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

/** \file
 * \ingroup bke
 *
 * MetaBalls are created from a single Object (with a name without number in it).
 * All objects with the same name (but with a number in it) are added to this.
 */

#include <cctype>
#include <cfloat>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <numbers>
#include <optional>

#include "DNA_ID.h"
#include "MEM_guardedalloc.h"

/* Allow using deprecated functionality for .blend file I/O. */
#define DNA_DEPRECATED_ALLOW

#include "DNA_material_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meta_types.h"
#include "DNA_object_types.h"
#include "DNA_scene_types.h"

#include "BLI_listbase.h"
#include "BLI_math_matrix.h"
#include "BLI_math_rotation.h"
#include "BLI_math_vector.h"
#include "BLI_string_utils.hh"
#include "BLI_utildefines.h"

#include "BLT_translation.hh"

#include "BKE_main.hh"

#include "BKE_geometry_set.hh"
#include "BKE_idtype.hh"
#include "BKE_lattice.hh"
#include "BKE_layer.hh"
#include "BKE_lib_id.hh"
#include "BKE_lib_query.hh"
#include "BKE_library.hh"
#include "BKE_mball.hh"
#include "BKE_mball_tessellate.hh"
#include "BKE_object.hh"
#include "BKE_object_types.hh"

#include "DEG_depsgraph.hh"
#include "DEG_depsgraph_query.hh"

#include "BLO_read_write.hh"

namespace blender {

static void metaball_init_data(ID *id)
{
  MetaBall *metaball = id_cast<MetaBall *>(id);
  INIT_DEFAULT_STRUCT_AFTER(metaball, id);
}

static void metaball_copy_data(Main * /*bmain*/,
                               std::optional<Library *> /*owner_library*/,
                               ID *id_dst,
                               const ID *id_src,
                               const int /*flag*/)
{
  MetaBall *metaball_dst = id_cast<MetaBall *>(id_dst);
  const MetaBall *metaball_src = id_cast<const MetaBall *>(id_src);

  BLI_duplicatelist(&metaball_dst->elems, &metaball_src->elems);

  metaball_dst->mat = MEM_dupalloc(metaball_src->mat);

  metaball_dst->editelems = nullptr;
  metaball_dst->lastelem = nullptr;
}

static void metaball_free_data(ID *id)
{
  MetaBall *metaball = id_cast<MetaBall *>(id);

  MEM_SAFE_DELETE(metaball->mat);

  metaball->elems.free_no_destruct();
}

static void metaball_foreach_id(ID *id, LibraryForeachIDData *data)
{
  MetaBall *metaball = reinterpret_cast<MetaBall *>(id);
  for (int i = 0; i < metaball->totcol; i++) {
    BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, metaball->mat[i], IDWALK_CB_USER);
  }
}

static void metaball_blend_write(BlendWriter *writer, ID *id, const void *id_address)
{
  MetaBall *mb = id_cast<MetaBall *>(id);

  /* Clean up, important in undo case to reduce false detection of changed datablocks. */
  mb->editelems = nullptr;
  /* Must always be cleared (meta's don't have their own edit-data). */
  mb->needs_flush_to_id = 0;
  mb->lastelem = nullptr;

  /* write LibData */
  writer->write_id_struct(id_address, mb);
  BKE_id_blend_write(writer, &mb->id);

  /* direct data */
  writer->write_pointer_array(mb->totcol, mb->mat);

  for (MetaElem &ml : mb->elems) {
    writer->write_struct(&ml);
  }
}

static void metaball_blend_read_data(BlendDataReader *reader, ID *id)
{
  MetaBall *mb = id_cast<MetaBall *>(id);

  BLO_read_pointer_array_and_validate_size(reader, &mb->mat, &mb->totcol);

  BLO_read_struct_list(reader, MetaElem, &(mb->elems));

  mb->editelems = nullptr;
  /* Must always be cleared (meta's don't have their own edit-data). */
  mb->needs_flush_to_id = 0;
  // mb->edit_elems.first = mb->edit_elems.last = nullptr;
  mb->lastelem = nullptr;
}

