/* SPDX-FileCopyrightText: 2001-2002 NaN Holding BV. All rights reserved.
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
#pragma once

/** \file
 * \ingroup bke
 */

#include <cstdint>

#include "BLI_array.hh"
#include "BLI_string_ref.hh"

#include "DNA_listBase.h"
#include "DNA_mesh_types.h"

namespace blender {

struct BMesh;
struct BMeshCreateParams;
struct BMeshFromMeshParams;
struct BMeshToMeshParams;
struct CustomData;
struct CustomData_MeshMasks;
struct Depsgraph;
struct KeyBlock;
struct LinkNode;
struct MDeformVert;
struct MDisps;
struct MFace;
struct Main;
struct MemArena;
struct Mesh;
struct Object;
struct Scene;
struct DispList;
struct Nurb;

namespace draw {
struct MeshBatchCache;
}

enum eMSelect_Type : int;

/* TODO: Move to `BKE_mesh_types.hh` when possible. */
enum eMeshBatchDirtyMode : int8_t {
  BKE_MESH_BATCH_DIRTY_ALL = 0,
  BKE_MESH_BATCH_DIRTY_SELECT,
  BKE_MESH_BATCH_DIRTY_SELECT_PAINT,
  BKE_MESH_BATCH_DIRTY_SHADING,
  BKE_MESH_BATCH_DIRTY_UVEDIT_ALL,
  BKE_MESH_BATCH_DIRTY_UVEDIT_SELECT,
};

/* `mesh.cc` */

BMesh *BKE_mesh_to_bmesh_ex(const Mesh *mesh,
                            const BMeshCreateParams *create_params,
                            const BMeshFromMeshParams *convert_params);
/**
 * \param active_shapekey: See #BMeshFromMeshParams::active_shapekey.
 * \param add_key_index: See #BMeshFromMeshParams::add_key_index.
 */
BMesh *BKE_mesh_to_bmesh(Mesh *mesh,
                         int active_shapekey,
                         bool add_key_index,
                         const BMeshCreateParams *params);

Mesh *BKE_mesh_from_bmesh_nomain(BMesh *bm,
                                 const BMeshToMeshParams *params,
                                 const Mesh *me_settings);
Mesh *BKE_mesh_from_bmesh_for_eval_nomain(BMesh *bm,
                                          const CustomData_MeshMasks *cd_mask_extra,
                                          const Mesh *me_settings);

/**
 * Add original index (#CD_ORIGINDEX) layers if they don't already exist. This is meant to be used
 * when creating an evaluated mesh from an original edit mode mesh, to allow mapping from the
 * evaluated vertices to the originals.
 *
 * The mesh is expected to of a `ME_WRAPPER_TYPE_MDATA` wrapper type. This is asserted.
 */
void BKE_mesh_ensure_default_orig_index_customdata(Mesh *mesh);

/**
 * Same as #BKE_mesh_ensure_default_orig_index_customdata but does not perform any checks: they
 * must be done by the caller.
 */
void BKE_mesh_ensure_default_orig_index_customdata_no_check(Mesh *mesh);

/**
 * Remove all geometry and derived data like caches from the mesh.
 */
void BKE_mesh_clear_geometry(Mesh *mesh);

/**
 * Same as #BKE_mesh_clear_geometry, but also clears attribute meta-data like active attribute
 * names and vertex group names. Used when the geometry is *entirely* replaced.
 */
void BKE_mesh_clear_geometry_and_metadata(Mesh *mesh);

Mesh *BKE_mesh_add(Main *bmain, const char *name);

/**
 * A version of #BKE_mesh_copy_parameters that is intended for evaluated output
 * (the modifier stack for example).
 *
 * \warning User counts are not handled for ID's.
 */
void BKE_mesh_copy_parameters_for_eval(Mesh *me_dst, const Mesh *me_src);
/**
 * Copy user editable settings that we want to preserve
 * when a new mesh is based on an existing mesh.
 */
void BKE_mesh_copy_parameters(Mesh *me_dst, const Mesh *me_src);
void BKE_mesh_ensure_skin_customdata(Mesh *mesh);

/** Add face offsets to describe faces to a new mesh. */
void BKE_mesh_face_offsets_ensure_alloc(Mesh *mesh);

Mesh *BKE_mesh_new_nomain(int verts_num, int edges_num, int faces_num, int corners_num);
Mesh *BKE_mesh_new_nomain_from_template(
    const Mesh *me_src, int verts_num, int edges_num, int faces_num, int corners_num);
Mesh *BKE_mesh_new_nomain_from_template_ex(const Mesh *me_src,
                                           int verts_num,
                                           int edges_num,
                                           int tessface_num,
                                           int faces_num,
                                           int corners_num,
                                           CustomData_MeshMasks mask);

