// Removing the Minimax Algorithm 

​

// https://thecodingtrain.com/CodingChallenges/154-tic-tac-toe-minimax.html

// https://youtu.be/I64-UTORVfU

// https://editor.p5js.org/codingtrain/sketches/0zyUhZdJD

​

let board = [

  ['', '', ''],

  ['', '', ''],

  ['', '', '']

];

let ai = 'AI';

let human = 'Justin';

let w, h;

let currentPlayer = human;

let using = [];  

let players = ['0', '1'];

let p;

​

function setup() {

  createCanvas(400, 400);

  firstTurn();

  w = width / 3;

  h = height / 3;

  p = random(players);

}

​

function equals3(a, b, c) {

  return (a == b && b == c && a != '');

}

​

function checkWinner() {

  let winner = null

​

  for (let i = 0; i < 3; i++) {

    if (equals3(board[i][0], board[i][1], board[i][2])) {

      winner = board[i][0];

    }

  }

​

  for (let i = 0; i < 3; i++) {

    if (equals3(board[0][i], board[1][i], board[2][i])) {

      winner = board[0][i];

    }

  }

​

  if (equals3(board[0][0], board[1][1], board[2][2])) {

    winner = board[0][0];

  }

  if (equals3(board[2][0], board[1][1], board[0][2])) {

    winner = board[2][0];

  }

​

  let openSpots = 0;

  for (let i = 0; i < 3; i++) {

    for (let j = 0; j < 3; j++) {

      if (board[i][j] == '') {

        openSpots++;

      }

    }

  }

  if (winner == null && openSpots == 0) {

    return 'tie';

  } else {

    return winner;

  }

}

​

​

function firstTurn() {

  let available = [];

  for (let i = 0; i < 3; i++) {

    for (let j = 0; j < 3; j++) {

      if (board[i][j] == '') {

        available.push({

          i,

          j

        });

      }

    }

  }

  let move = random(available);

  board[move.i][move.j] = ai;

  currentPlayer = human;

}

​

function mousePressed() {

  if (currentPlayer == human) {

    let i = floor(mouseX / w);

    let j = floor(mouseY / h);

    if (board[i][j] == '') {

      board[i][j] = human;

      firstTurn();

    }

  }

}

​

function draw() {

  background(255);

  strokeWeight(4);

​

  line(w, 0, w, height);

  line(w * 2, 0, w * 2, height);

  line(0, h, width, h);

  line(0, h * 2, width, h * 2);

​

  for (let j = 0; j < 3; j++) {

    for (let i = 0; i < 3; i++) {

​

      let x = w * i + w / 2;

      let y = h * j + h / 2;

      let spot = board[i][j];

      let r = w / 4;

      textSize(32);

​

      if (p == '0') {

        if (spot == ai) {

          noFill();

          ellipse(x, y, r * 2);

        } else if (spot == human) {

          line(x - r, y - r, x + r, y + r);

          line(x + r, y - r, x - r, y + r);

        }

      } else if (p == '1') {

        if (spot == ai) {

          line(x - r, y - r, x + r, y + r);

          line(x + r, y - r, x - r, y + r);

        } else if (spot == human) {

          noFill();

          ellipse(x, y, r * 2);

        } 

      }

    }

  }

  let result = checkWinner();

  if (result != null) {

    noLoop();

    let resultP = createP('');

    resultP.style('font-size', '32pt');

    resultP.position(50, 50)

    if (result == 'tie') {

      resultP.html('Tie!');

    } else {

      resultP.html(`${result} wins!`);

    }

  }

}