#include <Arduino.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

enum directions
{
  LEFT = 0,
  RIGHT = 1
};

char LCDline[] = "0123456789ABCDEF";
const char *myStrings[] = {"1. Short Length ",
                           "<<< Small Curl  ",

                           "2. Short Length ",
                           "<<< Medium Curl ",

                           "3. Short Length ",
                           "<<< Large Curl  ",

                           "4.Regular Length",
                           " Small Curl  >>>",

                           "5.Regular Length",
                           " Meduim Curl >>>",

                           "6.Regular Length",
                           " Large Curl  >>>",

                           " WRONG  PROGRAM ",
                           "!!! SELECTED !!!"};

int oldSelected = 0;
int selected = 1;

unsigned int scroll = 0;

long oldMillis;

directions direction = RIGHT;

void setup()
{
  lcd.init(); // Initialize the LCD I2C display
  lcd.backlight();
  pinMode(A0, INPUT);
  pinMode(A1, INPUT);
  pinMode(A2, INPUT);
  pinMode(A3, INPUT);
  oldMillis = millis();
  direction = LEFT;
}

void copyLine(const char *origin, int offset)
{
  for (int i = 0; i < 16; i++)
    LCDline[i] = origin[offset + i];
}

void LCDprint(const char *line, const int x, const int y)
{
  lcd.setCursor(x, y); // move cursor to   (3, 0)
  lcd.print(line);
}

void loop()
{
  bool Bit0 = digitalRead(A0); // read A output from sewitch
  bool Bit1 = digitalRead(A1); // read B output from sewitch
  bool Bit2 = digitalRead(A2); // read C output from sewitch
  bool Bit3 = digitalRead(A3); // read D output from sewitch

  selected = Bit0 + (Bit1 << 1) + (Bit2 << 2) + (Bit3 << 3); // convert bits to HEX
  if (selected < 1 || selected > 6)
    selected = 7;
  if (selected != oldSelected)
  {
    oldSelected = selected;
    oldMillis = millis();
    scroll = 0;
    direction = LEFT;
  }

  copyLine(myStrings[selected * 2 - 2], scroll);
  LCDprint(LCDline, 0, 0);
  // lcd.setCursor(0, 0); // move cursor to   (3, 0)
  // lcd.print(LCDline);
  LCDprint(myStrings[selected * 2 - 1], 0, 1);
  // lcd.setCursor(0, 1);                    // move cursor to   (0, 1)
  // lcd.print(myStrings[selected * 2 - 1]); // print message at (0, 1)

  if (millis() - oldMillis > 333)
  {
    oldMillis = millis();
    if (direction == LEFT)
    {
      if (scroll < strlen(myStrings[selected * 2 - 2]) - 16)
      {
        scroll++;
      }
      else
        direction = RIGHT;
    }
    else
    {
      if (scroll > 0)
      {
        scroll--;
      }
      else
        direction = LEFT;
    }
  }

  delay(100);
}