#ifndef slic3r_ExtrusionProcessor_hpp_
#define slic3r_ExtrusionProcessor_hpp_

// This algorithm is copied from PrusaSlicer, original author is Pavel Mikus(pavel.mikus.mail@seznam.cz)

#include "../AABBTreeLines.hpp"
//#include "../SupportSpotsGenerator.hpp"
#include "../libslic3r.h"
#include "../ExtrusionEntity.hpp"
#include "../Layer.hpp"
#include "../Point.hpp"
#include "../SVG.hpp"
#include "../BoundingBox.hpp"
#include "../Polygon.hpp"
#include "../ClipperUtils.hpp"
#include "../Flow.hpp"
#include "../Config.hpp"

#include <algorithm>
#include <cmath>
#include <cstddef>
#include <limits>
#include <numeric>
#include <unordered_map>
#include <utility>
#include <vector>

namespace Slic3r {

struct ExtendedPoint
{
    Vec2d position;
    float distance;
    float curvature;
};

template<bool SCALED_INPUT, bool ADD_INTERSECTIONS, bool PREV_LAYER_BOUNDARY_OFFSET, bool SIGNED_DISTANCE, typename POINTS, typename L>
std::vector<ExtendedPoint> estimate_points_properties(const POINTS                           &input_points,
                                                      const AABBTreeLines::LinesDistancer<L> &unscaled_prev_layer,
                                                      float                                   flow_width,
                                                      float                                   max_line_length = -1.0f)
{
    bool   looped     = input_points.front() == input_points.back();
    std::function<size_t(size_t,size_t)> get_prev_index = [](size_t idx, size_t count) {
        if (idx > 0) {
            return idx - 1;
        } else
            return idx;
    };
    if (looped) {
        get_prev_index = [](size_t idx, size_t count) {
            if (idx == 0)
                idx = count;
            return --idx;
        };
    };
    std::function<size_t(size_t,size_t)> get_next_index = [](size_t idx, size_t size) {
        if (idx + 1 < size) {
            return idx + 1;
        } else
            return idx;
    };
    if (looped) {
        get_next_index = [](size_t idx, size_t count) {
            if (++idx == count)
                idx = 0;
            return idx;
        };
    };

    using P = typename POINTS::value_type;

    using AABBScalar = typename AABBTreeLines::LinesDistancer<L>::Scalar;
    if (input_points.empty())
        return {};
    float boundary_offset = PREV_LAYER_BOUNDARY_OFFSET ? 0.5 * flow_width : 0.0f;
    auto  maybe_unscale   = [](const P &p) { return SCALED_INPUT ? unscaled(p) : p.template cast<double>(); };

    std::vector<ExtendedPoint> points;
    points.reserve(input_points.size() * (ADD_INTERSECTIONS ? 1.5 : 1));

    {
        ExtendedPoint start_point{maybe_unscale(input_points.front())};
        auto [distance, nearest_line,
              x] = unscaled_prev_layer.template distance_from_lines_extra<SIGNED_DISTANCE>(start_point.position.cast<AABBScalar>());
        start_point.distance = distance + boundary_offset;
        points.push_back(start_point);
    }
    for (size_t i = 1; i < input_points.size(); i++) {
        ExtendedPoint next_point{maybe_unscale(input_points[i])};
        auto [distance, nearest_line,
              x] = unscaled_prev_layer.template distance_from_lines_extra<SIGNED_DISTANCE>(next_point.position.cast<AABBScalar>());
        next_point.distance = distance + boundary_offset;

        if (ADD_INTERSECTIONS &&
            ((points.back().distance > boundary_offset + EPSILON) != (next_point.distance > boundary_offset + EPSILON))) {
            const ExtendedPoint &prev_point    = points.back();
            auto                 intersections = unscaled_prev_layer.template intersections_with_line<true>(
                L{prev_point.position.cast<AABBScalar>(), next_point.position.cast<AABBScalar>()});
            for (const auto &intersection : intersections) {
                ExtendedPoint p{};
                p.position = intersection.first.template cast<double>();
                p.distance = boundary_offset;
                points.push_back(p);
            }
        }
        points.push_back(next_point);
    }

    if (PREV_LAYER_BOUNDARY_OFFSET && ADD_INTERSECTIONS) {
        std::vector<ExtendedPoint> new_points;
        new_points.reserve(points.size() * 2);
        new_points.push_back(points.front());
        for (int point_idx = 0; point_idx < int(points.size()) - 1; ++point_idx) {
            const ExtendedPoint &curr = points[point_idx];
            const ExtendedPoint &next = points[point_idx + 1];