IDTypeInfo IDType_ID_MB = {
    .id_code = MetaBall::id_type,
    .id_filter = FILTER_ID_MB,
    .dependencies_id_types = FILTER_ID_MA,
    .main_listbase_index = INDEX_ID_MB,
    .struct_size = sizeof(MetaBall),
    .name = "Metaball",
    .name_plural = N_("metaballs"),
    .translation_context = BLT_I18NCONTEXT_ID_METABALL,
    .flags = IDTYPE_FLAGS_APPEND_IS_REUSABLE,
    .asset_type_info = nullptr,

    .init_data = metaball_init_data,
    .copy_data = metaball_copy_data,
    .free_data = metaball_free_data,
    .make_local = nullptr,
    .foreach_id = metaball_foreach_id,
    .foreach_cache = nullptr,
    .foreach_path = nullptr,
    .foreach_working_space_color = nullptr,
    .owner_pointer_get = nullptr,

    .blend_write = metaball_blend_write,
    .blend_read_data = metaball_blend_read_data,
    .blend_read_after_liblink = nullptr,

    .blend_read_undo_preserve = nullptr,

    .lib_override_apply_post = nullptr,
};

/* Functions */

MetaBall *BKE_mball_add(Main *bmain, const char *name)
{
  MetaBall *mb = BKE_id_new<MetaBall>(bmain, name);
  return mb;
}

MetaElem *BKE_mball_element_add(MetaBall *mb, const int type)
{
  MetaElem *ml = MEM_new<MetaElem>(__func__);

  unit_qt(ml->quat);

  ml->rad = 2.0;
  ml->s = 2.0;
  ml->flag = MB_SCALE_RAD;

  switch (type) {
    case MB_BALL:
      ml->type = MB_BALL;
      ml->expx = ml->expy = ml->expz = 1.0;

      break;
    case MB_TUBE:
      ml->type = MB_TUBE;
      ml->expx = ml->expy = ml->expz = 1.0;

      break;
    case MB_PLANE:
      ml->type = MB_PLANE;
      ml->expx = ml->expy = ml->expz = 1.0;

      break;
    case MB_ELIPSOID:
      ml->type = MB_ELIPSOID;
      ml->expx = 1.2f;
      ml->expy = 0.8f;
      ml->expz = 1.0;

      break;
    case MB_CUBE:
      ml->type = MB_CUBE;
      ml->expx = ml->expy = ml->expz = 1.0;

      break;
    default:
      break;
  }

  BLI_addtail(&mb->elems, ml);

  return ml;
}

float2 BKE_mball_element_display_radius_calc_with_stiffness(const MetaElem *ml)
{
  float2 radius_stiffness = {
      /* Display radius. */
      ml->rad,
      /* Display stiffness. */
      ml->rad * atanf(ml->s) * float(2.0 / std::numbers::pi),
  };

  if (ml->type == MB_CUBE) {
    /* Without this additional size, the cube can't be selected in solid mode.
     * Use the minimum size so this doesn't become too large because of one large axis.
     * See: #136396. */
    const float offset = std::min({ml->expx, ml->expy, ml->expz}) * M_SQRT2;
    radius_stiffness[0] += offset;
    radius_stiffness[1] += offset;
  }
  return radius_stiffness;
}
float BKE_mball_element_display_radius_calc(const MetaElem *ml)
{
  float radius = ml->rad;
  if (ml->type == MB_CUBE) {
    const float offset = std::min({ml->expx, ml->expy, ml->expz}) * M_SQRT2;
    radius += offset;
  }
  return radius;
}

bool BKE_mball_is_basis(const Object *ob)
{
  /* Meta-Ball Basis Notes from Blender-2.5x
   * =======================================
   *
   * NOTE(@ideasman42): This is a can of worms.
   *
   * This really needs a rewrite/refactor its totally broken in anything other than basic cases
   * Multiple Scenes + Set Scenes & mixing meta-ball basis _should_ work but fails to update the
   * depsgraph on rename and linking into scenes or removal of basis meta-ball.
   * So take care when changing this code.
   *
   * Main idiot thing here is that the system returns #BKE_mball_basis_find()
   * objects which fail a #BKE_mball_is_basis() test.
   *
   * Not only that but the depsgraph and their areas depend on this behavior,
   * so making small fixes here isn't worth it. */

  /* Just a quick test. */
  const int len = strlen(ob->id.name);
  return !isdigit(ob->id.name[len - 1]);
}

bool BKE_mball_is_same_group(const Object *ob1, const Object *ob2)
{
  int basis1nr, basis2nr;
  char basis1name[MAX_ID_NAME], basis2name[MAX_ID_NAME];

  if (ob1->id.name[2] != ob2->id.name[2]) {
    /* Quick return in case first char of both ID's names is not the same... */
    return false;
  }

