#include <WiFi.h>
#include <ThingSpeak.h>

#define ldrPin 2
const float gama = 0.7;
const float rl10 = 50;
const int LED=13;

char ssid[] = "Wokwi-GUEST";
char pass[] = "";
const char* server = "api.thingspeak.com";
unsigned long channelNumber = 2118331;
const char* writeAPIKey = "CY257U9Q0542NHCK";
WiFiClient client;

void setup() {
  Serial.begin(115200);
  pinMode(LED, OUTPUT);

  WiFi.mode(WIFI_STA);
  ThingSpeak.begin(client);
  delay(1500);
}

void loop() {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.print("Attempting to connect to WiFi");
    while (WiFi.status() != WL_CONNECTED) {
      WiFi.begin(ssid, pass);
      Serial.print(".");
      delay(5000);
    }
    Serial.println("\nConnected to WiFi.");
  }

  delay(10); 
  int value = analogRead(ldrPin);
  value = map(value, 4095, 0, 1024, 0);
  float voltage = value / 1024.*5;
  float resistans = 2000 * voltage / (1-voltage/5);
  float brightness = pow(rl10*1e3*pow(10,gama)/resistans,(1/gama));
  
  //led
  if(brightness <=200){
    Serial.println("It's night...");
    digitalWrite(LED, HIGH);
  }
  else{
    Serial.println("It's day...");
    digitalWrite(LED, LOW);
  }

  ThingSpeak.setField(1, brightness);

  int response = ThingSpeak.writeFields(channelNumber, writeAPIKey);
  if (response == 200) {
    Serial.println("Channel update successful.");
  } else {
    Serial.println("Problem writing to ThingSpeak.");
  }

  delay(10000);
}