import 'dart:io';

void main() {
  // ????? ??????? ?????? ??????????
  bool isLightsOn = false; // LightsOff
  double temperature = 20.0; // 20°C for thermostat
  String securityStatus = "disarmed"; // disarmed

  print("--- Welcome to Smart Home System ---");

  // ???? ????? ?????? ???????? ???????
  bool running = true;
  while (running) {
    print("\nSelect an option:");
    print("1. Toggle Lights (On/Off)");
    print("2. Set Thermostat Temperature");
    print("3. Arm/Disarm Security System");
    print("4. View System Status");
    print("5. Exit");
    stdout.write("Choice: ");

    String? choice = stdin.readLineSync();

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

      case '2':
        stdout.write("Enter temperature (15-30): ");
        double? inputTemp = double.tryParse(stdin.readLineSync()!);
        // ?????? ?? ??? ???????? (Input Validation)
        if (inputTemp != null && inputTemp >= 15 && inputTemp <= 30) {
          temperature = inputTemp;
          print("Temperature set to $temperature°C.");
        } else {
          print("Invalid input! Please enter a value between 15 and 30.");
        }
        break;

      case '3':
        securityStatus = (securityStatus == "disarmed") ? "armed" : "disarmed";
        print("Security System is now ${securityStatus.toUpperCase()}."); // ????? ???? ????? ?????
        break;

      case '4':
        // ??? ???? ?????? ???????? String Interpolation
        print("\n--- Current Status ---");
        print("Lights: ${isLightsOn ? 'ON' : 'OFF'}");
        print("Security: ${securityStatus.toUpperCase()}");
        
        // ???? FizzBuzz ???????
        String weatherMsg = "";
        int tempInt = temperature.round();
        if (tempInt % 3 == 0 && tempInt % 5 == 0) {
          weatherMsg = "Perfect Day";
        } else if (tempInt % 3 == 0) {
          weatherMsg = "Cool Day";
        } else if (tempInt % 5 == 0) {
          weatherMsg = "Warm Day";
        }
        print("Temperature: $temperature°C ${weatherMsg.isNotEmpty ? '- $weatherMsg' : ''}");
        break;

      case '5':
        running = false;
        print("Exiting system... Goodbye!");
        break;

      default:
        print("Invalid choice, try again.");
    }
  }
}