let gridSize = 20;

let cellSize = 20;

let snake;

let food;

​

// p5.js setup and draw functions

function setup() {

  createCanvas(gridSize * cellSize, gridSize * cellSize);

  snake = new Snake();

  food = new Food();

  frameRate(10);

}

​

function draw() {

  background(220);

  drawGrid();

​

  // AI logic for the snake to play itself

​

  // Update and display the snake and food

  snake.update();

  snake.show();

  food.show();

  autoPlay();

​

  // Check for collisions

  if (snake.eat(food)) {

    food = new Food();

  }

​

  if (snake.collide()) {

    // End the game or reset the snake

  }

}

​

// Helper functions

function drawGrid() {

  stroke(200);

  for (let i = 0; i < gridSize; i++) {

    for (let j = 0; j < gridSize; j++) {

      line(i * cellSize, 0, i * cellSize, gridSize * cellSize);

      line(0, j * cellSize, gridSize * cellSize, j * cellSize);

    }

  }

}

​

​

​

// Snake class

class Snake {

  constructor() {

    this.body = [];

    this.body[0] = createVector(floor(gridSize / 2) * cellSize, floor(gridSize / 2) * cellSize);

    this.xdir = 1;

    this.ydir = 0;

    this.size = cellSize;

  }

​

  // Update the snake's position

  update() {

    let head = this.body[this.body.length - 1].copy();

    head.x += this.xdir * cellSize;

    head.y += this.ydir * cellSize;

    this.body.shift();

    this.body.push(head);

  }

​

  // Display the snake on the canvas

  show() {

    fill(0);

    for (let i = 0; i < this.body.length; i++) {

      rect(this.body[i].x, this.body[i].y, this.size, this.size);

    }

  }

​

  // Set the snake's direction

  setDirection(x, y) {

    this.xdir = x;

    this.ydir = y;

  }

​

  // Check if the snake has collided with itself or the canvas edges

  collide() {

    let head = this.body[this.body.length - 1];

    if (head.x < 0 || head.x >= gridSize * cellSize || head.y < 0 || head.y >= gridSize * cellSize) {

      return true;

    }

    for (let i = 0; i < this.body.length - 1; i++) {

      if (head.x === this.body[i].x && head.y === this.body[i].y) {

        return true;

      }

    }

    return false;

  }

​

  // Check if the snake has eaten the food

  eat(food) {

    let head = this.body[this.body.length - 1];

    if (head.x === food.x && head.y === food.y) {

      this.grow();

      return true;

    }

    return false;

  }

​

  // Add a new segment to the snake

  grow() {

    let newSegment = this.body[this.body.length - 1].copy();

    this.body.push(newSegment);

  }

}

​

​

// Food class

class Food {

  constructor() {

    this.x = floor(random(gridSize)) * cellSize;

    this.y = floor(random(gridSize)) * cellSize;

    this.size = cellSize;

  }

​

  // Display the food on the canvas

  show() {

    fill(255, 0, 0);

    rect(this.x, this.y, this.size, this.size);

  }

​

  // Generate a new position for the food

  newLocation() {

    this.x = floor(random(gridSize)) * cellSize;

    this.y = floor(random(gridSize)) * cellSize;

  }

​

  // Check if the food is in the same position as any part of the snake

  isOnSnake(snake) {

    for (let i = 0; i < snake.body.length; i++) {

      if (this.x === snake.body[i].x && this.y === snake.body[i].y) {

        return true;

      }

    }

    return false;

  }

}

​

function autoPlay() {

  let head = snake.body[snake.body.length - 1];

  let nextMove = { x: snake.xdir, y: snake.ydir };

  let minDist = Infinity;

  let dista = 0;

​

  // Check all possible moves (up, down, left, right)

  let moves = [

    { x: 0, y: -1 },

    { x: 0, y: 1 },

    { x: -1, y: 0 },

    { x: 1, y: 0 },

  ];

​

  for (let move of moves) {

    let newX = head.x + move.x * cellSize;

    let newY = head.y + move.y * cellSize;

    let newHead = createVector(newX, newY);

​

    // Skip the move if it causes a collision with the snake's body or the grid borders

    if (

      newX < 0 ||

      newX >= gridSize * cellSize ||

      newY < 0 ||

      newY >= gridSize * cellSize ||

      snake.body.some((segment) => segment.x === newX && segment.y === newY)

    ) {

      continue;

    }

​

    // Calculate the distance between the new position and the food

    let dista = dist(newHead.x, newHead.y, food.x, food.y);

​

    // Update the best move if the distance is smaller

    if (dista < minDist) {

      minDist = dista;

      nextMove = move;

    }

  }

​

  // Set the direction of the snake according to the best move

  snake.setDirection(nextMove.x, nextMove.y);

}

​