// Copyright (c) 2009 INRIA Sophia-Antipolis (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL$
// $Id$
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Stéphane Tayeb
//
//******************************************************************************
// File Description : make_mesh_3 function definition.
//******************************************************************************

#ifndef CGAL_MAKE_MESH_3_H
#define CGAL_MAKE_MESH_3_H

#include <CGAL/license/Mesh_3.h>

#include <CGAL/Mesh_3/config.h>
#include <CGAL/refine_mesh_3.h>
#include <CGAL/tags.h>
#include <CGAL/Mesh_3/Protect_edges_sizing_field.h>
#include <CGAL/STL_Extension/internal/Has_features.h>
#include <CGAL/Mesh_3/C3T3_helpers.h>

#include <boost/mpl/has_xxx.hpp>

#include <atomic>

namespace CGAL {

// -----------------------------------
// Initialize c3t3 stuff
// -----------------------------------
namespace Mesh_3 {
namespace internal {

template < typename C3T3, typename MeshDomain, typename MeshCriteria >
void
init_c3t3(C3T3& c3t3, const MeshDomain& domain, const MeshCriteria&,
          const int nb_initial_points)
{
  typedef typename MeshDomain::Point_3 Point_3;
  typedef typename MeshDomain::Index Index;
  typedef std::vector<std::pair<Point_3, Index> > Initial_points_vector;
  typedef typename Initial_points_vector::iterator Ipv_iterator;
  typedef typename C3T3::Vertex_handle Vertex_handle;

  // Mesh initialization : get some points and add them to the mesh
  Initial_points_vector initial_points;
  if (nb_initial_points > -1)
    domain.construct_initial_points_object()(std::back_inserter(initial_points),
                                             nb_initial_points);
  else //use default number of points
    domain.construct_initial_points_object()(std::back_inserter(initial_points));

  typename C3T3::Triangulation::Geom_traits::Construct_weighted_point_3 cwp =
      c3t3.triangulation().geom_traits().construct_weighted_point_3_object();

  // Insert points and set their index and dimension
  for ( Ipv_iterator it = initial_points.begin() ;
       it != initial_points.end() ;
       ++it )
  {
    Vertex_handle v = c3t3.triangulation().insert(cwp(it->first));

    // v could be null if point is hidden
    if ( v != Vertex_handle() )
    {
      c3t3.set_dimension(v,2); // by construction, points are on surface
      c3t3.set_index(v,it->second);
    }
  }
}

template < typename EdgeCriteria >
struct Edge_criteria_sizing_field_wrapper
{
  typedef typename EdgeCriteria::Index    Index;
  typedef typename EdgeCriteria::FT       FT;
  typedef typename EdgeCriteria::Point_3  Point_3;

  Edge_criteria_sizing_field_wrapper(const EdgeCriteria& ec) : ec_(ec) {}
  FT operator()(const Point_3& p, const int dim, const Index& index) const
  { return ec_.sizing_field(p,dim,index); }

private:
  // No need to copy EdgeCriteria here
  const EdgeCriteria& ec_;
};

template < typename C3T3, typename MeshDomain, typename MeshCriteria>
void init_c3t3_with_features(C3T3& c3t3,
                             const MeshDomain& domain,
                             const MeshCriteria& criteria,
                             bool nonlinear = false,
                             std::size_t maximal_number_of_vertices = 0,
                             Mesh_error_code* pointer_to_error_code = 0
#ifndef CGAL_NO_ATOMIC
                             , std::atomic<bool>* pointer_to_stop = 0
#endif
                             )
{
  typedef typename MeshCriteria::Edge_criteria Edge_criteria;
  typedef Edge_criteria_sizing_field_wrapper<Edge_criteria> Sizing_field;

  CGAL::Mesh_3::Protect_edges_sizing_field<C3T3,MeshDomain,Sizing_field>
    protect_edges(c3t3,
                  domain,
                  Sizing_field(criteria.edge_criteria_object()),
                  typename Edge_criteria::FT(),
                  maximal_number_of_vertices,
                  pointer_to_error_code
#ifndef CGAL_NO_ATOMIC
                  , pointer_to_stop
#endif
                  );
  protect_edges.set_nonlinear_growth_of_balls(nonlinear);

  protect_edges(true);
}

// This class is only used as base for specializations of C3t3_initializer
// when MeshDomain::Has_features is a valid type and is defined to CGAL::Tag_true
//
// Its purpose is to make the protection process virtual because Periodic_3_mesh_3
// handles sharp features differently and has its own 'init_c3t3_with_features()' function,
// but everything else is identical.
template < typename C3T3, typename MeshDomain, typename MeshCriteria>
struct C3t3_initializer_base
{
  virtual ~C3t3_initializer_base() { }

