#ifndef ENGINE_GUIDANCE_ASSEMBLE_STEPS_HPP_
#define ENGINE_GUIDANCE_ASSEMBLE_STEPS_HPP_

#include "engine/guidance/route_step.hpp"
#include "engine/guidance/step_maneuver.hpp"
#include "engine/guidance/leg_geometry.hpp"
#include "engine/guidance/guidance_toolkit.hpp"
#include "engine/guidance/turn_instruction.hpp"
#include "engine/internal_route_result.hpp"
#include "engine/phantom_node.hpp"
#include "util/coordinate_calculation.hpp"
#include "util/coordinate.hpp"
#include "util/bearing.hpp"
#include "extractor/travel_mode.hpp"

#include <vector>
#include <boost/optional.hpp>

namespace osrm
{
namespace engine
{
namespace guidance
{
namespace detail
{
// FIXME move implementation to cpp
inline StepManeuver stepManeuverFromGeometry(TurnInstruction instruction,
                                             const LegGeometry &leg_geometry,
                                             const std::size_t segment_index,
                                             const unsigned exit)
{
    auto turn_index = leg_geometry.BackIndex(segment_index);
    BOOST_ASSERT(turn_index > 0);
    BOOST_ASSERT(turn_index < leg_geometry.locations.size() - 1);

    // TODO chose a bigger look-a-head to smooth complex geometry
    const auto pre_turn_coordinate = leg_geometry.locations[turn_index - 1];
    const auto turn_coordinate = leg_geometry.locations[turn_index];
    const auto post_turn_coordinate = leg_geometry.locations[turn_index + 1];

    const double pre_turn_bearing =
        util::coordinate_calculation::bearing(pre_turn_coordinate, turn_coordinate);
    const double post_turn_bearing =
        util::coordinate_calculation::bearing(turn_coordinate, post_turn_coordinate);

    return StepManeuver{turn_coordinate, pre_turn_bearing, post_turn_bearing, instruction, exit};
}
}

template <typename DataFacadeT>
std::vector<RouteStep> assembleSteps(const DataFacadeT &facade,
                                     const std::vector<PathData> &leg_data,
                                     const LegGeometry &leg_geometry,
                                     const PhantomNode &source_node,
                                     const PhantomNode &target_node,
                                     const bool source_traversed_in_reverse,
                                     const bool target_traversed_in_reverse,
                                     boost::optional<util::Coordinate> source_location,
                                     boost::optional<util::Coordinate> target_location)
{
    (void) source_location;
    const auto source_duration =
        (source_traversed_in_reverse ? source_node.GetReverseWeightPlusOffset()
                                     : source_node.GetForwardWeightPlusOffset()) /
        10.;
    const auto source_mode = source_traversed_in_reverse ? source_node.backward_travel_mode
                                                         : source_node.forward_travel_mode;

    const auto target_duration =
        (target_traversed_in_reverse ? target_node.GetReverseWeightPlusOffset()
                                     : target_node.GetForwardWeightPlusOffset()) /
        10.;
    const auto target_mode = target_traversed_in_reverse ? target_node.backward_travel_mode
                                                         : target_node.forward_travel_mode;

    const auto number_of_segments = leg_geometry.GetNumberOfSegments();

    std::vector<RouteStep> steps;
    steps.reserve(number_of_segments);

    // TODO do computation based on distance and choose better next vertex
    BOOST_ASSERT(leg_geometry.locations.size() >= 4); // source, phantom, closest positions on way

    auto segment_index = 0;
    if (leg_data.size() > 0)
    {

        StepManeuver maneuver = detail::stepManeuverFromGeometry(
            TurnInstruction{TurnType::Location, DirectionModifier::UTurn}, leg_geometry,
            segment_index, INVALID_EXIT_NR);
        maneuver.instruction.direction_modifier = bearingToDirectionModifier(maneuver.bearing_before);

        // TODO fix this: it makes no sense
        // PathData saves the information we need of the segment _before_ the turn,
        // but a RouteStep is with regard to the segment after the turn.
        // We need to skip the first segment because it is already covered by the
        // initial start of a route
        for (const auto &path_point : leg_data)
        {
            if (path_point.turn_instruction != TurnInstruction::NO_TURN())
            {
                const auto name = facade.get_name_for_id(path_point.name_id);
                const auto distance = leg_geometry.segment_distances[segment_index];
                steps.push_back(RouteStep{
                    path_point.name_id, name, path_point.duration_until_turn / 10.0, distance,
                    path_point.travel_mode, maneuver, leg_geometry.FrontIndex(segment_index),
                    leg_geometry.BackIndex(segment_index) + 1});
                maneuver = detail::stepManeuverFromGeometry(
                    path_point.turn_instruction, leg_geometry, segment_index, path_point.exit);
                segment_index++;
            }
        }
        // TODO remove this hack
        const auto distance = leg_geometry.segment_distances[segment_index];
        steps.push_back(RouteStep{target_node.name_id, facade.get_name_for_id(target_node.name_id),
                                  target_duration, distance, target_mode, maneuver,
                                  leg_geometry.FrontIndex(segment_index),
                                  leg_geometry.BackIndex(segment_index) + 1});
    }
    else
    {
        //
        // |-----s source_duration
        // |-------------t target_duration
        // x---*---*---*---z compressed edge
        //       |-------| duration
        StepManeuver maneuver = {source_node.location, 0., 0.,
                                 TurnInstruction{TurnType::Location, DirectionModifier::UTurn},
                                 INVALID_EXIT_NR};
        maneuver.instruction.direction_modifier = bearingToDirectionModifier(maneuver.bearing_before);

        steps.push_back(RouteStep{source_node.name_id, facade.get_name_for_id(source_node.name_id),
                                  target_duration - source_duration,
                                  leg_geometry.segment_distances[segment_index], source_mode,
                                  std::move(maneuver), leg_geometry.FrontIndex(segment_index),
                                  leg_geometry.BackIndex(segment_index) + 1});
    }

    BOOST_ASSERT(segment_index == number_of_segments - 1);
    const auto final_modifier =
        target_location ? angleToDirectionModifier(util::coordinate_calculation::computeAngle(
                              *(leg_geometry.locations.end() - 3),
                              *(leg_geometry.locations.end() - 1), target_location.get()))
                        : DirectionModifier::UTurn;
    // This step has length zero, the only reason we need it is the target location
    steps.push_back(RouteStep{
        target_node.name_id, facade.get_name_for_id(target_node.name_id), 0., 0., target_mode,
        StepManeuver{target_node.location, 0., 0.,
                     TurnInstruction{TurnType::Location, final_modifier}, INVALID_EXIT_NR},
        leg_geometry.locations.size(), leg_geometry.locations.size()});

    return steps;
}

} // namespace guidance
} // namespace engine
} // namespace osrm

#endif // ENGINE_GUIDANCE_SEGMENT_LIST_HPP_