import 'dart:io';

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

  const int minTemp = 15;
  const int maxTemp = 30;

  while (true) {
    print("\n=== Smart Home System ===");
    print("1. Toggle Lights");
    print("2. Set Temperature");
    print("3. Toggle Security System");
    print("4. Show 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): ");
      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! Try again.");
      }
    } else if (choice == '3') {
      securityArmed = !securityArmed;
      print("Security system is now ${securityArmed ? 'ARMED' : 'DISARMED'}.");
    } else if (choice == '4') {
      print("\n--- System Status ---");
      print("Lights: ${lightsOn ? 'ON' : 'OFF'}");
      print("Temperature: $temperature°C");
      print("Security: ${securityArmed ? 'ARMED' : 'DISARMED'}");

      if (temperature % 3 == 0 && temperature % 5 == 0) {
        print("Perfect Day");
      } else if (temperature % 3 == 0) {
        print("Cool Day");
      } else if (temperature % 5 == 0) {
        print("Warm Day");
      }
    } else if (choice == '5') {
      print("Goodbye!");
      break;
    } else {
      print("Invalid option!");
    }
  }
}