    // Copyright (C) 2011  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #ifndef DLIB_OBJECT_DeTECTOR_H__
    #define DLIB_OBJECT_DeTECTOR_H__

    #include "object_detector_abstract.h"
    #include "../geometry.h"
    #include <vector>
    #include "box_overlap_testing.h"
    #include "full_object_detection.h"

    namespace dlib
    {

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

        template <typename image_scanner_type>
        struct processed_weight_vector
        {
            processed_weight_vector(){}

            typedef typename image_scanner_type::feature_vector_type feature_vector_type;

            void init (
                const image_scanner_type&
            )
            /*!
                requires
                    - w has already been assigned its value.  Note that the point of this
                      function is to allow an image scanner to overload the
                      processed_weight_vector template and provide some different kind of
                      object as the output of get_detect_argument().  For example, the
                      scan_fhog_pyramid object uses an overload that causes
                      get_detect_argument() to return the special fhog_filterbank object
                      instead of a feature_vector_type.  This avoids needing to construct the
                      fhog_filterbank during each call to detect and therefore speeds up
                      detection.
            !*/
            {}

            // return the first argument to image_scanner_type::detect()
            const feature_vector_type& get_detect_argument() const { return w; }

            feature_vector_type w;
        };

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

        template <
            typename image_scanner_type
            >
        class object_detector
        {
        public:
            typedef typename image_scanner_type::feature_vector_type feature_vector_type;

            object_detector (
            );

            object_detector (
                const object_detector& item
            );

            object_detector (
                const image_scanner_type& scanner_,
                const test_box_overlap& overlap_tester_,
                const feature_vector_type& w_
            );

            object_detector (
                const image_scanner_type& scanner_,
                const test_box_overlap& overlap_tester_,
                const std::vector<feature_vector_type>& w_
            );

            explicit object_detector (
                const std::vector<object_detector>& detectors
            );

            unsigned long num_detectors (
            ) const { return w.size(); }

            const feature_vector_type& get_w (
                unsigned long idx = 0
            ) const { return w[idx].w; }

            const test_box_overlap& get_overlap_tester (
            ) const;

            const image_scanner_type& get_scanner (
            ) const;

            object_detector& operator= (
                const object_detector& item
            );

            template <
                typename image_type
                >
            std::vector<rectangle> operator() (
                const image_type& img,
                double adjust_threshold = 0
            );

            template <
                typename image_type
                >
            void operator() (
                const image_type& img,
                std::vector<std::pair<double, rectangle> >& final_dets,
                double adjust_threshold = 0
            );

            template <
                typename image_type
                >
            void operator() (
                const image_type& img,
                std::vector<std::pair<double, full_object_detection> >& final_dets,
                double adjust_threshold = 0
            );

            template <
                typename image_type
                >
            void operator() (
                const image_type& img,
                std::vector<full_object_detection>& final_dets,
                double adjust_threshold = 0
            );

            struct rect_detection
            {
                double detection_confidence;
                unsigned long weight_index;
                rectangle rect;

                bool operator<(const rect_detection& item) const { return detection_confidence < item.detection_confidence; }
            };

            struct full_detection
            {
                double detection_confidence;
                unsigned long weight_index;
                full_object_detection rect;

                bool operator<(const full_detection& item) const { return detection_confidence < item.detection_confidence; }
            };

            template <
                typename image_type
                >
            void operator() (
                const image_type& img,
                std::vector<rect_detection>& final_dets,
                double adjust_threshold = 0
            );

            template <
                typename image_type
                >
            void operator() (
                const image_type& img,
                std::vector<full_detection>& final_dets,
                double adjust_threshold = 0
            );

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

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

        private:

            bool overlaps_any_box (
                const std::vector<rect_detection>& rects,
                const dlib::rectangle& rect
            ) const
            {
                for (unsigned long i = 0; i < rects.size(); ++i)
                {
                    if (boxes_overlap(rects[i].rect, rect))
                        return true;
                }
                return false;
            }

            test_box_overlap boxes_overlap;
            std::vector<processed_weight_vector<image_scanner_type> > w;
            image_scanner_type scanner;
        };

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

        template <typename T>
        void serialize (
            const object_detector<T>& item,
            std::ostream& out
        )
        {
            int version = 2;
            serialize(version, out);

            T scanner;
            scanner.copy_configuration(item.scanner);
            serialize(scanner, out);
            serialize(item.boxes_overlap, out);
            // serialize all the weight vectors
            serialize(item.w.size(), out);
            for (unsigned long i = 0; i < item.w.size(); ++i)
                serialize(item.w[i].w, out);
        }

