/// <summary>
/// Processes game rules which apply after and between player turns.
/// </summary>
/// <param name="state">Game state immediately after a player turn has ended.</param>
/// <returns>Game over state, if a win was detected, or game state ready for next player turn</returns>
public static State PrepareNextTurn(State state)
{
state.Flags = state.Flags.HandleKingCaptureFlag();
CheckKingCreation(ref state);
BlessAnyBridges(ref state);
CheckBlessedKings(ref state);
ApplyCurses(ref state);
if (state.Flags.IsSecondTurn())
{
UnlockAllLockedPieces(ref state);
}
state.Flags = state.Flags.NextTurn();
if (!state.Flags.GameEnded())
{
var side = state.Flags.IsRedTurn() ? ActionSide.Red : ActionSide.Blue;
if (!AvailableActionController.AllActions(state, side).Any())
{
state.Flags = state.Flags.IsRedTurn() ? StateFlags.BlueWin : StateFlags.RedWin;
}
}
return(state);
}
private double AlphaBetaInternal(State state, int depth, double alpha, double beta, bool maximizingPlayer,
bool secondTurn, HashSet <Guid> seenStates)
{
if (depth == 0 || state.Flags.GameEnded())
{
return(GetScore(state));
}
if (maximizingPlayer)
{
var v = double.NegativeInfinity;
foreach (var proposed in AvailableActionController.GetAvailableActions(state, seenStates).OrderByDescending(kvp => kvp.Value.Heuristic))
{
v = Math.Max(v, AlphaBetaInternal(proposed.Value.Result, depth - 1, alpha, beta,
secondTurn ^ maximizingPlayer, !secondTurn, seenStates));
alpha = Math.Max(alpha, v);
if (alpha >= beta)
{
break;
}
}
return(v);
}
else
{
var v = double.PositiveInfinity;
foreach (var proposed in AvailableActionController.GetAvailableActions(state, seenStates)
.OrderByDescending(kvp => kvp.Value.Heuristic))
{
v = Math.Min(v, AlphaBetaInternal(proposed.Value.Result, depth - 1, alpha, beta,
secondTurn ^ maximizingPlayer, !secondTurn, seenStates));
beta = Math.Min(beta, v);
if (alpha >= beta)
{
break;
}
}
return(v);
}
}
