/* SPDX-FileCopyrightText: 2005 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

#include "node_shader_util.hh"

#include "BLI_math_base.h"

namespace blender {

namespace nodes::node_shader_eevee_specular_cc {

static void node_declare(NodeDeclarationBuilder &b)
{
  const bNodeTree *ntree = b.tree_or_null();
  const bool is_gpu_internal = ntree && (ntree->flag & NTREE_IS_GPU_SHADER_INTERNAL);

  b.add_input<decl::Color>("Base Color"_ustr).default_value({0.8f, 0.8f, 0.8f, 1.0f});
  b.add_input<decl::Color>("Specular"_ustr).default_value({0.03f, 0.03f, 0.03f, 1.0f});
  b.add_input<decl::Float>("Roughness"_ustr)
      .default_value(0.2f)
      .min(0.0f)
      .max(1.0f)
      .subtype(PROP_FACTOR);
  b.add_input<decl::Color>("Emissive Color"_ustr).default_value({0.0f, 0.0f, 0.0f, 1.0f});
  b.add_input<decl::Float>("Transparency"_ustr)
      .default_value(0.0f)
      .min(0.0f)
      .max(1.0f)
      .subtype(PROP_FACTOR);
  b.add_input<decl::Vector>("Normal"_ustr).hide_value();
  b.add_input<decl::Float>("Clear Coat"_ustr)
      .default_value(0.0f)
      .min(0.0f)
      .max(1.0f)
      .subtype(PROP_FACTOR);
  b.add_input<decl::Float>("Clear Coat Roughness"_ustr)
      .default_value(0.0f)
      .min(0.0f)
      .max(1.0f)
      .subtype(PROP_FACTOR);
  b.add_input<decl::Vector>("Clear Coat Normal"_ustr).hide_value();
  b.add_input<decl::Float>("Weight"_ustr).available(is_gpu_internal);
  b.add_output<decl::Shader>("BSDF"_ustr);
}

static int node_shader_gpu_eevee_specular(GPUMaterial *mat,
                                          bNode *node,
                                          bNodeExecData * /*execdata*/,
                                          GPUNodeStack *in,
                                          GPUNodeStack *out)
{
  /* Normals */
  if (!in[5].link) {
    GPU_link(mat, "world_normals_get", &in[5].link);
  }

  /* Coat Normals */
  if (!in[8].link) {
    GPU_link(mat, "world_normals_get", &in[8].link);
  }

  bool use_transparency = in[4].socket_not_zero();
  bool use_coat = in[6].socket_not_zero();

  eGPUMaterialFlag flag = GPU_MATFLAG_DIFFUSE | GPU_MATFLAG_GLOSSY;

  if (in[1].might_be_tinted()) {
    flag |= GPU_MATFLAG_REFLECTION_MAYBE_COLORED;
  }
  if (use_coat) {
    flag |= GPU_MATFLAG_COAT;
  }
  if (use_transparency) {
    flag |= GPU_MATFLAG_TRANSPARENT;
  }

  GPU_material_flag_set(mat, flag);

  float use_coat_f = use_coat ? 1.0f : 0.0f;
  return GPU_stack_link(mat, node, "node_eevee_specular", in, out, GPU_constant(&use_coat_f));
}

}  // namespace nodes::node_shader_eevee_specular_cc

/* node type definition */
void register_node_type_sh_eevee_specular()
{
  namespace file_ns = nodes::node_shader_eevee_specular_cc;

  static bke::bNodeType ntype;

  sh_node_type_base(&ntype, "ShaderNodeEeveeSpecular"_ustr, SH_NODE_EEVEE_SPECULAR);
  ntype.ui_name = "Specular BSDF";
  ntype.ui_description =
      "Similar to the Principled BSDF node but uses the specular workflow instead of metallic, "
      "which functions by specifying the facing (along normal) reflection color. Energy is not "
      "conserved, so the result may not be physically accurate";
  ntype.enum_name_legacy = "EEVEE_SPECULAR";
  ntype.nclass = NODE_CLASS_SHADER;
  ntype.declare = file_ns::node_declare;
  ntype.gather_link_search_ops = search_link_ops_for_shader_bsdf_node;
  ntype.add_ui_poll = object_eevee_shader_nodes_poll;
  ntype.gpu_fn = file_ns::node_shader_gpu_eevee_specular;

  bke::node_register_type(ntype);
}

}  // namespace blender