  BLI_string_split_name_number(ob1->id.name + 2, '.', basis1name, &basis1nr);
  BLI_string_split_name_number(ob2->id.name + 2, '.', basis2name, &basis2nr);

  return STREQ(basis1name, basis2name);
}

bool BKE_mball_is_basis_for(const Object *ob1, const Object *ob2)
{
  return BKE_mball_is_same_group(ob1, ob2) && BKE_mball_is_basis(ob1);
}

bool BKE_mball_is_any_selected(const MetaBall *mb)
{
  for (const MetaElem &ml : *mb->editelems) {
    if (ml.flag & SELECT) {
      return true;
    }
  }
  return false;
}

bool BKE_mball_is_any_selected_multi(const Span<Base *> bases)
{
  for (Base *base : bases) {
    Object *obedit = base->object;
    MetaBall *mb = id_cast<MetaBall *>(obedit->data);
    if (BKE_mball_is_any_selected(mb)) {
      return true;
    }
  }
  return false;
}

bool BKE_mball_is_any_unselected(const MetaBall *mb)
{
  for (const MetaElem &ml : *mb->editelems) {
    if ((ml.flag & SELECT) == 0) {
      return true;
    }
  }
  return false;
}

static void mball_data_properties_copy(MetaBall *mb_dst, MetaBall *mb_src)
{
  mb_dst->wiresize = mb_src->wiresize;
  mb_dst->rendersize = mb_src->rendersize;
  mb_dst->thresh = mb_src->thresh;
  mb_dst->flag = mb_src->flag;
  DEG_id_tag_update(&mb_dst->id, 0);
}

void BKE_mball_properties_copy(Main *bmain, MetaBall *metaball_src)
{
  /**
   * WARNING: This code does not cover all potential corner-cases. E.g. if:
   * <pre>
   * |   Object   |   ObData   |
   * | ---------- | ---------- |
   * | Meta_A     | Meta_A     |
   * | Meta_A.001 | Meta_A.001 |
   * | Meta_B     | Meta_A     |
   * | Meta_B.001 | Meta_B.001 |
   * </pre>
   *
   * Calling this function with `metaball_src` being `Meta_A.001` will update `Meta_A`, but NOT
   * `Meta_B.001`. So in the 'Meta_B' family, the two metaballs will have unmatching settings now.
   *
   * Solving this case would drastically increase the complexity of this code though, so don't
   * think it would be worth it.
   */
  for (Object *ob_src = static_cast<Object *>(bmain->objects.first);
       ob_src != nullptr && ID_IS_EDITABLE(ob_src);)
  {
    if (ob_src->data != id_cast<const ID *>(metaball_src)) {
      ob_src = static_cast<Object *>(ob_src->id.next);
      continue;
    }

    /* In this code we take advantage of two facts:
     *  - MetaBalls of the same family have the same basis name,
     *  - IDs are sorted by name in their Main listbase.
     * So, all MetaBall objects of the same family are contiguous in bmain list (potentially mixed
     * with non-meta-ball objects with same basis names).
     *
     * Using this, it is possible to process the whole set of meta-balls with a single loop on the
     * whole list of Objects, though additionally going backward on part of the list in some cases.
     */
    Object *ob_iter = nullptr;
    int obactive_nr, ob_nr;
    char obactive_name[MAX_ID_NAME], ob_name[MAX_ID_NAME];
    BLI_string_split_name_number(ob_src->id.name + 2, '.', obactive_name, &obactive_nr);

    for (ob_iter = static_cast<Object *>(ob_src->id.prev); ob_iter != nullptr;
         ob_iter = static_cast<Object *>(ob_iter->id.prev))
    {
      if (ob_iter->id.name[2] != obactive_name[0]) {
        break;
      }
      if (ob_iter->type != OB_MBALL || ob_iter->data == id_cast<const ID *>(metaball_src)) {
        continue;
      }
      BLI_string_split_name_number(ob_iter->id.name + 2, '.', ob_name, &ob_nr);
      if (!STREQ(obactive_name, ob_name)) {
        break;
      }

