// Copyright (c) 2020 GeometryFactory SARL (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v6.0.1/Shape_regularization/include/CGAL/Shape_regularization/regularize_segments.h $
// $Id: include/CGAL/Shape_regularization/regularize_segments.h 50cfbde3b84 $
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Dmitry Anisimov
//

#ifndef CGAL_SHAPE_REGULARIZATION_REGULARIZE_SEGMENTS_H
#define CGAL_SHAPE_REGULARIZATION_REGULARIZE_SEGMENTS_H

/// \cond SKIP_IN_MANUAL
#include <CGAL/license/Shape_regularization.h>
/// \endcond

/**
* \ingroup PkgShapeRegularizationRef
* \file CGAL/Shape_regularization/regularize_segments.h
* This header includes all classes for regularizing segments.
* It also includes the corresponding free functions.
*/

// Boost includes.
/// \cond SKIP_IN_MANUAL
#include <CGAL/boost/graph/named_params_helper.h>
#include <CGAL/Named_function_parameters.h>
/// \endcond

// Internal includes.
/// \cond SKIP_IN_MANUAL
#include <CGAL/Shape_regularization/internal/utils.h>
#include <CGAL/Shape_regularization/internal/Parallel_groups_2.h>
#include <CGAL/Shape_regularization/internal/Orthogonal_groups_2.h>
#include <CGAL/Shape_regularization/internal/Collinear_groups_2.h>
/// \endcond

/// \cond SKIP_IN_MANUAL
#if defined(CGAL_USE_OSQP)
#include <CGAL/OSQP_quadratic_program_traits.h>
#endif // CGAL_USE_OSQP
/// \endcond

#include <CGAL/Shape_regularization/QP_regularization.h>
#include <CGAL/Shape_regularization/Segments/Angle_regularization_2.h>
#include <CGAL/Shape_regularization/Segments/Offset_regularization_2.h>
#include <CGAL/Shape_regularization/Segments/Delaunay_neighbor_query_2.h>

namespace CGAL {
namespace Shape_regularization {
namespace Segments {

  /*!
    \ingroup PkgShapeRegularizationRefSegments

    \brief regularizes a set of 2D segments.

    Given a set of unordered 2D segments, this function enables to reinforce
    three types of regularities among these segments:
    - *Parallelism*: segments, which are detected as near parallel, are made exactly parallel.
    - *Orthogonality*: segments, which are detected as near orthogonal, are made exactly orthogonal.
    - *Collinearity*: parallel segments, which are detected as near collinear, are made exactly collinear.

    The user has to provide a `NeighborQuery` model to access local neighbors
    of a segment and a `RegularizationType` model to define the type of regularities
    that should be addressed. The function is based on the class `QP_regularization`.
    Please refer to that class and these concepts for more information.

    This class requires a `QPSolver` model which defaults to the \ref thirdpartyOSQP "OSQP"
    library, which must be available on the system.

    \tparam InputRange
    a model of `ConstRange` whose iterator type is `RandomAccessIterator`

    \tparam NeighQuery
    a model of `NeighborQuery`

    \tparam RegType
    a model of `RegularizationType`

    \tparam QPSolver
    a model of `QuadraticProgramTraits`

    \tparam NamedParameters
    a sequence of \ref bgl_namedparameters "Named Parameters"

    \param input_range
    a const range of input segments for shape regularization

    \param neighbor_query
    an instance of `NeighQuery` that is used internally to
    access neighbors of a segment; this parameter can be omitted together
    with the `regularization_type` parameter, in this case, all types of regularities
    will be reinforced on the whole input range and the default solver will be used (see below)

    \param regularization_type
    an instance of `RegType` that is used internally to
    obtain bounds and target values required by the regularization;
    this parameter can be omitted together with the `neighbor_query` parameter,
    in this case, all types of regularities will be reinforced on the whole input range
    and the default solver will be used (see below)

    \param quadratic_program
    an instance of `QPSolver` to solve the quadratic programming problem;
    this parameter can be omitted, the default solver is `CGAL::OSQP_quadratic_program_traits`

    \param np
    an optional sequence of \ref bgl_namedparameters "Named Parameters"
    among the ones listed below; this parameter can be omitted,
    the default values are then used