            if ((curr.distance > -boundary_offset && curr.distance < boundary_offset + 2.0f) ||
                (next.distance > -boundary_offset && next.distance < boundary_offset + 2.0f)) {
                double line_len = (next.position - curr.position).norm();
                if (line_len > 4.0f) {
                    double a0 = std::clamp((curr.distance + 3 * boundary_offset) / line_len, 0.0, 1.0);
                    double a1 = std::clamp(1.0f - (next.distance + 3 * boundary_offset) / line_len, 0.0, 1.0);
                    double t0 = std::min(a0, a1);
                    double t1 = std::max(a0, a1);

                    if (t0 < 1.0) {
                        auto p0     = curr.position + t0 * (next.position - curr.position);
                        auto [p0_dist, p0_near_l,
                              p0_x] = unscaled_prev_layer.template distance_from_lines_extra<SIGNED_DISTANCE>(p0.cast<AABBScalar>());
                        ExtendedPoint new_p{};
                        new_p.position = p0;
                        new_p.distance = float(p0_dist + boundary_offset);
                        new_points.push_back(new_p);
                    }
                    if (t1 > 0.0) {
                        auto p1     = curr.position + t1 * (next.position - curr.position);
                        auto [p1_dist, p1_near_l,
                              p1_x] = unscaled_prev_layer.template distance_from_lines_extra<SIGNED_DISTANCE>(p1.cast<AABBScalar>());
                        ExtendedPoint new_p{};
                        new_p.position = p1;
                        new_p.distance = float(p1_dist + boundary_offset);
                        new_points.push_back(new_p);
                    }
                }
            }
            new_points.push_back(next);
        }
        points = std::move(new_points);
    }

    if (max_line_length > 0) {
        std::vector<ExtendedPoint> new_points;
        new_points.reserve(points.size() * 2);
        {
            for (size_t i = 0; i + 1 < points.size(); i++) {
                const ExtendedPoint &curr = points[i];
                const ExtendedPoint &next = points[i + 1];
                new_points.push_back(curr);
                double len             = (next.position - curr.position).squaredNorm();
                double t               = sqrt((max_line_length * max_line_length) / len);
                size_t new_point_count = 1.0 / t;
                for (size_t j = 1; j < new_point_count + 1; j++) {
                    Vec2d pos  = curr.position * (1.0 - j * t) + next.position * (j * t);
                    auto [p_dist, p_near_l,
                          p_x] = unscaled_prev_layer.template distance_from_lines_extra<SIGNED_DISTANCE>(pos.cast<AABBScalar>());
                    ExtendedPoint new_p{};
                    new_p.position = pos;
                    new_p.distance = float(p_dist + boundary_offset);
                    new_points.push_back(new_p);
                }
            }
            new_points.push_back(points.back());
        }
        points = std::move(new_points);
    }

    float accumulated_distance = 0;
    std::vector<float> distances_for_curvature(points.size());
    for (size_t point_idx = 0; point_idx < points.size(); ++point_idx) {
        const ExtendedPoint &a = points[point_idx];
        const ExtendedPoint &b = points[get_prev_index(point_idx, points.size())];

        distances_for_curvature[point_idx] = (b.position - a.position).norm();
        accumulated_distance += distances_for_curvature[point_idx];
    }

    if (accumulated_distance > EPSILON)
        for (float window_size : {3.0f, 9.0f, 16.0f}) {
            for (int point_idx = 0; point_idx < int(points.size()); ++point_idx) {
                ExtendedPoint &current = points[point_idx];

                Vec2d back_position = current.position;
                {
                    size_t back_point_index = point_idx;
                    float  dist_backwards   = 0;
                    while (dist_backwards < window_size * 0.5 && back_point_index != get_prev_index(back_point_index, points.size())) {
                        float line_dist = distances_for_curvature[get_prev_index(back_point_index, points.size())];
                        if (dist_backwards + line_dist > window_size * 0.5) {
                            back_position = points[back_point_index].position +
                                            (window_size * 0.5 - dist_backwards) *
                                                (points[get_prev_index(back_point_index, points.size())].position -
                                                 points[back_point_index].position)
                                                    .normalized();
                            dist_backwards += window_size * 0.5 - dist_backwards + EPSILON;
                        } else {
                            dist_backwards += line_dist;
                            back_point_index = get_prev_index(back_point_index, points.size());
                        }
                    }
                }

