import 'dart:io';

const int MIN_TEMP = 15;
const int MAX_TEMP = 30;

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

void toggleLights() {
  lightsOn = !lightsOn; 
  
  if (lightsOn == true) {
      print("Lights are now ON.");
  } else {
      print("Lights are now OFF.");
  }
} 

void setThermostat() {
  stdout.write("Set temperature (${MIN_TEMP}°C - ${MAX_TEMP}°C): ");
  String? input = stdin.readLineSync();

  int? temp = int.tryParse(input ?? '');

  if (temp != null) {
    if (temp >= MIN_TEMP && temp <= MAX_TEMP) {
      temperature = temp;
      print("Thermostat set to ${temperature}°C.");
    } else {
      print("Error: Temperature must be between $MIN_TEMP°C and $MAX_TEMP°C.");
    }
  } else {
    print("Invalid input. Please enter a number.");
  }
}

void toggleSecurity() {
  securityArmed = !securityArmed; 
  
  if (securityArmed) {
      print("Security system is now ARMED.");
  } else {
      print("Security system is now DISARMED.");
  }
}

void displayStatus() {
  print("\n--- Current System Status ---");

  print("Lights: ${lightsOn ? 'ON' : 'OFF'}"); 
  print("Security System: ${securityArmed ? 'ARMED' : 'DISARMED'}"); 

  String dayMessage = "";
  if (temperature % 3 == 0 && temperature % 5 == 0) {
    dayMessage = "Perfect Day"; 
  } else if (temperature % 5 == 0) {
    dayMessage = "Warm Day"; 
  } else if (temperature % 3 == 0) {
    dayMessage = "Cool Day"; 
  }
  
  print("Thermostat: ${temperature}°C ${dayMessage.isNotEmpty ? '($dayMessage)' : ''}");
}

void main() {
  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("Enter your choice: ");
    String? choice = stdin.readLineSync();

    
    switch (choice) {
      case '1':
        toggleLights(); 
        break;
      case '2':
        setThermostat(); 
        break;
      case '3':
        toggleSecurity(); 
        break;
      case '4':
        displayStatus();
        break;
      case '5':
        print("Exiting the system. Goodbye!");
        return;
      default:
        print("Invalid choice. Please enter a number between 1 and 5.");
    }
  }
}