path: root/src/board.cpp

#include "board.hpp"
#include "bot.hpp"
#include "zobrist.hpp"
#include <cassert>
#include <cstdio>
#include <iostream>
#include <print>
#include <string>

std::string toChar(PieceType type, bool white) {
  switch (type) {
  case NONE:
    return " ";
  case KING:
    return white ? "♚" : "♔";
  case QUEEN:
    return white ? "♛" : "♕";
  case ROOK:
    return white ? "♜" : "♖";
  case BISHOP:
    return white ? "♝" : "♗";
  case KNIGHT:
    return white ? "♞" : "♘";
  case PAWN:
    return white ? "♟" : "♙";
  default:
    assert(false && "Unknown piece");
    return " ";
  }
}

Piece createPiece(PieceType type, bool color, bool moved) {
  Piece piece;
  piece.type = type;
  piece.color = color;
  piece.moved = moved;
  return piece;
}
void printBoard(Game *b) {
  std::string line = "  +------------------------+\n";
  std::string whiteLetters = "    a  b  c  d  e  f  g  h \n";
  std::string blackLetters = "    h  g  f  e  d  c  b  a \n";

  const char *lightSquare = "\033[48;5;245m";
  const char *darkSquare = "\033[48;5;29m";
  const char *reset = "\033[0m";

  std::cout << (b->turn ? whiteLetters : blackLetters);
  std::cout << line;

  if (b->turn) {
    for (int rank = 0; rank < 8; rank++) {
      std::printf("%d |", 8 - rank);

      for (int file = 0; file < 8; file++) {
        Piece piece = b->pieces[rank * 8 + file];
        std::string symbol = toChar(piece.type, piece.color);

        const char *bg = ((rank + file) % 2 == 0) ? lightSquare : darkSquare;

        std::cout << bg << " " << symbol << " " << reset;
      }

      std::printf("| %d\n", 8 - rank);
    }
  } else {
    for (int rank = 7; rank >= 0; rank--) {
      std::printf("%d |", 8 - rank);

      for (int file = 7; file >= 0; file--) {
        Piece piece = b->pieces[rank * 8 + file];
        std::string symbol = toChar(piece.type, piece.color);

        const char *bg = ((rank + file) % 2 == 0) ? lightSquare : darkSquare;

        std::cout << bg << " " << symbol << " " << reset;
      }

      std::printf("| %d\n", 8 - rank);
    }
  }

  std::cout << line;
  std::cout << (b->turn ? whiteLetters : blackLetters);

  std::println();
  std::println("Turn: {}", b->turn ? "White" : "Black");

  assert(b->castle != "");

  std::println("Castling: {}", b->castle);
  std::println("Can enpassant: {}", b->canEnpassant ? "Yes" : "No");
  std::println("Where enpassant: {}{}", (char)((int)b->enPassant.file + 'A'),
               8 - (int)b->enPassant.rank);
  std::printf("Move clock: %d\n", b->MoveClock);
  std::printf("Half move clock: %d\n", b->halfMoveClock);
  std::printf("Board Eval: %f\n", EvaluateBoardForWhite(b, 0));
}

void PlayMove(Move move, Game *b) {
  // TODO: add all fide behavior
  Piece piece = b->pieces[PositionToIndex(move.From)];
  Piece piece2 = b->pieces[PositionToIndex(move.To)];
  if (piece2.type != NONE) {
    if (piece2.color == b->turn) {
      assert(false && "capturing friendly piece error");
    }
  }
  piece.moved = true;
  if (piece.type == PAWN || piece2.type != NONE) {
    b->halfMoveClock = 0;
  } else {
    b->halfMoveClock++;
  }
  if (piece.type == PAWN && b->canEnpassant && move.To == b->enPassant) {
    Position capturedPawn = move.To;
    capturedPawn.rank += piece.color ? 1 : -1;
    b->pieces[PositionToIndex(capturedPawn)] = {false, NONE, false};
  }

  b->canEnpassant = false;
  b->MoveClock++;

  if (piece.type == PAWN) {
    Position to = move.To;
    to.rank -= (piece.color ? -2 : 2);
    if (to == move.From) {
      b->canEnpassant = true;
      Position target = move.From;
      target.rank += piece.color ? -1 : 1;
      b->enPassant = target;
    };
  }

  if (piece.type == PAWN && move.To.rank == (piece.color ? 0 : 7)) {
    // TODO parse the promote type from uci isntead of ignoreting it
    piece.type = move.promotion == NONE ? QUEEN : move.promotion;
  }
  if (b->halfMoveClock >= 50) {
    b->state = DRAW;
  }
  b->pieces[PositionToIndex(move.To)] = piece;
  b->pieces[PositionToIndex(move.From)] = {false, NONE, false};

  b->turn = !b->turn;

  uint64_t key = GenerateZobristKey(b);

  b->ThreeFoldMap[key]++;
  if (b->ThreeFoldMap[key] >= 3) {
    b->state = DRAW;
  }
};
int PositionToIndex(Position i) { return i.rank * 8 + i.file; }

