import 'dart:io';

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

  bool lightsOn = false;
  int thermostat = 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 system... Goodbye!');
      break;
    }

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

      case '2':
        stdout.write('Enter temperature ($minTemp - $maxTemp): ');
        int? temp = int.tryParse(stdin.readLineSync()!);
        if (temp != null && temp >= minTemp && temp <= maxTemp) {
          thermostat = temp;
          print('Thermostat set to $thermostat°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':
        String lightsStatus = lightsOn ? "ON" : "OFF";
        String securityStatus = securityArmed ? "ARMED" : "DISARMED";
        String dayMessage = "";

        if (thermostat % 3 == 0 && thermostat % 5 == 0) {
          dayMessage = "Perfect Day";
        } else if (thermostat % 3 == 0) {
          dayMessage = "Cool Day";
        } else if (thermostat % 5 == 0) {
          dayMessage = "Warm Day";
        }

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

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