Reduce search depth and fix turn-checking method

The search depth for the iterative deepening depth-first search (IDDFS) in the ChessEngine has been reduced for performance reasons. In addition, the method for checking whose turn it is in the PveController has been altered. This now checks the color of the pieces, rather than looking up the player's ID, yielding more accurate results.

src/Aiursoft.ChessServer/Controllers/PveController.cs

@@ -1,3 +1,4 @@
+using System.Drawing;
 using Aiursoft.AiurObserver;
 using Aiursoft.AiurObserver.WebSocket;
 using Aiursoft.ChessServer.Data;
@@ -6,6 +7,7 @@ using Aiursoft.CSTools.Services;
 using Microsoft.AspNetCore.Mvc;
 using Aiursoft.AiurObserver.Extensions;
 using Aiursoft.ChessServer.Services;
+using Chess;
 
 namespace Aiursoft.ChessServer.Controllers;
 
@@ -22,6 +24,7 @@ public class PveController(
         // Add a computer player
         var computerId = Guid.NewGuid();
         database.GetOrAddPlayer(computerId).NickName = "Computer";
+        //var asyncLock = new SemaphoreSlim(1, 1);
 
         // Create a challenge
         var player = database.GetOrAddPlayer(playerId);
@@ -53,7 +56,8 @@ public class PveController(
                 subscription = client.Subscribe(async fen =>
                 {
                     // When fen changes, it means someone has made a move. If it's the computer's turn, let the computer respond.
-                    if (acceptedChallenge?.GetTurnPlayer().Id == computerId)
+                    var board = ChessBoard.LoadFromFen(fen);
+                    if (board.Turn == PieceColor.Black)
                     {
                         // Wait for the UI to update
                         await Task.Delay(300);

src/Aiursoft.ChessServer/Services/ChessEngine.cs

@@ -21,7 +21,7 @@ public class ChessEngine
     public string GetBestMove(string fen)
     {
         _engine.AdjustPosition($"position fen {fen}");
-        return _engine.IDDFS(5, int.MaxValue)
+        return _engine.IDDFS(1, int.MaxValue)
             .BestMove
             .ToEPDString();
     }