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 turned ${lightsOn ? "ON" : "OFF"}.');
        break;

      case '2':
        stdout.write('Enter new temperature ($minTemp-$maxTemp °C): ');
        int? newTemp = int.tryParse(stdin.readLineSync() ?? '');
        if (newTemp != null && newTemp >= minTemp && newTemp <= maxTemp) {
          temperature = newTemp;
          print('Temperature set to $temperature °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 status = '''
Lights: ${lightsOn ? "ON" : "OFF"}
Thermostat: $temperature °C
Security System: ${securityArmed ? "ARMED" : "DISARMED"}
''';

        if (temperature % 3 == 0 && temperature % 5 == 0) {
          status += '→ Perfect Day!\n';
        } else if (temperature % 3 == 0) {
          status += '→ Cool Day!\n';
        } else if (temperature % 5 == 0) {
          status += '→ Warm Day!\n';
        }

        print('\n--- System Status ---');
        print(status);
        break;

      default:
        print('Invalid choice! Please select a valid option.');
    }
  }
}