#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

const int LDR_pin = A0;    		// pin that the LDR sensor is attached to
const int set_pot_pin = A1;
const int led_light_pin = 9;        	// pin that the LED array is attached to

// variables:
int sensorValue = 0;         // the sensor value
int sensorMin = 1023;        // minimum sensor value
int sensorMax = 0;           // maximum sensor value
int threshold = 0;
int light_intensity = 55, led_intensity = 20;

void setup()
{
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3c)) { // Address 0x3D for 128x64
  //  Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  display.clearDisplay();
  display.print("calibrating.....");
  display.display();
  analogWrite(led_light_pin, 0);
  digitalWrite(13, HIGH);
  while (millis() < 10000)
  {
    sensorValue = analogRead(LDR_pin);
    if (sensorValue > sensorMax) sensorMax = sensorValue;
    if (sensorValue < sensorMin) sensorMin = sensorValue;
  }
  display.clearDisplay();
  display.print("calibration over");
  display.setCursor(0, 1);
  display.print("max light:");
  display.print(sensorMax);
  display.setCursor(0, 2);
  display.print("min light:");
  display.print(sensorMin);
  display.display();
  delay(2000);
  display.clearDisplay();
  display.print("light intensity");
  display.setCursor(0, 2);
  display.print("threshold:");
  display.setCursor(0, 3);
  display.print("LED light:0%");
  display.display();
}

void loop()
{
  sensorValue = analogRead(LDR_pin);
  sensorValue = map(sensorValue, sensorMin, sensorMax, 0, 100);
  sensorValue = constrain(sensorValue,0,100);
  display.setCursor(0, 1);
  display.print(sensorValue);
  display.print('%');
  threshold = analogRead(set_pot_pin);
  threshold = map(threshold, 0, 1023, 0, 100);
  display.setCursor(11, 2);
  display.print(threshold);
  display.print('%');
  if (sensorValue < threshold)
  {
    analogWrite(led_light_pin, light_intensity);
    display.setCursor(11, 3);
    display.print(led_intensity);
    display.print('%');
    if(light_intensity<255)
      {
        light_intensity += 25;
        led_intensity += 10;
      }    
   }
  display.display();
  delay(2000); 
}