feat : allow custom starting fen

src/hooks/useChessActions.ts

@@ -14,9 +14,12 @@ export const useChessActions = (chessAtom: PrimitiveAtom<Chess>) => {
     [setGame]
   );
 
-  const reset = useCallback(() => {
-    setGame(new Chess());
-  }, [setGame]);
+  const reset = useCallback(
+    (fen?: string) => {
+      setGame(new Chess(fen));
+    },
+    [setGame]
+  );
 
   const copyGame = useCallback(() => {
     const newGame = new Chess();

src/lib/chess.ts

@@ -196,3 +196,11 @@ const getPieceValue = (piece: PieceSymbol): number => {
       return 0;
   }
 };
+
+export const getStartingFen = (pgn: string): string => {
+  const game = new Chess();
+  game.loadPgn(pgn);
+
+  const history = game.history({ verbose: true });
+  return history[0].before;
+};

src/sections/analysis/reviewPanelHeader/loadGame.tsx

@@ -12,6 +12,7 @@ import { useGameDatabase } from "@/hooks/useGameDatabase";
 import { useAtomValue, useSetAtom } from "jotai";
 import { Chess } from "chess.js";
 import { useRouter } from "next/router";
+import { getStartingFen } from "@/lib/chess";
 
 export default function LoadGame() {
   const router = useRouter();
@@ -25,7 +26,7 @@ export default function LoadGame() {
 
   const resetAndSetGamePgn = useCallback(
     (pgn: string) => {
-      resetBoard();
+      resetBoard(getStartingFen(pgn));
       setEval(undefined);
       setBoardOrientation(true);
       setGamePgn(pgn);

src/sections/analysis/reviewPanelToolbar/index.tsx

@@ -8,6 +8,7 @@ import NextMoveButton from "./nextMoveButton";
 import GoToLastPositionButton from "./goToLastPositionButton";
 import SaveButton from "./saveButton";
 import { useEffect } from "react";
+import { getStartingFen } from "@/lib/chess";
 
 export default function ReviewPanelToolBar() {
   const board = useAtomValue(boardAtom);
@@ -38,7 +39,7 @@ export default function ReviewPanelToolBar() {
       <Tooltip title="Reset board">
         <Grid>
           <IconButton
-            onClick={() => resetBoard()}
+            onClick={() => resetBoard(getStartingFen(board.pgn()))}
             disabled={boardHistory.length === 0}
           >
             <Icon icon="ri:skip-back-line" />