/**
 * Performs copy for use during evaluation.
 */
Mesh *BKE_mesh_copy_for_eval(const Mesh &source);

/**
 * These functions construct a new Mesh,
 * contrary to #BKE_mesh_to_curve_nurblist which modifies ob itself.
 */
Mesh *BKE_mesh_new_nomain_from_curve(const Object *ob);
Mesh *BKE_mesh_new_nomain_from_curve_displist(const Object *ob,
                                              const ListBaseT<DispList> *dispbase);

bool BKE_mesh_attribute_required(StringRef name);

Array<float3> BKE_mesh_orco_verts_get(const Object *ob);
void BKE_mesh_orco_verts_transform(Mesh *mesh, MutableSpan<float3> orco, bool invert);
void BKE_mesh_orco_verts_transform(Mesh *mesh, float (*orco)[3], int totvert, bool invert);

/**
 * Add a #CD_ORCO layer to the Mesh if there is none already.
 */
void BKE_mesh_orco_ensure(Object *ob, Mesh *mesh);

Mesh *BKE_mesh_from_object(Object *ob);
void BKE_mesh_assign_object(Main *bmain, Object *ob, Mesh *mesh);
void BKE_mesh_to_curve_nurblist(const Mesh *mesh, ListBaseT<Nurb> *nurblist, int edge_users_test);
void BKE_mesh_to_curve(Main *bmain, Depsgraph *depsgraph, Scene *scene, Object *ob);
void BKE_mesh_to_pointcloud(Main *bmain, Depsgraph *depsgraph, Scene *scene, Object *ob);
void BKE_pointcloud_to_mesh(Main *bmain, Depsgraph *depsgraph, Scene *scene, Object *ob);
void BKE_mesh_material_index_remove(Mesh *mesh, short index);
bool BKE_mesh_material_index_used(Mesh *mesh, short index);
void BKE_mesh_material_index_clear(Mesh *mesh);
void BKE_mesh_material_remap(Mesh *mesh, const unsigned int *remap, unsigned int remap_len);

void BKE_mesh_texspace_calc(Mesh *mesh);
void BKE_mesh_texspace_ensure(Mesh *mesh);
void BKE_mesh_texspace_get(Mesh *mesh, float r_texspace_location[3], float r_texspace_size[3]);
void BKE_mesh_texspace_get_reference(Mesh *mesh,
                                     char **r_texspace_flag,
                                     float **r_texspace_location,
                                     float **r_texspace_size);

/**
 * Create new mesh from the given object at its current state.
 * The caller owns the result mesh.
 *
 * If \a preserve_all_data_layers is true then the modifier stack is re-evaluated to ensure it
 * preserves all possible custom data layers.
 *
 * \note Dependency graph argument is required when preserve_all_data_layers is true, and is
 * ignored otherwise.
 */
Mesh *BKE_mesh_new_from_object(Depsgraph *depsgraph,
                               Object *object,
                               bool preserve_all_data_layers,
                               bool preserve_origindex,
                               bool ensure_subdivision);

/**
 * This is a version of BKE_mesh_new_from_object() which stores mesh in the given main database.
 * However, that function enforces object type to be a geometry one, and ensures a mesh is always
 * generated, be it empty.
 */
Mesh *BKE_mesh_new_from_object_to_bmain(Main *bmain,
                                        Depsgraph *depsgraph,
                                        Object *object,
                                        bool preserve_all_data_layers);

/**
 * Move data from a mesh outside of the main data-base into a mesh in the data-base.
 * Takes ownership of the source mesh.
 *
 * \param process_shape_keys: Whether to move #CD_SHAPEKEY layers to the destination mesh. If there
 * are no such layers and the number of vertices changed, the shape key data will be lost. If this
 * parameter is false, the caller is expected to handle shape keys itself.
 */
void BKE_mesh_nomain_to_mesh(Mesh *mesh_src,
                             Mesh *mesh_dst,
                             Object *ob,
                             bool process_shape_keys = true);
void BKE_mesh_nomain_to_meshkey(Mesh *mesh_src, Mesh *mesh_dst, KeyBlock *kb);

/* Vertex level transformations & checks (no evaluated mesh). */

void BKE_mesh_tessface_clear(Mesh *mesh);

void BKE_mesh_mselect_clear(Mesh *mesh);
void BKE_mesh_mselect_validate(Mesh *mesh);
/**
 * \return the index within `me->mselect`, or -1
 */
int BKE_mesh_mselect_find(const Mesh *mesh, int index, eMSelect_Type type);
/**
 * \return The index of the active element.
 */
int BKE_mesh_mselect_active_get(const Mesh *mesh, eMSelect_Type type);
void BKE_mesh_mselect_active_set(Mesh *mesh, int index, eMSelect_Type type);

void BKE_mesh_count_selected_items(const Mesh *mesh, int r_count[3]);

