add custom chess engine
This commit is contained in:
Josh-Heaps
@@ -0,0 +1,32 @@
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using JoshHeaps.Net.Services.Interfaces;
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using Microsoft.Extensions.Options;
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namespace JoshHeaps.Net.Services.Implementations;
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/// <summary>The available chess engine implementations.</summary>
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public enum ChessEngineKind
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{
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Stockfish,
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Custom
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}
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/// <summary>Configuration selecting which <see cref="IChessEngine"/> to use.</summary>
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public sealed class ChessEngineOptions
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{
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public const string SectionName = "ChessEngine";
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public ChessEngineKind Engine { get; set; } = ChessEngineKind.Stockfish;
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}
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/// <summary>Creates the configured <see cref="IChessEngine"/> per game.</summary>
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public sealed class ChessEngineFactory(IOptions<ChessEngineOptions> options) : IChessEngineFactory
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{
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private readonly ChessEngineKind _kind = options.Value.Engine;
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public IChessEngine Create(int skill) => _kind switch
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{
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ChessEngineKind.Custom => new CustomChessEngine(skill),
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ChessEngineKind.Stockfish => new Stockfish(skill),
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_ => throw new InvalidOperationException($"Unknown chess engine '{_kind}'.")
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};
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}
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@@ -0,0 +1,130 @@
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using JoshHeaps.Net.Models;
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using System.Text;
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namespace JoshHeaps.Net.Services.Implementations;
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public static class ChessEngineHelpers
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{
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public static MoveDto ToMoveDto(
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this string uci,
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GameState gameState,
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Guid playerId)
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{
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int fCol = uci[0] - 'a', fRow = 7 - (uci[1] - '1');
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int tCol = uci[2] - 'a', tRow = 7 - (uci[3] - '1');
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var piece = gameState.Board[fRow, fCol]
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?? throw new Exception("No piece at source square");
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PieceType? promo = uci.Length == 5 ? uci[4] switch
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{
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'q' => PieceType.Queen,
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'r' => PieceType.Rook,
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'b' => PieceType.Bishop,
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'n' => PieceType.Knight,
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_ => null
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} : null;
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return new MoveDto
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{
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GameId = gameState.GameId,
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PlayerId = playerId,
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PieceId = piece.Id,
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TargetRow = tRow,
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TargetCol = tCol,
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PromotionChoice = promo,
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SourceCol = fCol,
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SourceRow = fRow,
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};
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}
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/// <summary>
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/// Convert a 2-D board array (rank 8 = row 0, file a = col 0) to a FEN string.
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/// Only piece placement + active colour + castling are computed; the rest use
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/// safe defaults (-, 0, 1). That is all the engine needs.
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/// </summary>
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public static string ToFen(this GameState gs)
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{
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var sb = new StringBuilder(64);
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/* 1) piece placement */
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for (int row = 0; row < 8; row++)
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{
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int empty = 0;
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for (int col = 0; col < 8; col++)
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{
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var p = gs.Board[row, col];
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if (p is null)
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{
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empty++;
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}
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else
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{
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if (empty > 0) { sb.Append(empty); empty = 0; }
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sb.Append(ToFenChar(p)); // ← unchanged helper
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}
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}
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if (empty > 0) sb.Append(empty);
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if (row < 7) sb.Append('/');
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}
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/* 2) active colour */
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sb.Append(gs.CurrentPlayer == PieceColor.White ? " w " : " b ");
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/* 3) castling rights (from GameState flags) */
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sb.Append(GetCastlingFlags(gs));
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/* 4) en-passant target square */
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sb.Append(' ');
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sb.Append(gs.EnPassantTarget.HasValue
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? Alg(gs.EnPassantTarget.Value)
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: "-");
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/* 5-6) half-move clock + full-move number */
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int fullMoves = gs.MoveHistory.Count / 2 + 1;
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sb.Append(" 0 ").Append(fullMoves);
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return sb.ToString();
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}
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/* ---------- helpers ---------- */
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private static string GetCastlingFlags(GameState gs)
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{
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var flags = new StringBuilder(4);
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if (gs.WhiteCanCastleKingside) flags.Append('K');
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if (gs.WhiteCanCastleQueenside) flags.Append('Q');
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if (gs.BlackCanCastleKingside) flags.Append('k');
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if (gs.BlackCanCastleQueenside) flags.Append('q');
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return flags.Length == 0 ? "-" : flags.ToString();
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}
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private static string Alg(Position p)
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{
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char file = (char)('a' + p.Col);
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int rank = 8 - p.Row;
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return $"{file}{rank}";
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}
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private static char ToFenChar(ChessPiece p) => p switch
