fix: can make moves after undo

.env.example

@@ -1,3 +1,3 @@
 NODE_ENV=development
 PORT=5000
-ID_LENGTH=10
+ID_LENGTH=8

client/src/components/ChessUI.tsx

@@ -13,15 +13,16 @@ const ChessUI: React.FC<InferProps<[typeof ChessBoard, typeof History]>> = (
   const [showModal, setShowModal] = useState(true);
   const navigate = useNavigate();
   const chess = props.chess;
+  const currentChess = chess.getCurrentBoardPosition();
 
   return (
     <>
       <div className="w-screen h-screen flex items-center justify-center">
         <div className="m-4 flex flex-row gap-4">
           <ChessBoard
-            key={`${props.blackPerspective}` + chess.getFEN()}
+            key={`${props.blackPerspective}` + currentChess.getFEN()}
             {...props}
-            chess={chess.getCurrentBoardPosition()}
+            chess={currentChess}
             disabled={(props.disabled ?? false) || chess.isGameOver()}
           />
           <History {...props} />

client/src/components/Chessboard.tsx

@@ -57,9 +57,18 @@ const ChessBoard: React.FC<{
       isAttacked: false,
       isPromotion: false,
       isActive: false,
-      EndGameIcon: undefined,
+      endGameIcon: undefined,
     }));
 
+  const lastMove = chess.getHistory().history.at(-1)?.move;
+  console.log(chess.getHistory().history.at(-1));
+
+  if (lastMove) {
+    console.log(lastMove);
+    tileProps[squareIndex(lastMove.from)].isActive = true;
+    tileProps[squareIndex(lastMove.to)].isActive = true;
+  }
+
   if (activeTile != -1) {
     tileProps[activeTile].isActive = true;
     chess.getMovesForSquare(activeTile).forEach(({ to, flags }) => {
@@ -72,13 +81,13 @@ const ChessBoard: React.FC<{
   if (chess.isGameOver()) {
     const kings = chess.getKings();
     if (chess.isDraw()) {
-      tileProps[kings[COLOR.BLACK]].EndGameIcon = <HalfStar />;
-      tileProps[kings[COLOR.WHITE]].EndGameIcon = <HalfStar />;
+      tileProps[kings[COLOR.BLACK]].endGameIcon = <HalfStar />;
+      tileProps[kings[COLOR.WHITE]].endGameIcon = <HalfStar />;
     } else {
       const loser = chess.getTurn(),
         winner = swapColor(loser);
-      tileProps[kings[winner]].EndGameIcon = <Crown />;
-      tileProps[kings[loser]].EndGameIcon = <Hashtag />;
+      tileProps[kings[winner]].endGameIcon = <Crown />;
+      tileProps[kings[loser]].endGameIcon = <Hashtag />;
     }
   }
 
@@ -93,7 +102,7 @@ const ChessBoard: React.FC<{
 
     if (isNaN(tile)) return;
 
-    if (!chess.didUndo() && activeTile != -1 && tileProps[tile].isAttacked) {
+    if (activeTile != -1 && tileProps[tile].isAttacked) {
       const moveObj = {
         from: algebraic(activeTile),
         to: algebraic(tile),
@@ -180,14 +189,14 @@ const Tile: React.FC<{
   isActive: boolean;
   isAttacked: boolean;
   blackPerspective?: boolean;
-  EndGameIcon?: ReactNode;
+  endGameIcon?: ReactNode;
 }> = ({
   tileNumber,
   piece,
   isActive,
   isAttacked,
   blackPerspective,
-  EndGameIcon,
+  endGameIcon,
 }) => {
     const color = squareColor(tileNumber);
 
@@ -216,9 +225,9 @@ const Tile: React.FC<{
             className="max-w-full max-h-full aspect-square"
           />
         )}
-        <Show when={EndGameIcon != undefined}>
+        <Show when={endGameIcon != undefined}>
           <div className="absolute top-0 left-full -translate-x-1/2 -translate-y-1/2 bg-white z-10 rounded-full p-1 shadow-lg shadow-black aspect-square flex justify-center items-center">
-            {EndGameIcon}
+            {endGameIcon}
           </div>
         </Show>
         <Show when={isAttacked}>

client/src/routes/LocalGame.tsx

@@ -20,7 +20,7 @@ const LocalGame = () => {
     const rerender = () => aux((prev) => !prev);
 
     const makeMove = (move: Move) => {
-        if (chess.didUndo()) return;
+        if (chess.didUndo()) chess.undoMoves();
 
         chess.makeMove(move);
         rerender();

