#include "fen.hpp"
#include "board.hpp"
#include <cctype>
#include <cstdlib>
#include <print>
#include <string>

bool WHITE = true;
bool BLACK = false;

void setBoardFen(std::string fen, Game *g) {
  // example fen rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
  int file = 0;
  int rank = 0;

  enum parserState {
    POSITION,
    TURN,
    CASTLE,
    ENPASSANT,
    CLOCK1,
    CLOCK2,
  };
  parserState state = POSITION;

  for (uint i = 0; i < fen.length(); i++) {
    if (fen[i] == ' ') {
      if (state == POSITION) {
        state = TURN;
        continue;
      }
      if (state == TURN) {
        state = CASTLE;
        continue;
      }
      if (state == CASTLE) {
        state = ENPASSANT;
        continue;
      }
      if (state == ENPASSANT) {
        state = CLOCK1;
        continue;
      }
      if (state == CLOCK1) {
        state = CLOCK2;
        continue;
      }
    }
    if (state == ENPASSANT) {
      continue;
    }
    if (state == CASTLE) {
      if (fen[i] == '-') {
        g->blackCastleKing = false;
        g->blackCastleQueen = false;
        g->whiteCastleKing = false;
        g->whiteCastleQueen = false;
        continue;
      }
      if (fen[i] == 'K') {
        g->whiteCastleKing = true;
        continue;
      }
      if (fen[i] == 'Q') {
        g->whiteCastleQueen = true;
        continue;
      }
      if (fen[i] == 'k') {
        g->blackCastleKing = true;
        continue;
      }
      if (fen[i] == 'q') {
        g->blackCastleQueen = true;
        continue;
      }
    }
    if (state == TURN) {
      if (toupper(fen[i]) == 'W') {
        g->turn = WHITE;
        continue;
      }
      if (toupper(fen[i]) == 'B') {
        g->turn = BLACK;
        continue;
      }
    }
    if (state == POSITION) {
      if (isdigit(fen[i])) {
        int move = fen[i] - '0';
        file += move;
        if (file > 8) {
          std::println("Fatal: file was to big");
          exit(1);
          return; // malformed rank
        }
        continue;
      }
      if (fen[i] == '/') {
        file = 0;
        rank++;
        if (rank >= 8) {
          std::println("Fatal: rank was to big");
          exit(1);
          return; // malformed rank
        }
        continue;
      };
      if (toupper(fen[i]) == 'N') {
        Piece piece = createPiece(KNIGHT, isupper(fen[i]));
        g->pieces[rank * 8 + file] = piece;
        file++;
        continue;
      };
      if (toupper(fen[i]) == 'R') {
        Piece piece = createPiece(ROOK, isupper(fen[i]));
        g->pieces[rank * 8 + file] = piece;
        file++;
        continue;
      }
      if (toupper(fen[i]) == 'Q') {
        Piece piece = createPiece(QUEEN, isupper(fen[i]));
        g->pieces[rank * 8 + file] = piece;
        file++;
        continue;
      }
      if (toupper(fen[i]) == 'B') {
        Piece piece = createPiece(BISHOP, isupper(fen[i]));
        g->pieces[rank * 8 + file] = piece;
        file++;
        continue;
      }
      if (toupper(fen[i]) == 'P') {
        Piece piece = createPiece(PAWN, isupper(fen[i]));
        g->pieces[rank * 8 + file] = piece;
        file++;
        continue;
      }
      if (toupper(fen[i]) == 'K') {
        Piece piece = createPiece(KING, isupper(fen[i]));
        g->pieces[rank * 8 + file] = piece;
        file++;
        continue;
      }
    }
    break;
  }
  UpdateBitboards(g);
}