    // Copyright (C) 2012  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #ifndef DLIB_LOAD_IMAGE_DaTASET_H__
    #define DLIB_LOAD_IMAGE_DaTASET_H__

    #include "load_image_dataset_abstract.h"
    #include "../misc_api.h"
    #include "../dir_nav.h"
    #include "../image_io.h"
    #include "../array.h"
    #include <vector>
    #include "../geometry.h"
    #include "image_dataset_metadata.h"
    #include <string>
    #include <set>
    #include "../image_processing/full_object_detection.h"

    namespace dlib
    {

    // ----------------------------------------------------------------------------------------

        class image_dataset_file
        {
        public:
            image_dataset_file(const std::string& filename)
            {
                _skip_empty_images = false;
                _have_parts = false;
                _filename = filename;
            }

            image_dataset_file boxes_match_label(
                const std::string& label
            ) const
            {
                image_dataset_file temp(*this);
                temp._labels.insert(label);
                return temp;
            }

            image_dataset_file skip_empty_images(
            ) const
            {
                image_dataset_file temp(*this);
                temp._skip_empty_images = true;
                return temp;
            }

            image_dataset_file boxes_have_parts(
            ) const
            {
                image_dataset_file temp(*this);
                temp._have_parts = true;
                return temp;
            }

            bool should_load_box (
                const image_dataset_metadata::box& box
            ) const
            {
                if (_have_parts && box.parts.size() == 0)
                    return false;
                if (_labels.size() == 0)
                    return true;
                if (_labels.count(box.label) != 0)
                    return true;
                return false;
            }

            const std::string& get_filename() const { return _filename; }
            bool should_skip_empty_images() const { return _skip_empty_images; }
            bool should_boxes_have_parts() const { return _have_parts; }
            const std::set<std::string>& get_selected_box_labels() const { return _labels; }

        private:
            std::string _filename;
            std::set<std::string> _labels;
            bool _skip_empty_images;
            bool _have_parts;
        };

    // ----------------------------------------------------------------------------------------

        template <
            typename image_type,
            typename MM
            >
        std::vector<std::vector<rectangle> > load_image_dataset (
            array<image_type,MM>& images,
            std::vector<std::vector<rectangle> >& object_locations,
            const image_dataset_file& source
        )
        {
            images.clear();
            object_locations.clear();
            const std::string old_working_dir = get_current_dir();

            std::vector<std::vector<rectangle> > ignored_rects;

            using namespace dlib::image_dataset_metadata;
            dataset data;
            load_image_dataset_metadata(data, source.get_filename());

            // Set the current directory to be the one that contains the
            // metadata file. We do this because the file might contain
            // file paths which are relative to this folder.
            set_current_dir(get_parent_directory(file(source.get_filename())));

            image_type img;
            std::vector<rectangle> rects, ignored;
            for (unsigned long i = 0; i < data.images.size(); ++i)
            {
                rects.clear();
                ignored.clear();
                for (unsigned long j = 0; j < data.images[i].boxes.size(); ++j)
                {
                    if (source.should_load_box(data.images[i].boxes[j]))
                    {
                        if (data.images[i].boxes[j].ignore)
                            ignored.push_back(data.images[i].boxes[j].rect);
                        else
                            rects.push_back(data.images[i].boxes[j].rect);
                    }
                }

                if (!source.should_skip_empty_images() || rects.size() != 0)
                {
                    object_locations.push_back(rects);
                    ignored_rects.push_back(ignored);
                    load_image(img, data.images[i].filename);
                    images.push_back(img);
                }
            }

            set_current_dir(old_working_dir);
            return ignored_rects;
        }

    // ----------------------------------------------------------------------------------------

    // ******* THIS FUNCTION IS DEPRECATED, you should use another version of load_image_dataset() *******
        template <
            typename image_type,
            typename MM
            >
        std::vector<std::vector<rectangle> > load_image_dataset (
            array<image_type,MM>& images,
            std::vector<std::vector<rectangle> >& object_locations,
            const std::string& filename,
            const std::string& label,
            bool skip_empty_images = false
        )
        {
            image_dataset_file f(filename);
            if (label.size() != 0)
                f = f.boxes_match_label(label);
            if (skip_empty_images)
                f = f.skip_empty_images();
            return load_image_dataset(images, object_locations, f);
        }

    // ----------------------------------------------------------------------------------------

        template <
            typename image_type,
            typename MM
            >
        std::vector<std::vector<rectangle> > load_image_dataset (
            array<image_type,MM>& images,
            std::vector<std::vector<rectangle> >& object_locations,
            const std::string& filename
        )
        {
            return load_image_dataset(images, object_locations, image_dataset_file(filename));
        }

