/// <summary>
/// Verifies the legality of a move. Places the stone on the board. Finds prisoners and remove them.
/// </summary>
/// <param name="currentNode">Node of tree representing the previous move.</param>
/// <param name="moveToMake">Move to check.</param>
/// <returns>Object, which contains: the result of legality check, list of prisoners, the new state of game board, the new state of groups.</returns>
public MoveProcessingResult ProcessMove(GameTreeNode currentNode, Move moveToMake)
{
lock (RulesetInfo)
{
StoneColor player = moveToMake.WhoMoves;
Position position = moveToMake.Coordinates;
GameBoard[] history = new GameBoard[0];
GroupState previousGroupState, currentGroupState;
GameBoard previousBoard, currentBoard;
if (currentNode == null)
{
previousGroupState = new GroupState(RulesetInfo);
currentGroupState = new GroupState(RulesetInfo);
previousBoard = new GameBoard(RulesetInfo.BoardSize);
currentBoard = new GameBoard(RulesetInfo.BoardSize);
}
else
{
history = currentNode.GetGameBoardHistory().ToArray();
//set Ruleset state
previousGroupState = new GroupState(currentNode.GroupState, RulesetInfo);
currentGroupState = new GroupState(currentNode.GroupState, RulesetInfo);
previousBoard = new GameBoard(currentNode.BoardState);
currentBoard = new GameBoard(currentNode.BoardState);
}
SetRulesetInfo(currentBoard, currentGroupState);
MoveProcessingResult processingResult = new MoveProcessingResult
{
Captures = new List <Position>(),
NewBoard = previousBoard,
NewGroupState = previousGroupState
};
//1. step: check intersection
if (moveToMake.Kind == MoveKind.Pass)
{
processingResult.Result = Pass(currentNode);
return(processingResult);
}
else if (IsOutsideTheBoard(position) == MoveResult.OutsideTheBoard)
{
processingResult.Result = MoveResult.OutsideTheBoard;
return(processingResult);
}
else if (IsPositionOccupied(position) == MoveResult.OccupiedPosition)
{
processingResult.Result = MoveResult.OccupiedPosition;
return(processingResult);
}
else
{
//2. step: add stone
RulesetInfo.GroupState.AddStoneToBoard(moveToMake.Coordinates, moveToMake.WhoMoves);
//3. step: find captures and remove prisoners
List <int> capturedGroups = CheckCapturedGroups(moveToMake);
foreach (int groupID in capturedGroups)
{
processingResult.Captures.AddRange(RulesetInfo.GroupState.Groups[groupID].Members);
RulesetInfo.GroupState.Groups[groupID].DeleteGroup();
}
//4. step: check selfcapture, ko
MoveResult r = CheckSelfCaptureKoSuperko(moveToMake, history);
if (r == MoveResult.Legal)
{
RulesetInfo.GroupState.CountLiberties();
processingResult.NewBoard = currentBoard;
processingResult.NewGroupState = currentGroupState;
}
else
{
SetRulesetInfo(previousBoard, previousGroupState);
}
processingResult.Result = r;
return(processingResult);
}
}
}
/// <summary>
/// Determines whether a move is legal. Information about any captures and the new board state are discarded.
/// </summary>
/// <param name="currentNode">Node of tree representing the previous move.</param>
/// <param name="moveToMake">The move of a player.</param>
/// <returns>The result of legality check.</returns>
public MoveResult IsLegalMove(GameTreeNode currentNode, Move moveToMake)
{
MoveProcessingResult result = ProcessMove(currentNode, moveToMake);
return(result.Result);
}