      mball_data_properties_copy(id_cast<MetaBall *>(ob_iter->data), metaball_src);
    }

    for (ob_iter = static_cast<Object *>(ob_src->id.next); ob_iter != nullptr;
         ob_iter = static_cast<Object *>(ob_iter->id.next))
    {
      if (ob_iter->id.name[2] != obactive_name[0] || !ID_IS_EDITABLE(ob_iter)) {
        break;
      }
      if (ob_iter->type != OB_MBALL || ob_iter->data == id_cast<const ID *>(metaball_src)) {
        continue;
      }
      BLI_string_split_name_number(ob_iter->id.name + 2, '.', ob_name, &ob_nr);
      if (!STREQ(obactive_name, ob_name)) {
        break;
      }

      mball_data_properties_copy(id_cast<MetaBall *>(ob_iter->data), metaball_src);
    }

    ob_src = ob_iter;
  }
}

Object *BKE_mball_basis_find(const Main &bmain, Scene *scene, Object *object)
{
  Object *bob = object;
  int basisnr, obnr;
  char basisname[MAX_ID_NAME], obname[MAX_ID_NAME];

  BLI_string_split_name_number(object->id.name + 2, '.', basisname, &basisnr);

  for (ViewLayer &view_layer : scene->view_layers) {
    BKE_view_layer_synced_ensure(bmain, scene, &view_layer);
    for (Base &base : *BKE_view_layer_object_bases_get(&view_layer)) {
      Object *ob = base.object;
      if ((ob->type == OB_MBALL) && !(base.flag & BASE_FROM_DUPLI)) {
        if (ob != bob) {
          BLI_string_split_name_number(ob->id.name + 2, '.', obname, &obnr);

          /* Object ob has to be in same "group" ... it means,
           * that it has to have same base of its name. */
          if (STREQ(obname, basisname)) {
            if (obnr < basisnr) {
              object = ob;
              basisnr = obnr;
            }
          }
        }
      }
    }
  }

  return object;
}

bool BKE_mball_minmax_ex(
    const MetaBall *mb, float min[3], float max[3], const float obmat[4][4], const short flag)
{
  const float scale = obmat ? mat4_to_scale(obmat) : 1.0f;
  bool changed = false;
  float centroid[3], vec[3];

  INIT_MINMAX(min, max);

  for (const MetaElem &ml : mb->elems) {
    if ((ml.flag & flag) == flag) {
      const float scale_mb = (ml.rad * 0.5f) * scale;

      if (obmat) {
        mul_v3_m4v3(centroid, obmat, &ml.x);
      }
      else {
        copy_v3_v3(centroid, &ml.x);
      }

      /* TODO(@ideasman42): non circle shapes cubes etc, probably nobody notices. */
      for (int i = -1; i != 3; i += 2) {
        copy_v3_v3(vec, centroid);
        add_v3_fl(vec, scale_mb * i);
        minmax_v3v3_v3(min, max, vec);
      }
      changed = true;
    }
  }

  return changed;
}

bool BKE_mball_minmax(const MetaBall *mb, float min[3], float max[3])
{
  INIT_MINMAX(min, max);

  for (const MetaElem &ml : mb->elems) {
    minmax_v3v3_v3(min, max, &ml.x);
  }

  return (mb->elems.is_empty() == false);
}

bool BKE_mball_center_median(const MetaBall *mb, float r_cent[3])
{
  int total = 0;

  zero_v3(r_cent);

  for (const MetaElem &ml : mb->elems) {
    add_v3_v3(r_cent, &ml.x);
    total++;
  }

  if (total) {
    mul_v3_fl(r_cent, 1.0f / float(total));
  }

  return (total != 0);
}

bool BKE_mball_center_bounds(const MetaBall *mb, float r_cent[3])
{
  float min[3], max[3];

  if (BKE_mball_minmax(mb, min, max)) {
    mid_v3_v3v3(r_cent, min, max);
    return true;
  }

  return false;
}

void BKE_mball_transform(MetaBall *mb, const float mat[4][4], const bool do_props)
{
  float quat[4];
  const float scale = mat4_to_scale(mat);
  const float scale_sqrt = sqrtf(scale);

  mat4_to_quat(quat, mat);

  for (MetaElem &ml : mb->elems) {
    mul_m4_v3(mat, &ml.x);
    mul_qt_qtqt(ml.quat, quat, ml.quat);

