public GameBoardState(int[] mainBoard, int whiteCheckersOnBar, int whiteCheckersOnTarget, int blackCheckersOnBar, int blackCheckersOnTarget)
{
//Checking that both players have exactly 15 checkers on the board
int numberOfWhiteCheckers = mainBoard
.Where(i => i > 0) //Filtering out all positions that have negative numbers, or black checkers, on them
.Sum() + whiteCheckersOnBar + whiteCheckersOnTarget;
int numberOfBlackCheckers = mainBoard
.Where(i => i < 0) //Filtering out all positions that have positive numbers / white checkers
.Sum() * -1 //Making the black checkers count as positive
+ blackCheckersOnBar + blackCheckersOnTarget;
if (numberOfWhiteCheckers != NUMBER_OF_CHECKERS_PER_PLAYER ||
numberOfBlackCheckers != NUMBER_OF_CHECKERS_PER_PLAYER)
{
throw new InvalidOperationException("There is not the expected number of checkers. There are " + numberOfWhiteCheckers
+ " white checkers and " + numberOfBlackCheckers + " black checkers");
}
//Adding all the supplied information to the dictionary gameBoard
for (int i = 0; i < mainBoard.Length; i++)
{
gameBoard.Add(i + 1, mainBoard[i]);
}
gameBoard.Add(White.GetBar(), whiteCheckersOnBar);
gameBoard.Add(Black.GetBar(), blackCheckersOnBar);
gameBoard.Add(White.BearOffPositionID(), whiteCheckersOnTarget);
gameBoard.Add(Black.BearOffPositionID(), blackCheckersOnTarget);
}
//Given a position and a color, assumes the position is with regards to the other color and
//converts it to the perspective of the given color
private static int convertTo(CheckerColor color, int i)
{
if (color == BLACK)
{
if (i == WHITE.GetBar())
{
return(BLACK.GetBar());
}
if (i == WHITE.BearOffPositionID())
{
return(BLACK.BearOffPositionID());
}
return(25 - i);
}
if (i == color.OppositeColor().GetBar())
{
return(color.GetBar());
}
if (i == color.OppositeColor().BearOffPositionID())
{
return(color.BearOffPositionID());
}
return(25 - i);
}
internal static IEnumerable <int> GetMoveableCheckers(GameBoardState state, CheckerColor color, List <int> moves)
{
HashSet <int> output = new HashSet <int>();
if (new MovesCalculator(state, color, color.GetBar(), moves).GetReachablePositions().Count() > 0)
{
output.Add(color.GetBar());
}
for (int i = 1; i <= 24; i++)
{
if (new MovesCalculator(state, color, i, moves).GetReachablePositions().Count() > 0)
{
output.Add(i);
}
}
return(output);
}
internal void HighlightChecker(CheckerColor color, int i)
{
if (i == color.GetBar())
{
HighlightImage(GetOnBarPoint(color).GetTopChecker());
}
else
{
HighlightImage(Points[i].GetTopChecker());
}
}
//Performs a move and returns the resulting state. If the move is illegal, null will be returned instead.
internal static GameBoardState Move(GameBoardState state, CheckerColor color, int initialPosition, int distance)
{
//Since moving a checker from the black player is identical to moving a checker from the white player, if the white player's
//situation was the same as the black player, the game board and input is inverted so this is the case, and the code for
//moving a white checker is reused
if (color == BLACK)
{
//Transforming the input
state = state.InvertColor();
initialPosition = convertTo(WHITE, initialPosition);
state = Move(state, WHITE, initialPosition, distance);
//Returns null if the move is invalid, else transforms the move
//back into the perspective of the black player and returns it.
return(state == null ? null : state.InvertColor());
}
//The position of the white bar relative to the board is 25, as 24 is the first position
//for white when moving from the bar
int initialPositionRelativeToBoard = initialPosition == WHITE.GetBar() ? 25 : initialPosition;
int targetPosition = initialPositionRelativeToBoard - distance;
if (IsLegalMove(state, initialPosition, targetPosition))
{
//The previous definition of the target position is useful for determining whether or not
//A move is legal. However, we risk getting negative values, for example when
//the white player bears off a checker on position 4 using a die that shows 5
//Therefore the /actual/ target position is found using the below method call
targetPosition = GetPositionAfterMove(color, initialPosition, distance);
return(state.MoveChecker(initialPosition, targetPosition));
}
else
{
return(null);
}
}
public int getCheckersOnBar(CheckerColor color)
{
return(GetCheckersOnPosition(color.GetBar()));
}
internal static Move CapturingMove(CheckerColor color, int from)
{
return(new Move(color, from, color.GetBar()));
}