#include "extractor/guidance/turn_classification.hpp"

#include <algorithm>
#include <cstddef>
#include <cstdint>

namespace osrm
{
namespace extractor
{
namespace guidance
{

std::pair<util::guidance::EntryClass, util::guidance::BearingClass>
classifyIntersection(Intersection intersection)
{
    if (intersection.empty())
        return {};

    std::sort(intersection.begin(),
              intersection.end(),
              [](const ConnectedRoad &left, const ConnectedRoad &right) {
                  return left.bearing < right.bearing;
              });

    util::guidance::EntryClass entry_class;
    util::guidance::BearingClass bearing_class;

    const bool canBeDiscretized = [&]() {
        if (intersection.size() <= 1)
            return true;

        DiscreteBearing last_discrete_bearing = util::guidance::BearingClass::getDiscreteBearing(
            std::round(intersection.back().bearing));
        for (const auto &road : intersection)
        {
            const DiscreteBearing discrete_bearing =
                util::guidance::BearingClass::getDiscreteBearing(std::round(road.bearing));
            if (discrete_bearing == last_discrete_bearing)
                return false;
            last_discrete_bearing = discrete_bearing;
        }
        return true;
    }();

    // finally transfer data to the entry/bearing classes
    std::size_t number = 0;
    if (canBeDiscretized)
    {
        if (util::guidance::BearingClass::getDiscreteBearing(intersection.back().bearing) <
            util::guidance::BearingClass::getDiscreteBearing(intersection.front().bearing))
        {
            intersection.insert(intersection.begin(), intersection.back());
            intersection.pop_back();
        }
        for (const auto &road : intersection)
        {
            if (road.entry_allowed)
                entry_class.activate(number);
            auto discrete_bearing_class =
                util::guidance::BearingClass::getDiscreteBearing(std::round(road.bearing));
            bearing_class.add(std::round(discrete_bearing_class *
                                         util::guidance::BearingClass::discrete_step_size));
            ++number;
        }
    }
    else
    {
        for (const auto &road : intersection)
        {
            if (road.entry_allowed)
                entry_class.activate(number);
            bearing_class.add(std::round(road.bearing));
            ++number;
        }
    }
    return std::make_pair(entry_class, bearing_class);
}

} // namespace guidance
} // namespace extractor
} // namespace osrm