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

        template <typename T>
        void deserialize (
            object_detector<T>& item,
            std::istream& in
        )
        {
            int version = 0;
            deserialize(version, in);
            if (version == 1)
            {
                deserialize(item.scanner, in);
                item.w.resize(1);
                deserialize(item.w[0].w, in);
                item.w[0].init(item.scanner);
                deserialize(item.boxes_overlap, in);
            }
            else if (version == 2)
            {
                deserialize(item.scanner, in);
                deserialize(item.boxes_overlap, in);
                unsigned long num_detectors = 0;
                deserialize(num_detectors, in);
                item.w.resize(num_detectors);
                for (unsigned long i = 0; i < item.w.size(); ++i)
                {
                    deserialize(item.w[i].w, in);
                    item.w[i].init(item.scanner);
                }
            }
            else
            {
                throw serialization_error("Unexpected version encountered while deserializing a dlib::object_detector object.");
            }
        }

    // ----------------------------------------------------------------------------------------
    // ----------------------------------------------------------------------------------------
    //                      object_detector member functions
    // ----------------------------------------------------------------------------------------
    // ----------------------------------------------------------------------------------------

        template <
            typename image_scanner_type
            >
        object_detector<image_scanner_type>::
        object_detector (
        )
        {
        }

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

        template <
            typename image_scanner_type
            >
        object_detector<image_scanner_type>::
        object_detector (
            const object_detector& item
        )
        {
            boxes_overlap = item.boxes_overlap;
            w = item.w;
            scanner.copy_configuration(item.scanner);
        }

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

        template <
            typename image_scanner_type
            >
        object_detector<image_scanner_type>::
        object_detector (
            const image_scanner_type& scanner_,
            const test_box_overlap& overlap_tester,
            const feature_vector_type& w_
        ) :
            boxes_overlap(overlap_tester)
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(scanner_.get_num_detection_templates() > 0 &&
                        w_.size() == scanner_.get_num_dimensions() + 1,
                "\t object_detector::object_detector(scanner_,overlap_tester,w_)"
                << "\n\t Invalid inputs were given to this function "
                << "\n\t scanner_.get_num_detection_templates(): " << scanner_.get_num_detection_templates()
                << "\n\t w_.size():                     " << w_.size()
                << "\n\t scanner_.get_num_dimensions(): " << scanner_.get_num_dimensions()
                << "\n\t this: " << this
                );

            scanner.copy_configuration(scanner_);
            w.resize(1);
            w[0].w = w_;
            w[0].init(scanner);
        }

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

        template <
            typename image_scanner_type
            >
        object_detector<image_scanner_type>::
        object_detector (
            const image_scanner_type& scanner_,
            const test_box_overlap& overlap_tester,
            const std::vector<feature_vector_type>& w_
        ) :
            boxes_overlap(overlap_tester)
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(scanner_.get_num_detection_templates() > 0 && w_.size() > 0,
                "\t object_detector::object_detector(scanner_,overlap_tester,w_)"
                << "\n\t Invalid inputs were given to this function "
                << "\n\t scanner_.get_num_detection_templates(): " << scanner_.get_num_detection_templates()
                << "\n\t w_.size():                     " << w_.size()
                << "\n\t this: " << this
                );

    #ifdef ENABLE_ASSERTS
            for (unsigned long i = 0; i < w_.size(); ++i)
            {
                DLIB_ASSERT(w_[i].size() == scanner_.get_num_dimensions() + 1,
                    "\t object_detector::object_detector(scanner_,overlap_tester,w_)"
                    << "\n\t Invalid inputs were given to this function "
                    << "\n\t scanner_.get_num_detection_templates(): " << scanner_.get_num_detection_templates()
                    << "\n\t w_["<<i<<"].size():                     " << w_[i].size()
                    << "\n\t scanner_.get_num_dimensions(): " << scanner_.get_num_dimensions()
                    << "\n\t this: " << this
                    );
            }
    #endif

            scanner.copy_configuration(scanner_);
            w.resize(w_.size());
            for (unsigned long i = 0; i < w.size(); ++i)
            {
                w[i].w = w_[i];
                w[i].init(scanner);
            }
        }

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

        template <
            typename image_scanner_type
            >
        object_detector<image_scanner_type>::
        object_detector (
            const std::vector<object_detector>& detectors
        )
        {
            DLIB_ASSERT(detectors.size() != 0,
                    "\t object_detector::object_detector(detectors)"
                    << "\n\t Invalid inputs were given to this function "
                    << "\n\t this: " << this
            );
            std::vector<feature_vector_type> weights;
            weights.reserve(detectors.size());
            for (unsigned long i = 0; i < detectors.size(); ++i)
            {
                for (unsigned long j = 0; j < detectors[i].num_detectors(); ++j)
                    weights.push_back(detectors[i].get_w(j));
            }

            *this = object_detector(detectors[0].get_scanner(), detectors[0].get_overlap_tester(), weights);
        }

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

        template <
            typename image_scanner_type
            >
        object_detector<image_scanner_type>& object_detector<image_scanner_type>::
        operator= (
            const object_detector& item
        )
        {
            if (this == &item)
                return *this;

            boxes_overlap = item.boxes_overlap;
            w = item.w;
            scanner.copy_configuration(item.scanner);
            return *this;
        }

