// Boost.Geometry (aka GGL, Generic Geometry Library)

// Copyright (c) 2007-2015 Barend Gehrels, Amsterdam, the Netherlands.
// Copyright (c) 2008-2015 Bruno Lalande, Paris, France.
// Copyright (c) 2009-2015 Mateusz Loskot, London, UK.
// Copyright (c) 2014-2015 Adam Wulkiewicz, Lodz, Poland.

// This file was modified by Oracle on 2013-2024.
// Modifications copyright (c) 2013-2024 Oracle and/or its affiliates.
// Contributed and/or modified by Vissarion Fysikopoulos, on behalf of Oracle
// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle

// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.

// Use, modification and distribution is subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_SECTIONS_SECTIONALIZE_HPP
#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_SECTIONS_SECTIONALIZE_HPP

#include <cstddef>
#include <type_traits>
#include <vector>

#include <boost/concept/requires.hpp>
#include <boost/core/ignore_unused.hpp>
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
#include <boost/range/size.hpp>
#include <boost/range/value_type.hpp>

#include <boost/geometry/core/config.hpp>

#include <boost/geometry/algorithms/assign.hpp>
#include <boost/geometry/algorithms/envelope.hpp>
#include <boost/geometry/algorithms/expand.hpp>
#include <boost/geometry/algorithms/detail/expand_by_epsilon.hpp>
#include <boost/geometry/algorithms/detail/ring_identifier.hpp>
#include <boost/geometry/algorithms/detail/signed_size_type.hpp>

#include <boost/geometry/core/access.hpp>
#include <boost/geometry/core/closure.hpp>
#include <boost/geometry/core/exterior_ring.hpp>
#include <boost/geometry/core/point_order.hpp>
#include <boost/geometry/core/static_assert.hpp>
#include <boost/geometry/core/tag_cast.hpp>
#include <boost/geometry/core/tags.hpp>

#include <boost/geometry/geometries/concepts/check.hpp>
#include <boost/geometry/geometries/box.hpp>
#include <boost/geometry/geometries/segment.hpp>
#include <boost/geometry/util/math.hpp>
#include <boost/geometry/util/normalize_spheroidal_coordinates.hpp>
#include <boost/geometry/util/sequence.hpp>
#include <boost/geometry/views/detail/closed_clockwise_view.hpp>

// TEMP
#include <boost/geometry/strategy/envelope.hpp>
#include <boost/geometry/strategy/expand.hpp>

namespace boost { namespace geometry
{


/*!
    \brief Structure containing section information
    \details Section information consists of a bounding box, direction
        information (if it is increasing or decreasing, per dimension),
        index information (begin-end, ring, multi) and the number of
        segments in this section

    \tparam Box box-type
    \tparam DimensionCount number of dimensions for this section
    \ingroup sectionalize
 */
template
<
    typename Box,
    std::size_t DimensionCount
>
struct section
{
    using box_type = Box;
    static std::size_t const dimension_count = DimensionCount;

    int directions[DimensionCount];
    ring_identifier ring_id;
    Box bounding_box;

    // NOTE: size_type could be passed as template parameter
    // NOTE: these probably also could be of type std::size_t
    signed_size_type begin_index;
    signed_size_type end_index;
    std::size_t count;
    std::size_t range_count;
    bool duplicate;
    signed_size_type non_duplicate_index;

    bool is_non_duplicate_first;
    bool is_non_duplicate_last;

    inline section()
        : begin_index(-1)
        , end_index(-1)
        , count(0)
        , range_count(0)
        , duplicate(false)
        , non_duplicate_index(-1)
        , is_non_duplicate_first(false)
        , is_non_duplicate_last(false)
    {
        assign_inverse(bounding_box);
        for (std::size_t i = 0; i < DimensionCount; i++)
        {
            directions[i] = 0;
        }
    }
};


/*!
    \brief Structure containing a collection of sections
    \note Derived from a vector, proves to be faster than of deque
    \note vector might be templated in the future
    \ingroup sectionalize
 */
template <typename Box, std::size_t DimensionCount>
struct sections : std::vector<section<Box, DimensionCount> >
{
    using box_type = Box;
    static std::size_t const value = DimensionCount;
};


