#include <LiquidCrystal_I2C.h>

const int xPixels = 20;
const int yPixels = 4;
LiquidCrystal_I2C lcd(0x27, xPixels, yPixels);

int const buttonPinTop = 2;
int const buttonPinBottom = 3;

String const car = "I>>";
String const enemyCar = "<I";
String const spawnedCar = "<";
String const carEnd = "I";

int y = 0;
int del = 150;
int times = 0;
int score = 0;

void setup() {
  Serial.begin(115200);

  lcd.init();
  lcd.backlight();

  pinMode(buttonPinTop, INPUT_PULLUP);
  pinMode(buttonPinBottom, INPUT_PULLUP);
}

int last = 0;
int lastChanged = 0;

int i = xPixels - 2;
int posY = random(0, yPixels);
int lastBtn1State = HIGH;
int lastBtn2State = HIGH;

void loop() {
  if (i == xPixels - 2) {
    posY = random(0, yPixels);
  }

  if (millis() % del == 0) {
    Serial.println(i);
    validY();
    lcd.clear();
    printCar();
    lcd.setCursor(i, posY);
    lcd.print("<=");
    if(y == posY
      && (i == 0 || i == 1 || i == 2))
    {
      gameOver();
      return;
    }
    last = millis();
    i--;
  }

  int btn1State = digitalRead(buttonPinTop);
  if(btn1State != lastBtn1State) {
    if (lastBtn1State == LOW) {
      moveTop();
    }
  }
  lastBtn1State = btn1State;

  int btn2State = digitalRead(buttonPinBottom);
  if(btn2State != lastBtn2State) {
    if (lastBtn2State == LOW) {
      moveBottom();
    }
  }
  lastBtn2State = btn2State;


  if (i == 0) {
    if(del > 20) {
      del -= 3;
    }

    score++;
    i = 18;
  }
}

void gameOver()
{
  lcd.clear();
  char message1[] = "Game over";
  // char message2[] = "Click the button";
  // char message3[] = "to continue";
  char message2[] = "Score: ";
  lcd.setCursor(getPosition(message1), 0);
  lcd.print(message1);
  lcd.setCursor(getPosition(message2), 1);
  // lcd.print(message2);
  // lcd.setCursor(getPosition(message3), 2);
  // lcd.print(message3);
  lcd.setCursor(0, yPixels-1);
  lcd.print(message2);
  lcd.print(score);

  while((digitalRead(buttonPinBottom) != LOW) 
    && (digitalRead(buttonPinTop) != LOW))
    { }

  score = 0;
  del = 150;

  lcd.clear();
  return;
}

int getPosition(char *message)
{
  return (yPixels - strlen(message))/2;
}

void moveTop()
{
  lcd.setCursor(0, y);
  lcd.print("   ");
  y--;
}

void moveBottom()
{
  lcd.setCursor(0, y);
  lcd.print("   ");
  y++;
}

void validY()
{
  if(y == yPixels)
  {
    y = 0;
  }
  if(y == -1)
  {
    y = yPixels - 1;
  }
}

void printCar()
{
  lcd.setCursor(0, y);
  lcd.print(car);
}