made CastleSide a normal enum again to use &

not a pointer

cpp/.gitignore

@@ -0,0 +1,34 @@
+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Fortran module files
+*.mod
+*.smod
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.appobj/
+test_bin/
+main

cpp/Makefile

@@ -0,0 +1,56 @@
+# Add .d to Make's recognized suffixes.
+SUFFIXES += .d
+
+#We don't need to clean up when we're making these targets
+NODEPS:=clean tags svn
+#Find all the C++ files in the src/ directory
+SOURCES:=$(shell find src/ -name "*.cpp")
+OBJFILES := $(patsubst src/%.cpp,obj/%.o,$(SOURCES))
+#These are the dependency files, which make will clean up after it creates them
+DEPFILES:=$(patsubst %.cpp,%.d,$(SOURCES))
+
+#Don't create dependencies when we're cleaning, for instance
+ifeq (0, $(words $(findstring $(MAKECMDGOALS), $(NODEPS))))
+	#Chances are, these files don't exist.  GMake will create them and
+	#clean up automatically afterwards
+	-include $(DEPFILES)
+endif
+
+#This is the rule for creating the dependency files
+src/%.d: src/%.cpp
+	$(CXX) $(CXXFLAGS) -MM -MT '$(patsubst src/%.cpp,obj/%.o,$<)' $< -MF $@
+
+#This rule does the compilation
+obj/%.o:
+	@mkdir -p $(dir $@)
+	$(CXX) $(CXXFLAGS) -o $@ -c $<
+
+main: $(OBJFILES)
+	$(CXX) $(LDFLAGS) $(OBJFILES) $(LOADLIBES) $(LDLIBS) -o main
+
+clean:
+	rm -rf obj/* $(DEPFILES) test_bin/
+
+
+# --- Test Support ---
+# Find all test source files in the tests directory
+TESTS := $(shell find tests -name "*.cpp")
+# Define corresponding test executable names, e.g. tests/foo.cpp -> test_bin/foo
+TEST_BIN := $(patsubst tests/%.cpp,test_bin/%,$(TESTS))
+LIBS := $(filter-out obj/main.o,$(OBJFILES))
+
+# Pattern rule: how to build a test executable from a test source file.
+# You can adjust CXXFLAGS or add include directories if needed.
+test_bin/%: tests/%.cpp $(LIBS)
+	@echo $(LIBS)
+	@mkdir -p $(dir $@)
+	$(CXX) $(CXXFLAGS) -o $@ $< $(LIBS)
+
+# The 'test' target builds all tests and then runs each one.
+.PHONY: test
+test: $(TEST_BIN)
+	@echo "Running all tests..."
+	@for t in $(TEST_BIN); do \
+	    echo "---- Running $$t ----"; \
+	    ./$$t || exit 1; \
+	done

cpp/src/board.cpp

@@ -0,0 +1,131 @@
+#include "board.hpp"
+
+#include "coords.hpp"
+#include "pieces/piece.hpp"
+
+#include <algorithm>
+#include <cctype>
+#include <map>
+#include <stdexcept>
+
+Board Board::setup_fen_position(std::string fen) {
+    Board board;
+    std::map<char, Piece> c2p{
+        {'k', Piece::King},
+        {'p', Piece::Pawn},
+        {'n', Piece::Knigt},
+        {'b', Piece::Bishop},
+        {'r', Piece::Rook},
+        {'q', Piece::Queen},
+    };
+
+    std::string fen_board = fen.substr(0, fen.find(' '));
+    int rank = 7, file = 0;
+    for (char symbol : fen_board) {
+        if (symbol == '/') {
+            file = 0;
+            rank--;
+            continue;
+        }
+
+        if (std::isdigit(symbol))
+            file += symbol - '0';
+        else {
+            Colour colour =
+                std::isupper(symbol) ? Colour::White : Colour::Black;
+
+            Piece piece = c2p[std::tolower(symbol)];
+            board.squares[rank * 8 + file] = colour | piece;
+            file++;
+        }
+    }
+    return board;
+}
+
+std::string Board::to_fen() const {
+    std::map<int, char> p2c{
+        {Piece::King, 'k'},
+        {Piece::Pawn, 'p'},
+        {Piece::Knigt, 'n'},
+        {Piece::Bishop, 'b'},
+        {Piece::Rook, 'r'},
+        {Piece::Queen, 'q'},
+    };
+
+    std::string ret;
+    for (int rank = 7; rank >= 0; rank--) {
+        int empty_cell_counter = 0;
+        for (int file = 0; file < 8; file++) {
+            if (this->squares[rank * 8 + file] == Piece::None) {
+                empty_cell_counter++;
+                continue;
+            }
+
+            int full_piece = this->squares[rank * 8 + file];
+            char piece = p2c[full_piece & 0b111];
+            int8_t colour = colour_at({file, rank});
+
+            if (empty_cell_counter > 0) {
+                ret += std::to_string(empty_cell_counter);
+                empty_cell_counter = 0;
+            }
+            ret += colour == Colour::White ? std::toupper(piece) : piece;
+        }
+        if (empty_cell_counter > 0)
+            ret += std::to_string(empty_cell_counter);
+        if (rank > 0)
+            ret += "/";
+    }
+    return ret;
+}
+
+Board Board::make_move(Move move) const {
+    int8_t dest_piece = this->squares[move.target_square];
+
+    Board ret;
+    std::copy(
+        std::begin(this->squares),
+        std::end(this->squares),
+        std::begin(ret.squares)
+    );
+    ret.white_to_play = !this->white_to_play;
+
+    // -- Actually make the move
+    ret.squares[move.source_square] = Piece::None;
+    ret.squares[move.target_square] = this->squares[move.source_square];
+
+    // -- Handle en passant target being eaten
+    if (move.en_passant)
+        ret.squares[move.target_square - 8] = Piece::None;
+    return ret;
+}
+
+int8_t Board::get_king_of(int8_t colour) const {
+    for (int i = 0; i < 64; i++)
+        if (this->squares[i] == (colour | Piece::King))
+            return i;
+    throw std::domain_error(
+        "Apparently there no kings of the such color in this board"
+    );
+}
+
+std::vector<int8_t> to_target_square(std::vector<Move> moves) {
+    std::vector<int8_t> ret;
+    for (Move move : moves)
+        ret.push_back(move.target_square);
+    return ret;
+}
+
+bool Board::is_check_for(int8_t colour) const {
+    int8_t king_idx = this->get_king_of(colour);
+    for (int i = 0; i < 64; i++) {
+        if (this->squares[i] == Piece::None)
+            continue;
+        std::vector<Move> moves =
+            legal_moves(this->squares[i], *this, Coords::from_index(i), true);
+        std::vector<int8_t> targets = to_target_square(moves);
+        if (std::find(targets.begin(), targets.end(), i) != targets.end())
+            return true;
+    }
+    return false;
+}