/* *** mesh_normals.cc *** */

/** Return true if the mesh vertex normals either are not stored or are dirty. */
bool BKE_mesh_vert_normals_are_dirty(const Mesh *mesh);

/** Return true if the mesh face normals either are not stored or are dirty. */
bool BKE_mesh_face_normals_are_dirty(const Mesh *mesh);

/**
 * References a contiguous loop-fan.
 * Combined with the automatically calculated face corner normal, this gives a dimensional
 * coordinate space used to convert normals between the "custom normal" #short2 representation and
 * a regular #float3 format.
 */
struct MLoopNorSpace {
  /** The automatically computed face corner normal, not including influence of custom normals. */
  float vec_lnor[3];
  /**
   * Reference vector, orthogonal to #vec_lnor, aligned with one of the edges (borders) of the
   * smooth fan, called 'reference edge'.
   */
  float vec_ref[3];
  /** Third vector, orthogonal to #vec_lnor and #vec_ref. */
  float vec_ortho[3];
  /**
   * Reference angle around #vec_ortho, in (0, pi] range, between #vec_lnor and the reference edge.
   *
   * A 0.0 value marks that space as invalid, as it can only happen in extremely degenerate
   * geometry cases (it would mean that the default normal is perfectly aligned with the reference
   * edge).
   */
  float ref_alpha;
  /**
   * Reference angle around #vec_lnor, in (0, 2pi] range, between the reference edge and the other
   * border edge of the fan.
   *
   * A 0.0 value marks that space as invalid, as it can only happen in degenerate geometry cases
   * (it would mean that all the edges connected to that corner of the smooth fan are perfectly
   * aligned).
   */
  float ref_beta;
  /**
   * All loops using this lnor space (i.e. smooth fan of loops),
   * as (depending on owning MLoopNorSpaceArrary.data_type):
   * - Indices (uint_in_ptr), or
   * - BMLoop pointers. */
  struct LinkNode *loops;
  char flags;
};
/**
 * MLoopNorSpace.flags
 */
enum {
  MLNOR_SPACE_IS_SINGLE = 1 << 0,
};

/**
 * Collection of #MLoopNorSpace basic storage & pre-allocation.
 */
struct MLoopNorSpaceArray {
  /** Face corner aligned array. */
  MLoopNorSpace **lspacearr;
  /** Allocated once, avoids to call #BLI_linklist_prepend_arena() for each loop! */
  struct LinkNode *loops_pool;
  /** Whether we store loop indices, or pointers to #BMLoop. */
  char data_type;
  /** Number of `clnors` spaces defined in this array. */
  int spaces_num;
  struct MemArena *mem;
};
/**
 * MLoopNorSpaceArray.data_type
 */
enum {
  MLNOR_SPACEARR_LOOP_INDEX = 0,
  MLNOR_SPACEARR_BMLOOP_PTR = 1,
};

/* Low-level custom normals functions. */
void BKE_lnor_spacearr_init(MLoopNorSpaceArray *lnors_spacearr, int numLoops, char data_type);
void BKE_lnor_spacearr_clear(MLoopNorSpaceArray *lnors_spacearr);
void BKE_lnor_spacearr_free(MLoopNorSpaceArray *lnors_spacearr);

/**
 * Utility for multi-threaded calculation that ensures
 * `lnors_spacearr_tls` doesn't share memory with `lnors_spacearr`
 * that would cause it not to be thread safe.
 *
 * \note This works as long as threads never operate on the same loops at once.
 */
void BKE_lnor_spacearr_tls_init(MLoopNorSpaceArray *lnors_spacearr,
                                MLoopNorSpaceArray *lnors_spacearr_tls);
/**
 * Utility for multi-threaded calculation
 * that merges `lnors_spacearr_tls` into `lnors_spacearr`.
 */
void BKE_lnor_spacearr_tls_join(MLoopNorSpaceArray *lnors_spacearr,
                                MLoopNorSpaceArray *lnors_spacearr_tls);

MLoopNorSpace *BKE_lnor_space_create(MLoopNorSpaceArray *lnors_spacearr);

/**
 * Should only be called once.
 * Beware, this modifies ref_vec and other_vec in place!
 * In case no valid space can be generated, ref_alpha and ref_beta are set to zero
 * (which means 'use auto lnors').
 */
void BKE_lnor_space_define(MLoopNorSpace *lnor_space,
                           const float lnor[3],
                           const float vec_ref[3],
                           const float vec_other[3],
                           Span<float3> edge_vectors);