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{
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{ Type: PieceType.Pawn, Color: PieceColor.White } => 'P',
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{ Type: PieceType.Pawn, Color: PieceColor.Black } => 'p',
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{ Type: PieceType.Knight, Color: PieceColor.White } => 'N',
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{ Type: PieceType.Knight, Color: PieceColor.Black } => 'n',
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{ Type: PieceType.Bishop, Color: PieceColor.White } => 'B',
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{ Type: PieceType.Bishop, Color: PieceColor.Black } => 'b',
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{ Type: PieceType.Rook, Color: PieceColor.White } => 'R',
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{ Type: PieceType.Rook, Color: PieceColor.Black } => 'r',
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{ Type: PieceType.Queen, Color: PieceColor.White } => 'Q',
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{ Type: PieceType.Queen, Color: PieceColor.Black } => 'q',
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{ Type: PieceType.King, Color: PieceColor.White } => 'K',
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{ Type: PieceType.King, Color: PieceColor.Black } => 'k',
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_ => throw new ArgumentOutOfRangeException(nameof(p))
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};
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}
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@@ -0,0 +1,33 @@
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using JoshHeaps.Net.Hubs;
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using JoshHeaps.Net.Models;
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using JoshHeaps.Net.Services.Interfaces;
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using Microsoft.AspNetCore.SignalR;
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namespace JoshHeaps.Net.Services.Implementations;
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/// <summary>
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/// Engine-agnostic glue for computer moves: get a move from the engine, apply it
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/// through the rules service, and broadcast it to the game's clients.
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/// </summary>
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public sealed class ComputerMoveOrchestrator(
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IHubContext<ChessHub> chessHub,
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IChessService chessService) : IComputerMoveOrchestrator
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{
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public async Task<(MoveDto move, MoveResultDto result)> PlayAsync(GameState state, IChessEngine engine)
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{
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var uci = await engine.GetBestMoveAsync(state.ToFen());
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var move = uci.ToMoveDto(
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state,
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state.CurrentPlayer == PieceColor.White
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? state.WhitePlayerId
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: state.BlackPlayerId);
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var result = chessService.MakeMove(state, move);
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await chessHub.Clients.Group(state.GameId.ToString())
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.SendAsync("ReceiveMoveUpdate", state.GameId.ToString(), move, result);
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return (move, result);
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}
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}
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@@ -0,0 +1,118 @@
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using JoshHeaps.Net.Services.Interfaces;
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using System.Reflection;
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using System.Runtime.CompilerServices;
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using System.Runtime.InteropServices;
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namespace JoshHeaps.Net.Services.Implementations;
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/// <summary>
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/// Middleman wrapper over the native custom chess engine (chess_engine.dll / libchess_engine.so).
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/// Shares <see cref="IChessEngine"/> with <see cref="Stockfish"/> so the two are swappable.
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/// The boundary contract is FEN string in, UCI move string out — identical to Stockfish.
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/// </summary>
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public sealed partial class CustomChessEngine : IChessEngine
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{
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private readonly EngineSafeHandle _handle;
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public int Skill { get; }
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public CustomChessEngine(int skill = 20)
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{
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Skill = skill;
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var handle = NativeMethods.engine_create($"skill={skill}");
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if (handle == IntPtr.Zero)
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throw new InvalidOperationException("Native chess engine failed to initialize (engine_create returned null).");
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_handle = new EngineSafeHandle(handle);
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}
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public Task<string> GetBestMoveAsync(string fen) => Task.Run(() => GetBestMove(fen));
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private unsafe string GetBestMove(string fen)
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{
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const int bufferLength = 16; // longest UCI move is 5 chars ("e7e8q") + NUL
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byte* buffer = stackalloc byte[bufferLength];
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var added = false;
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try
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{
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_handle.DangerousAddRef(ref added);
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var code = NativeMethods.engine_best_move(_handle.DangerousGetHandle(), fen, buffer, bufferLength);
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if (code != 0)
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throw new InvalidOperationException($"Native chess engine failed to produce a move for FEN '{fen}' (engine_best_move returned {code}).");
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return Marshal.PtrToStringUTF8((IntPtr)buffer)
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?? throw new InvalidOperationException("Native chess engine returned an empty move.");
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}
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finally
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{
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if (added)
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_handle.DangerousRelease();
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}
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}
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public ValueTask DisposeAsync()
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{
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_handle.Dispose();
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return ValueTask.CompletedTask;
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}
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/// <summary>Guarantees the native handle is released exactly once via engine_destroy.</summary>
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private sealed class EngineSafeHandle : SafeHandle
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{
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public EngineSafeHandle(IntPtr handle) : base(IntPtr.Zero, ownsHandle: true) => SetHandle(handle);
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public override bool IsInvalid => handle == IntPtr.Zero;
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protected override bool ReleaseHandle()
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{
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NativeMethods.engine_destroy(handle);
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return true;
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}
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}
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/// <summary>
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/// P/Invoke surface for chess_engine.(dll|so). The resolver maps the logical name
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/// "chess_engine" to the platform binary in the Resources folder (mirrors Stockfish).