    \cgalNamedParamsBegin
      \cgalParamNBegin{geom_traits}
        \cgalParamDescription{an instance of geometric traits class}
        \cgalParamType{a model of `Kernel`}
        \cgalParamDefault{a CGAL `Kernel` deduced from the point type,
        using `CGAL::Kernel_traits`}
      \cgalParamNEnd
    \cgalNamedParamsEnd

    \pre input_range.size() >= 2

    \sa `regularize_angles()`
    \sa `regularize_offsets()`
  */
  template<
  typename InputRange,
  typename NeighQuery,
  typename RegType,
  typename QPSolver,
  typename NamedParameters = parameters::Default_named_parameters>
  void regularize_segments(
    InputRange& input_range,
    NeighQuery& neighbor_query,
    RegType& regularization_type,
    QPSolver& quadratic_program,
    const NamedParameters& np = parameters::default_values()) {

    using SegmentMap = typename internal::GetSegmentMap<InputRange, NamedParameters>::type;
    using Segment_2 = typename SegmentMap::value_type;
    using GeomTraits = typename CGAL::Kernel_traits<Segment_2>::Kernel;

    CGAL_precondition(input_range.size() >= 2);
    using Regularizer = QP_regularization<
      GeomTraits, InputRange, NeighQuery, RegType, QPSolver>;

    Regularizer regularizer(
      input_range, neighbor_query, regularization_type, quadratic_program, np);
    regularizer.regularize();
  }

  #if defined(CGAL_USE_OSQP) || defined(DOXYGEN_RUNNING)

  /// \cond SKIP_IN_MANUAL
  template<
  typename InputRange,
  typename NeighQuery,
  typename RegType>
  void regularize_segments(
    InputRange& input_range,
    NeighQuery& neighbor_query,
    RegType& regularization_type) {

    CGAL_precondition(input_range.size() >= 2);
    using Iterator_type = typename InputRange::const_iterator;
    using Segment_2 = typename std::iterator_traits<Iterator_type>::value_type;
    using GeomTraits = typename Kernel_traits<Segment_2>::Kernel;
    GeomTraits traits;

    using FT = typename GeomTraits::FT;
    using QP = CGAL::OSQP_quadratic_program_traits<FT>;
    QP quadratic_program;

    regularize_segments(
      input_range, neighbor_query, regularization_type, quadratic_program,
      CGAL::parameters::geom_traits(traits));
  }

  template<typename InputRange>
  void regularize_segments(
    InputRange& input_range) {

    CGAL_precondition(input_range.size() >= 2);
    using Iterator_type = typename InputRange::const_iterator;
    using Segment_2 = typename std::iterator_traits<Iterator_type>::value_type;
    using GeomTraits = typename Kernel_traits<Segment_2>::Kernel;

    using Indices = std::vector<std::size_t>;
    using Neighbor_query = Delaunay_neighbor_query_2<GeomTraits, InputRange>;
    using Angle_regularization = Angle_regularization_2<GeomTraits, InputRange>;
    using Offset_regularization = Offset_regularization_2<GeomTraits, InputRange>;

    // Regularize angles.
    Neighbor_query neighbor_query(input_range);
    Angle_regularization angle_regularization(input_range);
    regularize_segments(
      input_range, neighbor_query, angle_regularization);

    std::vector<Indices> parallel_groups;
    angle_regularization.parallel_groups(
      std::back_inserter(parallel_groups));

    // Regularize offsets.
    Offset_regularization offset_regularization(input_range);
    neighbor_query.clear();
    for (const auto& parallel_group : parallel_groups) {
      neighbor_query.add_group(parallel_group);
      offset_regularization.add_group(parallel_group);
    }
    regularize_segments(
      input_range, neighbor_query, offset_regularization);
  }
  /// \endcond

  /*!
    \ingroup PkgShapeRegularizationRefSegments

    \brief regularizes angles in a set of 2D segments.

    Given a set of unordered 2D segments, this function enables to reinforce
    two types of regularities among these segments:
    - *Parallelism*: segments, which are detected as near parallel, are made exactly parallel.
    - *Orthogonality*: segments, which are detected as near orthogonal, are made exactly orthogonal.

    This is an utility function based on `regularize_segments()` that is using default parameters.

