<link rel="stylesheet" href="style.css" rel="external nofollow" >
<link rel="preconnect"  rel="external nofollow" >
<link  rel="external nofollow"  rel="stylesheet">
<script src="index.js"></script>

<main class="background">
        <section class="title">
            <h1>井字游戲</h1>
        </section>
        <section class="display">
            玩家 <span class="display-player playerX">X</span> 的回合
        </section>
        <section class="container">
            <div class="tile"></div>
            <div class="tile"></div>
            <div class="tile"></div>
            <div class="tile"></div>
            <div class="tile"></div>
            <div class="tile"></div>
            <div class="tile"></div>
            <div class="tile"></div>
            <div class="tile"></div>
        </section>
        <section class="display announcer hide"></section>
        <section class="controls">
            <button id="reset">重新開始</button>
        </section>
    </main>

* {
    padding: 0;
    margin: 0;
    font-family: 'Itim', cursive;
}

.container {
    margin: 0 auto;
    display: grid;
    grid-template-columns: 33% 33% 33%;
    grid-template-rows: 33% 33% 33%;
    max-width: 300px;
}

.tile {
    border: 1px solid white;
    min-width: 100px;
    min-height: 100px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 50px;
    cursor: pointer;
}

.playerX {
    color: #09C372;
}

.playerO {
    color: #498AFB;
}

window.addEventListener('DOMContentLoaded', () => {

});

const tiles = Array.from(document.querySelectorAll('.tile'));
const playerDisplay = document.querySelector('.display-player');
const resetButton = document.querySelector('#reset');
const announcer = document.querySelector('.announcer');

let board = ['', '', '', '', '', '', '', '', ''];
let currentPlayer = 'X';
let isGameActive = true;

const PLAYERX_WON = 'PLAYERX_WON';
const PLAYERO_WON = 'PLAYERO_WON';
const TIE = 'TIE';

/*
   Indexes within the board
   [0] [1] [2]
   [3] [4] [5]
   [6] [7] [8]
*/

const winningConditions = [
   [0, 1, 2],
   [3, 4, 5],
   [6, 7, 8],
   [0, 3, 6],
   [1, 4, 7],
   [2, 5, 8],
   [0, 4, 8],
   [2, 4, 6]
];

const isValidAction = (tile) => {
    if (tile.innerText === 'X' || tile.innerText === 'O'){
        return false;
    }

    return true;
};

const updateBoard =  (index) => {
   board[index] = currentPlayer;
}

const changePlayer = () => {
    playerDisplay.classList.remove(`player${currentPlayer}`);
    currentPlayer = currentPlayer === 'X' ? 'O' : 'X';
    playerDisplay.innerText = currentPlayer;
    playerDisplay.classList.add(`player${currentPlayer}`);
}

const announce = (type) => {
    switch(type){
       case PLAYERO_WON:
            announcer.innerHTML = 'Player <span class="playerO">O</span> Won';
            break;
       case PLAYERX_WON:
            announcer.innerHTML = 'Player <span class="playerX">X</span> Won';
            break;
       case TIE:
            announcer.innerText = 'Tie';
        }
    announcer.classList.remove('hide');
};

function handleResultValidation() {
  let roundWon = false;
  for (let i = 0; i <= 7; i++) {
    const winCondition = winningConditions[i];
    const a = board[winCondition[0]];
    const b = board[winCondition[1]];
    const c = board[winCondition[2]];
    if (a === "" || b === "" || c === "") {
      continue;
    }
    if (a === b && b === c) {
      roundWon = true;
      break;
    }
  }

  if (roundWon) {
    announce(currentPlayer === "X" ? PLAYERX_WON : PLAYERO_WON);
    isGameActive = false;
    return;
  }

  if (!board.includes("")) announce(TIE);
}

const userAction = (tile, index) => {
  if (isValidAction(tile) && isGameActive) {
    tile.innerText = currentPlayer;
    tile.classList.add(`player${currentPlayer}`);
    updateBoard(index);
    handleResultValidation();
    changePlayer();
  }
};

tiles.forEach( (tile, index) => {
    tile.addEventListener('click', () => userAction(tile, index));
});

const resetBoard = () => {
    board = ['', '', '', '', '', '', '', '', ''];
    isGameActive = true;
    announcer.classList.add('hide');

    if (currentPlayer === 'O') {
        changePlayer();
    }

    tiles.forEach(tile => {
        tile.innerText = '';
        tile.classList.remove('playerX');
        tile.classList.remove('playerO');
    });
}

resetButton.addEventListener('click', resetBoard);