Problem 28.1 - Chess Moves

const { runTests } = require("./tests.js");

function validChessMoves(board, piece, r, c) {
  function isMoveValid(board, r, c) {
    const rows = board.length;
    const cols = board[0].length;

    return (
      (r >= 0 && r < rows) &&
      (c >= 0 && c < cols) &&
      board[r][c] != 1
    );
  }

  const knightDirections = [[-2,1],[-2,-1],[2,1],[2,-1],[-1,2],[1,2],[-1,-2],[1,-2]];
  const kingDirections = [[0, 1], [0,-1],[-1,0],[1,0],[-1,1], [-1,-1],[1,1], [1,-1]];
  const queenDirections = kingDirections;

  const moves = [];
  if (piece === "knight") {
    for (const [rDir, cDir] of knightDirections) {
      const [newR, newC] = [r + rDir, c + cDir];
      if (isMoveValid(board, newR, newC)) {
        moves.push([newR, newC]);
      }
    }
  }
  else if (piece === "king") {
    for (const [rDir, cDir] of kingDirections) {
      const newR = r + rDir;
      const newC = c + cDir;
      if (isMoveValid(board, newR, newC)) {
        moves.push([newR, newC]);
      }
    }
  }
  else {
    for (const [rDir, cDir] of queenDirections) {
      let newR = r + rDir;
      let newC = c + cDir;
      while (isMoveValid(board, newR, newC)) {
        moves.push([newR, newC]);
        newR += rDir;
        newC += cDir;
      }
    }
  }

  return moves;
}

runTests(validChessMoves);