cpp/src/board.hpp

@@ -0,0 +1,32 @@
+#pragma once
+
+#include "coords.hpp"
+#include "move.hpp"
+#include "pieces/piece.hpp"
+
+#include <string>
+
+struct Board {
+  private:
+    int8_t get_king_of(int8_t colour) const;
+
+  public:
+    int8_t squares[64] = {Piece::None};
+    bool white_to_play;
+    CastleSide w_castle_rights;
+    CastleSide b_castle_rights;
+
+    static Board setup_fen_position(std::string fen);
+
+    Board make_move(Move) const;
+    std::string to_fen() const;
+    bool is_check_for(int8_t) const;
+
+    int8_t colour_at(int8_t idx) const {
+        return squares[idx] & 0b11000;
+    }
+
+    int8_t colour_at(Coords xy) const {
+        return colour_at(xy.to_index());
+    }
+};

cpp/src/castle_side.hpp

@@ -0,0 +1,7 @@
+#include <cstdint>
+
+enum CastleSide : int8_t {
+    NeitherSide = 0,
+    KingSide = 1,
+    QueenSide = 2,
+};

cpp/src/coords.hpp

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <cstdint>
+
+struct Coords {
+    int x, y;
+
+    int8_t to_index() const {
+        return this->y * 8 + this->x;
+    }
+
+    static Coords from_index(int idx) {
+        return {idx % 8, idx / 8};
+    }
+
+    bool is_within_bounds() const {
+        return this->to_index() < 64;
+    }
+};

cpp/src/main.cpp

@@ -0,0 +1,10 @@
+#include "board.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);
+    return 0;
+}

cpp/src/move.hpp

@@ -0,0 +1,15 @@
+#pragma once
+
+#include "castle_side.hpp"
+
+#include <cstdint>
+
+struct Move {
+    int8_t source_square;
+    int8_t target_square;
+
+    bool is_capturing = false;
+    CastleSide castle_side = CastleSide::NeitherSide;
+    bool en_passant = false;
+    int8_t promoting_to = 0;
+};

cpp/src/pieces/bishop.cpp

@@ -0,0 +1,23 @@
+#include "../board.hpp"
+#include "../coords.hpp"
+#include "../move.hpp"
+#include "piece.hpp"
+
+#include <vector>
+
+std::vector<Move> bishop_moves(const Board& b, const Coords xy) {
+    std::vector<Move> ret;
+    auto ne = look_direction(b, xy, 1, 1);
+    ret.insert(ret.end(), ne.begin(), ne.end());
+
+    auto se = look_direction(b, xy, 1, -1);
+    ret.insert(ret.end(), se.begin(), se.end());
+
+    auto sw = look_direction(b, xy, -1, -1);
+    ret.insert(ret.end(), sw.begin(), sw.end());
+
+    auto nw = look_direction(b, xy, -1, 1);
+    ret.insert(ret.end(), nw.begin(), nw.end());
+
+    return ret;
+}

cpp/src/pieces/king.cpp

@@ -0,0 +1,76 @@
+#include "../board.hpp"
+#include "../coords.hpp"
+#include "piece.hpp"
+
+static bool is_clear_king_side(const Board& b, const Coords xy) {
+    for (int dx = 1; dx < 3; dx++) {
+        Coords c{xy.x + dx, xy.y};
+        if (b.squares[c.to_index()] != Piece::None)
+            return false;
+
+        std::optional<Move> move = move_for_position(b, xy, c);
+        Board board_after_move = b.make_move(move.value());
+        if (board_after_move.is_check_for(b.colour_at(xy)))
+            return false;
+    }
+    return true;
+}
+
+static bool is_clear_queen_side(const Board& b, const Coords xy) {
+    for (int dx = 1; dx < 4; dx++) {
+        Coords c{xy.x - dx, xy.y};
+        if (b.squares[c.to_index()] != Piece::None)
+            return false;
+
+        std::optional<Move> move = move_for_position(b, xy, c);
+        Board board_after_move = b.make_move(move.value());
+        if (dx < 3 && board_after_move.is_check_for(b.colour_at(xy)))
+            return false;
+    }
+    return true;
+}
+
+std::vector<Move> king_moves(const Board& b, const Coords xy) {
+    std::vector<Move> ret;
+
+    // -- Regular moves
+    for (int dx = -1; dx <= 1; dx++) {
+        for (int dy = -1; dy <= 1; dy++) {
+            if (dx == 0 && dy == 0) // skip staying in the same position
+                continue;
+            Coords c{xy.x + dx, xy.y + dy};
+            std::optional<Move> move = move_for_position(b, xy, c);
+            if (move.has_value())
+                ret.push_back(move.value());
+        }
+    }
+
+    if (b.is_check_for(b.colour_at(xy)))
+        return ret;
+
+    // -- Castles
+    CastleSide castling_rights = b.colour_at(xy) == Colour::White
+                                   ? b.w_castle_rights
+                                   : b.b_castle_rights;
+
+    if (castling_rights == CastleSide::NeitherSide)
+        return ret;
+
+    if (castling_rights & CastleSide::KingSide && is_clear_king_side(b, xy)) {
+        ret.push_back(Move{
+            xy.to_index(),
+            Coords{6, xy.y}.to_index(),
+            .castle_side = CastleSide::KingSide
+        });
+    }
+
+    if (castling_rights & CastleSide::QueenSide && is_clear_queen_side(b, xy)) {
+        ret.push_back(Move{
+            xy.to_index(),
+            Coords{2, xy.y}.to_index(),
+            .castle_side = CastleSide::QueenSide
+        });
+    }
+
+    return ret;
+}

