feat : show eval

src/lib/chess.ts

@@ -0,0 +1,64 @@
+import { Chess } from "chess.js";
+
+export const initPgn = new Chess().pgn();
+
+export const getGameFens = (pgn: string): string[] => {
+  const game = new Chess();
+  game.loadPgn(pgn);
+  return game.history({ verbose: true }).map((move) => move.before);
+};
+
+export const getLastFen = (pgn: string): string => {
+  const game = new Chess();
+  game.loadPgn(pgn);
+  return game.fen();
+};
+
+export const undoLastMove = (pgn: string): string => {
+  if (pgn === initPgn) return pgn;
+  const game = new Chess();
+  game.loadPgn(pgn);
+  game.undo();
+  return game.pgn();
+};
+
+export const addMove = (
+  pgn: string,
+  move: {
+    from: string;
+    to: string;
+    promotion?: string;
+  }
+): string => {
+  const game = new Chess();
+  game.loadPgn(pgn);
+  game.move(move);
+  return game.pgn();
+};
+
+export const addNextMove = (boardPgn: string, gamePgn: string): string => {
+  const board = new Chess();
+  board.loadPgn(boardPgn);
+
+  const game = new Chess();
+  game.loadPgn(gamePgn);
+
+  const nextMoveIndex = board.history().length;
+  const nextMove = game.history({ verbose: true })[nextMoveIndex];
+
+  if (nextMove) {
+    board.move({
+      from: nextMove.from,
+      to: nextMove.to,
+      promotion: nextMove.promotion,
+    });
+  }
+
+  return board.pgn();
+};
+
+export const getNextMoveIndex = (pgn: string): number => {
+  const game = new Chess();
+  game.loadPgn(pgn);
+  return game.history().length;
+};