import 'dart:io';

// Constant temperature limits
const int minTemperature = 15;
const int maxTemperature = 30;

void main() {
  // Initial device states
  bool lightState = false;
  int currentTemp = 20;
  bool securityState = false;

  print("=== SMART HOME SYSTEM ===");

  bool menuActive = true;

  while (menuActive) {
    print("\nSelect an option:");
    print("1) Lights Control");
    print("2) Thermostat Control");
    print("3) Security System Control");
    print("4) Show System Status");
    print("5) Exit");

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

    if (option == null) continue;

    // Main control flow
    if (option == "1") {
      _handleDevice("lights", () {
        lightState = !lightState;
        print("Lights are now ${lightState ? "ON" : "OFF"}.");
      });

    } else if (option == "2") {
      _handleDevice("thermostat", () {
        stdout.write("Set temperature ($minTemperature-$maxTemperature): ");
        String? input = stdin.readLineSync();

        int? temp = int.tryParse(input ?? "");

        if (temp == null || temp < minTemperature || temp > maxTemperature) {
          print("Invalid temperature. Try again.");
        } else {
          currentTemp = temp;
          print("Thermostat set to $currentTemp°C.");
        }
      });

    } else if (option == "3") {
      _handleDevice("security", () {
        securityState = !securityState;
        print("Security system is now ${securityState ? "ARMED" : "DISARMED"}.");
      });

    } else if (option == "4") {
      _showStatus(lightState, currentTemp, securityState);

    } else if (option == "5") {
      print("Shutting down system...");
      menuActive = false;

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

// Generic switch handler for devices
void _handleDevice(String device, Function action) {
  switch (device) {
    case "lights":
    case "thermostat":
    case "security":
      action();
      break;
    default:
      print("Unknown device.");
  }
}

// Display system status + FizzBuzz-like logic
void _showStatus(bool lights, int temp, bool security) {
  String mood = "";

  bool divisibleBy3 = temp % 3 == 0;
  bool divisibleBy5 = temp % 5 == 0;

  if (divisibleBy3 && divisibleBy5) {
    mood = "Perfect Day";
  } else if (divisibleBy3) {
    mood = "Cool Day";
  } else if (divisibleBy5) {
    mood = "Warm Day";
  }

  print("\n=== SYSTEM STATUS ===");
  print("Lights: ${lights ? "ON" : "OFF"}");
  print("Thermostat: $temp°C ${mood.isNotEmpty ? "($mood)" : ""}");
  print("Security: ${security ? "ARMED" : "DISARMED"}".toUpperCase());
}