export function formatClock(ms) {
  if (!Number.isFinite(ms) || ms < 0) {
    return "--:--";
  }

  const totalSeconds = Math.floor(ms / 1000);
  const minutes = Math.floor(totalSeconds / 60);
  const seconds = totalSeconds % 60;
  return `${String(minutes).padStart(2, "0")}:${String(seconds).padStart(2, "0")}`;
}

export function parseFenBoard(fen) {
  const boardPart = (fen || "").split(" ")[0] || "8/8/8/8/8/8/8/8";
  const rows = boardPart.split("/");
  const board = {};

  for (let r = 0; r < 8; r += 1) {
    let file = 0;
    for (const fenChar of rows[r]) {
      const num = Number(fenChar);
      if (!Number.isNaN(num)) {
        file += num;
        continue;
      }
      const square = `${"abcdefgh"[file]}${8 - r}`;
      board[square] = fenChar;
      file += 1;
    }
  }

  return board;
}