/// <summary>
/// Returns the possible bonus cards for the specified board.
/// </summary>
public static void GetPossibleBonusCardIndexes(ulong maxCardIndex, ref ByteList12 cardIndexes)
{
byte maxBonusCardIndex = (byte)(maxCardIndex - 3);
for(byte cardIndex = 4; cardIndex <= maxBonusCardIndex; cardIndex++)
cardIndexes.Add(cardIndex);
}
/// <summary>
/// Returns the quality value for shifting the specified board in the specified direction.
/// Returns null if shifting in that direction is not possible.
/// </summary>
private unsafe float?EvaluateMoveForBoard(FastBoard board, FastDeck deck, ulong knownNextCardIndex, ShiftDirection dir, int recursionsLeft, ref long movesEvaluated)
{
FastBoard shiftedBoard = board;
IntVector2D *newCardCells = stackalloc IntVector2D[4];
if (shiftedBoard.ShiftInPlace(dir, newCardCells))
{
float totalQuality = 0;
float totalWeight = 0;
if (knownNextCardIndex == ulong.MaxValue) // Special value for bonus card.
{
ByteList12 indexes = new ByteList12();
Game.GetPossibleBonusCardIndexes(board.GetMaxCardIndex(), ref indexes);
for (int i = 0; i < indexes.Count; i++)
{
ulong cardIndex = indexes.Items[i];
for (int j = 0; j < 4; j++)
{
IntVector2D cell = newCardCells[j];
if (cell.X < 0)
{
continue;
}
FastBoard newBoard = shiftedBoard;
newBoard.SetCardIndex(cell, cardIndex);
float quality;
if (recursionsLeft == 0 || GetBestMoveForBoard(newBoard, deck, 0, recursionsLeft - 1, out quality, ref movesEvaluated) == null)
{
quality = _evaluator(newBoard);
movesEvaluated++;
}
totalQuality += quality;
totalWeight += 1;
}
}
}
else if (knownNextCardIndex > 0)
{
FastDeck newDeck = deck;
newDeck.Remove(knownNextCardIndex);
for (int i = 0; i < 4; i++)
{
IntVector2D cell = newCardCells[i];
if (cell.X < 0)
{
continue;
}
FastBoard newBoard = shiftedBoard;
newBoard.SetCardIndex(cell, knownNextCardIndex);
float quality;
if (recursionsLeft == 0 || GetBestMoveForBoard(newBoard, newDeck, 0, recursionsLeft - 1, out quality, ref movesEvaluated) == null)
{
quality = _evaluator(newBoard);
movesEvaluated++;
}
totalQuality += quality;
totalWeight += 1;
}
}
else if (_moveSearchDepth - recursionsLeft - 1 < _cardCountDepth)
{
if (deck.Ones > 0)
{
FastDeck newDeck = deck;
newDeck.RemoveOne();
for (int i = 0; i < 4; i++)
{
IntVector2D cell = newCardCells[i];
if (cell.X < 0)
{
continue;
}
FastBoard newBoard = shiftedBoard;
newBoard.SetCardIndex(cell, 1);
float quality;
if (recursionsLeft == 0 || GetBestMoveForBoard(newBoard, newDeck, 0, recursionsLeft - 1, out quality, ref movesEvaluated) == null)
{
quality = _evaluator(newBoard);
movesEvaluated++;
}
totalQuality += quality * deck.Ones;
totalWeight += deck.Ones;
}
}
if (deck.Twos > 0)
{
FastDeck newDeck = deck;
newDeck.RemoveTwo();
for (int i = 0; i < 4; i++)
{
IntVector2D cell = newCardCells[i];
if (cell.X < 0)
{
continue;
}
FastBoard newBoard = shiftedBoard;
newBoard.SetCardIndex(cell, 2);
float quality;
if (recursionsLeft == 0 || GetBestMoveForBoard(newBoard, newDeck, 0, recursionsLeft - 1, out quality, ref movesEvaluated) == null)
{
quality = _evaluator(newBoard);
movesEvaluated++;
}
totalQuality += quality * deck.Twos;
totalWeight += deck.Twos;
}
}
if (deck.Threes > 0)
{
FastDeck newDeck = deck;
newDeck.RemoveThree();
for (int i = 0; i < 4; i++)
{
IntVector2D cell = newCardCells[i];
if (cell.X < 0)
{
continue;
}
FastBoard newBoard = shiftedBoard;
newBoard.SetCardIndex(cell, 3);
float quality;
if (recursionsLeft == 0 || GetBestMoveForBoard(newBoard, newDeck, 0, recursionsLeft - 1, out quality, ref movesEvaluated) == null)
{
quality = _evaluator(newBoard);
movesEvaluated++;
}
totalQuality += quality * deck.Threes;
totalWeight += deck.Threes;
}
}
// Note that we're not taking the chance of getting a bonus card into consideration. That would be way too expensive at not much benefit.
}
else
{
float quality;
if (recursionsLeft == 0 || GetBestMoveForBoard(shiftedBoard, deck, 0, recursionsLeft - 1, out quality, ref movesEvaluated) == null)
{
quality = _evaluator(shiftedBoard);
movesEvaluated++;
}
totalQuality += quality;
totalWeight += 1;
}
return(totalQuality / totalWeight);
}
else
{
return(null);
}
}
