/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
 *
 * SPDX-License-Identifier: Apache-2.0 */

#include "scene/curves.h"
#include "scene/hair.h"
#include "scene/light.h"
#include "scene/mesh.h"
#include "scene/object.h"
#include "scene/pointcloud.h"
#include "scene/volume.h"

#include "blender/sync.h"
#include "blender/util.h"

#include "util/task.h"

#include "BKE_material.hh"
#include "DNA_light_types.h"
#include "DNA_material_types.h"

CCL_NAMESPACE_BEGIN

static Geometry::Type determine_geom_type(BObjectInfo &b_ob_info, bool use_particle_hair)
{
  if (GS(b_ob_info.object_data->name) == blender::ID_LA) {
    blender::Light &b_light = *blender::id_cast<blender::Light *>(b_ob_info.object_data);
    switch (b_light.type) {
      case blender::LA_LOCAL:
        return Geometry::POINT_LIGHT;
      case blender::LA_SPOT:
        return Geometry::SPOT_LIGHT;
      case blender::LA_SUN:
        return Geometry::SUN_LIGHT;
      case blender::LA_AREA:
        return Geometry::AREA_LIGHT;
      default:
        /* Should be handled in `sync_background_light()`. */
        assert(false);
        return Geometry::BACKGROUND_LIGHT;
    }
  }

  if (GS(b_ob_info.object_data->name) == blender::ID_CV || use_particle_hair) {
    return Geometry::HAIR;
  }

  if (GS(b_ob_info.object_data->name) == blender::ID_PT) {
    return Geometry::POINTCLOUD;
  }

  if (GS(b_ob_info.object_data->name) == blender::ID_VO ||
      (b_ob_info.object_data ==
           object_get_data(*b_ob_info.real_object, b_ob_info.use_adaptive_subdivision) &&
       object_fluid_gas_domain_find(*b_ob_info.real_object)))
  {
    return Geometry::VOLUME;
  }

  return Geometry::MESH;
}

array<Node *> BlenderSync::find_used_shaders(blender::Object &b_ob)
{
  array<Node *> used_shaders;

  if (b_ob.type == blender::OB_LAMP) {
    find_shader(static_cast<blender::ID *>(b_ob.data), used_shaders, scene->default_light);
    return used_shaders;
  }

  blender::Material *material_override = view_layer.material_override;
  Shader *default_shader = (b_ob.type == blender::OB_VOLUME) ? scene->default_volume :
                                                               scene->default_surface;

  for (const int i : blender::IndexRange(BKE_object_material_count_eval(&b_ob))) {
    if (material_override) {
      find_shader(&material_override->id, used_shaders, default_shader);
    }
    else {
      blender::Material *b_material = BKE_object_material_get(&b_ob, i + 1);
      find_shader(reinterpret_cast<blender::ID *>(b_material), used_shaders, default_shader);
    }
  }

  if (used_shaders.size() == 0) {
    if (material_override) {
      find_shader(&material_override->id, used_shaders, default_shader);
    }
    else {
      used_shaders.push_back_slow(default_shader);
    }
  }

  return used_shaders;
}

Geometry *BlenderSync::sync_geometry(BObjectInfo &b_ob_info,
                                     bool object_updated,
                                     bool use_particle_hair,
                                     TaskPool *task_pool)
{
  /* Test if we can instance or if the object is modified. */
  const Geometry::Type geom_type = determine_geom_type(b_ob_info, use_particle_hair);
  blender::ID *const b_key_id = (b_ob_info.is_real_object_data() &&
                                 BKE_object_is_modified(*b_ob_info.real_object)) ?
                                    &b_ob_info.real_object->id :
                                    b_ob_info.object_data;
  const GeometryKey key(b_key_id, geom_type);

  /* Find shader indices. */
  array<Node *> used_shaders = find_used_shaders(*b_ob_info.iter_object);