    \tparam InputRange
    a model of `ConstRange` whose iterator type is `RandomAccessIterator`

    \param input_range
    a const range of input segments for angle regularization

    \pre input_range.size() >= 2

    \sa `regularize_segments()`
    \sa `regularize_offsets()`
  */
  template<typename InputRange>
  void regularize_angles(
    InputRange& input_range) {

    CGAL_precondition(input_range.size() >= 2);
    using Iterator_type = typename InputRange::const_iterator;
    using Segment_2 = typename std::iterator_traits<Iterator_type>::value_type;
    using GeomTraits = typename Kernel_traits<Segment_2>::Kernel;

    using Neighbor_query = Delaunay_neighbor_query_2<GeomTraits, InputRange>;
    using Angle_regularization = Angle_regularization_2<GeomTraits, InputRange>;

    Neighbor_query neighbor_query(input_range);
    Angle_regularization angle_regularization(input_range);
    regularize_segments(
      input_range, neighbor_query, angle_regularization);
  }

  /*!
    \ingroup PkgShapeRegularizationRefSegments

    \brief regularizes offsets in a set of 2D segments.

    Given a set of parallel 2D segments, this function enables to reinforce
    the collinearity property among these segments that is all parallel segments,
    which are detected as near collinear, are made exactly collinear.

    This is an utility function based on `regularize_segments()` that is using default parameters.

    \tparam InputRange
    a model of `ConstRange` whose iterator type is `RandomAccessIterator`

    \param input_range
    a const range of input segments for offset regularization

    \pre input_range.size() >= 2

    \sa `regularize_segments()`
    \sa `regularize_angles()`
  */
  template<typename InputRange>
  void regularize_offsets(
    InputRange& input_range) {

    CGAL_precondition(input_range.size() >= 2);
    using Iterator_type = typename InputRange::const_iterator;
    using Segment_2 = typename std::iterator_traits<Iterator_type>::value_type;
    using GeomTraits = typename Kernel_traits<Segment_2>::Kernel;

    using Neighbor_query = Delaunay_neighbor_query_2<GeomTraits, InputRange>;
    using Offset_regularization = Offset_regularization_2<GeomTraits, InputRange>;

    Neighbor_query neighbor_query(input_range);
    Offset_regularization offset_regularization(input_range);
    regularize_segments(
      input_range, neighbor_query, offset_regularization);
  }

  #endif // CGAL_USE_OSQP or DOXYGEN_RUNNING

  /*!
    \ingroup PkgShapeRegularizationRefSegments

    \brief finds groups of parallel segments in a set of 2D segments.

    This function enables to find groups of near parallel segments
    in a set of 2D segments. The groups are returned as vectors of indices.
    Note that two segments may be included at the same group even if they are
    far away from each other. This algorithm concerns only the angle relationship
    among segments, but not the distance.

    This function does not regularize input segments, but only groups them.

    \tparam InputRange
    a model of `ConstRange` whose iterator type is `RandomAccessIterator`

    \tparam OutIterator
    a model of `OutputIterator` that accepts elements of type `std::vector<std::size_t>`

    \tparam NamedParameters
    a sequence of \ref bgl_namedparameters "Named Parameters"

    \param input_range
    a const range of input segments

    \param groups
    an output iterator with groups of segment indices

    \param np
    an optional sequence of \ref bgl_namedparameters "Named Parameters"
    among the ones listed below; this parameter can be omitted,
    the default values are then used

    \cgalNamedParamsBegin
      \cgalParamNBegin{maximum_angle}
        \cgalParamDescription{maximum allowed angle deviation in degrees between two segments
          such that they are considered to be parallel}
        \cgalParamType{`GeomTraits::FT`}
        \cgalParamDefault{5 degrees}
      \cgalParamNEnd
      \cgalParamNBegin{preserve_order}
        \cgalParamDescription{indicates whether the order of input segments should be
          preserved or not}
        \cgalParamType{boolean}
        \cgalParamDefault{false}
      \cgalParamNEnd
      \cgalParamNBegin{segment_map}
        \cgalParamDescription{a property map that maps an item from `input_range`
        to `GeomTraits::Segment_2`}
        \cgalParamType{a model of `ReadablePropertyMap` whose key type is the value type of the input
        range and value type is `GeomTraits::Segment_2`}
        \cgalParamDefault{`CGAL::Identity_property_map`}
      \cgalParamNEnd
      \cgalParamNBegin{geom_traits}
        \cgalParamDescription{an instance of geometric traits class}
        \cgalParamType{a model of `Kernel`}
        \cgalParamDefault{a CGAL `Kernel` deduced from the point type,
        using `CGAL::Kernel_traits`}
      \cgalParamNEnd
    \cgalNamedParamsEnd

