#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#define POT A5
#define BL 6
#define BT 2
LiquidCrystal_I2C lcd(0x27, 16, 2);

int br = 0;
int pot = 0;
int stp = 0;
int sw = 1;
int lg = 0;

void setup() {
  Serial.begin(9600);
  pinMode(BL, OUTPUT);

  lcd.init();
  lcd.backlight();
  lcd.setCursor(2, 0);
  lcd.print("Hello");
  delay(2000);
  lcd.clear();
}

void loop() {
  pot = analogRead(POT);
  br = pot/4;
  if(br >= 0 && br <256) analogWrite(BL, br);
  else analogWrite(BL, 255);
  work(millis());
  button(digitalRead(BT));
  Serial.println(lg);
}

void work(int arg){
  if(arg% 500 == 0){
    lcd.setCursor(0, 0);
    lcd.clear();
    switch(stp){
      case 0: lcd.print("WORK"); break;
      case 1: lcd.print("WORK."); break;
      case 2: lcd.print("WORK.."); break;
      case 3: lcd.print("WORK..."); break;
      default: lcd.print("ERROR"); break;
    }
    if(stp <3) stp++;
    else stp = 0;
  }
}

void button(int arg){
  if(arg == HIGH){
    delay(500);
    if(sw){
      sw = 0;
      lcd.backlight();
    }
    else{
      sw = 1;
      lcd.noBacklight();
    }
  }
}