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('=== Smart Home Automation ===');

  while (true) {
    print('\nChoose an option:');
    print('1) Toggle lights');
    print('2) Change thermostat temperature (15-30)');
    print('3) Arm/Disarm security system');
    print('4) Show system status');
    print('5) Exit');

    stdout.write('> ');
    String? choice = stdin.readLineSync();

    if (choice == '5') {
      print('Exiting...');
      break;
    }

    if (choice == '1') {
      switch (lightsOn) {
        case true:
          lightsOn = false;
          print('Lights: OFF');
          break;
        case false:
          lightsOn = true;
          print('Lights: ON');
          break;
      }
    } else if (choice == '2') {
      stdout.write('Enter temperature ($MIN_TEMP-$MAX_TEMP): ');
      String? tempStr = stdin.readLineSync();
      int? temp = int.tryParse(tempStr ?? '');
      if (temp == null || temp < MIN_TEMP || temp > MAX_TEMP) {
        print('Invalid input. Try again.');
        continue;
      }
      thermostat = temp;
      print('Thermostat set to ${thermostat}°C');
    } else if (choice == '3') {
      if (!securityArmed) {
        securityArmed = true;
        print('Security system: ARMED');
      } else {
        securityArmed = false;
        print('Security system: DISARMED');
      }
    } else if (choice == '4') {
      String lightsStatus = lightsOn ? 'ON' : 'OFF';
      String securityStatus = securityArmed ? 'ARMED' : 'DISARMED';
      String tempStatus = '';

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

      if (multipleOf3 && multipleOf5) {
        tempStatus = 'Perfect Day';
      } else if (multipleOf3) {
        tempStatus = 'Cool Day';
      } else if (multipleOf5) {
        tempStatus = 'Warm Day';
      }

      print('\n--- System Status ---');
      print('Lights: $lightsStatus');
      print('Thermostat: ${thermostat}°C ($tempStatus)');
      print('Security: $securityStatus');
      print('---------------------');
    } else {
      print('Invalid choice. Try again.');
    }
  }
}