#include <LedControl.h>

LedControl mat=LedControl(13,12,11,1);

#define VRx A0
#define VRy A1

int x,y,i=0,snakeHeadX=3,snakeHeadY=3,tailX[64],tailY[64],snakeSize=2;
int foodX,foodY,score=0;

void setup()
{
  mat.shutdown(0,false);
  mat.setIntensity(0,8);
  mat.clearDisplay(0);
  pinMode(VRx, INPUT);
  pinMode(VRy, INPUT);
  tailX[0]=3;
  tailY[0]=3;
  tailX[1]=4;
  tailY[1]=3;
  foodPosn();
  Serial.begin(9600);
}

void readInput()
{
  x=analogRead(VRx);
  y=analogRead(VRy);

  if (tailX[1]==tailX[0]-1||tailX[1]==tailX[0]+1||tailX[1]==tailX[0]+7||tailX[1]==tailX[0]-7)
  {
    if(y>900)
    snakeHeadY--;
    else if(y<150)
    snakeHeadY++;
    else 
    {
      if(tailX[1]==tailX[0]-1||tailX[1]==tailX[0]+7)
      snakeHeadX++;
      else if (tailX[1]==tailX[0]+1||tailX[1]==tailX[0]-7)
      snakeHeadX--;
    }
  }
  else if (tailY[1]==tailY[0]-1||tailY[1]==tailY[0]+1||tailY[1]==tailY[0]+7||tailY[1]==tailY[0]-7)
  {
  if(x>900)
  snakeHeadX++;
  else if(x<150)
  snakeHeadX--;
    else 
    {
      if(tailY[1]==tailY[0]-1||tailY[1]==tailY[0]+7)
      snakeHeadY++;
      else if (tailY[1]==tailY[0]+1||tailY[1]==tailY[0]-7)
      snakeHeadY--;
    }
  }

}

void display()
{
  mat.clearDisplay(0);
  mat.setLed(0,foodY,foodX,1);
  for(i=0;i<snakeSize;i++)
    mat.setLed(0,tailY[i],tailX[i],1);
  delay(200);
}

void manageCoord()
{
  for(i=snakeSize-1;i>0;i--)
  {
    tailX[i]=tailX[i-1];
    tailY[i]=tailY[i-1];
  }

  tailX[0]=snakeHeadX;
  tailY[0]=snakeHeadY;
}

void manageSnakeOutOfBounds()
{
	if(snakeHeadX > 7) 
	  snakeHeadX = 0;
  else if(snakeHeadX < 0) 
	  snakeHeadX = 7;
	if(snakeHeadY > 7)
	  snakeHeadY = 0;
  else if(snakeHeadY < 0)
	  snakeHeadY = 7;
}

void foodPosn()
{
  foodX=rand()%8;
  foodY=rand()%8;
}

void manageEatenFood()
{
  if (snakeHeadX==foodX && snakeHeadY==foodY)
  {
    score++;
    snakeSize++;
    Serial.print("Score=");
    Serial.println(score);
    foodPosn();
  }
}

void loop()
{
  readInput();
  manageSnakeOutOfBounds();
  manageEatenFood();
  manageCoord();
  display();
}