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. Control Lights");
    print("2. Set Thermostat");
    print("3. Control Security System");
    print("4. View System Status");
    print("5. Exit");

    stdout.write("Choose an option: ");
    String? choice = stdin.readLineSync();

    if (choice == "5") {
      print("Exiting system...");
      break;
    }

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

      case "2":
        stdout.write("Enter temperature ($minTemp - $maxTemp): ");
        int? temp = int.tryParse(stdin.readLineSync() ?? "");

        if (temp != null && temp >= minTemp && temp <= maxTemp) {
          thermostat = temp;
          print("Thermostat set to $thermostat°C");
        } else {
          print("Invalid temperature! Try again.");
        }
        break;

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

      case "4":
        String lightStatus = lightsOn ? "ON" : "OFF";
        String securityStatus =
            (securityArmed ? "armed" : "disarmed").toUpperCase();

        print("\n--- System Status ---");
        print("Lights: $lightStatus");
        print("Thermostat: $thermostat°C");
        print("Security System: $securityStatus");

        if (thermostat % 3 == 0 && thermostat % 5 == 0) {
          print("Perfect Day 🌤");
        } else if (thermostat % 3 == 0) {
          print("Cool Day ❄");
        } else if (thermostat % 5 == 0) {
          print("Warm Day ☀");
        }
        break;

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