cpp/src/pieces/knight.cpp

@@ -0,0 +1,28 @@
+#include "../board.hpp"
+#include "../coords.hpp"
+#include "../move.hpp"
+#include "piece.hpp"
+
+#include <vector>
+
+std::vector<Move> knight_moves(const Board& b, const Coords xy) {
+    std::vector<Move> ret;
+    std::vector<std::pair<int, int>> moves = {
+        {+2, +1},
+        {+1, +2}, // north east
+        {+2, -1},
+        {+1, -2}, // south east
+        {-2, -1},
+        {-1, -2}, // south west
+        {-2, +1},
+        {-1, +2} // north west
+    };
+
+    for (const auto& [dx, dy] : moves) {
+        std::optional<Move> move =
+            move_for_position(b, xy, Coords{xy.x + dx, xy.y + dy});
+        if (move.has_value())
+            ret.push_back(move.value());
+    }
+    return ret;
+}

cpp/src/pieces/pawn.cpp

@@ -0,0 +1,51 @@
+#include "../board.hpp"
+#include "../coords.hpp"
+#include "../move.hpp"
+#include "piece.hpp"
+
+std::vector<Move> pawn_moves(const Board& b, const Coords xy) {
+    std::vector<Move> ret{};
+    int8_t my_colour = b.colour_at(xy);
+
+    // -- Capture to the left
+    if (xy.x > 0) {
+        int dy = my_colour == Colour::White ? 1 : -1;
+        Coords left{xy.x - 1, xy.y + dy};
+        int8_t capturable_piece = b.squares[left.to_index()];
+        if (capturable_piece != 0) {
+            if (my_colour != b.colour_at(left))
+                ret.push_back(Move{xy.to_index(), left.to_index()});
+        }
+    }
+
+    // -- Capture to the right
+    if (xy.x < 7) {
+        int dy = my_colour == Colour::White ? 1 : -1;
+        Coords right{xy.x + 1, xy.y + dy};
+        int8_t capturable_piece = b.squares[right.to_index()];
+        if (capturable_piece != 0) {
+            if (my_colour != b.colour_at(right))
+                ret.push_back(Move{xy.to_index(), right.to_index()});
+        }
+    }
+
+    // -- Promotion
+    bool is_on_starting_rank =
+        my_colour == Colour::White ? xy.y == 1 : xy.y == 6;
+    int max_dy = is_on_starting_rank ? 3 : 2;
+    for (int dy = 1; dy < max_dy; dy++) {
+        int actual_dy = my_colour == Colour::White ? dy : -dy;
+        Coords new_xy{xy.x, xy.y + actual_dy};
+        if (b.squares[new_xy.to_index()] != Piece::None)
+            break;
+        if (new_xy.y == 7 || new_xy.y == 0)
+            for (auto piece : {Queen, Knigt, Bishop, Rook})
+                ret.push_back(Move{
+                    xy.to_index(),
+                    new_xy.to_index(),
+                    .promoting_to = piece
+                });
+    }
+
+    return ret;
+}

cpp/src/pieces/piece.cpp

@@ -0,0 +1,72 @@
+#include "piece.hpp"
+
+#include "../board.hpp"
+#include "../coords.hpp"
+
+std::vector<Move>
+keep_only_blocking(const std::vector<Move> candidates, const Board& board) {
+    if (candidates.size() == 0)
+        return {};
+
+    int8_t my_colour = board.colour_at(candidates[0].source_square);
+    std::vector<Move> ret;
+    for (Move move : candidates) {
+        Board board_after_move = board.make_move(move);
+        if (!board_after_move.is_check_for(my_colour))
+            ret.push_back(move);
+    }
+    return ret;
+}
+
+std::vector<Move> legal_moves(
+    int8_t p, const Board& b, const Coords xy, bool looking_for_check = false
+) {
+    std::vector<Move> ret;
+    switch (p) {
+    case Piece::Pawn:
+        ret = pawn_moves(b, xy);
+    case Piece::Bishop:
+        break;
+    default:
+        break;
+    }
+
+    if (!looking_for_check)
+        return keep_only_blocking(ret, b);
+
+    return {};
+}
+
+std::optional<Move>
+move_for_position(const Board& board, const Coords source, const Coords dest) {
+    if (dest.is_within_bounds())
+        return {};
+
+    int8_t piece = board.squares[dest.to_index()];
+    if (piece == Piece::None)
+        return Move{source.to_index(), dest.to_index()};
+
+    int8_t source_colour = board.colour_at(source);
+    int8_t dest_colour = board.colour_at(dest);
+    if (source_colour != dest_colour)
+        return Move{source.to_index(), dest.to_index(), true};
+    return {};
+}
+
+std::vector<Move>
+look_direction(const Board& board, const Coords xy, int mult_dx, int mult_dy) {
+    std::vector<Move> ret;
+    for (int d = 0; d < 8; d++) {
+        int dx = mult_dx * d;
+        int dy = mult_dy * d;
+
+        std::optional<Move> move =
+            move_for_position(board, xy, Coords{xy.x + dx, xy.y + dy});
+        if (move.has_value()) {
+            ret.push_back(move.value());
+            if (move.value().is_capturing)
+                break;
+        }
+    }
+    return ret;
+}