#ifndef DOXYGEN_NO_DETAIL
namespace detail { namespace sectionalize
{

// NOTE: This utility will NOT work for latitudes, dimension 1 in spherical
// and geographic coordinate system because in these coordinate systems
// e.g. a segment on northern hemisphere may go towards greater latitude
// and then towards lesser latitude.
template
<
    typename Point,
    typename DimensionVector,
    std::size_t Index,
    std::size_t Count,
    typename CastedCSTag = tag_cast_t<cs_tag_t<Point>, spherical_tag>
>
struct get_direction_loop
{
    using dimension = typename util::sequence_element<Index, DimensionVector>::type;

    template <typename Segment>
    static inline void apply(Segment const& seg,
                int directions[Count])
    {
        auto const& c0 = geometry::get<0, dimension::value>(seg);
        auto const& c1 = geometry::get<1, dimension::value>(seg);

        directions[Index] = c1 > c0 ? 1 : c1 < c0 ? -1 : 0;

        get_direction_loop
        <
            Point,
            DimensionVector,
            Index + 1,
            Count,
            CastedCSTag
        >::apply(seg, directions);
    }
};

template
<
    typename Point,
    typename DimensionVector,
    std::size_t Count
>
struct get_direction_loop<Point, DimensionVector, 0, Count, spherical_tag>
{
    using dimension = typename util::sequence_element<0, DimensionVector>::type;

    template <typename Segment>
    static inline void apply(Segment const& seg,
                int directions[Count])
    {
        using coordinate_type = coordinate_type_t<Segment>;
        using units_t = detail::coordinate_system_units_t<Point>;

        coordinate_type const diff = math::longitude_distance_signed
                                        <
                                            units_t, coordinate_type
                                        >(geometry::get<0, 0>(seg),
                                          geometry::get<1, 0>(seg));

        coordinate_type zero = coordinate_type();
        directions[0] = diff > zero ? 1 : diff < zero ? -1 : 0;

        get_direction_loop
        <
            Point,
            DimensionVector,
            1,
            Count,
            spherical_tag
        >::apply(seg, directions);
    }
};

template
<
    typename Point,
    typename DimensionVector,
    std::size_t Count,
    typename CastedCSTag
>
struct get_direction_loop<Point, DimensionVector, Count, Count, CastedCSTag>
{
    template <typename Segment>
    static inline void apply(Segment const&, int [Count])
    {}
};


//! Copy one static array to another
template <typename T, std::size_t Index, std::size_t Count>
struct copy_loop
{
    static inline void apply(T const source[Count], T target[Count])
    {
        target[Index] = source[Index];
        copy_loop<T, Index + 1, Count>::apply(source, target);
    }
};

template <typename T, std::size_t Count>
struct copy_loop<T, Count, Count>
{
    static inline void apply(T const [Count], T [Count])
    {}
};

//! Compare two static arrays
template <typename T, std::size_t Index, std::size_t Count>
struct compare_loop
{
    static inline bool apply(T const array1[Count], T const array2[Count])
    {
        return array1[Index] != array2[Index]
            ? false
            : compare_loop
                <
                    T, Index + 1, Count
                >::apply(array1, array2);
    }
};

template <typename T, std::size_t Count>
struct compare_loop<T, Count, Count>
{
    static inline bool apply(T const [Count], T const [Count])
    {

        return true;
    }
};


template <std::size_t Dimension, std::size_t DimensionCount>
struct check_duplicate_loop
{
    template <typename Segment>
    static inline bool apply(Segment const& seg)
    {
        if (! geometry::math::equals
                (
                    geometry::get<0, Dimension>(seg),
                    geometry::get<1, Dimension>(seg)
                )
            )
        {
            return false;
        }

        return check_duplicate_loop
        <
                Dimension + 1, DimensionCount
        >::apply(seg);
    }
};

template <std::size_t DimensionCount>
struct check_duplicate_loop<DimensionCount, DimensionCount>
{
    template <typename Segment>
    static inline bool apply(Segment const&)
    {
        return true;
    }
};

//! Assign a value to a static array
template <typename T, std::size_t Index, std::size_t Count>
struct assign_loop
{
    static inline void apply(T dims[Count], T const value)
    {
        dims[Index] = value;
        assign_loop<T, Index + 1, Count>::apply(dims, value);
    }
};

template <typename T, std::size_t Count>
struct assign_loop<T, Count, Count>
{
    static inline void apply(T [Count], T const)
    {
    }
};

template <typename CSTag>
struct box_first_in_section
{
    template <typename Box, typename Point, typename Strategy>
    static inline void apply(Box & box, Point const& prev, Point const& curr,
                             Strategy const& strategy)
    {
        geometry::model::referring_segment<Point const> seg(prev, curr);
        geometry::envelope(seg, box, strategy);
    }
};

template <>
struct box_first_in_section<cartesian_tag>
{
    template <typename Box, typename Point, typename Strategy>
    static inline void apply(Box & box, Point const& prev, Point const& curr,
                             Strategy const& strategy)
    {
        geometry::envelope(prev, box, strategy);
        geometry::expand(box, curr, strategy);
    }
};

