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

    } else if (choice == "2") {
      stdout.write("Enter temperature ($minTemp-$maxTemp): ");
      String? tempInput = stdin.readLineSync();
      int? newTemp = int.tryParse(tempInput ?? "");
      if (newTemp != null && newTemp >= minTemp && newTemp <= maxTemp) {
        thermostat = newTemp;
        print("Thermostat set to ${thermostat}C.");
      } else {
        print("Invalid temperature.");
      }

    } else if (choice == "3") {
      securityArmed = !securityArmed;
      print("Security System is now ${securityArmed ? "ARMED" : "DISARMED"}.");

    } else if (choice == "4") {

      if (thermostat % 3 == 0 && thermostat % 5 == 0) {
        print("Perfect Day - ${thermostat}C");
      } else if (thermostat % 3 == 0) {
        print("Cool Day - ${thermostat}C");
      } else if (thermostat % 5 == 0) {
        print("Warm Day - ${thermostat}C");
      }

      print("Lights: ${lightsOn ? "ON" : "OFF"}");
      print("Thermostat: ${thermostat}C");
      print("Security System: ${securityArmed ? "ARMED" : "DISARMED"}");

    } else if (choice == "5") {
      print("Exiting system. Goodbye!");
      break;
    } else {
      print("Invalid choice. Try again.");
    }
  }
}