import 'dart:io';

// Constant temperature limits
const int minTemp = 15;
const int maxTemp = 30;

void main() {
  // Initial device states
  bool lightsOn = false;
  int thermostat = 20;
  bool securityArmed = false;

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

  bool active = true;

  while (active) {
    print("\nChoose an option:");
    print("1) Toggle Lights");
    print("2) Set Thermostat");
    print("3) Arm/Disarm Security System");
    print("4) View System Status");
    print("5) Exit");

    stdout.write("Your choice: ");
    final choice = stdin.readLineSync();

    if (choice == null) {
      print("Invalid input.");
      continue;
    }

    // if/else for main control flow
    if (choice == "1") {
      switch ("lights") {
        case "lights":
          lightsOn = !lightsOn;
          print("Lights are now ${lightsOn ? "ON" : "OFF"}.");
          break;
      }
    } else if (choice == "2") {
      switch ("thermostat") {
        case "thermostat":
          _setTemperature((value) => thermostat = value);
          break;
      }
    } else if (choice == "3") {
      switch ("security") {
        case "security":
          securityArmed = !securityArmed;
          print("Security system is now ${securityArmed ? "ARMED" : "DISARMED"}.");
          break;
      }
    } else if (choice == "4") {
      _displayStatus(
        lightsOn: lightsOn,
        thermostat: thermostat,
        securityArmed: securityArmed,
      );
    } else if (choice == "5") {
      print("Exiting system... Goodbye.");
      active = false;
    } else {
      print("Invalid option. Try again.");
    }
  }
}

// Handles thermostat input and validation
void _setTemperature(void Function(int) updateTemp) {
  stdout.write("Enter temperature ($minTemp–$maxTemp): ");
  final input = stdin.readLineSync();

  if (input == null) {
    print("Invalid input.");
    return;
  }

  final temp = int.tryParse(input);

  if (temp == null) {
    print("Please enter a valid number.");
    return;
  }

  if (temp < minTemp || temp > maxTemp) {
    print("Temperature out of range.");
    return;
  }

  updateTemp(temp);
  print("Thermostat set to $temp°C.");
}

// Displays system status + FizzBuzz-like temperature logic
void _displayStatus({
  required bool lightsOn,
  required int thermostat,
  required bool securityArmed,
}) {
  String mood = "";

  bool mult3 = thermostat % 3 == 0;
  bool mult5 = thermostat % 5 == 0;

  if (mult3 && mult5) {
    mood = "Perfect Day";
  } else if (mult3) {
    mood = "Cool Day";
  } else if (mult5) {
    mood = "Warm Day";
  }

  final lightsStatus = (lightsOn ? "ON" : "OFF").toUpperCase();
  final securityStatus = (securityArmed ? "ARMED" : "DISARMED").toUpperCase();

  print("\n=== SYSTEM STATUS ===");
  print("Lights: $lightsStatus");
  print("Thermostat: $thermostat°C ${mood.isNotEmpty ? "($mood)" : ""}");
  print("Security System: $securityStatus");
}