cpp/src/pieces/piece.hpp

@@ -0,0 +1,37 @@
+#pragma once
+
+#include "../move.hpp"
+
+#include <cstdint>
+#include <optional>
+#include <vector>
+
+enum Piece : int8_t {
+    None = 0,
+    King = 1,
+    Pawn = 2,
+    Knigt = 3,
+    Bishop = 4,
+    Rook = 5,
+    Queen = 6,
+};
+
+enum Colour : int8_t {
+    White = 8,
+    Black = 16,
+};
+
+class Board;
+struct Coords;
+
+std::vector<Move> legal_moves(int8_t, const Board&, const Coords, bool);
+std::vector<Move> keep_only_blocking(const std::vector<Move>, const Board&);
+std::optional<Move> move_for_position(const Board&, const Coords, const Coords);
+std::vector<Move> look_direction(const Board&, const Coords, int, int);
+
+std::vector<Move> pawn_moves(const Board&, const Coords);
+std::vector<Move> rook_moves(const Board&, const Coords);
+std::vector<Move> knight_moves(const Board&, const Coords);
+std::vector<Move> bishop_moves(const Board&, const Coords);
+std::vector<Move> queen_moves(const Board&, const Coords);
+std::vector<Move> king_moves(const Board&, const Coords);

cpp/src/pieces/queen.cpp

@@ -0,0 +1,35 @@
+#include "../board.hpp"
+#include "../coords.hpp"
+#include "../move.hpp"
+#include "piece.hpp"
+
+#include <vector>
+
+std::vector<Move> rook_moves(const Board& b, const Coords xy) {
+    std::vector<Move> ret;
+    auto e = look_direction(b, xy, 1, 0);
+    ret.insert(ret.end(), e.begin(), e.end());
+
+    auto s = look_direction(b, xy, 0, -1);
+    ret.insert(ret.end(), s.begin(), s.end());
+
+    auto w = look_direction(b, xy, -1, 0);
+    ret.insert(ret.end(), w.begin(), w.end());
+
+    auto n = look_direction(b, xy, 0, 1);
+    ret.insert(ret.end(), n.begin(), n.end());
+
+    auto ne = look_direction(b, xy, 1, 1);
+    ret.insert(ret.end(), ne.begin(), ne.end());
+
+    auto se = look_direction(b, xy, 1, -1);
+    ret.insert(ret.end(), se.begin(), se.end());
+
+    auto sw = look_direction(b, xy, -1, -1);
+    ret.insert(ret.end(), sw.begin(), sw.end());
+
+    auto nw = look_direction(b, xy, -1, 1);
+    ret.insert(ret.end(), nw.begin(), nw.end());
+
+    return ret;
+}

cpp/src/pieces/rook.cpp

@@ -0,0 +1,23 @@
+#include "../board.hpp"
+#include "../coords.hpp"
+#include "../move.hpp"
+#include "piece.hpp"
+
+#include <vector>
+
+std::vector<Move> rook_moves(const Board& b, const Coords xy) {
+    std::vector<Move> ret;
+    auto e = look_direction(b, xy, 1, 0);
+    ret.insert(ret.end(), e.begin(), e.end());
+
+    auto s = look_direction(b, xy, 0, -1);
+    ret.insert(ret.end(), s.begin(), s.end());
+
+    auto w = look_direction(b, xy, -1, 0);
+    ret.insert(ret.end(), w.begin(), w.end());
+
+    auto n = look_direction(b, xy, 0, 1);
+    ret.insert(ret.end(), n.begin(), n.end());
+
+    return ret;
+}

cpp/tests/fen.cpp

@@ -0,0 +1,22 @@
+#include "../src/board.hpp"
+#include "lib.hpp"
+
+int main() {
+    std::string pos = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR";
+    ASSERT_EQUALS(pos, Board::setup_fen_position(pos)->to_fen());
+
+    pos = "r1bk3r/p2pBpNp/n4n2/1p1NP2P/6P1/3P4/P1P1K3/q5b1";
+    ASSERT_EQUALS(pos, Board::setup_fen_position(pos)->to_fen());
+
+    pos = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR";
+    ASSERT_EQUALS(pos, Board::setup_fen_position(pos)->to_fen());
+
+    pos = "4k2r/6r1/8/8/8/8/3R4/R3K3";
+    ASSERT_EQUALS(pos, Board::setup_fen_position(pos)->to_fen());
+
+    pos = "8/8/8/4p1K1/2k1P3/8/8/8";
+    ASSERT_EQUALS(pos, Board::setup_fen_position(pos)->to_fen());
+
+    pos = "8/5k2/3p4/1p1Pp2p/pP2Pp1P/P4P1K/8/8";
+    ASSERT_EQUALS(pos, Board::setup_fen_position(pos)->to_fen());
+}

cpp/tests/lib.hpp

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <iostream>
+
+#define ASSERT_EQUALS(expected, actual)                                        \
+    {                                                                          \
+        if (expected != actual)                                                \
+            std::cout << "Expected: " << std::endl                             \
+                      << '\t' << expected << std::endl                         \
+                      << "Got: " << std::endl                                  \
+                      << '\t' << actual << std::endl;                          \
+    }

