GR.Gambling.Backgammon.Board.Recursion C# (CSharp) Method

        private static void Recursion(
            int player, 
            List<int> free_dice, 
            Board board, 
            List<Move> moves_made, 
            ref List<Play> plays,
            ref List<Play> partial_plays,
            ref HashSet<string> board_hash)
        {
            string hash = board.HashString();
            if (board_hash.Contains(hash))
                return;

            board_hash.Add(hash);

            if (free_dice.Count == 0)
            {
                plays.Add(new Play(moves_made));
                return;
            }

            bool further_moves = false;
            if (board.CapturedCount(player) > 0)
            {

                for (int i = 0; i < free_dice.Count; i++)
                {
                    int free_die = free_dice[i];
                    int to = 24 - free_die;
                    Move move = Move.CreateBarMove(to);

                    if (board.IsLegalMove(player, move, free_die))
                    {
                        further_moves = true;

                        if (board.PointCount(player, to) == -1)
                            move.AddHitPoint(to);

                        free_dice.RemoveAt(i);

                        moves_made.Add(move);

                        board.MakeMove(player, move);

                        Recursion(player, free_dice, board, moves_made, ref plays, ref partial_plays, ref board_hash);

                        board.UndoMove(player, move);

                        moves_made.RemoveAt(moves_made.Count - 1);

                        free_dice.Insert(i, free_die);
                    }
                }

                // No need to check for further moves here because bar moves are forced and if there aren't any, we can't move at all

                if (!further_moves && plays.Count == 0 && moves_made.Count > 0)
                {
                    partial_plays.Add(new Play(moves_made));
                }

                return;
            }

            further_moves = false;
            for (int slot = 23; slot >= 0; slot--)
            {
                if (board.PointCount(player, slot) > 0)
                {
                    for (int i = 0; i < free_dice.Count; i++)
                    {
                        int free_die = free_dice[i];
                        int to = slot - free_die;
                        Move move = (to >= 0) ? new Move(slot, to) : Move.CreateBearoffMove(slot);

                        if (board.IsLegalMove(player, move, free_die))
                        {
                            further_moves = true;

                            if (!move.IsBearOff && board.PointCount(player, to) == -1)
                                move.AddHitPoint(to);

                            free_dice.RemoveAt(i);

                            moves_made.Add(move);

                            board.MakeMove(player, move);

                            Recursion(player, free_dice, board, moves_made, ref plays, ref partial_plays, ref board_hash);

                            board.UndoMove(player, move);

                            moves_made.RemoveAt(moves_made.Count - 1);

                            free_dice.Insert(i, free_die);
                        }
                    }
                }
            }

            if (!further_moves && plays.Count == 0 && moves_made.Count > 0)
            {
                partial_plays.Add(new Play(moves_made));
            }
        }