int RLed = 13;
int BLed = 12;
int GLed = 11;
int YLed = 10;
int WLed = 9;
int LDR_Pin = A0;
int NTC_Pin = A1;
int potentiometerPin = A2;
int val = 0;

// Thermistor characteristics:
const float BETA = 3950; 

// LDR Characteristics:
const float GAMMA = 0.8; 
// https://lednique.com/tag/ldr-gamma/ 

const float RL10 = 20; 
// from the datasheet https://files.coventry.aula.education/6aee55e75412820efe43a09ee4298211ldr_datasheet_rs.pdf
// RL10 is the resistance of the LDR at 10 lux.


void setup() {
  Serial.begin(9600);
  pinMode(RLed, OUTPUT);
  pinMode(BLed, OUTPUT);
  pinMode(GLed, OUTPUT);
  pinMode(YLed, OUTPUT);
  pinMode(WLed, OUTPUT);
}
 
void temperature(){
  // https://docs.wokwi.com/parts/wokwi-ntc-temperature-sensor 
  // below converts from analogue to celsius.

  int analogTemperature = analogRead(NTC_Pin);
  float temperatureInCelsius = 1 / (log(1 / (1023. / analogTemperature - 1)) / BETA + 1.0 / 298.15) - 273.15;

  if (temperatureInCelsius<5){
    digitalWrite(BLed, HIGH);
  }else{
    digitalWrite(BLed, LOW);
  }
  Serial.print("Temperature: ");
  Serial.print(temperatureInCelsius);
  Serial.println(" ℃");
  delay(1000);
}

void timeOfDay(){

  int AnalogLDRVal = analogRead(LDR_Pin); 
  float voltage = AnalogLDRVal / 1024. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));

  Serial.print("Light Level: ");
  Serial.print(lux);
  Serial.println(" lux");
  delay(1000);

  // https://wokwi.com/projects/347552240227058259

  if (lux < 200) { // night
    Serial.println("It is night time. Red LED is on.");
    digitalWrite(RLed, HIGH);
    digitalWrite(GLed, LOW);
    digitalWrite(YLed, LOW);
    delay(500);
  } else if (lux>=200 && lux<800){ // day
    Serial.println("It is day time. Green LED is on.");
    digitalWrite(GLed, HIGH);
    digitalWrite(RLed, LOW);
    digitalWrite(YLed, LOW);
    delay(500);
  } else if (lux>=800){ // day and too bright
  Serial.println("It is day time but it is too bright. Green and Yellow LED are on.");
    digitalWrite(YLed, HIGH); 
    digitalWrite(GLed, HIGH);
    delay(500);
  }
}

void loop() {

  val = analogRead(potentiometerPin);

  int AnalogLDRVal = analogRead(LDR_Pin); 
  float voltage = AnalogLDRVal / 1024. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));

  int analogTemperature = analogRead(NTC_Pin);
  float temperatureInCelsius = 1 / (log(1 / (1023. / analogTemperature - 1)) / BETA + 1.0 / 298.15) - 273.15;

  timeOfDay();
  temperature();
  if (lux<200 && temperatureInCelsius<5){ // night and temp below 5℃
    digitalWrite(BLed, HIGH);
    digitalWrite(RLed, HIGH);
  } else if ((lux>=200 && lux<800) && temperatureInCelsius<5){
    digitalWrite(BLed, HIGH);
    digitalWrite(GLed, HIGH);
  }
}





// References:
// https://wokwi.com/projects/305193592908939842 
// https://wokwi.com/projects/305193627138654786