first version of stickfosh, simply evaluates a

position based on the material (no AB-pruning)

cpp/src/main.cpp

@@ -1,12 +1,11 @@
-#include "board.hpp"
-#include "perft.hpp"
+#include "stickfosh.hpp"
 
 #include <iostream>
 
 int main(int argc, char* argv[]) {
     std::string pos =
         "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
-    // Board b = Board::setup_fen_position(pos);
-    perft();
+    std::string move = search(pos, 4);
+    std::cout << move << std::endl;
     return 0;
 }

cpp/src/stickfosh.cpp

@@ -0,0 +1,96 @@
+#include "stickfosh.hpp"
+
+#include "pieces/piece.hpp"
+#include "threadpool.hpp"
+
+#include <future>
+#include <map>
+
+static int INFINITY = std::numeric_limits<int>::max();
+
+std::string search(std::string pos, int depth) {
+    Board b = Board::setup_fen_position(pos);
+
+    ThreadPool pool(std::thread::hardware_concurrency());
+
+    std::vector<Move> moves = b.all_legal_moves();
+    std::map<std::string, std::future<int>> futures;
+    for (const Move& move : moves) {
+        Board tmp_board = b.make_move(move);
+        futures.insert(
+            {move.to_string(), pool.enqueue(minimax, tmp_board, depth - 1)}
+        );
+    }
+
+    std::string best_move;
+    int best_eval = -INFINITY;
+    for (auto& [move, future] : futures) {
+        int eval = future.get();
+        if (eval > best_eval) {
+            best_eval = eval;
+            best_move = move;
+        }
+    }
+
+    return best_move;
+}
+
+int minimax(const Board& b, int depth) {
+    if (b.is_checkmate_for(b.white_to_play ? White : Black))
+        return -INFINITY;
+
+    if (depth == 0)
+        return eval(b);
+
+    std::vector<Move> moves = b.all_legal_moves();
+    int best_evaluation = 0;
+    Move best_move;
+    for (const Move& move : moves) {
+        Board tmp_board = b.make_move(move);
+        int tmp_eval = -minimax(tmp_board, depth - 1);
+        best_evaluation = std::max(best_evaluation, tmp_eval);
+    }
+    return best_evaluation;
+}
+
+static int PawnValue = 100;
+static int KnightValue = 300;
+static int BishopValue = 320;
+static int RookValue = 500;
+static int QueenValue = 900;
+
+int count_material(const Board& b, int8_t colour) {
+    int ret = 0;
+    for (int i = 0; i < 64; i++) {
+        if (b.colour_at(i) == colour)
+            switch (b.squares[i] & 0b111) {
+            case Piece::Pawn:
+                ret += PawnValue;
+                break;
+            case Piece::Knigt:
+                ret += KnightValue;
+                break;
+            case Piece::Bishop:
+                ret += BishopValue;
+                break;
+            case Piece::Rook:
+                ret += RookValue;
+                break;
+            case Piece::Queen:
+                ret += QueenValue;
+                break;
+            }
+    }
+    return ret;
+}
+
+int eval(const Board& b) {
+    int white_eval = count_material(b, Colour::White);
+    int black_eval = count_material(b, Colour::Black);
+
+    int evaluation = white_eval - black_eval;
+
+    int perspective = b.white_to_play ? 1 : -1;
+
+    return perspective * evaluation;
+}

cpp/src/stickfosh.hpp

@@ -0,0 +1,9 @@
+#pragma once
+
+#include "board.hpp"
+
+#include <string>
+
+std::string search(std::string, int);
+int minimax(const Board&, int);
+int eval(const Board&);