import 'dart:io';

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

// Device Status
bool lightsOn = false;
int thermostatTemp = 20;
bool securityArmed = false;

// Main Method
void main() {
  print("Welcome to the Smart Home System!");

  while (true) {
    print("\nChoose an option:");
    print("1. Toggle lights ON/OFF");
    print("2. Set thermostat temperature");
    print("3. Arm/Disarm security system");
    print("4. Show system status");
    print("5. Exit");

    String? choice = stdin.readLineSync();

    if (choice == '5') {
      print("Program terminated. Goodbye!");
      break;
    }

    switch (choice) {
      case '1':
        toggleLights();
        break;
      case '2':
        setThermostat();
        break;
      case '3':
        toggleSecurity();
        break;
      case '4':
        showStatus();
        break;
      default:
        print("Please enter a valid option.");
    }
  }
}

// Toggle Lights
void toggleLights() {
  lightsOn = !lightsOn;
  print("Lights have been ${lightsOn ? 'turned ON' : 'turned OFF'}.");
}

// Set Thermostat
void setThermostat() {
  print("Enter temperature between $minTemp and $maxTemp:");
  String? input = stdin.readLineSync();
  int? temp = int.tryParse(input ?? '');

  if (temp != null && temp >= minTemp && temp <= maxTemp) {
    thermostatTemp = temp;
    print("Temperature set to $thermostatTemp°C.");
  } else {
    print("Invalid temperature. Please try again.");
  }
}

// Toggle Security System
void toggleSecurity() {
  securityArmed = !securityArmed;
  print("Security system has been ${securityArmed ? 'armed' : 'disarmed'}.");
}

// Show System Status
void showStatus() {
  String lightsStatus = lightsOn ? "ON" : "OFF";
  String securityStatus = securityArmed ? "ARMED" : "DISARMED";

  print("\n--- System Status ---");
  print("Lights: $lightsStatus");
  print("Temperature: $thermostatTemp°C");

  // FizzBuzz-like logic
  if (thermostatTemp % 3 == 0 && thermostatTemp % 5 == 0) {
    print("Perfect Day");
  } else if (thermostatTemp % 3 == 0) {
    print("Cool Day");
  } else if (thermostatTemp % 5 == 0) {
    print("Warm Day");
  }

  print("Security System: ${securityStatus.toUpperCase()}");
}