import 'dart:io';

void main() {
  print('Welcome to the Smart Home System!');
  
  bool lightsOn = false;
  int temperature = 20;
  bool securityArmed = false;

  const int minTemp = 15;
  const int maxTemp = 30;

  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();

    switch (choice) {
      case '1':
        lightsOn = !lightsOn;
        print('\nLights are now ${lightsOn ? 'ON' : 'OFF'}.\n');
        break;

      case '2':
        stdout.write(
            '\nSet thermostat temperature ($minTemp°C - $maxTemp°C): ');
        int? newTemp = int.tryParse(stdin.readLineSync()!);
        if (newTemp != null && newTemp >= minTemp && newTemp <= maxTemp) {
          temperature = newTemp;
          print('Thermostat set to $temperature°C.\n');
        } else {
          print('Invalid temperature! Please enter between 15°C and 30°C.\n');
        }
        break;

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

      case '4':
        String mood = '';
        if (temperature % 3 == 0 && temperature % 5 == 0) {
          mood = 'Perfect Day';
        } else if (temperature % 3 == 0) {
          mood = 'Cool Day';
        } else if (temperature % 5 == 0) {
          mood = 'Warm Day';
        }

        print('\nSystem Status:');
        print('- Lights: ${lightsOn ? 'ON' : 'OFF'}');
        print('- Thermostat: $temperature°C${mood.isNotEmpty ? ' - $mood' : ''}');
        print('- Security System: ${securityArmed ? 'ARMED' : 'DISARMED'}\n');
        break;

      case '5':
        print('\nExiting the system. Goodbye!\n');
        return;

      default:
        print('\nInvalid choice. Please try again.\n');
    }
  }
}