template <typename CSTag>
struct box_next_in_section
{
    template <typename Box, typename Point, typename Strategy>
    static inline void apply(Box & box, Point const& prev, Point const& curr,
                             Strategy const& strategy)
    {
        geometry::model::referring_segment<Point const> seg(prev, curr);
        geometry::expand(box, seg, strategy);
    }
};

template <>
struct box_next_in_section<cartesian_tag>
{
    template <typename Box, typename Point, typename Strategy>
    static inline void apply(Box & box, Point const& , Point const& curr,
                             Strategy const& strategy)
    {
        geometry::expand(box, curr, strategy);
    }
};

/// @brief Helper class to create sections of a part of a range, on the fly
template<typename DimensionVector>
struct sectionalize_part
{
    static const std::size_t dimension_count
        = util::sequence_size<DimensionVector>::value;

    template
    <
        typename Iterator,
        typename Sections,
        typename Strategy
    >
    static inline void apply(Sections& sections,
                             Iterator begin, Iterator end,
                             Strategy const& strategy,
                             ring_identifier ring_id,
                             std::size_t max_count)
    {
        using section_type = typename boost::range_value<Sections>::type;
        using box_type = typename section_type::box_type;
        using point_type = geometry::point_type_t<box_type>;

        BOOST_STATIC_ASSERT
            (
                section_type::dimension_count
                 == util::sequence_size<DimensionVector>::value
            );

        std::size_t const count = std::distance(begin, end);
        if (count == 0)
        {
            return;
        }

        signed_size_type index = 0;
        signed_size_type ndi = 0; // non duplicate index
        section_type section;

        bool mark_first_non_duplicated = true;
        std::size_t last_non_duplicate_index = sections.size();

        Iterator it = begin;
        point_type previous_point;
        geometry::detail::conversion::convert_point_to_point(*it, previous_point);

        for (Iterator previous = it++; it != end; ++previous, ++it, index++)
        {
            point_type current_point;
            geometry::detail::conversion::convert_point_to_point(*it, current_point);
            model::referring_segment<point_type> segment(previous_point, current_point);

            int direction_classes[dimension_count] = {0};
            get_direction_loop
            <
                point_type, DimensionVector, 0, dimension_count
            >::apply(segment, direction_classes);

            // if "dir" == 0 for all point-dimensions, it is duplicate.
            // Those sections might be omitted, if wished, lateron
            bool duplicate = false;

            if (direction_classes[0] == 0)
            {
                // Recheck because ALL dimensions should be checked,
                // not only first one.
                // (dimension_count might be < dimension<P>::value)
                if (check_duplicate_loop
                    <
                        0, geometry::dimension<point_type>::type::value
                    >::apply(segment)
                    )
                {
                    duplicate = true;

                    // Change direction-info to force new section
                    // Note that wo consecutive duplicate segments will generate
                    // only one duplicate-section.
                    // Actual value is not important as long as it is not -1,0,1
                    assign_loop
                    <
                        int, 0, dimension_count
                    >::apply(direction_classes, -99);
                }
            }

            if (section.count > 0
                && (! compare_loop
                        <
                            int, 0, dimension_count
                        >::apply(direction_classes, section.directions)
                    || section.count > max_count)
                )
            {
                if (! section.duplicate)
                {
                    last_non_duplicate_index = sections.size();
                }

                sections.push_back(section);
                section = section_type();
            }

            if (section.count == 0)
            {
                section.begin_index = index;
                section.ring_id = ring_id;
                section.duplicate = duplicate;
                section.non_duplicate_index = ndi;
                section.range_count = count;

                if (mark_first_non_duplicated && ! duplicate)
                {
                    section.is_non_duplicate_first = true;
                    mark_first_non_duplicated = false;
                }

                copy_loop
                    <
                        int, 0, dimension_count
                    >::apply(direction_classes, section.directions);

                // In cartesian this is envelope of previous point expanded with current point
                // in non-cartesian this is envelope of a segment
                box_first_in_section<cs_tag_t<point_type>>
                    ::apply(section.bounding_box, previous_point, current_point, strategy);
            }
            else
            {
                // In cartesian this is expand with current point
                // in non-cartesian this is expand with a segment
                box_next_in_section<cs_tag_t<point_type>>
                    ::apply(section.bounding_box, previous_point, current_point, strategy);
            }

            section.end_index = index + 1;
            section.count++;
            if (! duplicate)
            {
                ndi++;
            }
            previous_point = current_point;
        }