python/src/ai/ai.py

@@ -0,0 +1,169 @@
+from collections import defaultdict
+import time
+
+from tqdm import tqdm
+from logic.board import INITIAL_BOARD, Board
+from logic.move import Move
+from logic.pieces.piece import Colour
+
+pos2expected = {
+    # -- Position 1
+    "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1": {
+        1: 20,
+        2: 400,
+        3: 8_902,
+        4: 197_281,
+    },
+
+    # -- Position 2
+    "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1": {
+        1: 48,
+        2: 2_039,
+        3: 97_862,
+        4: 4_085_603,
+    },
+
+    # -- Position 3
+    "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1": {
+        1: 14,
+        2: 191,
+        3: 2_812,
+        4: 43_238,
+        5: 674_624,
+    },
+
+    # -- Position 4
+    "r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1": {
+        1: 6,
+        2: 264,
+        3: 9467,
+        4: 422_333,
+    },
+
+    # -- Position 5
+    "rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8": {
+        1: 44,
+        2: 1486,
+        3: 62379,
+        4: 2103487,
+    },
+
+    # -- Position 6
+    "r4rk1/1pp1qppp/p1np1n2/2b1p1B1/2B1P1b1/P1NP1N2/1PP1QPPP/R4RK1 w - - 0 10": {
+        1: 46,
+        2: 2079,
+        3: 89890,
+        4: 3894594,
+    },
+}
+
+tick = "\033[92m✔️\033[0m"  # Green Tick
+cross = "\033[91m❌\033[0m"  # Red Cross
+
+res = defaultdict(lambda : 0)
+
+def peft(pos: str):
+    global res
+    expected = pos2expected[pos]
+    board = Board.setup_FEN_position(pos)
+    for depth in expected:
+        with tqdm(total=expected[depth], desc=f"Depth: {depth}") as bar:
+            start = time.process_time()
+            moves = move_generation_test(bar, board, depth, depth)
+            bar.close()
+            elapsed = time.process_time() - start
+            elapsed *= 1_000
+
+            print("Depth:", depth, end=" ")
+            print("Result:", moves, end=" ")
+            if moves == expected[depth]:
+                print(f"{tick}", end=" ")
+            else:
+                print(f"{cross} (expected {expected[depth]})", end=" ")
+            print("positions Time:", int(elapsed), "milliseconds")
+
+            if moves != expected[depth]:
+                print()
+                for key, value in res.items():
+                    print(f"{key}: {value}")
+
+
+
+def move_generation_test(bar, board: Board, depth: int, max_depth, first = None):
+    global res
+    if first is None:
+        res = defaultdict(lambda : 0)
+
+    if board.is_terminal():
+        # bar.update(1)
+        # res[first] += 1
+        return 0
+
+    if depth == 0:
+        res[first] += 1
+        bar.update(1)
+        return 1
+
+    moves = board.legal_moves()
+    if depth == 1:
+        res[first] += len(moves)
+        bar.update(len(moves))
+        return len(moves)
+
+    num_pos = 0
+    for move in moves:
+        tmp_board = board.make_move(move)
+        if first is None:
+            first = move.piece.pos.to_algebraic() + move.pos.to_algebraic()
+
+        if first == "f7h8":
+            print(tmp_board.legal_moves())
+        num_pos += move_generation_test(bar, tmp_board, depth - 1, max_depth, first = first)
+
+        if depth == max_depth:
+            first = None
+
+    return num_pos
+
+
+
+def play_game(board: Board, strategies: dict, verbose: bool = False) -> Board:
+    """Play a turn-taking game. `strategies` is a {player_name: function} dict,
+    where function(state) is used to get the player's move."""
+    state = board
+    move_counter = 1
+    while not (board.is_checkmate_for(board._turn) or board.is_stalemate_for(board._turn)):
+        player = board._turn
+        move = strategies[player](state)
+        state = board.make_move(move)
+        if verbose:
+            if player == Colour.WHITE:
+                print(str(move_counter) + ".", move, end=" ")
+            else:
+                print(move)
+
+    return state
+
+def minmax_search(state: Board) -> tuple[float, Move]:
+    """Search game tree to determine best move; return (value, move) pair."""
+    return _max_value(state) if state._turn == Colour.WHITE else _min_value(state)
+
+def _max_value(state: Board) -> tuple[float, Move]:
+    if state.is_terminal():
+        return state.utility(), None
+    v, move = -float("inf"), None
+    for a in state.legal_moves():
+        v2, _ = _min_value(state.make_move(a))
+        if v2 > v:
+            v, move = v2, a
+    return v, move
+
+def _min_value(state: Board) -> tuple[float, Move]:
+    if state.is_terminal():
+        return state.utility(), None
+    v, move = float("inf"), None
+    for a in state.legal_moves():
+        v2, _ = _min_value(state.make_move(a))
+        if v2 < v:
+            v, move = v2, a
+    return v, move

python/src/logic/board.py

@@ -18,6 +18,8 @@ class Board:
         self._white_castling_rights = set()
         self._black_castling_rights = set()
         self._en_passant_target = None
+        self._n_moves = 0
+        self._n_half_moves = 0
 
     @staticmethod
     def _piece_class_from_char(c: str) -> Type[Piece]:
@@ -83,6 +85,8 @@ class Board:
         for c in position[index:]:
             index += 1
             if c == "-" or c == " ":
+                if c == "-":
+                    index += 1
                 break
 
             sides = "kq"
@@ -98,7 +102,24 @@ class Board:
 
         # -- En passant target
         if position[index] != "-":
-            ret._en_passant_target = position[index:index+2]
+            pos = Position.from_algebraic(position[index:index+2]) 
+            index += 2
+            if pos.y == 2:
+                pos.y += 1
+                assert pos in ret._white, "En passant target is not in the position"
+                ret._en_passant_target = ret._white[pos]
+            elif pos.y == 5:
+                pos.y -= 1
+                assert pos in ret._black, "En passant target is not in the position"
+                ret._en_passant_target = ret._black[pos]
+            else:
+                raise ValueError("You can't have a en passant target that is not on the third or sixth rank")
+        else:
+            index += 1
+        index += 1
+
+        ret._n_half_moves = int(position[index:position.find(" ", index + 1)])
+        ret._n_moves = int(position[position.find(" ", index)+1:])
 
         return ret
 
@@ -180,10 +201,22 @@ class Board:
         if move.pos in other_pieces:
             del other_pieces[move.pos]
 
