    // Copyright (C) 2013  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #ifndef DLIB_SCAN_IMAGE_CuSTOM_H__
    #define DLIB_SCAN_IMAGE_CuSTOM_H__

    #include "scan_image_custom_abstract.h"
    #include "../matrix.h"
    #include "../geometry.h"
    #include <vector>
    #include "../image_processing/full_object_detection.h"

    namespace dlib
    {

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

        template <
            typename Feature_extractor_type
            >
        class scan_image_custom : noncopyable
        {

        public:

            typedef matrix<double,0,1> feature_vector_type;
            typedef Feature_extractor_type feature_extractor_type;

            scan_image_custom (
            );

            template <
                typename image_type
                >
            void load (
                const image_type& img
            );

            inline bool is_loaded_with_image (
            ) const;

            inline void copy_configuration(
                const feature_extractor_type& fe
            );

            const Feature_extractor_type& get_feature_extractor (
            ) const { return feats; }

            inline void copy_configuration (
                const scan_image_custom& item
            );

            inline long get_num_dimensions (
            ) const;

            void detect (
                const feature_vector_type& w,
                std::vector<std::pair<double, rectangle> >& dets,
                const double thresh
            ) const;

            void get_feature_vector (
                const full_object_detection& obj,
                feature_vector_type& psi
            ) const;

            full_object_detection get_full_object_detection (
                const rectangle& rect,
                const feature_vector_type& w
            ) const;

            const rectangle get_best_matching_rect (
                const rectangle& rect
            ) const;

            inline unsigned long get_num_detection_templates (
            ) const { return 1; }

            inline unsigned long get_num_movable_components_per_detection_template (
            ) const { return 0; }

            template <typename T>
            friend void serialize (
                const scan_image_custom<T>& item,
                std::ostream& out
            );

            template <typename T>
            friend void deserialize (
                scan_image_custom<T>& item,
                std::istream& in
            );

        private:
            static bool compare_pair_rect (
                const std::pair<double, rectangle>& a,
                const std::pair<double, rectangle>& b
            )
            {
                return a.first < b.first;
            }

            DLIB_MAKE_HAS_MEMBER_FUNCTION_TEST(
                has_compute_object_score,
                double,
                compute_object_score,
                ( const matrix<double,0,1>& w, const rectangle& obj) const
            );

            template <typename fe_type>
            typename enable_if<has_compute_object_score<fe_type> >::type compute_all_rect_scores (
                const fe_type& feats,
                const feature_vector_type& w,
                std::vector<std::pair<double, rectangle> >& dets,
                const double thresh
            ) const
            {
                for (unsigned long i = 0; i < search_rects.size(); ++i)
                {
                    const double score = feats.compute_object_score(w, search_rects[i]);
                    if (score >= thresh)
                    {
                        dets.push_back(std::make_pair(score, search_rects[i]));
                    }
                }
            }

            template <typename fe_type>
            typename disable_if<has_compute_object_score<fe_type> >::type compute_all_rect_scores (
                const fe_type& feats,
                const feature_vector_type& w,
                std::vector<std::pair<double, rectangle> >& dets,
                const double thresh
            ) const
            {
                matrix<double,0,1> psi(w.size());
                psi = 0;
                double prev_dot = 0;
                for (unsigned long i = 0; i < search_rects.size(); ++i)
                {
                    // Reset these back to zero every so often to avoid the accumulation of
                    // rounding error.  Note that the only reason we do this loop in this
                    // complex way is to avoid needing to zero the psi vector every iteration.
                    if ((i%500) == 499)
                    {
                        psi = 0;
                        prev_dot = 0;
                    }

                    feats.get_feature_vector(search_rects[i], psi);
                    const double cur_dot = dot(psi, w);
                    const double score = cur_dot - prev_dot;
                    if (score >= thresh)
                    {
                        dets.push_back(std::make_pair(score, search_rects[i]));
                    }
                    prev_dot = cur_dot;
                }
            }

            feature_extractor_type feats;
            std::vector<rectangle> search_rects;
            bool loaded_with_image;
        };

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

        template <typename T>
        void serialize (
            const scan_image_custom<T>& item,
            std::ostream& out
        )
        {
            int version = 1;
            serialize(version, out);
            serialize(item.feats, out);
            serialize(item.search_rects, out);
            serialize(item.loaded_with_image, out);
            serialize(item.get_num_dimensions(), out);
        }

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

        template <typename T>
        void deserialize (
            scan_image_custom<T>& item,
            std::istream& in
        )
        {
            int version = 0;
            deserialize(version, in);
            if (version != 1)
                throw serialization_error("Unsupported version found when deserializing a scan_image_custom object.");

            deserialize(item.feats, in);
            deserialize(item.search_rects, in);
            deserialize(item.loaded_with_image, in);

