#include <LiquidCrystal_I2C.h>

int clk = 2;
int dt = 3;
int sw = 4;
int led1 = 8;
int led2 = 9;
int led3 = 10;
int led4 = 11;

int counter = 0;

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {

  lcd.init();
  lcd.backlight();
  
  pinMode(clk, INPUT);
  pinMode(dt, INPUT);
  pinMode(sw, INPUT);
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);

  attachInterrupt(digitalPinToInterrupt(clk), readEncoder, FALLING);

}

void readEncoder(){
  int value = digitalRead(dt);
  if(value == HIGH){
    counter++;
  } else if(value == LOW){
    counter--;
  }
}

int getCounter(){
  int value;
  noInterrupts();
  value = counter;
  interrupts();
  return value;
}

void resetCounter(){
  noInterrupts();
  counter = 0;
  interrupts();
}

void led_nyala_putarkanan(){
  if(counter == 1){
    digitalWrite(led1, HIGH);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  }else if(counter == 2){
    digitalWrite(led1, LOW);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  }else if(counter == 3){
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, HIGH);
    digitalWrite(led4, LOW);
  }else if(counter == 4){
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(led4, HIGH);
  }else if(counter > 4){
    counter = 0;
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  }
}

void led_nyala_putarkiri(){
  if(counter == -4){
    digitalWrite(led1, HIGH);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  }else if(counter == -3){
    digitalWrite(led1, LOW);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  }else if(counter == -2){
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, HIGH);
    digitalWrite(led4, LOW);
  }else if(counter == -1){
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(led4, HIGH);
  }else if(counter < -4){
    counter = 0;
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  }
}

void loop() {
  lcd.setCursor(0,0);
  lcd.print("Counter: ");
  lcd.setCursor(0,1);
  lcd.print(getCounter());

  led_nyala_putarkanan();
  led_nyala_putarkiri();
}