const PLAYERS = [
  { symbol: 'X',       color: '#FF4757', label: 'Player 1' },
  { symbol: 'Circle',  color: '#2ED7F8', label: 'Player 2' },
  { symbol: 'Triangle',color: '#2ECC71', label: 'Player 3' },
  { symbol: 'Square',  color: '#FFD32A', label: 'Player 4' },
];

function getPlayer(sym) {
  return PLAYERS.find(p => p.symbol === sym) || PLAYERS[0];
}

function makeBoard(size) {
  const hLines = Array.from({ length: size }, () => Array(size - 1).fill(null));
  const vLines = Array.from({ length: size - 1 }, () => Array(size).fill(null));
  const boxes = Array.from({ length: size - 1 }, () => Array(size - 1).fill(null));
  return { size, hLines, vLines, boxes };
}

function getCompletedBoxes(hLines, vLines, boxes, row, col, isHorizontal) {
  const size = hLines.length;
  const completed = [];
  if (isHorizontal) {
    if (row > 0 && vLines[row-1][col] && vLines[row-1][col+1] && hLines[row-1][col]) {
      completed.push([row-1, col]);
    }
    if (row < size - 1 && vLines[row][col] && vLines[row][col+1] && hLines[row+1][col]) {
      completed.push([row, col]);
    }
  } else {
    if (col > 0 && hLines[row][col-1] && hLines[row+1][col-1] && vLines[row][col-1]) {
      completed.push([row, col-1]);
    }
    if (col < size - 1 && hLines[row][col] && hLines[row+1][col] && vLines[row][col+1]) {
      completed.push([row, col]);
    }
  }
  return completed.filter(([br, bc]) => !boxes[br][bc]);
}

function isGameOver(boxes) {
  return boxes.every(row => row.every(cell => cell !== null));
}

function getWinner(boxes, players) {
  const counts = {};
  players.forEach(p => counts[p.symbol] = 0);
  for (let r = 0; r < boxes.length; r++)
    for (let c = 0; c < boxes[r].length; c++)
      if (boxes[r][c]) counts[boxes[r][c]]++;
  const max = Math.max(...Object.values(counts));
  const tops = Object.keys(counts).filter(k => counts[k] === max);
  if (tops.length === 1) return tops[0];
  return null;
}

function getScores(boxes) {
  const counts = {};
  for (let r = 0; r < boxes.length; r++)
    for (let c = 0; c < boxes[r].length; c++)
      if (boxes[r][c]) counts[boxes[r][c]] = (counts[boxes[r][c]] || 0) + 1;
  return counts;
}

function makeSVG(symbol, color, size) {
  const ns = 'http://www.w3.org/2000/svg';
  const svg = document.createElementNS(ns, 'svg');
  svg.setAttribute('viewBox', '0 0 48 48');
  svg.setAttribute('width', size);
  svg.setAttribute('height', size);
  svg.innerHTML = makeSVGPath(symbol, color);
  return svg;
}

function makeSVGString(symbol, color, size) {
  return `<svg viewBox="0 0 48 48" width="${size}" height="${size}" xmlns="http://www.w3.org/2000/svg">${makeSVGPath(symbol, color)}</svg>`;
}

function makeSVGPath(symbol, color) {
  switch (symbol) {
    case 'X':
      return `
        <line x1="8" y1="8" x2="40" y2="40" stroke="${color}" stroke-width="6" stroke-linecap="round"/>
        <line x1="40" y1="8" x2="8" y2="40" stroke="${color}" stroke-width="6" stroke-linecap="round"/>`;
    case 'Circle':
      return `<circle cx="24" cy="24" r="16" fill="none" stroke="${color}" stroke-width="5"/>`;
    case 'Triangle':
      return `<polygon points="24,6 42,40 6,40" fill="none" stroke="${color}" stroke-width="4" stroke-linejoin="round"/>`;
    case 'Square':
      return `<rect x="8" y="8" width="32" height="32" rx="4" fill="none" stroke="${color}" stroke-width="5"/>`;
    default:
      return '';
  }
}

function escapeHtml(str) {
  const d = document.createElement('div');
  d.appendChild(document.createTextNode(str));
  return d.innerHTML;
}