            // When developing some feature extractor, it's easy to accidentally change its
            // number of dimensions and then try to deserialize data from an older version of
            // your extractor into the current code.  This check is here to catch that kind of
            // user error.
            long dims;
            deserialize(dims, in);
            if (item.get_num_dimensions() != dims)
                throw serialization_error("Number of dimensions in serialized scan_image_custom doesn't match the expected number.");
        }

    // ----------------------------------------------------------------------------------------
    // ----------------------------------------------------------------------------------------
    //                         scan_image_custom member functions
    // ----------------------------------------------------------------------------------------
    // ----------------------------------------------------------------------------------------

        template <
            typename Feature_extractor_type
            >
        scan_image_custom<Feature_extractor_type>::
        scan_image_custom (
        ) :
            loaded_with_image(false)
        {
        }

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

        template <
            typename Feature_extractor_type
            >
        template <
            typename image_type
            >
        void scan_image_custom<Feature_extractor_type>::
        load (
            const image_type& img
        )
        {
            feats.load(img, search_rects);
            loaded_with_image = true;
        }

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

        template <
            typename Feature_extractor_type
            >
        bool scan_image_custom<Feature_extractor_type>::
        is_loaded_with_image (
        ) const
        {
            return loaded_with_image;
        }

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

        template <
            typename Feature_extractor_type
            >
        void scan_image_custom<Feature_extractor_type>::
        copy_configuration(
            const feature_extractor_type& fe
        )
        {
            feats.copy_configuration(fe);
        }

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

        template <
            typename Feature_extractor_type
            >
        void scan_image_custom<Feature_extractor_type>::
        copy_configuration (
            const scan_image_custom& item
        )
        {
            feats.copy_configuration(item.feats);
        }

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

        template <
            typename Feature_extractor_type
            >
        long scan_image_custom<Feature_extractor_type>::
        get_num_dimensions (
        ) const
        {
            return feats.get_num_dimensions();
        }

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

        template <
            typename Feature_extractor_type
            >
        void scan_image_custom<Feature_extractor_type>::
        detect (
            const feature_vector_type& w,
            std::vector<std::pair<double, rectangle> >& dets,
            const double thresh
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(is_loaded_with_image() &&
                        w.size() >= get_num_dimensions(),
                "\t void scan_image_custom::detect()"
                << "\n\t Invalid inputs were given to this function "
                << "\n\t is_loaded_with_image(): " << is_loaded_with_image()
                << "\n\t w.size():               " << w.size()
                << "\n\t get_num_dimensions():   " << get_num_dimensions()
                << "\n\t this: " << this
                );

            dets.clear();
            compute_all_rect_scores(feats, w,dets,thresh);
            std::sort(dets.rbegin(), dets.rend(), compare_pair_rect);
        }

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

        template <
            typename Feature_extractor_type
            >
        const rectangle scan_image_custom<Feature_extractor_type>::
        get_best_matching_rect (
            const rectangle& rect
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(is_loaded_with_image(),
                "\t const rectangle scan_image_custom::get_best_matching_rect()"
                << "\n\t Invalid inputs were given to this function "
                << "\n\t is_loaded_with_image(): " << is_loaded_with_image()
                << "\n\t this: " << this
                );

            double best_score = -1;
            rectangle best_rect;
            for (unsigned long i = 0; i < search_rects.size(); ++i)
            {
                const double score = (rect.intersect(search_rects[i])).area()/(double)(rect+search_rects[i]).area();
                if (score > best_score)
                {
                    best_score = score;
                    best_rect = search_rects[i];
                }
            }
            return best_rect;
        }

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

        template <
            typename Feature_extractor_type
            >
        full_object_detection scan_image_custom<Feature_extractor_type>::
        get_full_object_detection (
            const rectangle& rect,
            const feature_vector_type& /*w*/
        ) const
        {
            return full_object_detection(rect);
        }

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

        template <
            typename Feature_extractor_type
            >
        void scan_image_custom<Feature_extractor_type>::
        get_feature_vector (
            const full_object_detection& obj,
            feature_vector_type& psi
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(is_loaded_with_image() &&
                        psi.size() >= get_num_dimensions() &&
                        obj.num_parts() == 0,
                "\t void scan_image_custom::get_feature_vector()"
                << "\n\t Invalid inputs were given to this function "
                << "\n\t is_loaded_with_image(): " << is_loaded_with_image()
                << "\n\t psi.size():             " << psi.size()
                << "\n\t get_num_dimensions():   " << get_num_dimensions()
                << "\n\t obj.num_parts():                            " << obj.num_parts()
                << "\n\t this: " << this
                );

            feats.get_feature_vector(get_best_matching_rect(obj.get_rect()), psi);
        }

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

    }

    #endif // DLIB_SCAN_IMAGE_CuSTOM_H__