        // Add last section if applicable
        if (section.count > 0)
        {
            if (! section.duplicate)
            {
                last_non_duplicate_index = sections.size();
            }

            sections.push_back(section);
        }

        if (last_non_duplicate_index < sections.size()
            && ! sections[last_non_duplicate_index].duplicate)
        {
            sections[last_non_duplicate_index].is_non_duplicate_last = true;
        }
    }
};


template
<
    closure_selector Closure,
    bool Reverse,
    typename DimensionVector
>
struct sectionalize_range
{
    template
    <
        typename Range,
        typename Sections,
        typename Strategy
    >
    static inline void apply(Range const& range,
                             Sections& sections,
                             Strategy const& strategy,
                             ring_identifier ring_id,
                             std::size_t max_count)
    {
        detail::closed_clockwise_view
            <
                Range const,
                Closure,
                Reverse ? counterclockwise : clockwise
            > const view(range);

        std::size_t const n = boost::size(view);
        if (n == 0)
        {
            // Zero points, no section
            return;
        }

        if (n == 1)
        {
            // Line with one point ==> no sections
            return;
        }

        sectionalize_part<DimensionVector>::apply(sections,
            boost::begin(view), boost::end(view),
            strategy,
            ring_id, max_count);
    }
};

template
<
    bool Reverse,
    typename DimensionVector
>
struct sectionalize_polygon
{
    template
    <
        typename Polygon,
        typename Sections,
        typename Strategy
    >
    static inline void apply(Polygon const& poly,
                Sections& sections,
                Strategy const& strategy,
                ring_identifier ring_id,
                std::size_t max_count)
    {
        using sectionalizer = sectionalize_range
            <
                closure<Polygon>::value, Reverse, DimensionVector
            >;

        ring_id.ring_index = -1;
        sectionalizer::apply(exterior_ring(poly), sections,
                         strategy, ring_id, max_count);

        ring_id.ring_index++;
        auto const& rings = interior_rings(poly);
        for (auto it = boost::begin(rings); it != boost::end(rings);
             ++it, ++ring_id.ring_index)
        {
            sectionalizer::apply(*it, sections,
                             strategy, ring_id, max_count);
        }
    }
};

template <typename DimensionVector>
struct sectionalize_box
{
    template
    <
        typename Box,
        typename Sections,
        typename Strategy
    >
    static inline void apply(Box const& box,
                Sections& sections,
                Strategy const& strategy,
                ring_identifier const& ring_id, std::size_t max_count)
    {
        using point_type = point_type_t<Box>;

        assert_dimension<Box, 2>();

        // Add all four sides of the 2D-box as separate section.
        // Easiest is to convert it to a polygon.
        // However, we don't have the polygon type
        // (or polygon would be a helper-type).
        // Therefore we mimic a linestring/std::vector of 5 points

        // TODO: might be replaced by assign_box_corners_oriented
        // or just "convert"
        point_type ll, lr, ul, ur;
        geometry::detail::assign_box_corners(box, ll, lr, ul, ur);

        std::vector<point_type> points;
        points.push_back(ll);
        points.push_back(ul);
        points.push_back(ur);
        points.push_back(lr);
        points.push_back(ll);

        // NOTE: Use cartesian envelope strategy in all coordinate systems
        //       because edges of a box are not geodesic segments
        sectionalize_range
            <
                closed, false, DimensionVector
            >::apply(points, sections,
                     strategy, ring_id, max_count);
    }
};

template <typename DimensionVector, typename Policy>
struct sectionalize_multi
{
    template
    <
        typename MultiGeometry,
        typename Sections,
        typename Strategy
    >
    static inline void apply(MultiGeometry const& multi,
                Sections& sections,
                Strategy const& strategy,
                ring_identifier ring_id,
                std::size_t max_count)
    {
        ring_id.multi_index = 0;
        for (auto it = boost::begin(multi); it != boost::end(multi); ++it, ++ring_id.multi_index)
        {
            Policy::apply(*it, sections,
                          strategy,
                          ring_id, max_count);
        }
    }
};

template <typename Sections, typename Strategy>
inline void enlarge_sections(Sections& sections, Strategy const&)
{
    // Expand the box to avoid missing any intersection.
    // About the value itself: the smaller it is,
    // the higher the risk to miss intersections.
    // The larger it is, the more comparisons are made,
    // which is not harmful for the result,
    // but it might be for the performance.
    // So it should be on the higher side.
    //
    // The current value:
    // - for double :~ 2.22e-13
    // - for float  :~ 1e-4
    // - for Boost.Multiprecision (50) :~ 5.35e-48
    // - for Boost.Rational : 0/1

