#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

byte pBar[8] =
{
B11111,
B11111,
B11111,
B11111,
B11111,
B11111,
B11111,
};

int rows = 2;
int columns = 16;

int buffer[2][16];

int row = 0;
int column = 0;
int symbol = 0;

const int pinX = A5;
const int pinY = A0;

const int pinBtn = 2;
int last_button = LOW;
int curr_button = LOW;

int debounce (int last)
{
  int current = digitalRead(pinBtn);
  if (last != current)
  {
    delay(5);
    current = digitalRead(pinBtn);
  }
  return current;
}

void buttonPressed(int &last_button, int &curr_button, int &row)
{
  curr_button = debounce(last_button);
  if (last_button == LOW && curr_button == HIGH)
  {
    if (row == 0)
    {
      row = 1;
    } else 
    {
      row = 0;
    }
  }
  last_button = curr_button;
}

void axisX(int x, int &column)
{
  delay(10);
  if (x > 512 && x <= 1023 && column > 0)
  {
    --column;
  } 
  else if (x >= 0 && x < 512 && column < 15)
  {
    ++column;
  }
}

void axisY(int y, int &symbol)
{
  delay(10);
  if (y >= 0 && y < 512 && symbol > -1)
  {
    symbol -= 1;
  } 
  else if (y > 512 && y <= 1023 && symbol < 25)
  {
    symbol += 1;
  }
}

void setup()
{
  lcd.begin(columns, rows);
  lcd.createChar(0, pBar);
  lcd.clear();

  pinMode(pinX, INPUT);
  pinMode(pinY, INPUT);
  pinMode(pinBtn, INPUT);

  digitalWrite(pinBtn, curr_button);

  for (int i = 0; i < 16; ++i)
  {
    for (int j = 0; j < 2; ++j)
    {
      buffer[j][i] = -1;
    }
  }
}

void loop()
{
  int x = analogRead(pinX);
  int y = analogRead(pinY);

  buttonPressed(last_button, curr_button, row);
  axisX(x, column);
  axisY(y, buffer[row][column]);

  lcd.setCursor(column, row);
  lcd.print("_");
  delay(25);

  for (int i = 0; i < 16; ++i)
  {
    for (int j = 0; j < 2; ++j)
    {
      lcd.setCursor(i, j);
      if (buffer[j][i] == -1)
      {
        lcd.print(" ");
      } else 
      {
        char output = buffer[j][i] + 65;
        lcd.print(output);
      }
    }
  }
  delay(25);
}