module;

#include <boost/geometry.hpp>

export module routemon:geo;

export namespace bgeo = boost::geometry;

export namespace routemon::geo {

using point =
    bgeo::model::point<double, 2, bgeo::cs::spherical_equatorial<bgeo::degree>>;
using linestring = bgeo::model::linestring<point>;
using box = bgeo::model::box<point>;
using stype = bgeo::srs::spheroid<double>;
using vincenty_strategy = bgeo::strategy::distance::vincenty<stype>;

auto split_linestring_with_overlap_segments(
    linestring const& ls, double max_split_distance_m,
    std::vector<linestring>& append_to) -> void
{
  if (bgeo::is_empty(ls))
    return;

  auto current_ls = linestring{};
  auto current_ls_length = 0.0;
  auto previous = std::optional<point>{};
  bgeo::for_each_point(
      ls,
      [&](point p) -> void
      {
        bgeo::append(current_ls, p);
        if (previous)
        {
          auto d = bgeo::distance(*previous, p, vincenty_strategy());
          current_ls_length += d;
          if (current_ls_length > max_split_distance_m)
          {
            append_to.push_back(std::move(current_ls));
            current_ls = linestring{*previous, p};
            current_ls_length = d;
          }
        }
        previous = p;
      });
  append_to.emplace_back(std::move(current_ls));
}

} // namespace routemon::geo