Method copy

src/main/java/game/Board.java:650–671

()

    }

    public Board copy() {
        final Board board = new Board();
        pieces.forEach(board.pieces::put);
        playerPieces.forEach((color, pieces) -> board.playerPieces.put(color, new ArrayList<>(pieces)));
        moves.forEach((cell, moves) -> board.moves.put(cell, new HashSet<>(moves)));
        guards.forEach((cell, moves) -> board.guards.put(cell, new HashSet<>(moves)));
        System.arraycopy(positions, 0, board.positions, 0, positions.length);
        board.positionIndex = positionIndex;
        board.moveList.addAll(moveList);
        System.arraycopy(kings, 0, board.kings, 0, 2);
        for (int i = 0; i < 2; i++) {
            System.arraycopy(canCastle[i], 0, board.canCastle[i], 0, 2);
        }
        board.previousMove = previousMove;
        board.zobristHash = zobristHash;
        board.playerToMove = playerToMove;
        board.isThreeFoldRepetition = isThreeFoldRepetition;
        board.halfMoves = halfMoves;
        board.fiftyMoveDraw = fiftyMoveDraw;
        board.inCheck = inCheck;
        return board;
    }

    //todo: idea: Should we compare a list of positions and choose the best? We do not evaluate positions in isolation,
    // but rather rank them by comparing the top 20 positions possible