// smart_home.dart
import 'dart:io';

const double MIN_TEMP = 15.0;
const double MAX_TEMP = 30.0;

void main() {
  bool lightsOn = false;
  double thermostat = 20.0;
  bool securityArmed = false;

  print('Welcome to the Smart Home System!');

  while (true) {
    print('\nPlease choose an action:');
    print('1. Toggle lights');
    print('2. Set thermostat temperature');
    print('3. Arm/disarm security system');
    print('4. View system status');
    print('5. Exit');

    stdout.write('\nEnter your choice: ');
    String? choice = stdin.readLineSync();
    if (choice == null) continue;

    switch (choice.trim()) {
      case '1':
        lightsOn = !lightsOn;
        print('Lights are now ${lightsOn ? "ON" : "OFF"}.');
        break;
      case '2':
        stdout.write('Set thermostat temperature (${MIN_TEMP.toStringAsFixed(0)}°C - ${MAX_TEMP.toStringAsFixed(0)}°C): ');
        String? tempStr = stdin.readLineSync();
        double? t = _parseDoubleInRange(tempStr, MIN_TEMP, MAX_TEMP);
        if (t == null) {
          print('Invalid temperature. Must be between ${MIN_TEMP.toInt()} and ${MAX_TEMP.toInt()}.');
        } else {
          thermostat = t;
          print('Thermostat set to ${thermostat.toStringAsFixed(1)}°C.');
          _fizzBuzzTempMessage(thermostat);
        }
        break;
      case '3':
        securityArmed = !securityArmed;
        print('Security system is now ${securityArmed ? "ARMED" : "DISARMED"}.');
        break;
      case '4':
        _printStatus(lightsOn, thermostat, securityArmed);
        break;
      case '5':
        print('\nExiting the system. Goodbye!');
        return;
      default:
        print('Invalid choice. Please enter 1-5.');
    }
  }
}

double? _parseDoubleInRange(String? s, double min, double max) {
  if (s == null) return null;
  double? val = double.tryParse(s.trim());
  if (val == null) return null;
  if (val < min || val > max) return null;
  return val;
}

void _printStatus(bool lightsOn, double thermostat, bool securityArmed) {
  print('\nSystem Status:');
  print('- Lights: ${lightsOn ? "ON" : "OFF"}');
  String tempNote = _tempNote(thermostat);
  print('- Thermostat: ${thermostat.toStringAsFixed(1)}°C - $tempNote');
  print('- Security System: ${securityArmed ? "ARMED" : "DISARMED"}');
}

String _tempNote(double t) {
  bool multipleOf3 = (t % 3).abs() < 1e-9;
  bool multipleOf5 = (t % 5).abs() < 1e-9;
  if (multipleOf3 && multipleOf5) return 'Perfect Day';
  if (multipleOf3) return 'Cool Day';
  if (multipleOf5) return 'Warm Day';
  return 'Normal';
}

void _fizzBuzzTempMessage(double t) {
  String note = _tempNote(t);
  print('Note: $note');
}