Pawn Promotion - Automatic Queen Promotion as there is nothing in GUI to

select it

src/backend/Board.java

@@ -518,6 +518,14 @@ public void undoLastMove() {
 		    // Update the moved piece's position
 		    piece.setPosition(move.getToX(), move.getToY());
 		    
+		    if (piece.getType() == PieceType.Pawn) {
+		        // white promotes on y == height‐1, black on y == 0
+		        int promotionRank = piece.isWhite() ? height - 1 : 0;
+		        if (piece.getY() == promotionRank) {
+		            piece.setType(PieceType.Queen);
+		        }
+		    }
+
 		    // Save move in history for undo
 		    moveHistory.add(move);
 

src/backend/Piece.java

@@ -24,6 +24,9 @@ public class Piece {
 	public void setY(int y) {
 		this.y = y;
 	}
+	public void setType(PieceType newType) {
+        this.type = newType;
+    }
 	
 	public PieceType getType() {
 		return type;
@@ -57,5 +60,4 @@ public class Piece {
 	}
 	
 	
-	
 }