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

        template <
            typename image_scanner_type
            >
        template <
            typename image_type
            >
        void object_detector<image_scanner_type>::
        operator() (
            const image_type& img,
            std::vector<rect_detection>& final_dets,
            double adjust_threshold
        )
        {
            scanner.load(img);
            std::vector<std::pair<double, rectangle> > dets;
            std::vector<rect_detection> dets_accum;
            for (unsigned long i = 0; i < w.size(); ++i)
            {
                const double thresh = w[i].w(scanner.get_num_dimensions());
                scanner.detect(w[i].get_detect_argument(), dets, thresh + adjust_threshold);
                for (unsigned long j = 0; j < dets.size(); ++j)
                {
                    rect_detection temp;
                    temp.detection_confidence = dets[j].first-thresh;
                    temp.weight_index = i;
                    temp.rect = dets[j].second;
                    dets_accum.push_back(temp);
                }
            }

            // Do non-max suppression
            final_dets.clear();
            for (unsigned long i = 0; i < dets_accum.size(); ++i)
            {
                if (overlaps_any_box(final_dets, dets_accum[i].rect))
                    continue;

                final_dets.push_back(dets_accum[i]);
            }
            std::sort(final_dets.rbegin(), final_dets.rend());
        }

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

        template <
            typename image_scanner_type
            >
        template <
            typename image_type
            >
        void object_detector<image_scanner_type>::
        operator() (
            const image_type& img,
            std::vector<full_detection>& final_dets,
            double adjust_threshold
        )
        {
            std::vector<rect_detection> dets;
            (*this)(img,dets,adjust_threshold);

            final_dets.resize(dets.size());

            // convert all the rectangle detections into full_object_detections.
            for (unsigned long i = 0; i < dets.size(); ++i)
            {
                final_dets[i].detection_confidence = dets[i].detection_confidence;
                final_dets[i].weight_index = dets[i].weight_index;
                final_dets[i].rect = scanner.get_full_object_detection(dets[i].rect, w[dets[i].weight_index].w);
            }
        }

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

        template <
            typename image_scanner_type
            >
        template <
            typename image_type
            >
        std::vector<rectangle> object_detector<image_scanner_type>::
        operator() (
            const image_type& img,
            double adjust_threshold
        )
        {
            std::vector<rect_detection> dets;
            (*this)(img,dets,adjust_threshold);

            std::vector<rectangle> final_dets(dets.size());
            for (unsigned long i = 0; i < dets.size(); ++i)
                final_dets[i] = dets[i].rect;

            return final_dets;
        }

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

        template <
            typename image_scanner_type
            >
        template <
            typename image_type
            >
        void object_detector<image_scanner_type>::
        operator() (
            const image_type& img,
            std::vector<std::pair<double, rectangle> >& final_dets,
            double adjust_threshold
        )
        {
            std::vector<rect_detection> dets;
            (*this)(img,dets,adjust_threshold);

            final_dets.resize(dets.size());
            for (unsigned long i = 0; i < dets.size(); ++i)
                final_dets[i] = std::make_pair(dets[i].detection_confidence,dets[i].rect);
        }

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

        template <
            typename image_scanner_type
            >
        template <
            typename image_type
            >
        void object_detector<image_scanner_type>::
        operator() (
            const image_type& img,
            std::vector<std::pair<double, full_object_detection> >& final_dets,
            double adjust_threshold
        )
        {
            std::vector<rect_detection> dets;
            (*this)(img,dets,adjust_threshold);

            final_dets.clear();
            final_dets.reserve(dets.size());

            // convert all the rectangle detections into full_object_detections.
            for (unsigned long i = 0; i < dets.size(); ++i)
            {
                final_dets.push_back(std::make_pair(dets[i].detection_confidence,
                                                    scanner.get_full_object_detection(dets[i].rect, w[dets[i].weight_index].w)));
            }
        }

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

        template <
            typename image_scanner_type
            >
        template <
            typename image_type
            >
        void object_detector<image_scanner_type>::
        operator() (
            const image_type& img,
            std::vector<full_object_detection>& final_dets,
            double adjust_threshold
        )
        {
            std::vector<rect_detection> dets;
            (*this)(img,dets,adjust_threshold);

            final_dets.clear();
            final_dets.reserve(dets.size());

            // convert all the rectangle detections into full_object_detections.
            for (unsigned long i = 0; i < dets.size(); ++i)
            {
                final_dets.push_back(scanner.get_full_object_detection(dets[i].rect, w[dets[i].weight_index].w));
            }
        }

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

        template <
            typename image_scanner_type
            >
        const test_box_overlap& object_detector<image_scanner_type>::
        get_overlap_tester (
        ) const
        {
            return boxes_overlap;
        }

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

        template <
            typename image_scanner_type
            >
        const image_scanner_type& object_detector<image_scanner_type>::
        get_scanner (
        ) const
        {
            return scanner;
        }

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

    }

    #endif // DLIB_OBJECT_DeTECTOR_H__