SMART HOME AUTOMATION SYSTEM - QUESTION 1

import 'dart:io';

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

void main() {
  bool lightsOn = false;
  int thermostat = 20;
  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('Enter choice (1-5): ');
    String? input = stdin.readLineSync();
    int? choice = int.tryParse(input ?? '');

    if (choice == null) {
      print('Invalid input. Please try again.');
      continue;
    }

    switch (choice) {
      case 1:
        lightsOn = !lightsOn;
        print('Lights turned ${lightsOn ? 'ON' : 'OFF'}.');
        break;

      case 2:
        stdout.write('Enter temperature ($MIN_TEMP°C - $MAX_TEMP°C): ');
        int? newTemp = int.tryParse(stdin.readLineSync() ?? '');
        if (newTemp == null || newTemp < MIN_TEMP || newTemp > MAX_TEMP) {
          print('Invalid temperature. Must be within range.');
        } else {
          thermostat = newTemp;
          print('Thermostat set to ${thermostat}°C.');
        }
        break;

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

      case 4:
        _printSystemStatus(lightsOn, thermostat, securityArmed);
        break;

      case 5:
        print('Exiting program. Goodbye!');
        return;

      default:
        print('Invalid choice.');
    }
  }
}

void _printSystemStatus(bool lightsOn, int thermostat, bool securityArmed) {
  String securityStatus = securityArmed ? 'ARMED' : 'DISARMED';
  String lightsStatus = lightsOn ? 'ON' : 'OFF';

  print('\n----- System Status -----');
  print('Lights: $lightsStatus');
  print('Thermostat: ${thermostat}°C');
  print('Security: $securityStatus');

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

  if (multipleOf3 && multipleOf5) {
    print('Temperature note: Perfect Day.');
  } else if (multipleOf3) {
    print('Temperature note: Cool Day.');
  } else if (multipleOf5) {
    print('Temperature note: Warm Day.');
  } else {
    print('Temperature note: Normal Day.');
  }
  print('-------------------------\n');
}