/* SPDX-License-Identifier: GPL-2.0-or-later */

/** \file
 * \ingroup modifiers
 */

#include <cstring>

#include "MEM_guardedalloc.h"

#include "BLI_utildefines.h"

#include "BLT_translation.h"

#include "DNA_defaults.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_object_types.h"
#include "DNA_screen_types.h"

#include "BKE_context.h"
#include "BKE_mesh.hh"
#include "BKE_modifier.h"
#include "BKE_screen.h"

#include "UI_interface.h"
#include "UI_resources.h"

#include "RNA_access.h"
#include "RNA_prototypes.h"

#include "bmesh.h"
#include "bmesh_tools.h"

#include "MOD_modifiertypes.h"
#include "MOD_ui_common.h"

static Mesh *triangulate_mesh(Mesh *mesh,
                              const int quad_method,
                              const int ngon_method,
                              const int min_vertices,
                              const int flag)
{
  Mesh *result;
  BMesh *bm;
  CustomData_MeshMasks cd_mask_extra{};
  cd_mask_extra.vmask = CD_MASK_ORIGINDEX;
  cd_mask_extra.emask = CD_MASK_ORIGINDEX;
  cd_mask_extra.pmask = CD_MASK_ORIGINDEX;

  bool keep_clnors = (flag & MOD_TRIANGULATE_KEEP_CUSTOMLOOP_NORMALS) != 0;

  if (keep_clnors) {
    BKE_mesh_calc_normals_split(mesh);
    /* We need that one to 'survive' to/from BMesh conversions. */
    CustomData_clear_layer_flag(&mesh->ldata, CD_NORMAL, CD_FLAG_TEMPORARY);
    cd_mask_extra.lmask |= CD_MASK_NORMAL;
  }

  BMeshCreateParams bmesh_create_params{};
  BMeshFromMeshParams bmesh_from_mesh_params{};
  bmesh_from_mesh_params.calc_face_normal = true;
  bmesh_from_mesh_params.calc_vert_normal = false;
  bmesh_from_mesh_params.cd_mask_extra = cd_mask_extra;

  bm = BKE_mesh_to_bmesh_ex(mesh, &bmesh_create_params, &bmesh_from_mesh_params);

  BM_mesh_triangulate(
      bm, quad_method, ngon_method, min_vertices, false, nullptr, nullptr, nullptr);

  result = BKE_mesh_from_bmesh_for_eval_nomain(bm, &cd_mask_extra, mesh);
  BM_mesh_free(bm);

  if (keep_clnors) {
    float(*lnors)[3] = static_cast<float(*)[3]>(
        CustomData_get_layer_for_write(&result->ldata, CD_NORMAL, result->totloop));
    BLI_assert(lnors != nullptr);

    BKE_mesh_set_custom_normals(result, lnors);

    /* Do some cleanup, we do not want those temp data to stay around. */
    CustomData_set_layer_flag(&mesh->ldata, CD_NORMAL, CD_FLAG_TEMPORARY);
    CustomData_set_layer_flag(&result->ldata, CD_NORMAL, CD_FLAG_TEMPORARY);
  }

  return result;
}

static void initData(ModifierData *md)
{
  TriangulateModifierData *tmd = (TriangulateModifierData *)md;

  BLI_assert(MEMCMP_STRUCT_AFTER_IS_ZERO(tmd, modifier));

  MEMCPY_STRUCT_AFTER(tmd, DNA_struct_default_get(TriangulateModifierData), modifier);

  /* Enable in editmode by default */
  md->mode |= eModifierMode_Editmode;
}

static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext * /*ctx*/, Mesh *mesh)
{
  TriangulateModifierData *tmd = (TriangulateModifierData *)md;
  Mesh *result;
  if (!(result = triangulate_mesh(
            mesh, tmd->quad_method, tmd->ngon_method, tmd->min_vertices, tmd->flag))) {
    return mesh;
  }

  return result;
}

static void panel_draw(const bContext * /*C*/, Panel *panel)
{
  uiLayout *layout = panel->layout;

  PointerRNA ob_ptr;
  PointerRNA *ptr = modifier_panel_get_property_pointers(panel, &ob_ptr);

  uiLayoutSetPropSep(layout, true);

  uiItemR(layout, ptr, "quad_method", 0, nullptr, ICON_NONE);
  uiItemR(layout, ptr, "ngon_method", 0, nullptr, ICON_NONE);
  uiItemR(layout, ptr, "min_vertices", 0, nullptr, ICON_NONE);
  uiItemR(layout, ptr, "keep_custom_normals", 0, nullptr, ICON_NONE);

  modifier_panel_end(layout, ptr);
}

static void panelRegister(ARegionType *region_type)
{
  modifier_panel_register(region_type, eModifierType_Triangulate, panel_draw);
}

ModifierTypeInfo modifierType_Triangulate = {
    /*name*/ N_("Triangulate"),
    /*structName*/ "TriangulateModifierData",
    /*structSize*/ sizeof(TriangulateModifierData),
    /*srna*/ &RNA_TriangulateModifier,
    /*type*/ eModifierTypeType_Constructive,
    /*flags*/ eModifierTypeFlag_AcceptsMesh | eModifierTypeFlag_SupportsEditmode |
        eModifierTypeFlag_SupportsMapping | eModifierTypeFlag_EnableInEditmode |
        eModifierTypeFlag_AcceptsCVs,
    /*icon*/ ICON_MOD_TRIANGULATE,

    /*copyData*/ BKE_modifier_copydata_generic,

    /*deformVerts*/ nullptr,
    /*deformMatrices*/ nullptr,
    /*deformVertsEM*/ nullptr,
    /*deformMatricesEM*/ nullptr,
    /*modifyMesh*/ modifyMesh,
    /*modifyGeometrySet*/ nullptr,

    /*initData*/ initData,
    /*requiredDataMask*/ nullptr,  // requiredDataMask,
    /*freeData*/ nullptr,
    /*isDisabled*/ nullptr,
    /*updateDepsgraph*/ nullptr,
    /*dependsOnTime*/ nullptr,
    /*dependsOnNormals*/ nullptr,
    /*foreachIDLink*/ nullptr,
    /*foreachTexLink*/ nullptr,
    /*freeRuntimeData*/ nullptr,
    /*panelRegister*/ panelRegister,
    /*blendWrite*/ nullptr,
    /*blendRead*/ nullptr,
};