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/// </summary>
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private static partial class NativeMethods
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{
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private const string LibName = "chess_engine";
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static NativeMethods() =>
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NativeLibrary.SetDllImportResolver(typeof(NativeMethods).Assembly, Resolve);
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private static IntPtr Resolve(string libraryName, Assembly assembly, DllImportSearchPath? searchPath)
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{
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if (libraryName != LibName)
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return IntPtr.Zero;
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var fileName = RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
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? "chess_engine.dll"
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: "libchess_engine.so";
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var path = Path.Combine(AppContext.BaseDirectory, "Resources", fileName);
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if (NativeLibrary.TryLoad(path, out var handle))
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return handle;
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return NativeLibrary.Load(libraryName, assembly, searchPath);
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}
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[LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
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[UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
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internal static partial IntPtr engine_create(string? options);
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[LibraryImport(LibName, StringMarshalling = StringMarshalling.Utf8)]
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[UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
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internal static unsafe partial int engine_best_move(IntPtr engine, string fen, byte* outBuffer, int outLength);
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[LibraryImport(LibName)]
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[UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
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internal static partial void engine_destroy(IntPtr engine);
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}
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}
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@@ -1,22 +1,19 @@
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using JoshHeaps.Net.Hubs;
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using JoshHeaps.Net.Models;
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using JoshHeaps.Net.Services.Interfaces;
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using Microsoft.AspNetCore.SignalR;
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using System.Diagnostics;
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using System.Reflection;
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using System.Runtime.InteropServices;
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using System.Text;
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using System.Threading.Channels;
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namespace JoshHeaps.Net.Services.Implementations;
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public sealed class Stockfish : IAsyncDisposable
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public sealed class Stockfish : IChessEngine
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{
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private readonly Process _p;
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private readonly StreamWriter _stdin;
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private readonly Channel<string> _stdout = Channel.CreateUnbounded<string>();
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private readonly int _skill;
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public int Skill => _skill;
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public Stockfish(int skill = 20, int hash = 256)
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{
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_skill = skill;
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@@ -28,13 +25,13 @@ public sealed class Stockfish : IAsyncDisposable
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: "stockfish-ubuntu-x86-64-sse41-popcnt"; // default: Linux
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string exePath = Path.Combine(baseDir, "Resources", fileName);
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if (!File.Exists(exePath))
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{
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throw new FileNotFoundException($"Stockfish executable not found at {exePath}. " +
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"Ensure the file is present in the Resources folder of your project.");
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}
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Console.Write(exePath);
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_p = new Process
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@@ -109,145 +106,4 @@ public sealed class Stockfish : IAsyncDisposable
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await _p.WaitForExitAsync();
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_p.Dispose();
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}
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public async Task MakeMove(GameState state, IHubContext<ChessHub> chessHub, IChessService chessService)
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{
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var move = await GetBestMoveAsync(state.ToFen());
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var moveDto = move.ToMoveDto(
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state,
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state.CurrentPlayer == PieceColor.White
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? state.WhitePlayerId
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: state.BlackPlayerId);
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var result = chessService.MakeMove(state, moveDto);
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await chessHub.Clients.Group(state.GameId.ToString()).SendAsync("ReceiveMoveUpdate", state.GameId.ToString(), moveDto, result);
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}
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}
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public static class StockfishHelpers
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{
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public static MoveDto ToMoveDto(
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this string uci,
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GameState gameState,
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Guid playerId)
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{
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int fCol = uci[0] - 'a', fRow = 7 - (uci[1] - '1');
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int tCol = uci[2] - 'a', tRow = 7 - (uci[3] - '1');
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var piece = gameState.Board[fRow, fCol]
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?? throw new Exception("No piece at source square");
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PieceType? promo = uci.Length == 5 ? uci[4] switch
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{
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'q' => PieceType.Queen,
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'r' => PieceType.Rook,
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'b' => PieceType.Bishop,
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'n' => PieceType.Knight,
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_ => null
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} : null;
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return new MoveDto
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{
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GameId = gameState.GameId,
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PlayerId = playerId,
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PieceId = piece.Id,
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TargetRow = tRow,
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TargetCol = tCol,
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PromotionChoice = promo,
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SourceCol = fCol,
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SourceRow = fRow,
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};
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}
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/// <summary>
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/// Convert a 2-D board array (rank 8 = row 0, file a = col 0) to a FEN string.
