import 'dart:io';

void main() {
  bool lights = false;
  int temp = 20;
  bool security = false;

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

  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 == '1') {
      lights = !lights;
      print('Lights are now ${lights ? 'ON' : 'OFF'}.');
    } 
    else if (choice == '2') {
      stdout.write('Set thermostat temperature ($minTemp°C – $maxTemp°C): ');
      int? newTemp = int.tryParse(stdin.readLineSync() ?? '');

      if (newTemp != null && newTemp >= minTemp && newTemp <= maxTemp) {
        temp = newTemp;
        print('Thermostat set to $temp°C.');
      } else {
        print('Invalid temperature!');
      }
    } 
    else if (choice == '3') {
      security = !security;
      print('Security system is now ${security ? 'ARMED' : 'DISARMED'}.');
    } 
    else if (choice == '4') {
      String status = '';
      if (temp % 3 == 0 && temp % 5 == 0) {
        status = 'Perfect Day';
      } else if (temp % 3 == 0) {
        status = 'Cool Day';
      } else if (temp % 5 == 0) {
        status = 'Warm Day';
      }

      print('\nSystem Status:');
      print('- Lights: ${lights ? 'ON' : 'OFF'}');
      print('- Thermostat: $temp°C ${status.isNotEmpty ? '- $status' : ''}');
      print('- Security System: ${security ? 'ARMED' : 'DISARMED'}');
    } 
    else if (choice == '5') {
      print('Exiting the system. Goodbye!');
      break;
    } 
    else {
      print('Invalid choice.');
    }
  }
}