    // ----------------------------------------------------------------------------------------
    // ----------------------------------------------------------------------------------------
    // ----------------------------------------------------------------------------------------

        template <
            typename image_type,
            typename MM
            >
        std::vector<std::vector<rectangle> > load_image_dataset (
            array<image_type,MM>& images,
            std::vector<std::vector<full_object_detection> >& object_locations,
            const image_dataset_file& source,
            std::vector<std::string>& parts_list
        )
        {
            parts_list.clear();
            images.clear();
            object_locations.clear();
            const std::string old_working_dir = get_current_dir();

            using namespace dlib::image_dataset_metadata;
            dataset data;
            load_image_dataset_metadata(data, source.get_filename());

            // Set the current directory to be the one that contains the
            // metadata file. We do this because the file might contain
            // file paths which are relative to this folder.
            set_current_dir(get_parent_directory(file(source.get_filename())));

            std::set<std::string> all_parts;

            // find out what parts are being used in the dataset.  Store results in all_parts.
            for (unsigned long i = 0; i < data.images.size(); ++i)
            {
                for (unsigned long j = 0; j < data.images[i].boxes.size(); ++j)
                {
                    if (source.should_load_box(data.images[i].boxes[j]))
                    {
                        const std::map<std::string,point>& parts = data.images[i].boxes[j].parts;
                        std::map<std::string,point>::const_iterator itr;

                        for (itr = parts.begin(); itr != parts.end(); ++itr)
                        {
                            all_parts.insert(itr->first);
                        }
                    }
                }
            }

            // make a mapping between part names and the integers [0, all_parts.size())
            std::map<std::string,int> parts_idx;
            for (std::set<std::string>::iterator i = all_parts.begin(); i != all_parts.end(); ++i)
            {
                parts_idx[*i] = parts_list.size();
                parts_list.push_back(*i);
            }

            std::vector<std::vector<rectangle> > ignored_rects;
            std::vector<rectangle> ignored;
            image_type img;
            std::vector<full_object_detection> object_dets;
            for (unsigned long i = 0; i < data.images.size(); ++i)
            {
                object_dets.clear();
                ignored.clear();
                for (unsigned long j = 0; j < data.images[i].boxes.size(); ++j)
                {
                    if (source.should_load_box(data.images[i].boxes[j]))
                    {
                        if (data.images[i].boxes[j].ignore)
                        {
                            ignored.push_back(data.images[i].boxes[j].rect);
                        }
                        else
                        {
                            std::vector<point> partlist(parts_idx.size(), OBJECT_PART_NOT_PRESENT);

                            // populate partlist with all the parts present in this box.
                            const std::map<std::string,point>& parts = data.images[i].boxes[j].parts;
                            std::map<std::string,point>::const_iterator itr;
                            for (itr = parts.begin(); itr != parts.end(); ++itr)
                            {
                                partlist[parts_idx[itr->first]] = itr->second;
                            }

                            object_dets.push_back(full_object_detection(data.images[i].boxes[j].rect, partlist));
                        }
                    }
                }

                if (!source.should_skip_empty_images() || object_dets.size() != 0)
                {
                    object_locations.push_back(object_dets);
                    ignored_rects.push_back(ignored);
                    load_image(img, data.images[i].filename);
                    images.push_back(img);
                }
            }

            set_current_dir(old_working_dir);

            return ignored_rects;
        }

    // ----------------------------------------------------------------------------------------

        template <
            typename image_type,
            typename MM
            >
        std::vector<std::vector<rectangle> > load_image_dataset (
            array<image_type,MM>& images,
            std::vector<std::vector<full_object_detection> >& object_locations,
            const image_dataset_file& source
        )
        {
            std::vector<std::string> parts_list;
            return load_image_dataset(images, object_locations, source, parts_list);
        }

    // ----------------------------------------------------------------------------------------

        template <
            typename image_type,
            typename MM
            >
        std::vector<std::vector<rectangle> > load_image_dataset (
            array<image_type,MM>& images,
            std::vector<std::vector<full_object_detection> >& object_locations,
            const std::string& filename
        )
        {
            std::vector<std::string> parts_list;
            return load_image_dataset(images, object_locations, image_dataset_file(filename), parts_list);
        }

    // ----------------------------------------------------------------------------------------

    }

    #endif // DLIB_LOAD_IMAGE_DaTASET_H__