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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