UndoMove MakeMove(Move move, Game *g) {
  UndoMove undo = {};

  undo.from = move.From;
  undo.to = move.To;

  undo.movedPiece = g->pieces[PositionToIndex(move.From)];
  undo.capturedPiece = g->pieces[PositionToIndex(move.To)];

  undo.oldTurn = g->turn;
  undo.oldCanEnpassant = g->canEnpassant;
  undo.oldEnPassant = g->enPassant;

  undo.oldHalfMoveClock = g->halfMoveClock;
  undo.oldMoveClock = g->MoveClock;

  undo.oldState = g->state;
  undo.oldCaslte = g->castle;

  // play move

  Piece piece = g->pieces[PositionToIndex(move.From)];
  Piece piece2 = g->pieces[PositionToIndex(move.To)];

  if (piece2.type != NONE) {
    if (piece2.color == g->turn) {
      assert(false && "capturing friendly piece error");
    }
  }
  piece.moved = true;

  // clock
  g->MoveClock++;
  if (piece.type == PAWN || piece2.type != NONE) {
    g->halfMoveClock = 0;
  } else {
    g->halfMoveClock++;
  }

  // Playing enpasstant
  if (piece.type == PAWN && g->canEnpassant && move.To == g->enPassant) {
    Position capturedPawn = move.To;
    capturedPawn.rank += piece.color ? 1 : -1;
    g->pieces[PositionToIndex(capturedPawn)] = {false, NONE, false};

    undo.wasEnPassantCapture = true;
    undo.enPassantCapturedSquare = capturedPawn;
    undo.enPassantCapturedPiece = g->pieces[PositionToIndex(capturedPawn)];
  }

  g->canEnpassant = false;

  // Adding enpassant
  if (piece.type == PAWN) {
    Position to = move.To;
    to.rank -= (piece.color ? -2 : 2);
    if (to == move.From) {
      g->canEnpassant = true;
      Position target = move.From;
      target.rank += piece.color ? -1 : 1;
      g->enPassant = target;
    };
  }

  // Promotions
  if (piece.type == PAWN && move.To.rank == (piece.color ? 0 : 7)) {
    // TODO parse the promote type from uci isntead of ignoreting it
    piece.type = move.promotion == NONE ? QUEEN : move.promotion;
  }

  // setting the moves
  g->pieces[PositionToIndex(move.To)] = piece;
  g->pieces[PositionToIndex(move.From)] = {false, NONE, false};

  // post move change

  // changing who turn it is
  g->turn = !g->turn;

  // 3 fold check
  uint64_t key = GenerateZobristKey(g);

  undo.zobristKey = key;

  if (g->ThreeFoldMap[key] >= 3) {
    g->state = DRAW;
  }

  g->ThreeFoldMap[key]++;

  if (g->halfMoveClock >= 50) {
    g->state = DRAW;
  }

  return undo;
};
void UnMake(UndoMove undo, Game *g) {
  g->pieces[PositionToIndex(undo.from)] = undo.movedPiece;

  g->pieces[PositionToIndex(undo.to)] = undo.capturedPiece;

  if (undo.wasEnPassantCapture) {
    g->pieces[PositionToIndex(undo.enPassantCapturedSquare)] =
        undo.enPassantCapturedPiece;
  }

  g->turn = undo.oldTurn;

  g->canEnpassant = undo.oldCanEnpassant;
  g->enPassant = undo.oldEnPassant;

  g->halfMoveClock = undo.oldHalfMoveClock;
  g->MoveClock = undo.oldMoveClock;

  g->state = undo.oldState;

  g->castle = undo.oldCaslte;

  if (--g->ThreeFoldMap[undo.zobristKey] <= 0) {
    g->ThreeFoldMap.erase(undo.zobristKey);
  }
};