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 temperature ($minTemp - $maxTemp): ');
        int? temp = int.tryParse(stdin.readLineSync()!);
        if (temp != null && temp >= minTemp && temp <= maxTemp) {
          temperature = temp;
          print('Temperature set to $temperature°C');
        } else {
          print('❌ Invalid temperature. Must be 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 tempMessage = '';

        if (temperature % 3 == 0 && temperature % 5 == 0)
          tempMessage = 'Perfect Day';
        else if (temperature % 3 == 0)
          tempMessage = 'Cool Day';
        else if (temperature % 5 == 0)
          tempMessage = 'Warm Day';

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

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