+        if piece.colour == Colour.BLACK:
+            ret._n_moves = self._n_moves + 1
+
+        if move.is_capturing or type(piece) == Pawn:
+            ret._n_half_moves = 0
+        else:
+            ret._n_half_moves = self._n_half_moves + 1
+
         if move.en_passant:
             pos_to_remove = Position(move.pos.x, move.pos.y + (1 if self._turn == Colour.BLACK else -1))
             del other_pieces[pos_to_remove]
 
+        if move.promotes_to is not None:
+            assert type(piece) == Pawn, "Trying to promote something that is not a pawn: not good!"
+            pieces_moving[move.pos] = move.promotes_to(move.pos, piece.colour)
+
         # -- Set en passant target if needed
         if move.becomes_en_passant_target:
             ret._en_passant_target = pieces_moving[move.pos]
@@ -215,6 +248,12 @@ class Board:
                     ret._white_castling_rights.remove(CastleSide.Queen)
                 elif piece.pos.x == 7 and CastleSide.King in ret._white_castling_rights:
                     ret._white_castling_rights.remove(CastleSide.King)
+
+            if move.is_capturing and move.pos.y == 7 and move.pos in self._black and type(self._black[move.pos]) == Rook:
+                if move.pos.x == 0 and CastleSide.Queen in ret._black_castling_rights:
+                    ret._black_castling_rights.remove(CastleSide.Queen)
+                elif move.pos.x == 7 and CastleSide.King in ret._black_castling_rights:
+                    ret._black_castling_rights.remove(CastleSide.King)
         else:
             if type(piece) == King:
                 ret._black_castling_rights = set()
@@ -225,5 +264,97 @@ class Board:
                 elif piece.pos.x == 7 and CastleSide.King in ret._black_castling_rights:
                     ret._black_castling_rights.remove(CastleSide.King)
 
+            if move.is_capturing and move.pos.y == 0 and move.pos in self._white and type(self._white[move.pos]) == Rook:
+                if move.pos.x == 0 and CastleSide.Queen in ret._white_castling_rights:
+                    ret._white_castling_rights.remove(CastleSide.Queen)
+                elif move.pos.x == 7 and CastleSide.King in ret._white_castling_rights:
+                    ret._white_castling_rights.remove(CastleSide.King)
 
         return ret
+
+    def to_fen_string(self):
+        ret = ""
+        for y in range(7, -1, -1):
+            empty_cell_counter = 0
+            for x in range(8):
+                pos = Position(x, y)
+
+                piece = None
+                if pos in self._white:
+                    piece = self._white[pos]
+                elif pos in self._black:
+                    piece = self._black[pos]
+
+                if piece is None:
+                    empty_cell_counter += 1
+                    continue
+
+                if empty_cell_counter > 0:
+                    ret += str(empty_cell_counter)
+                    empty_cell_counter = 0
+                letter = piece.letter()
+                ret += letter.lower() if piece.colour == Colour.BLACK else letter.upper()
+
+            if empty_cell_counter > 0:
+                ret += str(empty_cell_counter)
+
+            if y > 0:
+                ret += "/"
+        ret += " "
+
+        ret += "w" if self._turn == Colour.WHITE else "b"
+        ret += " "
+
+        if len(self._white_castling_rights) == 0 and len(self._black_castling_rights) == 0:
+            ret += "-"
+        else: 
+            if CastleSide.King in self._white_castling_rights:
+                ret += "K"
+            if CastleSide.Queen in self._white_castling_rights:
+                ret += "Q"
+
+            if CastleSide.King in self._black_castling_rights:
+                ret += "k"
+            if CastleSide.Queen in self._black_castling_rights:
+                ret += "q"
+        ret += " "
+
+        if self._en_passant_target is not None:
+            pos = Position(self._en_passant_target.pos.x, self._en_passant_target.pos.y)
+            pos.y += -1 if self._en_passant_target.colour == Colour.WHITE else 1
+            ret += pos.to_algebraic()
+        else:
+            ret += "-"
+        ret += " "
+
+        ret += str(self._n_half_moves)
+        ret += " "
+        ret += str(self._n_moves)
+
+        return ret
+
+
+    def legal_moves(self) -> list[Move]:
+        ret = []
+        pieces = self._white if self._turn == Colour.WHITE else self._black
+        for piece in pieces.values():
+            ret += piece.legal_moves(self)
+        return ret
+
+    def is_terminal(self) -> bool:
+        return self.is_stalemate_for(Colour.WHITE) or self.is_stalemate_for(Colour.BLACK) or self.is_checkmate_for(Colour.WHITE) or self.is_checkmate_for(Colour.BLACK)
+
+    def utility(self) -> int:
+        if self.is_stalemate_for(Colour.WHITE) or self.is_stalemate_for(Colour.BLACK):
+            return 0
+
+        if self.is_checkmate_for(Colour.WHITE):
+            return 1
+
+        if self.is_checkmate_for(Colour.BLACK):
+            return -1
+        
+        raise ValueError("Cannot determine the utility of board become it neither checkmate nor stalemate for either players")
+
+_fen_pos = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+INITIAL_BOARD = Board.setup_FEN_position(_fen_pos)

python/src/logic/move.py

@@ -1,4 +1,5 @@
 # from logic.pieces.piece import Piece
+from typing import Type
 from logic.position import Position
 from enum import Enum
 
