import 'dart:io';

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

  // Default device states
  bool lightsOn = false;       // lightsOff
  int thermostat = 20;         // 20°C
  bool securityArmed = false;  // disarmed

  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: ');
    final String choice = (stdin.readLineSync() ?? '').trim();

    // Control Flow using if/else
    if (choice == '1') {
      switchDevice(
        device: 'lights',
        lightsOnRef: () => lightsOn,
        setLightsOn: (v) => lightsOn = v,
        securityArmedRef: () => securityArmed,
        setSecurityArmed: (v) => securityArmed = v,
        thermostatRef: () => thermostat,
        setThermostat: (v) => thermostat = v,
      );
    } else if (choice == '2') {
      stdout.write('Set thermostat temperature ($minTemp°C - $maxTemp°C): ');
      final String raw = (stdin.readLineSync() ?? '').trim();
      final int? temp = int.tryParse(raw);

      if (temp == null) {
        print('Invalid input! Please enter a number.');
        continue;
      }

      // logical/relational operators
      if (temp >= minTemp && temp <= maxTemp) {
        //Switch statement for device commands
        switchDevice(
          device: 'thermostat',
          newTemp: temp,
          lightsOnRef: () => lightsOn,
          setLightsOn: (v) => lightsOn = v,
          securityArmedRef: () => securityArmed,
          setSecurityArmed: (v) => securityArmed = v,
          thermostatRef: () => thermostat,
          setThermostat: (v) => thermostat = v,
        );
      } else {
        print('Invalid temperature! Please enter between $minTemp and $maxTemp.');
      }
    } else if (choice == '3') {
      // Switch statement for device commands
      switchDevice(
        device: 'security',
        lightsOnRef: () => lightsOn,
        setLightsOn: (v) => lightsOn = v,
        securityArmedRef: () => securityArmed,
        setSecurityArmed: (v) => securityArmed = v,
        thermostatRef: () => thermostat,
        setThermostat: (v) => thermostat = v,
      );
    } else if (choice == '4') {
      showStatus(lightsOn, thermostat, securityArmed);
    } else if (choice == '5') {
      print('\nExiting the system. Goodbye!');
      break;
    } else {
      print('Invalid choice! Please select 1-5.');
    }
  }
}
void switchDevice({
  required String device,
  int? newTemp,
  required bool Function() lightsOnRef,
  required void Function(bool) setLightsOn,
  required bool Function() securityArmedRef,
  required void Function(bool) setSecurityArmed,
  required int Function() thermostatRef,
  required void Function(int) setThermostat,
}) {
  switch (device) {
    case 'lights':
      final bool now = !lightsOnRef();
      setLightsOn(now);
      print('Lights are now ${now ? 'ON' : 'OFF'}.');
      break;

    case 'thermostat':
      if (newTemp == null) return;
      setThermostat(newTemp);
      print('Thermostat set to ${thermostatRef()}°C.');
      break;

    case 'security':
      final bool now = !securityArmedRef();

      if (now == true) {
        setSecurityArmed(true);
      } else {
        setSecurityArmed(false);
      }

      //String ops: convert to upper-case when displaying
      final String status = (securityArmedRef() ? 'armed' : 'disarmed').toUpperCase();
      print('Security System: $status');
      break;

    default:
      print('Unknown device command.');
  }
}

void showStatus(bool lightsOn, int temp, bool securityArmed) {
  final String lightsStatus = lightsOn ? 'ON' : 'OFF';

  //String operations (armed -> ARMED, disarmed -> DISARMED)
  final String securityStatus = (securityArmed ? 'disarmed' : 'disarmed');
  final String securityUpper = (securityArmed ? 'armed' : 'disarmed').toUpperCase();

  //FizzBuzz-like exercise for temperature display
  String tempMessage = '';
  if (temp % 3 == 0 && temp % 5 == 0) {
    tempMessage = 'Perfect Day';
  } else if (temp % 3 == 0) {
    tempMessage = 'Cool Day';
  } else if (temp % 5 == 0) {
    tempMessage = 'Warm Day';
  }

  print('\nSystem Status:');
  print('- Lights: $lightsStatus');
  print('- Thermostat: ${temp}°C${tempMessage.isEmpty ? '' : ' — $tempMessage'}');
  print('- Security System: $securityUpper');
}