import 'dart:io';

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

  print("Welcome to the Smart Home System!");

  while (true) {
    print("\nPlease choose an action:");
    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("\nEnter your choice: ");
    String? choice = stdin.readLineSync();

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

    } else if (choice == '2') {
      stdout.write("Set thermostat temperature (15°C - 30°C): ");
      int? temp = int.tryParse(stdin.readLineSync() ?? '');

      if (temp != null && temp >= 15 && temp <= 30) {
        temperature = temp;
        print("Thermostat set to ${temperature}°C.");
      } else {
        print("Invalid temperature! Please enter between 15 and 30.");
      }

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

    } else if (choice == '4') {
      String weatherStatus = '';
      if (temperature % 3 == 0 && temperature % 5 == 0) {
        weatherStatus = "Perfect Day";
      } else if (temperature % 3 == 0) {
        weatherStatus = "Cool Day";
      } else if (temperature % 5 == 0) {
        weatherStatus = "Warm Day";
      }

      print("\nSystem Status:");
      print("- Lights: ${lightsOn ? 'ON' : 'OFF'}");
      print("- Thermostat: ${temperature}°C ${weatherStatus.isNotEmpty ? '– $weatherStatus' : ''}");
      print("- Security System: ${securityArmed ? 'ARMED' : 'DISARMED'}");

    } else if (choice == '5') {
      print("Exiting the system. Goodbye!");
      break;

    } else {
      print("Invalid choice. Please try again.");
    }
  }
}