// Copyright 2018-2022 David Robillard <d@drobilla.net>
// SPDX-License-Identifier: GPL-2.0-or-later

#include "chilbert/chilbert.hpp"

#include <array>
#include <climits>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>

int
main(int argc, char** argv)
{
  if (argc != 2) {
    fprintf(stderr, "Usage: %s NUM_POINTS\n", argv[0]);
    return 1;
  }

  const unsigned long num_points = std::strtoul(argv[1], nullptr, 10);
  if (num_points == 0 || num_points == ULONG_MAX) {
    fprintf(stderr, "Usage: %s NUM_POINTS\n", argv[0]);
    return 1;
  }

  const uint32_t w =
    static_cast<uint32_t>(sqrt(1U << static_cast<uint32_t>(ceil(
                                 log2(static_cast<double>(num_points)))))) -
    1U;

  // Header
  printf("<svg xmlns='http://www.w3.org/2000/svg'"
         " version='1.2' baseProfile='tiny' viewBox='0 0 %u %u'>\n",
         w,
         w);
  printf("<desc>Hilbert Curve</desc>\n");
  printf("<polyline vector-effect='non-scaling-stroke' fill='none' "
         "stroke='black' stroke-width='1' points='");

  // One polyline through all vertices
  for (uint64_t i = 0; i <= num_points; ++i) {
    std::array<uint32_t, 2> point{};
    chilbert::index_to_coords(point, 32, 2, i);
    printf("%u,%u ", point[0], point[1]);
  }

  // Close off document
  printf("' />\n</svg>\n");

  return 0;
}