#include "sliding_tile_lib.h"

#include <istream>

signed char adjacent[BOARD_SIZE][5] = {
  1,   4,   -1,  -1,  -1,
  0,   2,   5,   -1,  -1,
  1,   3,   6,   -1,  -1,
  2,   7,   -1,  -1,  -1,
  0,   5,   8,   -1,  -1,
  1,   4,   6,   9,   -1,
  2,   5,   7,   10,  -1,
  3,   6,   11,  -1,  -1,
  4,   9,   12,  -1,  -1,
  5,   8,   10,  13,  -1,
  6,   9,   11,  14,  -1,
  7,   10,  15,  -1,  -1,
  8,   13,  -1,  -1,  -1,
  9,   12,  14,  -1,  -1,
  10,  13,  15,  -1,  -1,
  11,  14,  -1,  -1,  -1,
};

std::istream& operator>>(std::istream& is, Board& board) {
  for (int i = 0; i < BOARD_SIZE; i++) {
    if (!is.good()) {
      is.setstate(std::istream::failbit);
      break;
    }
    if (i > 0 && is.get() != ',') {
      is.setstate(std::istream::failbit);
      break;
    }
    int numeric;
    is >> numeric;
    board[i] = numeric;
  }
  return is;
}