    // WARNING: don't use decltype here.
    // Earlier code used decltype(section.bonding_box) below,
    // but that somehow is not accepted by the NVCC (CUDA 12.4) compiler.
    using section_t = typename boost::range_value<Sections>::type;
    using box_t = typename section_t::box_type;
    using coor_t = geometry::coordinate_type_t<box_t>;

    static auto const eps = math::scaled_epsilon<coor_t>(1000);

    for (auto& section : sections)
    {
        expand_by_epsilon(section.bounding_box, eps);
    }
}


}} // namespace detail::sectionalize
#endif // DOXYGEN_NO_DETAIL


#ifndef DOXYGEN_NO_DISPATCH
namespace dispatch
{

template
<
    typename Tag,
    typename Geometry,
    bool Reverse,
    typename DimensionVector
>
struct sectionalize
{
    BOOST_GEOMETRY_STATIC_ASSERT_FALSE(
        "Not or not yet implemented for this Geometry type.",
        Tag, Geometry);
};

template
<
    typename Box,
    bool Reverse,
    typename DimensionVector
>
struct sectionalize<box_tag, Box, Reverse, DimensionVector>
    : detail::sectionalize::sectionalize_box<DimensionVector>
{};

template
<
    typename LineString,
    typename DimensionVector
>
struct sectionalize
    <
        linestring_tag,
        LineString,
        false,
        DimensionVector
    >
    : detail::sectionalize::sectionalize_range<closed, false, DimensionVector>
{};

template
<
    typename Ring,
    bool Reverse,
    typename DimensionVector
>
struct sectionalize<ring_tag, Ring, Reverse, DimensionVector>
    : detail::sectionalize::sectionalize_range
        <
            geometry::closure<Ring>::value, Reverse,
            DimensionVector
        >
{};

template
<
    typename Polygon,
    bool Reverse,
    typename DimensionVector
>
struct sectionalize<polygon_tag, Polygon, Reverse, DimensionVector>
    : detail::sectionalize::sectionalize_polygon
        <
            Reverse, DimensionVector
        >
{};

template
<
    typename MultiPolygon,
    bool Reverse,
    typename DimensionVector
>
struct sectionalize<multi_polygon_tag, MultiPolygon, Reverse, DimensionVector>
    : detail::sectionalize::sectionalize_multi
        <
            DimensionVector,
            detail::sectionalize::sectionalize_polygon
                <
                    Reverse,
                    DimensionVector
                >
        >

{};

template
<
    typename MultiLinestring,
    bool Reverse,
    typename DimensionVector
>
struct sectionalize<multi_linestring_tag, MultiLinestring, Reverse, DimensionVector>
    : detail::sectionalize::sectionalize_multi
        <
            DimensionVector,
            detail::sectionalize::sectionalize_range<closed, false, DimensionVector>
        >

{};

} // namespace dispatch
#endif


/*!
    \brief Split a geometry into monotonic sections
    \ingroup sectionalize
    \tparam Geometry type of geometry to check
    \tparam Sections type of sections to create
    \param geometry geometry to create sections from
    \param sections structure with sections
    \param strategy strategy for envelope calculation
    \param source_index index to assign to the ring_identifiers
    \param max_count maximal number of points per section
        (defaults to 10, this seems to give the fastest results)

 */
template
<
    bool Reverse,
    typename DimensionVector,
    typename Geometry,
    typename Sections,
    typename Strategy
>
inline void sectionalize(Geometry const& geometry,
                Sections& sections,
                Strategy const& strategy,
                int source_index = 0,
                std::size_t max_count = 10)
{
    concepts::check<Geometry const>();

    sections.clear();

    ring_identifier ring_id;
    ring_id.source_index = source_index;

    dispatch::sectionalize
        <
            tag_t<Geometry>,
            Geometry,
            Reverse,
            DimensionVector
        >::apply(geometry, sections,
                 strategy,
                 ring_id, max_count);

    detail::sectionalize::enlarge_sections(sections, strategy);
}


template
<
    bool Reverse,
    typename DimensionVector,
    typename Geometry,
    typename Sections
>
inline void sectionalize(Geometry const& geometry,
                         Sections& sections,
                         int source_index = 0,
                         std::size_t max_count = 10)
{
    using box_type = typename Sections::box_type;
    using strategy_type = typename strategies::envelope::services::default_strategy
        <
            Geometry,
            box_type
        >::type;

    boost::geometry::sectionalize
        <
            Reverse, DimensionVector
        >(geometry, sections,
          strategy_type(),
          source_index, max_count);
}

}} // namespace boost::geometry


#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_SECTIONS_SECTIONALIZE_HPP
