#ifndef slic3r_AvoidCrossingPerimeters_hpp_
#define slic3r_AvoidCrossingPerimeters_hpp_

#include "../libslic3r.h"
#include "../ExPolygon.hpp"
#include "../EdgeGrid.hpp"

#include <unordered_set>
#include <boost/functional/hash.hpp>

namespace Slic3r {

// Forward declarations.
class GCode;
class Layer;
class Point;
class Print;
class PrintObject;

struct PrintInstance;
using PrintObjectPtrs = std::vector<PrintObject *>;

class AvoidCrossingPerimeters
{
public:
    struct Intersection
    {
        // Index of the polygon containing this point of intersection.
        size_t border_idx;
        // Index of the line on the polygon containing this point of intersection.
        size_t line_idx;
        // Point of intersection projected on the travel path.
        Point  point_transformed;
        // Point of intersection.
        Point  point;

        Intersection(size_t border_idx, size_t line_idx, const Point &point_transformed, const Point &point)
            : border_idx(border_idx), line_idx(line_idx), point_transformed(point_transformed), point(point){};

        inline bool operator<(const Intersection &other) const { return this->point_transformed.x() < other.point_transformed.x(); }
    };

    struct TravelPoint
    {
        Point point;
        // Index of the polygon containing this point. A negative value indicates that the point is not on any border
        int   border_idx;
    };

    struct AllIntersectionsVisitor
    {
        AllIntersectionsVisitor(const EdgeGrid::Grid &grid, std::vector<AvoidCrossingPerimeters::Intersection> &intersections)
            : grid(grid), intersections(intersections)
        {}

        AllIntersectionsVisitor(const EdgeGrid::Grid                               &grid,
                                std::vector<AvoidCrossingPerimeters::Intersection> &intersections,
                                const Matrix2d                                     &transform_to_x_axis,
                                const Line                                         &travel_line)
            : grid(grid), intersections(intersections), transform_to_x_axis(transform_to_x_axis), travel_line(travel_line)
        {}

        void reset() {
            intersection_set.clear();
        }

        bool operator()(coord_t iy, coord_t ix)
        {
            // Called with a row and colum of the grid cell, which is intersected by a line.
            auto cell_data_range = grid.cell_data_range(iy, ix);
            for (auto it_contour_and_segment = cell_data_range.first; it_contour_and_segment != cell_data_range.second;
                 ++it_contour_and_segment) {
                // End points of the line segment and their vector.
                auto segment = grid.segment(*it_contour_and_segment);

                Point intersection_point;
                if (travel_line.intersection(Line(segment.first, segment.second), &intersection_point) &&
                    intersection_set.find(*it_contour_and_segment) == intersection_set.end()) {
                    intersections.emplace_back(it_contour_and_segment->first, it_contour_and_segment->second,
                                               (transform_to_x_axis * intersection_point.cast<double>()).cast<coord_t>(), intersection_point);
                    intersection_set.insert(*it_contour_and_segment);
                }
            }
            // Continue traversing the grid along the edge.
            return true;
        }

        const EdgeGrid::Grid                                                                 &grid;
        std::vector<AvoidCrossingPerimeters::Intersection>                                   &intersections;
        Matrix2d                                                                              transform_to_x_axis;
        Line                                                                                  travel_line;
        std::unordered_set<std::pair<size_t, size_t>, boost::hash<std::pair<size_t, size_t>>> intersection_set;
    };

    enum class Direction { Forward, Backward };

private:
    static ExPolygons get_boundary(const Layer &layer);

    static ExPolygons get_boundary_external(const Layer &layer);

    static Direction get_shortest_direction(
        const Lines &lines, const size_t start_idx, const size_t end_idx, const Point &intersection_first, const Point &intersection_last);

    static std::vector<AvoidCrossingPerimeters::TravelPoint> simplify_travel(const EdgeGrid::Grid           &edge_grid,
                                                                             const std::vector<TravelPoint> &travel,
                                                                             const Polygons                 &boundaries,
                                                                             const bool                      use_heuristics);

    static std::vector<AvoidCrossingPerimeters::TravelPoint> simplify_travel_heuristics(const EdgeGrid::Grid           &edge_grid,
                                                                                        const std::vector<TravelPoint> &travel,
                                                                                        const Polygons                 &boundaries);

    static size_t avoid_perimeters(const Polygons           &boundaries,
                                   const EdgeGrid::Grid     &grid,
                                   const Point              &start,
                                   const Point              &end,
                                   const bool                use_heuristics,
                                   std::vector<TravelPoint> *result_out);

    bool need_wipe(const GCode &gcodegen, const Line &original_travel, const Polyline &result_travel, const size_t intersection_count);

    // Slice of layer with elephant foot compensation
    ExPolygons     m_slice;
    // Collection of boundaries used for detection of crossing perimetrs for travels inside object
    Polygons       m_boundaries;
    // Collection of boundaries used for detection of crossing perimetrs for travels outside object
    Polygons       m_boundaries_external;
    // Bounding box of m_boundaries
    BoundingBox    m_bbox;
    // Bounding box of m_boundaries_external
    BoundingBox    m_bbox_external;
    EdgeGrid::Grid m_grid;
    EdgeGrid::Grid m_grid_external;

public:
    // this flag triggers the use of the external configuration space
    bool           use_external_mp { false };
    // just for the next travel move
    bool           use_external_mp_once { false };
    // this flag disables avoid_crossing_perimeters just for the next travel move
    // we enable it by default for the first travel move in print
    bool           disable_once { true };

    AvoidCrossingPerimeters() = default;

    Polyline travel_to(const GCode& gcodegen, const Point& point)
    {
        bool could_be_wipe_disabled;
        return this->travel_to(gcodegen, point, &could_be_wipe_disabled);
    }

    Polyline travel_to(const GCode& gcodegen, const Point& point, bool* could_be_wipe_disabled);

    void init_layer(const Layer &layer);
};

} // namespace Slic3r

#endif // slic3r_AvoidCrossingPerimeters_hpp_