  // Not calling 'init_c3t3_with_features' directly to leave it as a free function
  // outside of the C3T3_initializer class
  virtual void
  initialize_features(C3T3& c3t3,
                      const MeshDomain& domain,
                      const MeshCriteria& criteria,
                      const parameters::internal::Mesh_3_options& mesh_options)
  {
    return Mesh_3::internal::init_c3t3_with_features
      (c3t3, domain, criteria,
       mesh_options.nonlinear_growth_of_balls,
       mesh_options.maximal_number_of_vertices,
       mesh_options.pointer_to_error_code
#ifndef CGAL_NO_ATOMIC
       , mesh_options.pointer_to_stop_atomic_boolean
#endif
       );
  }
};

// C3t3_initializer: initialize c3t3
template < typename C3T3,
           typename MeshDomain,
           typename MeshCriteria,
           bool MeshDomainHasHasFeatures,
           typename HasFeatures = int>
struct C3t3_initializer { };

// Partial specialization of C3t3_initializer
// Handle cases where MeshDomain::Has_features is not a valid type
template < typename C3T3, typename MD, typename MC, typename HasFeatures >
struct C3t3_initializer < C3T3, MD, MC, false, HasFeatures >
{
  typedef parameters::internal::Mesh_3_options Mesh_3_options;
  void operator()(C3T3& c3t3,
                  const MD& domain,
                  const MC& criteria,
                  bool with_features,
                  Mesh_3_options mesh_options = Mesh_3_options())
  {
    if ( with_features )
    {
      std::cerr << "Warning: you requested a mesh with features from a domain"
                << " without features !" << std::endl;
    }

    init_c3t3(c3t3,domain,criteria,
              mesh_options.number_of_initial_points);
  }
};

// Partial specialization of C3t3_initializer
// Handles cases where MeshDomain::Has_features is a valid type
template < typename C3T3, typename MD, typename MC, typename HasFeatures >
struct C3t3_initializer < C3T3, MD, MC, true, HasFeatures >
{
  typedef parameters::internal::Mesh_3_options Mesh_3_options;
  void operator()(C3T3& c3t3,
                  const MD& domain,
                  const MC& criteria,
                  bool with_features,
                  Mesh_3_options mesh_options = Mesh_3_options())
  {
    C3t3_initializer < C3T3, MD, MC, true, typename MD::Has_features >()
      (c3t3,domain,criteria,with_features,mesh_options);
  }
};

// Partial specialization of C3t3_initializer
// Handles cases where MeshDomain::Has_features is a valid type and is defined
// to CGAL::Tag_true
template < typename C3T3, typename MD, typename MC >
struct C3t3_initializer < C3T3, MD, MC, true, CGAL::Tag_true >
  : public C3t3_initializer_base < C3T3, MD, MC >
{
  virtual ~C3t3_initializer() { }

  typedef parameters::internal::Mesh_3_options Mesh_3_options;
  void operator()(C3T3& c3t3,
                  const MD& domain,
                  const MC& criteria,
                  bool with_features,
                  Mesh_3_options mesh_options = Mesh_3_options())
  {
    if ( with_features ) {
      this->initialize_features(c3t3, domain, criteria,mesh_options);

      // If c3t3 initialization is not sufficient (may happen if there is only
      // a planar curve as feature for example), add some surface points

      bool need_more_init = c3t3.triangulation().dimension() != 3;
      if(!need_more_init) {
        CGAL::Mesh_3::C3T3_helpers<C3T3, MD> helper(c3t3, domain);
        helper.update_restricted_facets();

        if (c3t3.number_of_facets() == 0) {
          need_more_init = true;
        }
        else
        {
          helper.update_restricted_cells();
          if(c3t3.number_of_cells() == 0) {
            need_more_init = true;
          }
        }
      }
      if(need_more_init) {
        init_c3t3(c3t3, domain, criteria,
                  mesh_options.number_of_initial_points);
      }
    }
    else { init_c3t3(c3t3,domain,criteria,
                     mesh_options.number_of_initial_points); }
  }
};