@@ -8,13 +9,14 @@ class CastleSide(Enum):
     Queen = "O-O-O"
 
 class Move:
-    def __init__(self, piece: "Piece", pos: Position,/, is_capturing: bool = False, castle_side: CastleSide = CastleSide.Neither, en_passant: bool = False, becomes_en_passant_target: bool = False) -> None:
+    def __init__(self, piece: "Piece", pos: Position,/, is_capturing: bool = False, castle_side: CastleSide = CastleSide.Neither, en_passant: bool = False, becomes_en_passant_target: bool = False, promotes_to: Type["Piece"] = None) -> None:
         self.piece = piece
         self.pos = pos
         self.is_capturing = is_capturing
         self.castle_side = castle_side
         self.becomes_en_passant_target = becomes_en_passant_target
         self.en_passant = en_passant
+        self.promotes_to = promotes_to
 
     def to_algebraic(self) -> str:
         raise NotImplementedError("The move can't be translated to algbraic notation, as it was not implemented")
@@ -30,10 +32,19 @@ class Move:
             return "O-O-O"
 
         ret = ""
-        if type(self.piece).__name__ != "Pawn":
+        if type(self.piece).__name__ == "Pawn":
+            if self.is_capturing:
+                ret += self.piece.pos.to_algebraic()[0]
+                ret += "x"
+                ret += self.pos.to_algebraic()
+            else:
+                ret += self.pos.to_algebraic()
+        else:
             ret += self.piece.letter().upper()
-
+            if self.is_capturing:
+                ret += "x"
             ret += str(self.pos)
+        
         return ret
     
     def __repr__(self) -> str:

python/src/logic/pieces/bishop.py

@@ -17,7 +17,7 @@ class Bishop(Piece):
         # looking north west
         ret.extend(self._look_direction(board, -1, 1))
 
-        if not looking_for_check and board.is_check_for(self.colour):
+        if not looking_for_check:# and board.is_check_for(self.colour):
             return self.keep_only_blocking(ret, board)
 
         return ret

python/src/logic/pieces/king.py

@@ -47,7 +47,7 @@ class King(Piece):
 
         if CastleSide.Queen in castling_rights:
             clear = True
-            for dx in range(1, 3):
+            for dx in range(1, 4):
                 x = self.pos.x - dx
                 y = self.pos.y
 
@@ -57,7 +57,7 @@ class King(Piece):
 
                 move = self._move_for_position(board, x, y)
                 board_after_move = board.make_move(move)
-                if board_after_move.is_check_for(self.colour):
+                if dx < 3 and board_after_move.is_check_for(self.colour):
                     clear = False
                     break
 

python/src/logic/pieces/knight.py

@@ -16,7 +16,7 @@ class Knight(Piece):
             if move is not None:
                 ret.append(move)
 
-        if not looking_for_check and board.is_check_for(self.colour):
+        if not looking_for_check:# and board.is_check_for(self.colour):
             return self.keep_only_blocking(ret, board)
 
         return ret

python/src/logic/pieces/pawn.py

@@ -1,5 +1,9 @@
 from logic.move import Move
+from logic.pieces.bishop import Bishop
+from logic.pieces.knight import Knight
 from logic.pieces.piece import Colour, Piece
+from logic.pieces.queen import Queen
+from logic.pieces.rook import Rook
 from logic.position import Position
 
 class Pawn(Piece):
@@ -13,6 +17,10 @@ class Pawn(Piece):
             (self.colour == Colour.BLACK and (capturable_piece := board.piece_at(self.pos.x - 1, self.pos.y - 1)))
         ):
             if capturable_piece.colour != self.colour:
+                if (self.colour == Colour.WHITE and capturable_piece.pos.y == 7) or (self.colour == Colour.BLACK and capturable_piece.pos.y == 0):
+                    for piece in [Queen, Knight, Bishop, Rook]:
+                        ret.append(Move(self, capturable_piece.pos, is_capturing=True, promotes_to=piece))
+                else:
                     ret.append(Move(self, capturable_piece.pos, is_capturing = True))
 
         # can we capture to the right?
@@ -22,6 +30,10 @@ class Pawn(Piece):
             (self.colour == Colour.BLACK and (capturable_piece := board.piece_at(self.pos.x + 1, self.pos.y - 1)))
         ):
             if capturable_piece.colour != self.colour:
+                if (self.colour == Colour.WHITE and capturable_piece.pos.y == 7) or (self.colour == Colour.BLACK and capturable_piece.pos.y == 0):
+                    for piece in [Queen, Knight, Bishop, Rook]:
+                        ret.append(Move(self, capturable_piece.pos, is_capturing=True, promotes_to=piece))
+                else:
                     ret.append(Move(self, capturable_piece.pos, is_capturing = True))
 
         # -- Can we capture en passant?
@@ -38,18 +50,31 @@ class Pawn(Piece):
         # -- Normal moves
         if self.colour == Colour.WHITE:
             for dy in range(1, 3 if self.pos.y == 1 else 2):
-                if self.pos.y + dy > 7 or board.piece_at(self.pos.x, self.pos.y + dy):
+                y = self.pos.y + dy
+                if y > 7 or board.piece_at(self.pos.x, y):
                     break
-                pos = Position(self.pos.x, self.pos.y + dy)
+                pos = Position(self.pos.x, y)
+                if y == 7:
+                    for piece in [Queen, Knight, Bishop, Rook]:
+                        ret.append(Move(self, pos, promotes_to=piece))
+                else:
                     ret.append(Move(self, pos, becomes_en_passant_target=dy==2))
         else:
             for dy in range(1, 3 if self.pos.y == 6 else 2):
-                if self.pos.y - dy < 0 or board.piece_at(self.pos.x, self.pos.y - dy):
+                y = self.pos.y - dy
+                if y < 0 or board.piece_at(self.pos.x, y):
                     break
-                pos = Position(self.pos.x, self.pos.y - dy)
+                pos = Position(self.pos.x, y)
+                if y == 0:
+                    for piece in [Queen, Knight, Bishop, Rook]:
+                        ret.append(Move(self, pos, promotes_to=piece))
+                else:
                     ret.append(Move(self, pos, becomes_en_passant_target=dy==2))
 