    if (do_props) {
      ml.rad *= scale;
      /* hrmf, probably elems shouldn't be
       * treating scale differently - campbell */
      if (!MB_TYPE_SIZE_SQUARED(ml.type)) {
        mul_v3_fl(&ml.expx, scale);
      }
      else {
        mul_v3_fl(&ml.expx, scale_sqrt);
      }
    }
  }
}

void BKE_mball_translate(MetaBall *mb, const float offset[3])
{
  for (MetaElem &ml : mb->elems) {
    add_v3_v3(&ml.x, offset);
  }
}

int BKE_mball_select_count(const MetaBall *mb)
{
  int sel = 0;
  for (const MetaElem &ml : *mb->editelems) {
    if (ml.flag & SELECT) {
      sel++;
    }
  }
  return sel;
}

int BKE_mball_select_count_multi(const Span<Base *> bases)
{
  int sel = 0;
  for (Base *base : bases) {
    Object *obedit = base->object;
    const MetaBall *mb = id_cast<MetaBall *>(obedit->data);
    sel += BKE_mball_select_count(mb);
  }
  return sel;
}

bool BKE_mball_select_all(MetaBall *mb)
{
  bool changed = false;
  for (MetaElem &ml : *mb->editelems) {
    if ((ml.flag & SELECT) == 0) {
      ml.flag |= MB_SELECT;
      changed = true;
    }
  }
  return changed;
}

bool BKE_mball_select_all_multi_ex(const Span<Base *> bases)
{
  bool changed_multi = false;
  for (Base *base : bases) {
    Object *obedit = base->object;
    MetaBall *mb = id_cast<MetaBall *>(obedit->data);
    changed_multi |= BKE_mball_select_all(mb);
  }
  return changed_multi;
}

bool BKE_mball_deselect_all(MetaBall *mb)
{
  bool changed = false;
  for (MetaElem &ml : *mb->editelems) {
    if ((ml.flag & SELECT) != 0) {
      ml.flag &= ~MB_SELECT;
      changed = true;
    }
  }
  return changed;
}

bool BKE_mball_deselect_all_multi_ex(const Span<Base *> bases)
{
  bool changed_multi = false;
  for (Base *base : bases) {
    Object *obedit = base->object;
    MetaBall *mb = id_cast<MetaBall *>(obedit->data);
    changed_multi |= BKE_mball_deselect_all(mb);
    DEG_id_tag_update(&mb->id, ID_RECALC_SELECT);
  }
  return changed_multi;
}

bool BKE_mball_select_swap(MetaBall *mb)
{
  bool changed = false;
  for (MetaElem &ml : *mb->editelems) {
    ml.flag ^= MB_SELECT;
    changed = true;
  }
  return changed;
}

bool BKE_mball_select_swap_multi_ex(const Span<Base *> bases)
{
  bool changed_multi = false;
  for (Base *base : bases) {
    Object *obedit = base->object;
    MetaBall *mb = id_cast<MetaBall *>(obedit->data);
    changed_multi |= BKE_mball_select_swap(mb);
  }
  return changed_multi;
}

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

void BKE_mball_data_update(Depsgraph *depsgraph, Scene *scene, Object *ob)
{
  using namespace blender::bke;
  BLI_assert(ob->type == OB_MBALL);

  BKE_object_free_derived_caches(ob);

  const Object *basis_object = BKE_mball_basis_find(*DEG_get_bmain(depsgraph), scene, ob);
  if (ob != basis_object) {
    return;
  }

  Mesh *mesh = BKE_mball_polygonize(depsgraph, scene, ob);
  if (mesh == nullptr) {
    return;
  }

  const MetaBall *mball = id_cast<MetaBall *>(ob->data);
  mesh->mat = MEM_dupalloc(mball->mat);
  mesh->totcol = mball->totcol;

  if (ob->parent && ob->parent->type == OB_LATTICE && ob->partype == PARSKEL) {
    BKE_lattice_deform_coords(
        ob->parent,
        ob,
        reinterpret_cast<float (*)[3]>(mesh->vert_positions_for_write().data()),
        mesh->verts_num,
        0,
        nullptr,
        1.0f);
    mesh->tag_positions_changed();
  }

  ob->runtime->geometry_set_eval = new GeometrySet(GeometrySet::from_mesh(mesh));
};

}  // namespace blender