// /var/www/minitactix/static/game.js
let board = []
let playerSymbol = ''
let npcSymbol = ''
let gameOver = false

function startGame(symbol) {
  playerSymbol = symbol
  npcSymbol = symbol === 'X' ? 'O' : 'X'
  document.getElementById('symbol-chooser').classList.add('hidden')
  document.getElementById('board').classList.remove('hidden')
  document.getElementById('restart').classList.remove('hidden')
  initBoard()
  randomNPCMoves(3 + Math.floor(Math.random() * 3))
  renderBoard()
}

function initBoard() {
  board = Array(16).fill('')
}

function renderBoard() {
  const boardDiv = document.getElementById('board')
  boardDiv.innerHTML = ''
  board.forEach((val, idx) => {
    const tile = document.createElement('div')
    tile.className = 'tile'
    tile.textContent = val
    tile.onclick = () => playerMove(idx)
    if (val !== '' || gameOver) tile.onclick = null
    boardDiv.appendChild(tile)
  })
}

function playerMove(index) {
  if (board[index] !== '' || gameOver) return
  board[index] = playerSymbol
  if (checkWin(playerSymbol)) {
    endGame('You win!')
    return
  }
  if (board.includes('')) {
    randomNPCMoves(1)
    if (checkWin(npcSymbol)) {
      endGame('NPC wins!')
      return
    }
  }
  if (!board.includes('')) endGame("It's a draw!")
  renderBoard()
}

function randomNPCMoves(count) {
  for (let i = 0; i < count; i++) {
    const free = board.map((v, i) => v === '' ? i : null).filter(v => v !== null)
    if (free.length === 0) return
    const pick = free[Math.floor(Math.random() * free.length)]
    board[pick] = npcSymbol
  }
}

function checkWin(sym) {
  const lines = [
    // rows
    [0,1,2], [1,2,3],
    [4,5,6], [5,6,7],
    [8,9,10], [9,10,11],
    [12,13,14], [13,14,15],
    // cols
    [0,4,8], [4,8,12],
    [1,5,9], [5,9,13],
    [2,6,10], [6,10,14],
    [3,7,11], [7,11,15],
    // diagonals
    [0,5,10], [1,6,11],
    [4,9,14], [5,10,15],
    [2,5,8], [3,6,9],
    [6,9,12], [7,10,13]
  ]
  return lines.some(line => line.every(i => board[i] === sym))
}

function endGame(msg) {
  document.getElementById('status').textContent = msg
  gameOver = true
  renderBoard()
}