    \return an output iterator to the element in the destination range,
    one past the last group stored

    \pre input_range.size() >= 1
    \pre maximum_angle >= 0 && maximum_angle <= 90
  */
  template<
  typename InputRange,
  typename OutIterator,
  typename NamedParameters = parameters::Default_named_parameters>
  OutIterator parallel_groups(
    const InputRange& input_range,
    OutIterator groups,
    const NamedParameters& np = parameters::default_values()) {

    using SegmentMap = typename internal::GetSegmentMap<InputRange, NamedParameters>::type;
    using Segment_2 = typename SegmentMap::value_type;
    using GeomTraits = typename CGAL::Kernel_traits<Segment_2>::Kernel;

    const SegmentMap segment_map = parameters::choose_parameter(
      parameters::get_parameter(np, internal_np::segment_map), SegmentMap());
    const GeomTraits traits = parameters::choose_parameter(
      parameters::get_parameter(np, internal_np::geom_traits), GeomTraits());

    CGAL_precondition(input_range.size() >= 1);
    using Parallel_groups_2 = internal::Parallel_groups_2<
      GeomTraits, InputRange, SegmentMap>;

    Parallel_groups_2 grouping(
      input_range, np, segment_map, traits);
    return grouping.groups(groups);
  }

  /*!
    \ingroup PkgShapeRegularizationRefSegments

    \brief finds groups of collinear segments in a set of 2D segments.

    This function enables to find groups of near collinear segments
    in a set of 2D segments. The groups are returned as vectors of indices.
    This algorithm first finds the groups of parallel segments using the function
    `Segments::parallel_groups()` and then splits these groups into groups of collinear segments.

    This function does not regularize input segments, but only groups them.

    \tparam InputRange
    a model of `ConstRange` whose iterator type is `RandomAccessIterator`

    \tparam OutIterator
    a model of `OutputIterator` that accepts elements of type `std::vector<std::size_t>`

    \tparam NamedParameters
    a sequence of \ref bgl_namedparameters "Named Parameters"

    \param input_range
    a const range of input segments

    \param groups
    an output iterator with groups of segment indices

    \param np
    an optional sequence of \ref bgl_namedparameters "Named Parameters"
    among the ones listed below; this parameter can be omitted,
    the default values are then used

    \cgalNamedParamsBegin
      \cgalParamNBegin{maximum_offset}
        \cgalParamDescription{maximum allowed orthogonal distance between two parallel segments
          such that they are considered to be collinear}
        \cgalParamType{`GeomTraits::FT`}
        \cgalParamDefault{0.2 unit length}
      \cgalParamNEnd
      \cgalParamNBegin{preserve_order}
        \cgalParamDescription{indicates whether the order of input segments should be
          preserved or not}
        \cgalParamType{boolean}
        \cgalParamDefault{false}
      \cgalParamNEnd
      \cgalParamNBegin{segment_map}
        \cgalParamDescription{a property map that maps an item from `input_range`
        to `GeomTraits::Segment_2`}
        \cgalParamType{a model of `ReadablePropertyMap` whose key type is the value type of the input
        range and value type is `GeomTraits::Segment_2`}
        \cgalParamDefault{`CGAL::Identity_property_map`}
      \cgalParamNEnd
      \cgalParamNBegin{geom_traits}
        \cgalParamDescription{an instance of geometric traits class}
        \cgalParamType{a model of `Kernel`}
        \cgalParamDefault{a CGAL `Kernel` deduced from the point type,
        using `CGAL::Kernel_traits`}
      \cgalParamNEnd
    \cgalNamedParamsEnd

    \return an output iterator to the element in the destination range,
    one past the last group stored