client/src/routes/OnlineGame.tsx

@@ -7,7 +7,6 @@ import { socket } from "../utils/socket";
 import { CaretLeft, CaretRight, CopyIcon } from "../components/icons";
 import Show from "../utils/Show";
 import ErrorNorification from "../components/ErrorNotification";
-import Modal, { ModalButton } from "../components/Modal";
 import ChessUI from "../components/ChessUI";
 import { removeLocationState } from "../utils/utils";
 import InferProps from "../utils/InferProps";
@@ -106,7 +105,7 @@ const Game = () => {
         chess={chess}
         makeMove={makeMove}
         blackPerspective={color === COLOR.BLACK}
-        disabled={color !== chess.getTurn()}
+        disabled={color !== chess.getTurn() || chess.didUndo()}
         buttons={buttons}
       />
     </Show>

server/src/engine.ts

@@ -509,7 +509,9 @@ export default class Chess {
 
   private _moves: Array<InternalMove> = [];
   private _attacks: Array<number> = [];
-  private _history: Array<Readonly<{ fen: string; san: string }>> = [];
+  private _history: Array<
+    Readonly<{ fen: string; san: string; move: InternalMove }>
+  > = [];
   private _boardPositionCounter = new Map<string, number>();
   private _undoCount = 0;
 
@@ -600,19 +602,26 @@ export default class Chess {
     }
   }
 
-  private _getPositionCounter() {
-    const trimFEN = this.getFEN(true);
+  private _trimFEN(fen: string) {
+    const split = fen.split(" ");
+    return split.splice(0, 4).join(" ");
+  }
+
+  private _getPositionCounter(fen: string) {
+    const trimFEN = this._trimFEN(fen);
     return this._boardPositionCounter.get(trimFEN) ?? 0;
   }
 
+  private _incrementPositionCounter(fen: string) {
+    const trimFEN = this._trimFEN(fen);
+    const counter = this._boardPositionCounter.get(trimFEN) ?? 0;
+    this._boardPositionCounter.set(trimFEN, counter + 1);
+  }
+
   private _processBoardState() {
     this._computeMoves();
 
-    if (this._enableHistory) {
-      const trimFEN = this.getFEN(true);
-      const counter = this._boardPositionCounter.get(trimFEN) ?? 0;
-      this._boardPositionCounter.set(trimFEN, counter + 1);
-    }
+    if (this._enableHistory) this._incrementPositionCounter(this.getFEN());
   }
 
   private static _load(
@@ -660,7 +669,7 @@ export default class Chess {
     return this._load(fen, { enableProcessMoves: true, enableHistory: true });
   }
 
-  getFEN(trim = false) {
+  getFEN() {
     let position = "";
     let emptySquares = 0;
 
@@ -702,10 +711,10 @@ export default class Chess {
       this._turn,
       castling,
       this._enPassant,
+      this._halfMoves,
+      this._fullMoves,
     ];
 
-    if (!trim) arr.push(this._halfMoves, this._fullMoves);
-
     return arr.join(" ");
   }
 
@@ -752,6 +761,7 @@ export default class Chess {
       this._history.push({
         fen: this.getFEN(),
         san: this._generateSan(move),
+        move,
       });
 
     this._board[squareIndex(move.to)] =
@@ -998,7 +1008,7 @@ export default class Chess {
   }
 
   isThreefoldRepetition() {
-    return this._getPositionCounter() >= 3;
+    return this._getPositionCounter(this.getFEN()) >= 3;
   }
 
   is50Rule() {
@@ -1041,11 +1051,33 @@ export default class Chess {
       enableHistory: false,
       enableProcessMoves: true,
     });
-    chess._undoCount = this._undoCount;
+    chess._undoCount = 0;
+    chess._history = this._history.slice(
+      0,
+      this._history.length - this._undoCount
+    );
 
     return chess;
   }
 
+  undoMoves() {
+    const chess = this.getCurrentBoardPosition();
+
+    this._board = chess._board;
+    this._turn = chess._turn;
+    this._castling = chess._castling;
+    this._enPassant = chess._enPassant;
+    this._halfMoves = chess._halfMoves;
+    this._fullMoves = chess._fullMoves;
+    this._kings = chess._kings;
+    this._history = chess._history;
+    this._undoCount = 0;
+    this._boardPositionCounter = new Map<string, number>();
+    this._history.forEach(({ fen }) => this._incrementPositionCounter(fen));
+
+    this._processBoardState();
+  }
+
   getTurn() {
     return this._turn;
   }

server/src/server.ts

@@ -9,7 +9,7 @@ import { nanoid as nanoidOriginal } from "nanoid";
 dotenv.config();
 
 const ID_LENGTH = isNaN(parseInt(process.env.ID_LENGTH!))
-  ? 10
+  ? 8
   : parseInt(process.env.ID_LENGTH!);
 
 const nanoid = () => nanoidOriginal(ID_LENGTH);