                Vec2d front_position = current.position;
                {
                    size_t front_point_index = point_idx;
                    float  dist_forwards     = 0;
                    while (dist_forwards < window_size * 0.5 && front_point_index != get_next_index(front_point_index, points.size())) {
                        float line_dist = distances_for_curvature[front_point_index];
                        if (dist_forwards + line_dist > window_size * 0.5) {
                            front_position = points[front_point_index].position +
                                             (window_size * 0.5 - dist_forwards) *
                                                 (points[get_next_index(front_point_index, points.size())].position -
                                                  points[front_point_index].position)
                                                     .normalized();
                            dist_forwards += window_size * 0.5 - dist_forwards + EPSILON;
                        } else {
                            dist_forwards += line_dist;
                            front_point_index = get_next_index(front_point_index, points.size());
                        }
                    }
                }

                float new_curvature = angle(current.position - back_position, front_position - current.position) / window_size;
                if (abs(current.curvature) < abs(new_curvature)) {
                    current.curvature = new_curvature;
                }
            }
        }

    return points;
}

struct ProcessedPoint
{
    Point p;
    float speed = 1.0f;
    float overlap = 1.0f;
};

class ExtrusionQualityEstimator
{
    std::unordered_map<const PrintObject *, AABBTreeLines::LinesDistancer<Linef>> prev_layer_boundaries;
    std::unordered_map<const PrintObject *, AABBTreeLines::LinesDistancer<Linef>> next_layer_boundaries;
    std::unordered_map<const PrintObject *, AABBTreeLines::LinesDistancer<CurledLine>> prev_curled_extrusions;
    std::unordered_map<const PrintObject *, AABBTreeLines::LinesDistancer<CurledLine>> next_curled_extrusions;
    const PrintObject                                                            *current_object;

public:
    void set_current_object(const PrintObject *object) { current_object = object; }

    void prepare_for_new_layer(const PrintObject * obj, const Layer *layer)
    {
        if (layer == nullptr) return;
        const PrintObject *object = obj;
        prev_layer_boundaries[object] = next_layer_boundaries[object];
        next_layer_boundaries[object] = AABBTreeLines::LinesDistancer<Linef>{to_unscaled_linesf(layer->lslices)};
        prev_curled_extrusions[object] = next_curled_extrusions[object];
        next_curled_extrusions[object] = AABBTreeLines::LinesDistancer<CurledLine>{layer->curled_lines};
    }

    std::vector<ProcessedPoint> estimate_extrusion_quality(const ExtrusionPath                &path,
                                                           const ConfigOptionPercents         &overlaps,
                                                           const ConfigOptionFloatsOrPercents &speeds,
                                                           float                               ext_perimeter_speed,
                                                           float                               original_speed,
                                                           bool								   slowdown_for_curled_edges)
    {
        size_t                               speed_sections_count = std::min(overlaps.values.size(), speeds.values.size());
        std::vector<std::pair<float, float>> speed_sections;
        
        
        
        for (size_t i = 0; i < speed_sections_count; i++) {
            float distance = path.width * (1.0 - (overlaps.get_at(i) / 100.0));
            float speed    = speeds.get_at(i).percent ? (ext_perimeter_speed * speeds.get_at(i).value / 100.0) : speeds.get_at(i).value;
            speed_sections.push_back({distance, speed});
        }
        std::sort(speed_sections.begin(), speed_sections.end(),
                  [](const std::pair<float, float> &a, const std::pair<float, float> &b) { 
                    if (a.first == b.first) {
                        return a.second > b.second;
                    }
                    return a.first < b.first; });

        std::pair<float, float> last_section{INFINITY, 0};
        for (auto &section : speed_sections) {
            if (section.first == last_section.first) {
                section.second = last_section.second;
            } else {
                last_section = section;
            }
        }

        std::vector<ExtendedPoint> extended_points =
            estimate_points_properties<true, true, true, true>(path.polyline.points, prev_layer_boundaries[current_object], path.width);
        const auto width_inv = 1.0f / path.width;
        std::vector<ProcessedPoint> processed_points;
        processed_points.reserve(extended_points.size());
        for (size_t i = 0; i < extended_points.size(); i++) {
            const ExtendedPoint &curr = extended_points[i];
            const ExtendedPoint &next = extended_points[i + 1 < extended_points.size() ? i + 1 : i];
            
