#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
int upBtn = 11;
int downBtn = 12;
int bulletBtn = 13;
int playerXPos = 0;
int playerYPos = 0;
int bulletYPos = 1;
int alienYPos = 0;
int spawn;
int y=15;

void setup() {
  pinMode(upBtn, INPUT);
  pinMode(downBtn, INPUT);
  pinMode(bulletBtn, INPUT);
  lcd.init();
  lcd.backlight();

}

void loop() {
  lcd.clear();
  if(digitalRead(upBtn))
  {
    delay(100);
    playerYPos = 0;
  }
  if(digitalRead(downBtn))
  {
    delay(100);
    playerYPos = 1;
  }
  lcd.setCursor(playerXPos, playerYPos);
  lcd.print(">");

  if(digitalRead(bulletBtn))
  {
    bulletYPos = playerYPos;
    bullet();
  }
  spawn = random(0,5);
  if (spawn == 3);
    {
      delay(100);
      randomSeed(analogRead(0));
      alienYPos = random(0,2);
      lcd.setCursor(y, alienYPos);
      lcd.print("X");
      y--;
      if(y==0)
      {
        y=15;
      }
    }

}

void bullet()
{
  for(int x = 1; x<=15; x++)
  {
    delay(100);
    lcd.clear();
    if(digitalRead(upBtn))
      {
        delay(100);
        playerYPos = 0;
      }
    if(digitalRead(downBtn))
      {
        delay(100);
        playerYPos = 1;
      }
    if(digitalRead(bulletBtn))
      {
        bulletYPos = playerYPos;
        bullet();
      } 
    if (spawn == 3);
    {
      delay(100);
      randomSeed(analogRead(0));
      alienYPos = random(0,2);
      lcd.setCursor(y, alienYPos);
      lcd.print("X");
      y--;
      if ((y==0))
      {
        y=15;
        lcd.clear();
        lcd.setCursor(0,0);
        lcd.print("Game Over");
        delay(500);
        lcd.setCursor(0,0);
        lcd.print("Retry in 3");
        delay(1000);
        lcd.setCursor(0,0);
        lcd.print("Retry in 2");
        delay(1000);
        lcd.setCursor(0,0);
        lcd.print("Retry in 1");
        delay(1000);
        break;
      }
    }
    if ((bulletYPos == alienYPos) && (x==y))
    {
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.print("Alien Killed");
      delay(2000);
      break;
    }


  lcd.setCursor(playerXPos, playerYPos);
  lcd.print(">");
  lcd.setCursor(x,bulletYPos);
  lcd.print("-");
  }
}