import 'dart:io';

const int MIN_TEMP = 15;
const int MAX_TEMP = 30;

void main() {
  bool lightsOn = false;
  int thermostat = 20;
  String security = 'disarmed';

  print('Welcome to Smart Home CLI!');
  bool running = true;

  while (running) {
    print('\nMain Menu:');
    print('1. Control Lights');
    print('2. Control Thermostat');
    print('3. Control Security System');
    print('4. View System Status');
    print('5. Exit');

    stdout.write('Select an option (1-5): ');
    String choice = (stdin.readLineSync() ?? '').trim();

    if (choice == '1') {
      _handleLights((value) {
        lightsOn = value;
      }, lightsOn);
    } else if (choice == '2') {
      thermostat = _handleThermostat(thermostat);
    } else if (choice == '3') {
      security = _handleSecurity(security);
    } else if (choice == '4') {
      _displayStatus(lightsOn, thermostat, security);
    } else if (choice == '5') {
      running = false;
      print('Exiting Smart Home CLI. Goodbye!');
    } else {
      print('Invalid choice. Please enter a number between 1 and 5.');
    }
  }
}

void _handleLights(void Function(bool) updateLights, bool currentState) {
  print('\nLights Control:');
  print('1. Turn ON');
  print('2. Turn OFF');
  print('3. Back');

  stdout.write('Choose: ');
  String input = (stdin.readLineSync() ?? '').trim();

  if (input == '1') {
    if (!currentState) {
      updateLights(true);
      print('Lights turned ON.');
    } else {
      print('Lights are already ON.');
    }
  } else if (input == '2') {
    if (currentState) {
      updateLights(false);
      print('Lights turned OFF.');
    } else {
      print('Lights are already OFF.');
    }
  } else if (input == '3') {
  } else {
    print('Invalid selection for lights.');
  }
}

int _handleThermostat(int currentTemp) {
  print('\nThermostat Control:');
  print('Current temperature: ${currentTemp}°C');
  stdout.write('Enter new temperature ($MIN_TEMP-$MAX_TEMP) or press Enter to cancel: ');
  String raw = (stdin.readLineSync() ?? '').trim();
  if (raw.isEmpty) {
    print('Thermostat unchanged.');
    return currentTemp;
  }

  int? newTemp = int.tryParse(raw);
  if (newTemp == null) {
    print('Invalid input. Please enter an integer temperature.');
    return currentTemp;
  }

  if (newTemp < MIN_TEMP || newTemp > MAX_TEMP) {
    print('Temperature must be between $MIN_TEMP°C and $MAX_TEMP°C.');
    return currentTemp;
  }

  print('Thermostat set to ${newTemp}°C.');
  return newTemp;
}

String _handleSecurity(String current) {
  print('\nSecurity System Control:');
  print('1. Arm System');
  print('2. Disarm System');
  print('3. Back');

  stdout.write('Choose: ');
  String input = (stdin.readLineSync() ?? '').trim();

  if (input == '1') {
    if (current.toLowerCase() == 'armed') {
      print('Security system is already ARMED.');
      return current;
    } else {
      print('Security system is now ARMED.');
      return 'armed';
    }
  } else if (input == '2') {
    if (current.toLowerCase() == 'disarmed') {
      print('Security system is already DISARMED.');
      return current;
    } else {
      print('Security system is now DISARMED.');
      return 'disarmed';
    }
  } else if (input == '3') {
    return current;
  } else {
    print('Invalid selection for security system.');
    return current;
  }
}

void _displayStatus(bool lightsOn, int thermostat, String security) {
  print('\n--- System Status ---');
  String lightsStatus = lightsOn ? 'ON' : 'OFF';
  String securityStatusUpper = security.toUpperCase();
  print('Lights: $lightsStatus');
  print('Thermostat: ${thermostat}°C');
  print('Security System: $securityStatusUpper');

  bool multipleOf3 = (thermostat % 3 == 0);
  bool multipleOf5 = (thermostat % 5 == 0);

  if (multipleOf3 && multipleOf5) {
    print('${thermostat}°C — Perfect Day');
  } else if (multipleOf3) {
    print('${thermostat}°C — Cool Day');
  } else if (multipleOf5) {
    print('${thermostat}°C — Warm Day');
  }

  print('---------------------');
}