-        if not looking_for_check and board.is_check_for(self.colour):
+        if not looking_for_check:# and board.is_check_for(self.colour):
             return self.keep_only_blocking(ret, board)
 
         return ret
+
+    def letter(self):
+        return "p"

python/src/logic/pieces/queen.py

@@ -29,7 +29,7 @@ class Queen(Piece):
         # looking north
         ret.extend(self._look_direction(board, 0, 1))
 
-        if not looking_for_check and board.is_check_for(self.colour):
+        if not looking_for_check:# and board.is_check_for(self.colour):
             return self.keep_only_blocking(ret, board)
 
         return ret

python/src/logic/pieces/rook.py

@@ -17,7 +17,7 @@ class Rook(Piece):
         # looking north
         ret.extend(self._look_direction(board, 0, 1))
 
-        if not looking_for_check and board.is_check_for(self.colour):
+        if not looking_for_check:# and board.is_check_for(self.colour):
             return self.keep_only_blocking(ret, board)
 
         return ret

python/src/logic/position.py

@@ -17,6 +17,14 @@ class Position:
         return x >= Position._MIN_POS and x <= Position._MAX_POS \
             and y >= Position._MIN_POS and y <= Position._MAX_POS
 
+    @staticmethod
+    def from_algebraic(square: str) -> "Position":
+        assert len(square) == 2, f"'{square}' is malformed"
+        x = Position._FILES.index(square[0])
+        y = Position._RANKS.index(int(square[1]))
+
+        return Position(x, y)
+
     def to_algebraic(self) -> str:
         return f"{Position._FILES[self.x]}{Position._RANKS[self.y]}"
 

python/src/main.py

@@ -0,0 +1,27 @@
+import time
+from pprint import pprint
+from tqdm import tqdm
+
+from ai.ai import move_generation_test
+from controller.controller import Controller
+from logic.board import INITIAL_BOARD, Board
+from logic.position import Position
+from view.gui import GUI
+from view.tui import TUI
+
+from ai.ai import peft
+
+if __name__ == "__main__":
+    board = INITIAL_BOARD
+
+    pos = "rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8"
+    board = Board.setup_FEN_position(pos)
+
+    view = GUI()
+
+    controller = Controller(board, view)
+
+    # view.show()
+    # exit()
+
+    peft(pos)

python/tests/fen.py

@@ -0,0 +1,30 @@
+import unittest
+
+import sys
+sys.path.append('src') # you must execute pytest from the stickfosh dir for this to work
+
+from logic.board import Board
+
+class FENTests(unittest.TestCase):
+    def testInitialPosition(self):
+        pos = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+        self.assertEqual(pos, Board.setup_FEN_position(pos).to_fen_string())
+
+    def testRandomPositions(self):
+        pos = "r1bk3r/p2pBpNp/n4n2/1p1NP2P/6P1/3P4/P1P1K3/q5b1 b Qk - 0 1"
+        self.assertEqual(pos, Board.setup_FEN_position(pos).to_fen_string())
+
+        pos = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1"
+        self.assertEqual(pos, Board.setup_FEN_position(pos).to_fen_string())
+
+        pos = "4k2r/6r1/8/8/8/8/3R4/R3K3 w Qk - 0 1"
+        self.assertEqual(pos, Board.setup_FEN_position(pos).to_fen_string())
+
+        pos = "8/8/8/4p1K1/2k1P3/8/8/8 b - - 0 1"
+        self.assertEqual(pos, Board.setup_FEN_position(pos).to_fen_string())
+
+        pos = "8/5k2/3p4/1p1Pp2p/pP2Pp1P/P4P1K/8/8 b - - 99 50"
+        self.assertEqual(pos, Board.setup_FEN_position(pos).to_fen_string())
+
+
+

python/tests/position.py

@@ -0,0 +1,30 @@
+import unittest
+
+import sys
+sys.path.append('src') # you must execute pytest from the stickfosh dir for this to work
+
+from logic.position import Position
+
+class PositionTests(unittest.TestCase):
+    def testXY2Algebraic(self):
+        self.assertEqual(Position(0, 0).to_algebraic(), "a1")
+        self.assertEqual(Position(1, 0).to_algebraic(), "b1")
+
+        self.assertEqual(Position(2, 1).to_algebraic(), "c2")
+        self.assertEqual(Position(4, 2).to_algebraic(), "e3")
+
+        self.assertEqual(Position(7, 7).to_algebraic(), "h8")
+
+    def testAlgebraic2XY(self):
+        self.assertEqual(Position.from_algebraic("a1"), Position(0, 0))
+        self.assertEqual(Position.from_algebraic("b1"), Position(1, 0))
+
+        self.assertEqual(Position.from_algebraic("c2"), Position(2, 1))
+        self.assertEqual(Position.from_algebraic("e3"), Position(4, 2))
+
+        self.assertEqual(Position.from_algebraic("h8"), Position(7, 7))
+
+        self.assertRaises(AssertionError, lambda : Position.from_algebraic("a11"))
+
+        self.assertRaises(ValueError, lambda : Position.from_algebraic("j1"))
+        self.assertRaises(ValueError, lambda : Position.from_algebraic("a9"))

src/main.py

@@ -1,14 +0,0 @@
-from controller.controller import Controller
-from logic.board import Board
-from view.gui import GUI
-from view.tui import TUI
-
-if __name__ == "__main__":
-    initial_board_position = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
-    board = Board.setup_FEN_position(initial_board_position)
-
-    view = GUI()
-
-    controller = Controller(board, view)
-
-    view.show()