            float artificial_distance_to_curled_lines = 0.0;
            if(slowdown_for_curled_edges) {
            	// The following code artifically increases the distance to provide slowdown for extrusions that are over curled lines
            	const double dist_limit = 10.0 * path.width;
				{
				Vec2d middle = 0.5 * (curr.position + next.position);
				auto line_indices = prev_curled_extrusions[current_object].all_lines_in_radius(Point::new_scale(middle), scale_(dist_limit));
					if (!line_indices.empty()) {
						double len   = (next.position - curr.position).norm();
						// For long lines, there is a problem with the additional slowdown. If by accident, there is small curled line near the middle of this long line
                    	//  The whole segment gets slower unnecesarily. For these long lines, we do additional check whether it is worth slowing down.
                    	// NOTE that this is still quite rough approximation, e.g. we are still checking lines only near the middle point
                    	// TODO maybe split the lines into smaller segments before running this alg? but can be demanding, and GCode will be huge
                    	if (len > 8) {
                        	Vec2d dir   = Vec2d(next.position - curr.position) / len;
                        	Vec2d right = Vec2d(-dir.y(), dir.x());

                        	Polygon box_of_influence = {
                            	scaled(Vec2d(curr.position + right * dist_limit)),
                            	scaled(Vec2d(next.position + right * dist_limit)),
                            	scaled(Vec2d(next.position - right * dist_limit)),
                            	scaled(Vec2d(curr.position - right * dist_limit)),
                        	};

                        	double projected_lengths_sum = 0;
                        	for (size_t idx : line_indices) {
                            	const CurledLine &line   = prev_curled_extrusions[current_object].get_line(idx);
                            	Lines             inside = intersection_ln({{line.a, line.b}}, {box_of_influence});
                            	if (inside.empty())
                                	continue;
                            	double projected_length = abs(dir.dot(unscaled(Vec2d((inside.back().b - inside.back().a).cast<double>()))));
                            	projected_lengths_sum += projected_length;
                        	}
                        	if (projected_lengths_sum < 0.4 * len) {
                            	line_indices.clear();
                        	}
                    	}
                    
                    	for (size_t idx : line_indices) {
                        	const CurledLine &line                 = prev_curled_extrusions[current_object].get_line(idx);
                        	float             distance_from_curled = unscaled(line_alg::distance_to(line, Point::new_scale(middle)));
                        	float             dist                 = path.width * (1.0 - (distance_from_curled / dist_limit)) *
                                     (1.0 - (distance_from_curled / dist_limit)) *
                                     (line.curled_height / (path.height * 10.0f)); // max_curled_height_factor from SupportSpotGenerator
                        	artificial_distance_to_curled_lines = std::max(artificial_distance_to_curled_lines, dist);
                    	}
					}
				}
			}	

            auto calculate_speed = [&speed_sections, &original_speed](float distance) {
                float final_speed;
                if (distance <= speed_sections.front().first) {
                    final_speed = original_speed;
                } else if (distance >= speed_sections.back().first) {
                    final_speed = speed_sections.back().second;
                } else {
                    size_t section_idx = 0;
                    while (distance > speed_sections[section_idx + 1].first) {
                        section_idx++;
                    }
                    float t = (distance - speed_sections[section_idx].first) /
                              (speed_sections[section_idx + 1].first - speed_sections[section_idx].first);
                    t           = std::clamp(t, 0.0f, 1.0f);
                    final_speed = (1.0f - t) * speed_sections[section_idx].second + t * speed_sections[section_idx + 1].second;
                }
                return final_speed;
            };
            
            float extrusion_speed = std::min(calculate_speed(curr.distance), calculate_speed(next.distance));
            if(slowdown_for_curled_edges) {
                float curled_speed = calculate_speed(artificial_distance_to_curled_lines);
            	extrusion_speed       = std::min(curled_speed, extrusion_speed); // adjust extrusion speed based on what is smallest - the calculated overhang speed or the artificial curled speed
            }
            
            float overlap = std::min(1 - (curr.distance+artificial_distance_to_curled_lines) * width_inv, 1 - (next.distance+artificial_distance_to_curled_lines) * width_inv);
			
            processed_points.push_back({ scaled(curr.position), extrusion_speed, overlap });
        }
        return processed_points;
    }
};

} // namespace Slic3r

#endif // slic3r_ExtrusionProcessor_hpp_