// Partial specialization of C3t3_initializer
// Handles cases where MeshDomain::Has_features is a valid type and is defined
// to CGAL::Tag_false
template < typename C3T3, typename MD, typename MC >
struct C3t3_initializer < C3T3, MD, MC, true, CGAL::Tag_false >
{
  typedef parameters::internal::Mesh_3_options Mesh_3_options;
  void operator()(C3T3& c3t3,
                  const MD& domain,
                  const MC& criteria,
                  bool with_features,
                  Mesh_3_options mesh_options = Mesh_3_options())
  {
    if ( with_features )
    {
      std::cerr << "Warning: you requested a mesh with features from a domain"
                << " without features !" << std::endl;
    }

    init_c3t3(c3t3,domain,criteria,
              mesh_options.number_of_initial_points);
  }
};

} // end namespace internal
} // end namespace Mesh_3


// -----------------------------------
// make_mesh_3 stuff
// -----------------------------------

/*!
 * \ingroup PkgMesh3Functions
 *
 * The function `make_mesh_3()` is a 3D
 * mesh generator. It produces simplicial meshes which discretize
 * 3D domains.
 *
 * The mesh generation algorithm is a Delaunay refinement process
 * followed by an optimization phase.
 * The criteria driving the Delaunay refinement
 * process may be tuned to achieve the user needs with respect to
 * the size of mesh elements, the accuracy of boundaries approximation,
 * etc.
 *
 * The optimization phase is a sequence of optimization processes,
 * amongst the following available optimizers: an ODT-smoothing,
 * a Lloyd-smoothing, a sliver perturber, and a sliver exuder.
 * Each optimization process
 * can be activated or not,
 * according to the user requirements
 * and available time.
 * By default, only the perturber and the exuder are activated.
 * Note that the benefits of the exuder will be lost if the mesh
 * is further refined afterward, and that ODT-smoothing, Lloyd-smoothing,
 * and sliver perturber should never be called after the sliver exuder.
 * In the case of further refinement, only the sliver exuder can be used.
 *
 * The function outputs the mesh to an object which provides iterators to
 * traverse the resulting mesh data structure or can be written to a file
 * (see \ref Mesh_3_section_examples ).
 *
 * \tparam C3T3 either a model of the concept `MeshComplex_3InTriangulation_3` or
 *              of `MeshComplexWithFeatures_3InTriangulation_3` if `MD`
 *              is a model of `MeshDomainWithFeatures_3`.
 *              The type `C3T3` is in particular required to provide a nested type
 *              `C3T3::Triangulation` for the 3D triangulation
 *              embedding the mesh. The vertex and cell base classes of the
 *              triangulation `C3T3::Triangulation` are required to be models of the
 *              concepts `MeshVertexBase_3` and `MeshCellBase_3` respectively.
 *
 * \tparam MD either a model of the concept `MeshDomain_3` or of
 *            `MeshDomainWithFeatures_3` if 0 and 1-dimensional features
 *            of the input complex have to be accurately represented in the mesh.
 *
 * \tparam MC either a model of the concept `MeshCriteria_3` or a model
 *            of `MeshCriteriaWithFeatures_3` if the domain has exposed features.
 *
 * \tparam NamedParameters a sequence of \ref bgl_namedparameters "Named Parameters"
 *
 * \param domain the domain used to create the `c3t3` parameter. It is the sole link through which the domain
 *               to be discretized is known by the mesh generation algorithm.
 * \param criteria specifies the size and shape requirements for mesh tetrahedra
 *                 and surface facets. These criteria form the rules which drive
 *                 the refinement process. All mesh elements satisfy those criteria
 *                 at the end of the refinement process.
 *                 In addition, if the domain has features, the argument
 *                 `criteria` provides a sizing field to guide the discretization
 *                 of 1-dimensional exposed features.
 *
 *  \param np an optional sequence of \ref bgl_namedparameters "Named Parameters" among the ones listed below:
 *
 * \cgalNamedParamsBegin
 *   \cgalParamSectionBegin{Feature preservation options}
 *     \cgalParamDescription{If the domain is a model of `MeshDomainWithFeatures_3`, 0 and 1-dimensional features can be
 *                           taken into account while generating the mesh. The following two named parameters control
 *                           this option:
 *                           <UL>
 *                             <LI>\link parameters::features() `parameters::features(domain)` \endlink
 *                             <LI>`parameters::no_features()`
 *                           </UL>}
 *     \cgalParamDefault{`parameters::features(domain)`}
 *   \cgalParamSectionEnd
 *   \cgalParamSectionBegin{Topological options (manifoldness)}
