#include <array>
#include <cstdint>

#include "board.hpp"
#include "moves.hpp"

std::vector<Move> GetLegalMoves(board *b) {
  std::vector<Move> moves;
  moves.reserve(50); // almost all position dont have that many moves

  constexpr std::array<int, 4> rook_Moves{-1, 1, 8, -8};
  constexpr std::array<int, 4> bishop_Moves{-9, 9, -7, 7};

  for (int i = 0; i < sizeof(b->pieces) / sizeof(b->pieces[0]); i++) {
    Piece piece = b->pieces[i];
    if (piece.type == NONE) {
      continue;
    }
    if (piece.color != b->turn)
      continue;

    // Add support for other pieces
    if (piece.type == BISHOP) {
      GenerateSlidingMoves(b, i, bishop_Moves, moves);
    }
    if (piece.type == ROOK) {
      GenerateSlidingMoves(b, i, rook_Moves, moves);
    }
    if (piece.type == QUEEN) {
      GenerateSlidingMoves(b, i, rook_Moves, moves);
      GenerateSlidingMoves(b, i, bishop_Moves, moves);
    }
  };

  return moves;
}
Position IndexToPosition(int i) {
  uint8_t rank = i / 8; // 0-7
  uint8_t file = i % 8; // 0-7
  return {rank, file};
}
void GenerateSlidingMoves(board *b, int from,
                          const std::array<int, 4> &directions,
                          std::vector<Move> &moves) {
  for (int i = 0; i < directions.size(); i++) {
    int direction = directions[i];

    int i2 = from;
    while (true) {
      i2 += direction;
      int oldFile = (i2 - direction) % 8;
      int newFile = i2 % 8;

      if (direction == 7 || direction == -7 || direction == 9 ||
          direction == -9) {
        if (std::abs(newFile - oldFile) != 1)
          break;
      }
      if (i2 >= 64 || i2 < 0) {
        break;
      }
      if (b->pieces[i2].color == b->turn && b->pieces[i2].type != NONE) {
        break;
      }
      if ((direction == 1 || direction == -1) &&
          (i2 / 8 != (i2 - direction) / 8)) {
        break;
      }
      moves.push_back({IndexToPosition(from), IndexToPosition(i2)});
      if (b->pieces[i2].color != b->turn && b->pieces[i2].type != NONE) {
        break;
      }
    }
  };
};