import 'dart:io';

void main() {
  // 💻 Display startup hint
  print('💻 To run this program again, use: dart run Smarthome.dart');

  // 🔹 Constants (final / const variables)
  const int minTemp = 15;
  const int maxTemp = 30;

  // 🔹 Default device states
  bool lightsOn = false;
  int thermostat = 20;
  bool securityArmed = false;

  // 🔹 Welcome message
  print('=====================================');
  print('🤖 Welcome Ahmed to Smart Home System');
  print('=====================================');

  // 🔹 Main loop for user interaction
  while (true) {
    print('\n=== SMART HOME AUTOMATION SYSTEM ===');
    print('1️⃣  Toggle Lights');
    print('2️⃣  Set Thermostat Temperature');
    print('3️⃣  Arm/Disarm Security System');
    print('4️⃣  View System Status');
    print('5️⃣  Exit');
    stdout.write('\nEnter your choice: ');
    String? choice = stdin.readLineSync();

    if (choice == null) continue;

    if (choice == '5') {
      print('\nShutting down Smart Home System...');
      print('Goodbye, Ahmed! 👋');
      break;
    }

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

      case '2':
        stdout.write('\nEnter temperature ($minTemp°C - $maxTemp°C): ');
        String? input = stdin.readLineSync();
        if (input != null) {
          int? temp = int.tryParse(input);
          if (temp != null && temp >= minTemp && temp <= maxTemp) {
            thermostat = temp;
            print('🌡️ Thermostat set to $thermostat°C');
          } else {
            print('⚠️ Invalid temperature! Must be between $minTemp°C and $maxTemp°C.');
          }
        }
        break;

      case '3':
        securityArmed = !securityArmed;
        print('🔒 Security System is now ${securityArmed ? "ARMED" : "DISARMED"}');
        break;

      case '4':
        // 🔹 FizzBuzz-like logic
        String dayMessage = '';
        if (thermostat % 3 == 0 && thermostat % 5 == 0) {
          dayMessage = 'Perfect Day';
        } else if (thermostat % 3 == 0) {
          dayMessage = 'Cool Day';
        } else if (thermostat % 5 == 0) {
          dayMessage = 'Warm Day';
        }

        // 🔹 Display system status
        String lightsStatus = lightsOn ? 'ON' : 'OFF';
        String securityStatus = securityArmed ? 'ARMED' : 'DISARMED';

        print('\n--- 🏠 SYSTEM STATUS ---');
        print('💡 Lights: $lightsStatus');
        print('🌡️ Thermostat: $thermostat°C ${dayMessage.isNotEmpty ? "($dayMessage)" : ""}');
        print('🔐 Security System: ${securityStatus.toUpperCase()}');
        print('--------------------------');
        break;

      default:
        print('❌ Invalid choice! Please select a valid option (1–5).');
    }
  }
}