public virtual bool IsLegal(Board board, int x, int y, Game.Space.Color color)
{
if (board.Game.Spaces.GetSpace(x, y).SpaceColor != Game.Space.Color.None)
{
return(false);
}
// make a copy to test this move
Game.Game game = board.Game.Copy();
// add the new stone; make sure there's not already a stone there
Game.Space newStone = game.AddStone(x, y, color);
if (newStone == null)
{
return(false);
}
// remove dead stones and make sure this group isn't dead
game.RemoveDeadStones(x, y);
if (game.GetGroupLiberties(newStone.GetGroup()) == 0)
{
return(false);
}
// check for ko
if (board.Game.HistoryIndex >= 1)
{
bool ko = true;
foreach (Game.Space space in board.Game.History[board.Game.HistoryIndex - 1].Spaces)
{
if (space.SpaceColor != game.Spaces.GetSpace(space.X, space.Y).SpaceColor)
{
ko = false;
}
}
if (ko)
{
return(false);
}
}
return(true);
}