#include <Arduino_GFX_Library.h>

#define TFT_SCK 18
#define TFT_MOSI 23
#define TFT_MISO 19
#define TFT_CS 22
#define TFT_DC 21
#define TFT_RESET 17
#define ldrPin 2

const int ledPin = 13;
const float gama = 0.7;
const float rl10 = 50;

void setup() {
  Serial.begin(115200);
  pinMode(13, OUTPUT);
}

void loop() 
{
  int ValueLDR = analogRead(ldrPin); 
  ValueLDR = map(ValueLDR, 4095, 0, 1024, 0); 
  float voltage = ValueLDR / 1024.*5;
  float resistance
   = 2000 * voltage / (1-voltage/5);
  float brightness = pow(rl10*1e3*pow(10,gama)/resistance,(1/gama));
 
  Arduino_ESP32SPI bus = Arduino_ESP32SPI(TFT_DC, TFT_CS, TFT_SCK, TFT_MOSI, TFT_MISO);
  Arduino_ILI9341 display = Arduino_ILI9341(&bus, TFT_RESET);

  display.begin();
  display.fillScreen(WHITE);
  display.setCursor(0, 40);
  display.setTextSize(2);
  display.setTextColor(GREEN);

  if(brightness < 100)
  {
    digitalWrite(13, HIGH);
    display.println("LDR->DARK, LED->ON");
    display.println("brightness");
    display.print(brightness);
  }
else
  {
    digitalWrite(13, LOW);
    display.println("LDR->BRIGHT, LED->OFF");
    display.println("brightness");
    display.print(brightness);
  }
  delay(1000);
}