 == 0) {
            tempMessage += ' - Cool Day';
        } else if (thermostatTemp % 5 == 0) {
            tempMessage += ' - Warm Day';
        }
        print(tempMessage);

        print('- Security System: ${securityArmed ? "ARMED".toUpperCase() : "DISARMED".toUpperCase()}');
        break;
      case '5':
        print('Exiting the system. Goodbye!');
        return;
      default:
        print('Invalid choice. Please try again.');
    }
  }
}