const float BETA = 3950; //from wokwi-ntc-temperature-sensor reference (BETA CONSTANT)
int pushButton = LOW; 
void setup() {
  pinMode(A0, INPUT); //temperature sensor
  pinMode(7, INPUT); //push button
  pinMode(2, OUTPUT); //blue LED
  pinMode(3, OUTPUT); //green LED
  pinMode(4, OUTPUT); //red LED
  Serial.begin(9600);
}

void loop() {
  pushButton = digitalRead(7);
  int temperature = readTemperature();
  if (pushButton == HIGH) { //Start checking temperature when push button is HIGH
    delay(55); //an attempt to debounce push button
    /* 
    - If Temperature is less than 0 degrees C, Blue LED is on
    - If Temperature is greater than 0 degrees & less than 40 degrees C, Green LED is on
    - If Temperature is greater than 40 degrees C, Red LED is on
    */
    if (temperature < 0) {
      digitalWrite(2, HIGH); //blue LED is on
      digitalWrite(3, LOW);
      digitalWrite(4, LOW);
    } else if (temperature > 40) {
      digitalWrite(2, LOW);
      digitalWrite(3, LOW);
      digitalWrite(4, HIGH); //red LED is on
    } else if (temperature < 40 && temperature > 0) {
      digitalWrite(2, LOW);
      digitalWrite(3, HIGH); //green LED is on
      digitalWrite(4, LOW);
    }
    Serial.println(String(temperature)); //print temp in C degrees when any LED is on
  } else if (pushButton == LOW) { //all LEDs stay LOW when push button isn't pressed
    digitalWrite(2, LOW);
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
  }
}

//Utilized wokwi-ntc-temperature-sensor reference for the NTC temperature sensor
int readTemperature() {
  int analogValue = analogRead(A0);
  float celsius = 1 / (log(1 / (1023. / analogValue - 1 )) / BETA + 1.0 / 298.15) - 273.15;
  return celsius;
}