Snake snake;
char [][] pix;
int gridUnit = 3;
int gridSize = 40;
int xc,yc;
int xEgg,yEgg,xBigEgg,yBigEgg,bigEgg;
int bestScore = 10;
boolean gameOver = true;
void setup(){
  size(120,120);
  newGame();
  framerate(24);
  xc = (width>>1)-60;
  yc = (height>>1)-60;
}
void draw(){
  background(255);
  noFill();
  stroke(0);
  rect(xc,yc,gridSize*gridUnit,gridSize*gridUnit);
  noStroke();
  fill(0);
  if(!gameOver){
    snake.move();
    snake.draw();
    fill(255,0,0);
    drawEgg();
    if(bigEgg > 0){
      checkBigEgg();
      fill(0,0,255);
      drawBigEgg();
    } 
    else if (random(200) == 0){
      spawnBigEgg();
    }
  }
  else{
    gameOver();
  }
}
void keyPressed(){
  if(!gameOver){
    switch(key){
    case '6':
      if(snake.d != 2){
        snake.d = 0;
      }
      break;
    case '8':
      if(snake.d != 3){
        snake.d = 1;
      }
      break;
    case '4':
      if(snake.d != 0){
        snake.d = 2;
      }
      break;
    case '2':
      if(snake.d != 1){
        snake.d = 3;
      }
      break;
    }
    switch(keyCode){
    case 5:
      if(snake.d != 2){
        snake.d = 0;
      }
      break;
    case 6:
      if(snake.d != 3){
        snake.d = 1;
      }
      break;
    case 2:
      if(snake.d != 0){
        snake.d = 2;
      }
      break;
    case 1:
      if(snake.d != 1){
        snake.d = 3;
      }
      break;
    }
  }
  else{
    newGame();
    gameOver = false;
  }
}
void hiScore(){
  if(snake.len > bestScore){
    bestScore = snake.len;
  }
}
void gameOver(){
  for(int i = 0; i < bestScore; i++){
    if(i > snake.len){
      fill(255,0,0);
    }
    else{
      fill(0);
    }
    rect(xc+(i%gridSize)*gridUnit,yc+(i/gridSize)*gridUnit,gridUnit,gridUnit);
  }
}
void newGame(){
  pix = new char[gridSize][gridSize];
  snake = new Snake(10);
  spawnEgg();
  bigEgg = 0;
}
void drawEgg(){
  rect(xc+xEgg*gridUnit,yc+yEgg*gridUnit,gridUnit,gridUnit);
}
void drawBigEgg(){
  rect(xc+xBigEgg*gridUnit,yc+yBigEgg*gridUnit,gridUnit,gridUnit);
}
void checkBigEgg(){
  if(bigEgg > 0){
    bigEgg--;
  }
  else if(bigEgg == 1){
    pix[xBigEgg][yBigEgg] = 0;
  }
}
void spawnEgg(){
  while(true){
    xEgg = random(0,gridSize-1);
    yEgg = random(0,gridSize-1);
    if(pix[xEgg][yEgg] == 0){
      break;
    }
  }
  pix[xEgg][yEgg] = 2;
}
void spawnBigEgg(){
  while(true){
    xBigEgg = random(0,gridSize-1);
    yBigEgg = random(0,gridSize-1);
    if(pix[xBigEgg][yBigEgg] == 0 ){
      break;
    }
  }
  bigEgg = random(35,50);
  pix[xBigEgg][yBigEgg] = 3;
}
class Snake{
  int [] x,y;//snake body array
  int d,len;//direction and length
  Snake(int len){
    this.len = len;
    x = new int[len];
    y = new int[len];
    d = 0;
    for(int i = 0; i < len; i++){
      x[i] = (gridSize>>1)-10;
      y[i] = gridSize>>1;
    }
    for(int i = 0; i < len; i++){
      move();
    }
  }
  void move(){
    //shift values along one
    pix[x[0]][y[0]] = 0;
    for (int i = 1; i < len; i++){
      x[i-1] = x[i];
      y[i-1] = y[i];
    }
    switch(d){
    case 0:
      x[len-1]++;
      break;
    case 1:
      y[len-1]++;
      break;
    case 2:
      x[len-1]--;
      break;
    case 3:
      y[len-1]--;
      break;
    }
    //check for own body, walls and eggs
    if(x[len-1] < gridSize && x[len-1] > -1 && y[len-1] < gridSize && y[len-1] > -1){
      switch(pix[x[len-1]][y[len-1]]){
      case 1:
        hiScore();
        gameOver = true;
        break;
      case 2:
        for(int i = 0; i < random(1,6); i++){
          x = append(x, x[len-1]);
          y = append(y, y[len-1]);
          len++;
          pix[x[len-1]][y[len-1]] = 1;
        }
        spawnEgg();
        break;
      case 3:
        for(int i = 0; i < random(7,15); i++){
          x = append(x, x[len-1]);
          y = append(y, y[len-1]);
          len++;
          pix[x[len-1]][y[len-1]] = 1;
        }
        bigEgg = 0;
      default:
        pix[x[len-1]][y[len-1]] = 1;
        break;
      }
    }
    else{
      hiScore();
      gameOver = true;
    }
  }
  void draw(){
    for(int i = 0; i < len; i++){
      rect(xc+x[i]*gridUnit,yc+y[i]*gridUnit,gridUnit,gridUnit);
    }
  }
}