#include <LiquidCrystal_I2C.h>

#define I2C_ADDR 0x27
#define LCD_COLLUMNS 20
#define LCD_ROWS 4

LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLLUMNS, LCD_ROWS);

#define LEFT_BTN  A1
#define RIGHT_BTN A0
const int WAIT_TIME = 200; //200 milliseconds

int POSITION = 0; 

int PREVIOUS_LEFT_BTN = HIGH;
int PREVIOUS_RIGHT_BTN = HIGH;
unsigned long timeSinceLeftPress = 0;
unsigned long timeSinceRightPress = 0;

void setup() {
  lcd.init();
  lcd.backlight();

  lcd.setCursor(5, 0);
  lcd.print("TUG OF WAR");
  delay(1000);
  lcd.init();

  Serial.begin(115200);

  pinMode(LEFT_BTN, INPUT_PULLUP);
  pinMode(RIGHT_BTN, INPUT_PULLUP);
}

void loop() {
  
  unsigned long nowTime = millis();

  int LEFT_BTN_STATE = digitalRead(LEFT_BTN);
  int RIGHT_BTN_STATE = digitalRead(RIGHT_BTN);
  
  if (LEFT_BTN_STATE == LOW && PREVIOUS_LEFT_BTN == HIGH && (nowTime - timeSinceLeftPress) > WAIT_TIME && POSITION > -9)
  {
    timeSinceLeftPress = nowTime; //Track current time
    POSITION = POSITION - 1;
  }

  if (RIGHT_BTN_STATE == LOW && PREVIOUS_RIGHT_BTN == HIGH && (nowTime - timeSinceLeftPress) > WAIT_TIME && POSITION < 9)
  {
    timeSinceRightPress = nowTime; //Track current time
    POSITION = POSITION + 1;
  }

  lcd.init();

  lcd.setCursor(9 + POSITION, 1);
  lcd.print("|");
  lcd.setCursor(9 + POSITION, 2);
  lcd.print("|");

  int PREVIOUS_LEFT_BTN = LEFT_BTN_STATE;
  int PREVIOUS_RIGHT_BTN = RIGHT_BTN_STATE;
}