AIsOfCatan.GameController.BuildRoad C# (CSharp) Method

        public GameState BuildRoad(Player player, Edge edge)
        {
            var r = player.Resources;
            if (!(r.Contains(Resource.Brick) && r.Contains(Resource.Lumber)))
                throw new InsufficientResourcesException("Not enough resources to buy a road");
            if (player.RoadsLeft == 0)
                throw new IllegalActionException("No more road pieces left of your color");
            if (board.GetRoad(edge) != -1)
                throw new IllegalBuildPositionException("The chosen position is occupied by another road");
            if (!RoadConnected(board, edge, player.Id))
                throw new IllegalBuildPositionException("The chosen position is not connected to any of your pieces");
            if (!board.CanBuildRoad(edge))
                throw new IllegalBuildPositionException("The chosen position is not valid");

            PayResource(player, Resource.Brick);
            PayResource(player, Resource.Lumber);

            Log(new BuildRoadLogEvent(player.Id, edge));

            player.RoadsLeft--;
            board = board.PlaceRoad(edge, player.Id);
            UpdateLongestRoad();
            return CurrentGamestate();
        }

 public GameState BuildRoad(Edge edge)
 {
     if (!valid)
     {
         throw new IllegalActionException("Tried to perform an action on an invalid GameAction");
     }
     if (!isAfterDieRoll)
     {
         throw new IllegalActionException("Tried to build before the die roll");
     }
     return(controller.BuildRoad(player, edge));
 }