import 'dart:io';

void main() {
const double minTemp = 15.0;
const double maxTemp = 30.0;

bool lightsOn = false;
double thermostat = 20.0;
bool securityArmed = false;

print('Welcome to the Smart Home System!');

while (true) {
print('\nChoose an option:');
print('1. Toggle lights on/off');
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? choice = stdin.readLineSync();

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

case '2':
stdout.write('Enter temperature (${minTemp.toInt()}-${maxTemp.toInt()}): ');
String? tempInput = stdin.readLineSync();
double? temp = double.tryParse(tempInput ?? '');
if (temp != null && temp >= minTemp && temp <= maxTemp) {
thermostat = temp;
print('Thermostat set to $thermostat°C');
} else {
print('Invalid temperature. Please enter a value between $minTemp and $maxTemp.');
}
break;

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

case '4':
String coolOrWarm;
if (thermostat % 3 == 0 && thermostat % 5 == 0) {
coolOrWarm = 'Perfect Day';
} else if (thermostat % 3 == 0) {
coolOrWarm = 'Cool Day';
} else if (thermostat % 5 == 0) {
coolOrWarm = 'Warm Day';
} else {
coolOrWarm = '';
}

print('\n--- System Status ---');
print('Lights: ${lightsOn ? 'ON' : 'OFF'}');
print('Thermostat: $thermostat°C ${coolOrWarm.isNotEmpty ? '- $coolOrWarm' : ''}');
print('Security: ${securityArmed ? 'ARMED' : 'DISARMED'}');
print('---------------------\n');
break;

case '5':
print('Exiting system. Goodbye!');
return;

default:
print('Invalid choice. Try again.');
}
}
}