import 'dart:io';

void main() {
  const int MIN_TEMP = 15;
  const int MAX_TEMP = 30;
  
  bool lightsOn = false;
  double thermostatTemp = 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('Enter your choice: ');
    String? choiceInput = stdin.readLineSync();
    
    if (choiceInput == null || choiceInput.isEmpty) {
      print('Invalid input. Please try again.');
      continue;
    }
    
    int choice = int.tryParse(choiceInput) ?? 0;
    
    switch (choice) {
      case 1:
        lightsOn = !lightsOn;
        print('Lights are now ${lightsOn ? 'ON' : 'OFF'}.');
        break;
      
      case 2:
        stdout.write('Set thermostat temperature (${MIN_TEMP}°C - ${MAX_TEMP}°C): ');
        String? tempInput = stdin.readLineSync();
        double temp = double.tryParse(tempInput ?? '') ?? 0.0;
        
        if (temp >= MIN_TEMP && temp <= MAX_TEMP) {
          thermostatTemp = temp;
          print('Thermostat set to ${thermostatTemp}°C.');
        } else {
          print('Invalid temperature. Please enter between ${MIN_TEMP}°C and ${MAX_TEMP}°C.');
        }
        break;
      
      case 3:
        securityArmed = !securityArmed;
        print('Security system is now ${securityArmed ? 'ARMED' : 'DISARMED'}.');
        break;
      
      case 4:
        print('\nSystem Status:');
        print('- Lights: ${lightsOn ? 'ON' : 'OFF'}');
        
        String tempMessage;
        if (thermostatTemp % 15 == 0) {
          tempMessage = 'Perfect Day';
        } else if (thermostatTemp % 3 == 0) {
          tempMessage = 'Cool Day';
        } else if (thermostatTemp % 5 == 0) {
          tempMessage = 'Warm Day';
        } else {
          tempMessage = '';
        }
        
        print('- Thermostat: ${thermostatTemp}°C ${tempMessage.isNotEmpty ? '- $tempMessage' : ''}');
        print('- Security System: ${securityArmed ? 'ARMED' : 'DISARMED'}');
        break;
      
      case 5:
        print('Exiting the system. Goodbye!');
        exit(0);
      
      default:
        print('Invalid choice. Please try again.');
    }
  }
}