    \pre input_range.size() >= 1
    \pre maximum_offset >= 0
  */
  template<
  typename InputRange,
  typename OutIterator,
  typename NamedParameters = parameters::Default_named_parameters>
  OutIterator collinear_groups(
    const InputRange& input_range,
    OutIterator groups,
    const NamedParameters& np = parameters::default_values()) {

    using SegmentMap = typename internal::GetSegmentMap<InputRange, NamedParameters>::type;
    using Segment_2 = typename SegmentMap::value_type;
    using GeomTraits = typename CGAL::Kernel_traits<Segment_2>::Kernel;

    const SegmentMap segment_map = parameters::choose_parameter(
      parameters::get_parameter(np, internal_np::segment_map), SegmentMap());
    const GeomTraits traits = parameters::choose_parameter(
      parameters::get_parameter(np, internal_np::geom_traits), GeomTraits());

    CGAL_precondition(input_range.size() >= 1);
    using Collinear_groups_2 = internal::Collinear_groups_2<
      GeomTraits, InputRange, SegmentMap>;

    Collinear_groups_2 grouping(
      input_range, np, segment_map, traits);
    return grouping.groups(groups);
  }

  /*!
    \ingroup PkgShapeRegularizationRefSegments

    \brief finds groups of orthogonal segments in a set of 2D segments.

    This function enables to find groups of near orthogonal segments
    in a set of 2D segments. The groups are returned as vectors of indices.
    This algorithm first finds the groups of parallel segments using the function
    `Segments::parallel_groups()` and then merges these groups into groups of orthogonal segments.

    This function does not regularize input segments, but only groups them.

    \tparam InputRange
    a model of `ConstRange` whose iterator type is `RandomAccessIterator`

    \tparam OutIterator
    a model of `OutputIterator` that accepts elements of type `std::vector<std::size_t>`

    \tparam NamedParameters
    a sequence of \ref bgl_namedparameters "Named Parameters"

    \param input_range
    a const range of input segments

    \param groups
    an output iterator with groups of segment indices

    \param np
    an optional sequence of \ref bgl_namedparameters "Named Parameters"
    among the ones listed below; this parameter can be omitted,
    the default values are then used

    \cgalNamedParamsBegin
      \cgalParamNBegin{maximum_angle}
        \cgalParamDescription{maximum allowed angle deviation in degrees between two segments
          such that they are considered to be parallel or orthogonal}
        \cgalParamType{`GeomTraits::FT`}
        \cgalParamDefault{5 degrees}
      \cgalParamNEnd
      \cgalParamNBegin{preserve_order}
        \cgalParamDescription{indicates whether the order of input segments should be
          preserved or not}
        \cgalParamType{boolean}
        \cgalParamDefault{false}
      \cgalParamNEnd
      \cgalParamNBegin{segment_map}
        \cgalParamDescription{a property map that maps an item from `input_range`
        to `GeomTraits::Segment_2`}
        \cgalParamType{a model of `ReadablePropertyMap` whose key type is the value type of the input
        range and value type is `GeomTraits::Segment_2`}
        \cgalParamDefault{`CGAL::Identity_property_map`}
      \cgalParamNEnd
      \cgalParamNBegin{geom_traits}
        \cgalParamDescription{an instance of geometric traits class}
        \cgalParamType{a model of `Kernel`}
        \cgalParamDefault{a CGAL `Kernel` deduced from the point type,
        using `CGAL::Kernel_traits`}
      \cgalParamNEnd
    \cgalNamedParamsEnd

    \return an output iterator to the element in the destination range,
    one past the last group stored

    \pre input_range.size() >= 1
    \pre maximum_angle >= 0 && maximum_angle <= 90
  */
  template<
  typename InputRange,
  typename OutIterator,
  typename NamedParameters = parameters::Default_named_parameters>
  OutIterator orthogonal_groups(
    const InputRange& input_range,
    OutIterator groups,
    const NamedParameters& np = parameters::default_values()) {

    using SegmentMap = typename internal::GetSegmentMap<InputRange, NamedParameters>::type;
    using Segment_2 = typename SegmentMap::value_type;
    using GeomTraits = typename CGAL::Kernel_traits<Segment_2>::Kernel;

    const SegmentMap segment_map = parameters::choose_parameter(
      parameters::get_parameter(np, internal_np::segment_map), SegmentMap());
    const GeomTraits traits = parameters::choose_parameter(
      parameters::get_parameter(np, internal_np::geom_traits), GeomTraits());