 *     \cgalParamDescription{In order to drive the meshing algorithm and ensure that the output mesh follows a desired topological criterion,
 *                           three named parameters control this option:
 *                           <UL>
 *                             <LI>`parameters::manifold()`
 *                             <LI>`parameters::manifold_with_boundary()`
 *                             <LI>`parameters::non_manifold()`
 *                           </UL>
 *                           Note that the meshing algorithm cannot generate a manifold surface if the input surface is not manifold.}
 *     \cgalParamDefault{`parameters::non_manifold()`}
 *   \cgalParamSectionEnd
 *   \cgalParamSectionBegin{Lloyd optimization}
 *     \cgalParamDescription{`lloyd_optimize_mesh_3()` can optionally be called after the meshing process.
 *                           Two named parameters control this behavior:
 *                           <UL>
 *                             <LI> `parameters::no_lloyd()`
 *                             <LI> `parameters::lloyd_optimize_mesh_3()`
 *                           </UL>}
 *     \cgalParamDefault{`parameters::no_lloyd()`}
 *   \cgalParamSectionEnd
 *   \cgalParamSectionBegin{ODT optimization}
 *     \cgalParamDescription{`odt_optimize_mesh_3()` can optionally be called after the meshing process.
 *                           Two named parameters control this behavior:
 *                           <UL>
 *                             <LI> `parameters::no_odt()`
 *                             <LI> `parameters::odt()`
 *                           </UL>}
 *     \cgalParamDefault{`parameters::no_odt()`}
 *   \cgalParamSectionEnd
 *   \cgalParamSectionBegin{Mesh perturbation}
 *     \cgalParamDescription{`perturb_mesh_3()` can optionally be called after the meshing process.
 *                           Two named parameters control this behavior:
 *                           <UL>
 *                             <LI> `parameters::no_perturb()`
 *                             <LI> `parameters::perturb()`
 *                           </UL>}
 *     \cgalParamDefault{`parameters::perturb()`}
 *   \cgalParamSectionEnd
 *   \cgalParamSectionBegin{Mesh exudation}
 *     \cgalParamDescription{`exude_mesh_3()` can optionally be called after the meshing process.
 *                           Two named parameters control this behavior:
 *                           <UL>
 *                             <LI> `parameters::no_exude()`
 *                             <LI> `parameters::exude()`
 *                           </UL>}
 *     \cgalParamDefault{`parameters::exude()`}
 *   \cgalParamSectionEnd
 * \cgalNamedParamsEnd
 *
 * Note that regardless of which optimization processes are activated,
 * they are always launched in the order that is a suborder
 * of the following (see user manual for further
 * details): *ODT-smoother*, *Lloyd-smoother*, *perturber*, and *exuder*.
 *
 * Beware that optimization of the mesh is obtained
 * by perturbing mesh vertices and modifying the mesh connectivity
 * and that this has an impact
 * on the strict compliance to the refinement criteria.
 * Though a strict compliance to mesh criteria
 * is guaranteed at the end of the Delaunay refinement, this may no longer be true after
 * some optimization processes. Also beware that the default behavior does involve some
 * optimization processes.
 *
 * \sa `refine_mesh_3()`
 * \sa `exude_mesh_3()`
 * \sa `perturb_mesh_3()`
 * \sa `lloyd_optimize_mesh_3()`
 * \sa `odt_optimize_mesh_3()`
 */
template<typename C3T3, typename MeshDomain, typename MeshCriteria, typename CGAL_NP_TEMPLATE_PARAMETERS>
C3T3 make_mesh_3(const MeshDomain& domain, const MeshCriteria& criteria, const CGAL_NP_CLASS& np = parameters::default_values())
{
    using parameters::choose_parameter;
    using parameters::get_parameter;
    C3T3 c3t3;
    parameters::internal::Exude_options exude_param = choose_parameter(get_parameter(np, internal_np::exude_options_param), parameters::exude().v);
    parameters::internal::Perturb_options perturb_param = choose_parameter(get_parameter(np, internal_np::perturb_options_param), parameters::perturb().v);
    parameters::internal::Odt_options odt_param = choose_parameter(get_parameter(np, internal_np::odt_options_param), parameters::no_odt().v);
    parameters::internal::Lloyd_options lloyd_param = choose_parameter(get_parameter(np, internal_np::lloyd_options_param), parameters::no_lloyd().v);
    parameters::internal::Features_options features_param = choose_parameter(get_parameter(np, internal_np::features_options_param), parameters::features(domain).v);
    parameters::internal::Mesh_3_options mesh_options_param = choose_parameter(get_parameter(np, internal_np::mesh_param), parameters::internal::Mesh_3_options());
    parameters::internal::Manifold_options manifold_options_param = choose_parameter(get_parameter(np, internal_np::manifold_param), parameters::internal::Manifold_options());

