import 'dart:io';

void main() {
  const int minTemp = 15;
  const int maxTemp = 30;

  bool lightsOn = false;
  int temperature = 20;
  bool securityArmed = false;

  while (true) {
    print('\n--- Smart Home Automation ---');
    print('1. Toggle Lights');
    print('2. Set Thermostat');
    print('3. Arm/Disarm Security');
    print('4. View System Status');
    print('5. Exit');
    stdout.write('Choose an option: ');
    String? choice = stdin.readLineSync();

    if (choice == '5') {
      print('Exiting Smart Home... Goodbye!');
      break;
    } else if (choice == '1') {
      lightsOn = !lightsOn;
      print('Lights turned ${lightsOn ? 'ON' : 'OFF'}.');
    } else if (choice == '2') {
      stdout.write('Enter temperature ($minTemp–$maxTemp): ');
      int? temp = int.tryParse(stdin.readLineSync()!);
      if (temp != null && temp >= minTemp && temp <= maxTemp) {
        temperature = temp;
        print('Temperature set to $temperature°C.');
      } else {
        print('Invalid temperature. Try again.');
      }
    } else if (choice == '3') {
      securityArmed = !securityArmed;
      print('Security system ${securityArmed ? 'ARMED' : 'DISARMED'}.');
    } else if (choice == '4') {
      String lightsStatus = lightsOn ? 'ON' : 'OFF';
      String securityStatus = securityArmed ? 'ARMED' : 'DISARMED';
      String tempMessage = '';

      if (temperature % 3 == 0 && temperature % 5 == 0) {
        tempMessage = 'Perfect Day';
      } else if (temperature % 3 == 0) {
        tempMessage = 'Cool Day';
      } else if (temperature % 5 == 0) {
        tempMessage = 'Warm Day';
      }

      print('\n--- System Status ---');
      print('Lights: $lightsStatus');
      print('Thermostat: $temperature°C ${tempMessage.isNotEmpty ? "($tempMessage)" : ""}');
      print('Security: $securityStatus');
    } else {
      print('Invalid choice, try again.');
    }
  }
}