/// <summary>
/// Gets the next move.
/// </summary>
/// <param name="fen">The board configuration.</param>
/// <param name="repetitionMoveCandidate">
/// The move that, if made, it will result a draw by repetition.
/// The engine will try to avoid the move if there is a better one.
/// </param>
/// <param name="depth">Search depth level.</param>
/// <returns></returns>
public string GetNextMove(string fen, string repetitionMoveCandidate, int depth)
{
// the engine is still thinking, return
if (thinking) { return null; }
// initialize the engine
try
{
Initialize(fen);
}
catch
{
return null;
}
int hash;
// look in the opening book (OBookMem.cs) in memory buffer...
short obMove=0;
if (moves <= Settings_Default_OpeningBookMaxMoveNo) obMove=obookmem.OBookGet(hash = GetHashCode());
if(obMove>0)
{
Move move = new Move();
move.from = (byte)(obMove>> 8);
move.to = (byte)(obMove & 255);
return move.ToString();
}
// look in the opening book
if (book != null && moves <= Settings_Default_OpeningBookMaxMoveNo && book.ContainsKey(hash = GetHashCode()))
{
// get the list of available moves for this board
List<short> list = book[hash];
//return a random move from the list
short shortMove = list[random.Next(list.Count)];
Move move = new Move();
move.from = (byte)(shortMove >> 8);
move.to = (byte)(shortMove & 255);
return move.ToString();
}
else
{
// set repetition move
// a repetition move cannot be a promotion move, a castling move, a capture move or a pawn move
// so the move bits and capture are 0
repMove = Move.ParseRegularCAN(repetitionMoveCandidate);
// the depth must be between 1 and ChessEngineMaxDepth
if (depth < 1)
depth = 1;
else if (depth > Settings_Default_ChessEngineMaxDepth)
depth = Settings_Default_ChessEngineMaxDepth;
// else if (depth > Settings.Default.ChessEngineMaxDepth)
// depth = Settings.Default.ChessEngineMaxDepth;
// search
try
{
thinking = true;
Think(depth);
}
catch
{
// the search has ended abruptly or something went wrong
}
finally
{
thinking = false;
}
// pv[0, 0] is the best move
return pv[0, 0].ToString();
}
}
