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packages/draughts/core/utilities/index.js

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+import { BOARD_SIZE, Pieces, Players } from '@draughts/core';
+
+const isQueenMap = {
+  [Pieces.NONE]: false,
+  [Pieces.BLACK]: false,
+  [Pieces.WHITE]: false,
+  [Pieces.BLACK_QUEEN]: true,
+  [Pieces.WHITE_QUEEN]: true,
+};
+
+export const pieceIsQueen = (piece) => isQueenMap[piece];
+
+const isPlayerMap = {
+  [Players.NONE]: new Set([Pieces.NONE]),
+  [Players.WHITE]: new Set([Pieces.WHITE, Pieces.WHITE_QUEEN]),
+  [Players.BLACK]: new Set([Pieces.BLACK, Pieces.BLACK_QUEEN]),
+};
+
+export const pieceIsPlayer = (piece, player) => {
+  return isPlayerMap[player].has(piece);
+};
+
+export const cellWithinBounds = ({ row, col }) =>
+  row < BOARD_SIZE && row >= 0 && col < BOARD_SIZE && col >= 0;
+
+export const cellIsEmpty = (position, { row, col }) =>
+  position[row][col] === Pieces.NONE;
+
+export function* eachCell(position) {
+  for (const [row, rowArray] of position.entries()) {
+    for (const [col, piece] of rowArray.entries()) {
+      yield { cell: { col, row }, piece };
+    }
+  }
+}
+
+const crownQueenMap = {
+  [Pieces.BLACK]: Pieces.BLACK_QUEEN,
+  [Pieces.WHITE]: Pieces.WHITE_QUEEN,
+  [Pieces.BLACK_QUEEN]: Pieces.BLACK_QUEEN,
+  [Pieces.WHITE_QUEEN]: Pieces.WHITE_QUEEN,
+};
+
+export const queenPiece = (piece) => crownQueenMap[piece];
+
+export const shouldQueen = (cell, piece) => {
+  if (pieceIsQueen(piece)) return false;
+  return (
+    (pieceIsPlayer(piece, Players.WHITE) && cell.row === 0) ||
+    (pieceIsPlayer(piece, Players.BLACK) && cell.row === BOARD_SIZE - 1)
+  );
+};
+
+export const filterToLongestCaptures = (moves) => {
+  let longestCaptures = [];
+  let recordLength = 0;
+  for (const move of moves) {
+    if (move.captures.length > recordLength) {
+      longestCaptures = [move];
+      recordLength = move.captures.length;
+    } else if (move.captures.length === recordLength) {
+      longestCaptures.push(move);
+    }
+  }
+  return longestCaptures;
+};
+
+export const clonePosition = (position) => [...position.map((row) => [...row])];
+
+export const compareCells = (cellOne, cellTwo) => {
+  if (!cellOne || !cellTwo) return false;
+  return cellOne.row === cellTwo.row && cellOne.col === cellTwo.col;
+};
+
+const formatPlayerMap = {
+  [Players.NONE]: 'none',
+  [Players.WHITE]: 'white',
+  [Players.BLACK]: 'black',
+};
+
+export const formatPlayer = (player) => formatPlayerMap[player];