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

#include "DNA_mesh_types.h"

#include "BKE_mesh.h"
#include "BKE_mesh_runtime.h"

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

#include "node_geometry_util.hh"

namespace blender::nodes::node_geo_edge_split_cc {

static void node_declare(NodeDeclarationBuilder &b)
{
  b.add_input<decl::Geometry>(N_("Mesh")).supported_type(GEO_COMPONENT_TYPE_MESH);
  b.add_input<decl::Bool>(N_("Selection")).default_value(true).hide_value().supports_field();
  b.add_output<decl::Geometry>(N_("Mesh"));
}

static Mesh *mesh_edge_split(const Mesh &mesh, const IndexMask selection)
{
  BMeshCreateParams bmesh_create_params{};
  bmesh_create_params.use_toolflags = true;
  const BMAllocTemplate allocsize = {0, 0, 0, 0};
  BMesh *bm = BM_mesh_create(&allocsize, &bmesh_create_params);

  BMeshFromMeshParams bmesh_from_mesh_params{};
  bmesh_from_mesh_params.cd_mask_extra.vmask = CD_MASK_ORIGINDEX;
  bmesh_from_mesh_params.cd_mask_extra.emask = CD_MASK_ORIGINDEX;
  bmesh_from_mesh_params.cd_mask_extra.pmask = CD_MASK_ORIGINDEX;
  BM_mesh_bm_from_me(bm, &mesh, &bmesh_from_mesh_params);

  BM_mesh_elem_table_ensure(bm, BM_EDGE);
  for (const int i : selection) {
    BMEdge *edge = BM_edge_at_index(bm, i);
    BM_elem_flag_enable(edge, BM_ELEM_TAG);
  }

  BM_mesh_edgesplit(bm, false, true, false);

  Mesh *result = BKE_mesh_from_bmesh_for_eval_nomain(bm, nullptr, &mesh);
  BM_mesh_free(bm);

  return result;
}

static void node_geo_exec(GeoNodeExecParams params)
{
  GeometrySet geometry_set = params.extract_input<GeometrySet>("Mesh");

  const Field<bool> selection_field = params.extract_input<Field<bool>>("Selection");

  geometry_set.modify_geometry_sets([&](GeometrySet &geometry_set) {
    if (const Mesh *mesh = geometry_set.get_mesh_for_write()) {

      bke::MeshFieldContext field_context{*mesh, ATTR_DOMAIN_EDGE};
      fn::FieldEvaluator selection_evaluator{field_context, mesh->totedge};
      selection_evaluator.add(selection_field);
      selection_evaluator.evaluate();
      const IndexMask selection = selection_evaluator.get_evaluated_as_mask(0);

      Mesh *result = mesh_edge_split(*mesh, selection);

      geometry_set.replace_mesh(result);
    }
  });

  params.set_output("Mesh", std::move(geometry_set));
}

}  // namespace blender::nodes::node_geo_edge_split_cc

void register_node_type_geo_edge_split()
{
  namespace file_ns = blender::nodes::node_geo_edge_split_cc;

  static bNodeType ntype;

  geo_node_type_base(&ntype, GEO_NODE_SPLIT_EDGES, "Split Edges", NODE_CLASS_GEOMETRY);
  ntype.geometry_node_execute = file_ns::node_geo_exec;
  ntype.declare = file_ns::node_declare;
  nodeRegisterType(&ntype);
}