    CGAL_precondition(input_range.size() >= 1);
    using Orthogonal_groups_2 = internal::Orthogonal_groups_2<
      GeomTraits, InputRange, SegmentMap>;

    Orthogonal_groups_2 grouping(
      input_range, np, segment_map, traits);
    return grouping.groups(groups);
  }

  /*!
    \ingroup PkgShapeRegularizationRefSegments

    \brief substitutes groups of 2D collinear segments by average segments.

    This function first calls `Segments::collinear_groups()`
    and then substitutes each group of collinear segments by an average segment.
    The number of returned segments is the number of detected collinear groups.

    This function does not regularize input segments, but only groups and then simplifies them.

    \tparam InputRange
    a model of `ConstRange` whose iterator type is `RandomAccessIterator`

    \tparam OutIterator
    a model of `OutputIterator` that accepts segments of type `GeomTraits::Segment_2`

    \tparam NamedParameters
    a sequence of \ref bgl_namedparameters "Named Parameters"

    \param input_range
    a const range of input segments

    \param segments
    an output iterator with the simplified segments

    \param np
    an optional sequence of \ref bgl_namedparameters "Named Parameters"
    among the ones listed below; this parameter can be omitted,
    the default values are then used

    \cgalNamedParamsBegin
      \cgalParamNBegin{maximum_offset}
        \cgalParamDescription{maximum allowed orthogonal distance between two parallel segments
          such that they are considered to be collinear}
        \cgalParamType{`GeomTraits::FT`}
        \cgalParamDefault{0.2 unit length}
      \cgalParamNEnd
      \cgalParamNBegin{preserve_order}
        \cgalParamDescription{indicates whether the order of input segments should be
          preserved or not}
        \cgalParamType{boolean}
        \cgalParamDefault{false}
      \cgalParamNEnd
      \cgalParamNBegin{segment_map}
        \cgalParamDescription{a property map that maps an item from `input_range`
        to `GeomTraits::Segment_2`}
        \cgalParamType{a model of `ReadablePropertyMap` whose key type is the value type of the input
        range and value type is `GeomTraits::Segment_2`}
        \cgalParamDefault{`CGAL::Identity_property_map`}
      \cgalParamNEnd
      \cgalParamNBegin{geom_traits}
        \cgalParamDescription{an instance of geometric traits class}
        \cgalParamType{a model of `Kernel`}
        \cgalParamDefault{a CGAL `Kernel` deduced from the point type,
        using `CGAL::Kernel_traits`}
      \cgalParamNEnd
    \cgalNamedParamsEnd

    \return an output iterator to the element in the destination range,
    one past the last segment stored

    \pre input_range.size() >= 1
    \pre maximum_offset >= 0
  */
  template<
  typename InputRange,
  typename OutIterator,
  typename NamedParameters = parameters::Default_named_parameters>
  OutIterator unique_segments(
    const InputRange& input_range,
    OutIterator segments,
    const NamedParameters& np = parameters::default_values()) {

    using SegmentMap = typename internal::GetSegmentMap<InputRange, NamedParameters>::type;
    using Segment_2 = typename SegmentMap::value_type;
    using GeomTraits = typename CGAL::Kernel_traits<Segment_2>::Kernel;

    const SegmentMap segment_map = parameters::choose_parameter(
      parameters::get_parameter(np, internal_np::segment_map), SegmentMap());
    const GeomTraits traits = parameters::choose_parameter(
      parameters::get_parameter(np, internal_np::geom_traits), GeomTraits());

    CGAL_precondition(input_range.size() >= 1);
    using Unique_segments_2 = internal::Unique_segments_2<
      GeomTraits, InputRange, SegmentMap>;

    const Unique_segments_2 unique(
      input_range, np, segment_map, traits);
    return unique.segments(segments);
  }

} // namespace Segments
} // namespace Shape_regularization
} // namespace CGAL

#endif // CGAL_SHAPE_REGULARIZATION_REGULARIZE_SEGMENTS_H