/**
 * Add a new given loop to given lnor_space.
 * Depending on \a lnor_space->data_type, we expect \a bm_loop to be a pointer to BMLoop struct
 * (in case of BMLOOP_PTR), or nullptr (in case of LOOP_INDEX), loop index is then stored in
 * pointer. If \a is_single is set, the BMLoop or loop index is directly stored in \a
 * lnor_space->loops pointer (since there is only one loop in this fan), else it is added to the
 * linked list of loops in the fan.
 */
void BKE_lnor_space_add_loop(MLoopNorSpaceArray *lnors_spacearr,
                             MLoopNorSpace *lnor_space,
                             int corner,
                             void *bm_loop,
                             bool is_single);
void BKE_lnor_space_custom_data_to_normal(const MLoopNorSpace *lnor_space,
                                          const short clnor_data[2],
                                          float r_custom_lnor[3]);
void BKE_lnor_space_custom_normal_to_data(const MLoopNorSpace *lnor_space,
                                          const float custom_lnor[3],
                                          short r_clnor_data[2]);

/**
 * High-level custom normals functions.
 */
bool BKE_mesh_has_custom_loop_normals(Mesh *mesh);

/* *** mesh_evaluate.cc *** */

float BKE_mesh_calc_area(const Mesh *mesh);

bool BKE_mesh_center_median(const Mesh *mesh, float r_cent[3]);
/**
 * Calculate the center from faces,
 * use when we want to ignore vertex locations that don't have connected faces.
 */
bool BKE_mesh_center_median_from_faces(const Mesh *mesh, float r_cent[3]);
bool BKE_mesh_center_of_surface(const Mesh *mesh, float r_cent[3]);
/**
 * \note Mesh must be manifold with consistent face-winding,
 * see #mesh_calc_face_volume_centroid for details.
 */
bool BKE_mesh_center_of_volume(const Mesh *mesh, float r_cent[3]);

/**
 * Calculate the volume and center.
 *
 * \param r_volume: Volume (unsigned).
 * \param r_center: Center of mass.
 */
void BKE_mesh_calc_volume(const float (*vert_positions)[3],
                          int mverts_num,
                          const int3 *corner_tris,
                          int corner_tris_num,
                          const int *corner_verts,
                          float *r_volume,
                          float r_center[3]);

/**
 * Flip a single corner's #MDisps structure,
 * low level function to be called from face-flipping code which re-arranged the mdisps themselves.
 */
void BKE_mesh_mdisp_flip(MDisps *md, bool use_loop_mdisp_flip);

/**
 * Account for custom-data such as UVs becoming detached because of imprecision
 * in custom-data interpolation.
 * Without running this operation subdivision surface can cause UVs to be disconnected,
 * see: #81065.
 */
void BKE_mesh_merge_customdata_for_apply_modifier(Mesh *mesh);

/* Flush flags. */

/* spatial evaluation */
/**
 * This function takes the difference between 2 vertex-coord-arrays
 * (\a vert_cos_src, \a vert_cos_dst),
 * and applies the difference to \a vert_cos_new relative to \a vert_cos_org.
 *
 * \param vert_cos_src: reference deform source.
 * \param vert_cos_dst: reference deform destination.
 *
 * \param vert_cos_org: reference for the output location.
 * \param vert_cos_new: resulting coords.
 */
void BKE_mesh_calc_relative_deform(const int *face_offsets,
                                   int faces_num,
                                   const int *corner_verts,
                                   int totvert,

                                   const float (*vert_cos_src)[3],
                                   const float (*vert_cos_dst)[3],

                                   const float (*vert_cos_org)[3],
                                   float (*vert_cos_new)[3]);

/* **** Depsgraph evaluation **** */

void BKE_mesh_eval_geometry(Depsgraph *depsgraph, Mesh *mesh);

/* Draw Cache */
void BKE_mesh_batch_cache_dirty_tag(Mesh *mesh, eMeshBatchDirtyMode mode);
void BKE_mesh_batch_cache_free(draw::MeshBatchCache *batch_cache);

extern void (*BKE_mesh_batch_cache_dirty_tag_cb)(Mesh *mesh, eMeshBatchDirtyMode mode);
extern void (*BKE_mesh_batch_cache_free_cb)(draw::MeshBatchCache *batch_cache);

/* `mesh_debug.cc` */

#ifndef NDEBUG
char *BKE_mesh_debug_info(const Mesh *mesh) ATTR_NONNULL(1) ATTR_MALLOC ATTR_WARN_UNUSED_RESULT;
void BKE_mesh_debug_print(const Mesh *mesh) ATTR_NONNULL(1);
#endif

}  // namespace blender