    make_mesh_3_impl(c3t3, domain, criteria,
            exude_param, perturb_param, odt_param, lloyd_param,
            features_param.features(), mesh_options_param,
            manifold_options_param);
    return c3t3;
}

#ifndef DOXYGEN_RUNNING
// Overload handling parameters passed with operator=
template<typename C3T3, typename MeshDomain, typename MeshCriteria,
         typename CGAL_NP_TEMPLATE_PARAMETERS_NO_DEFAULT_1,
         typename CGAL_NP_TEMPLATE_PARAMETERS_NO_DEFAULT_2,
         typename ... NP>
C3T3 make_mesh_3(const MeshDomain& domain, const MeshCriteria& criteria,
                 const CGAL_NP_CLASS_1&  np1,
                 const CGAL_NP_CLASS_2&  np2,
                 const NP& ... nps)
{
  return make_mesh_3<C3T3>(domain, criteria, internal_np::combine_named_parameters(np1, np2, nps...));
}

/**
 * @brief This function meshes the domain defined by mesh_traits
 * (respecting criteria), and outputs the mesh to c3t3
 *
 * @param domain the domain to be discretized
 * @param criteria the criteria
 * @param exude if it is set to `true`, an exudation step will be done at
 *   the end of the Delaunay refinement process
 *
 * @return The mesh as a C3T3 object
 */
template<class C3T3, class MeshDomain, class MeshCriteria>
void make_mesh_3_impl(C3T3& c3t3,
                      const MeshDomain&   domain,
                      const MeshCriteria& criteria,
                      const parameters::internal::Exude_options& exude,
                      const parameters::internal::Perturb_options& perturb,
                      const parameters::internal::Odt_options& odt,
                      const parameters::internal::Lloyd_options& lloyd,
                      const bool with_features,
                      const parameters::internal::Mesh_3_options&
                        mesh_options = parameters::internal::Mesh_3_options(),
                      const parameters::internal::Manifold_options&
                        manifold_options = parameters::internal::Manifold_options())
{
#ifdef CGAL_MESH_3_INITIAL_POINTS_NO_RANDOM_SHOOTING
  CGAL::get_default_random() = CGAL::Random(0);
#endif

  // Initialize c3t3
  Mesh_3::internal::C3t3_initializer<
    C3T3,
    MeshDomain,
    MeshCriteria,
    ::CGAL::internal::has_Has_features<MeshDomain>::value > () (c3t3,
            domain,
            criteria,
            with_features,
            mesh_options);

  CGAL_assertion( c3t3.triangulation().dimension() >= 2 );

  // Build mesher and launch refinement process
  // Don't reset c3t3 as we just created it
  refine_mesh_3(c3t3, domain, criteria,
                parameters::exude_options=exude, parameters::perturb_options=perturb, parameters::odt_options=odt, parameters::lloyd_options= lloyd,
                parameters::no_reset_c3t3(), parameters::mesh_options= mesh_options,
                parameters::manifold_option= manifold_options);
}

#endif //DOXYGEN_RUNNING
} // end namespace CGAL

#endif // CGAL_MAKE_MESH_3_H