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/// Only piece placement + active colour + castling are computed; the rest use
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/// safe defaults (-, 0, 1). That is all Stockfish needs.
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/// </summary>
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public static string ToFen(this GameState gs)
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{
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var sb = new StringBuilder(64);
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/* 1) piece placement */
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for (int row = 0; row < 8; row++)
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{
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int empty = 0;
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for (int col = 0; col < 8; col++)
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{
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var p = gs.Board[row, col];
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if (p is null)
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{
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empty++;
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}
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else
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{
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if (empty > 0) { sb.Append(empty); empty = 0; }
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sb.Append(ToFenChar(p)); // ← unchanged helper
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}
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}
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if (empty > 0) sb.Append(empty);
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if (row < 7) sb.Append('/');
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}
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/* 2) active colour */
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sb.Append(gs.CurrentPlayer == PieceColor.White ? " w " : " b ");
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/* 3) castling rights (from GameState flags) */
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sb.Append(GetCastlingFlags(gs));
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/* 4) en-passant target square */
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sb.Append(' ');
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sb.Append(gs.EnPassantTarget.HasValue
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? Alg(gs.EnPassantTarget.Value)
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: "-");
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/* 5-6) half-move clock + full-move number */
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int fullMoves = gs.MoveHistory.Count / 2 + 1;
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sb.Append(" 0 ").Append(fullMoves);
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return sb.ToString();
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}
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/* ---------- helpers ---------- */
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private static string GetCastlingFlags(GameState gs)
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{
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var flags = new StringBuilder(4);
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if (gs.WhiteCanCastleKingside) flags.Append('K');
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if (gs.WhiteCanCastleQueenside) flags.Append('Q');
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if (gs.BlackCanCastleKingside) flags.Append('k');
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if (gs.BlackCanCastleQueenside) flags.Append('q');
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return flags.Length == 0 ? "-" : flags.ToString();
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}
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private static string Alg(Position p)
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{
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char file = (char)('a' + p.Col);
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int rank = 8 - p.Row;
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return $"{file}{rank}";
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}
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private static char ToFenChar(ChessPiece p) => p switch
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{
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{ Type: PieceType.Pawn, Color: PieceColor.White } => 'P',
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{ Type: PieceType.Pawn, Color: PieceColor.Black } => 'p',
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{ Type: PieceType.Knight, Color: PieceColor.White } => 'N',
|
||||
{ Type: PieceType.Knight, Color: PieceColor.Black } => 'n',
|
||||
{ Type: PieceType.Bishop, Color: PieceColor.White } => 'B',
|
||||
{ Type: PieceType.Bishop, Color: PieceColor.Black } => 'b',
|
||||
{ Type: PieceType.Rook, Color: PieceColor.White } => 'R',
|
||||
{ Type: PieceType.Rook, Color: PieceColor.Black } => 'r',
|
||||
{ Type: PieceType.Queen, Color: PieceColor.White } => 'Q',
|
||||
{ Type: PieceType.Queen, Color: PieceColor.Black } => 'q',
|
||||
{ Type: PieceType.King, Color: PieceColor.White } => 'K',
|
||||
{ Type: PieceType.King, Color: PieceColor.Black } => 'k',
|
||||
_ => throw new ArgumentOutOfRangeException(nameof(p))
|
||||
};
|
||||
}
|
||||
Reference in New Issue
Block a user