import 'dart:io';

void main() {
  bool lightsOn = false;
  int thermostat = 20;
  bool securityArmed = false;

  while (true) {
    print("\nWelcome to the Smart Home System!");
    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: ");
    int? choice = int.tryParse(stdin.readLineSync()!);

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

      case 2:
        stdout.write("Enter temperature (15 - 30): ");
        int? temp = int.tryParse(stdin.readLineSync()!);
        if (temp != null && temp >= 15 && temp <= 30) {
          thermostat = temp;
          print("Thermostat set to $thermostat°C.");
        } else {
          print("Invalid temperature!");
        }
        break;

      case 3:
        securityArmed = !securityArmed;
        print("Security system is now ${securityArmed ? "ARMED" : "DISARMED"}.");
        break;

      case 4:
        String dayType = "";
        if (thermostat % 3 == 0 && thermostat % 5 == 0) {
          dayType = "Perfect Day";
        } else if (thermostat % 3 == 0) {
          dayType = "Cool Day";
        } else if (thermostat % 5 == 0) {
          dayType = "Warm Day";
        }

        print("\nSystem Status:");
        print("Lights: ${lightsOn ? "ON" : "OFF"}");
        print("Thermostat: $thermostat°C ${dayType.isNotEmpty ? "- $dayType" : ""}");
        print("Security: ${securityArmed ? "ARMED" : "DISARMED"}");
        break;

      case 5:
        print("Exiting... Goodbye!");
        return;

      default:
        print("Invalid choice!");
    }
  }
}