  /* Ensure we only sync instanced geometry once. */
  Geometry *geom = geometry_map.find(key);
  if (geom) {
    if (geometry_synced.contains(geom)) {
      return geom;
    }
  }

  /* Test if we need to sync. */
  bool sync = true;
  if (geom == nullptr) {
    /* Add new geometry if it did not exist yet. */
    if (geom_type == Geometry::POINT_LIGHT) {
      geom = scene->create_light_node<PointLight>();
    }
    else if (geom_type == Geometry::SPOT_LIGHT) {
      geom = scene->create_light_node<SpotLight>();
    }
    else if (geom_type == Geometry::SUN_LIGHT) {
      geom = scene->create_light_node<SunLight>();
    }
    else if (geom_type == Geometry::AREA_LIGHT) {
      geom = scene->create_light_node<AreaLight>();
    }
    else if (geom_type == Geometry::HAIR) {
      geom = scene->create_node<Hair>();
    }
    else if (geom_type == Geometry::VOLUME) {
      geom = scene->create_node<Volume>();
    }
    else if (geom_type == Geometry::POINTCLOUD) {
      geom = scene->create_node<PointCloud>();
    }
    else {
      assert(geom_type == Geometry::MESH);
      geom = scene->create_node<Mesh>();
    }
    geometry_map.add(key, geom);
  }
  else {
    /* Test if we need to update existing geometry. */
    sync = geometry_map.update(geom, b_key_id);
  }

  if (!sync) {
    /* If transform was applied to geometry, need full update. */
    if (object_updated && geom->transform_applied) {
      ;
    }
    /* Test if shaders changed, these can be object level so geometry
     * does not get tagged for recalc. */
    else if (geom->get_used_shaders() != used_shaders) {
      ;
    }
    else {
      /* Even if not tagged for recalc, we may need to sync anyway
       * because the shader needs different geometry attributes. */
      bool attribute_recalc = false;

      for (Node *node : geom->get_used_shaders()) {
        Shader *shader = static_cast<Shader *>(node);
        if (shader->need_update_geometry()) {
          attribute_recalc = true;
        }
      }

      if (!attribute_recalc) {
        return geom;
      }
    }
  }

  geometry_synced.insert(geom);

  geom->name = ustring(BKE_id_name(*b_ob_info.object_data));

  /* Store the shaders immediately for the object attribute code. */
  geom->set_used_shaders(used_shaders);

  auto sync_func = [this, geom_type, b_ob_info, geom]() mutable {
    if (progress.get_cancel()) {
      return;
    }

    progress.set_sync_status("Synchronizing object", BKE_id_name(b_ob_info.real_object->id));

    if (geom->is_light()) {
      Light *light = static_cast<Light *>(geom);
      sync_light(b_ob_info, light);
    }
    else if (geom_type == Geometry::HAIR) {
      Hair *hair = static_cast<Hair *>(geom);
      sync_hair(b_ob_info, hair);
    }
    else if (geom_type == Geometry::VOLUME) {
      Volume *volume = static_cast<Volume *>(geom);
      sync_volume(b_ob_info, volume);
    }
    else if (geom_type == Geometry::POINTCLOUD) {
      PointCloud *pointcloud = static_cast<PointCloud *>(geom);
      sync_pointcloud(pointcloud, b_ob_info);
    }
    else {
      Mesh *mesh = static_cast<Mesh *>(geom);
      sync_mesh(b_ob_info, mesh);
    }
  };

  /* Defer the actual geometry sync to the task_pool for multithreading */
  if (task_pool) {
    task_pool->push(sync_func);
  }
  else {
    sync_func();
  }

  return geom;
}

void BlenderSync::sync_geometry_motion(BObjectInfo &b_ob_info,
                                       Object *object,
                                       const float motion_time,
                                       bool use_particle_hair,
                                       TaskPool *task_pool)
{
  /* Ensure we only sync instanced geometry once. */
  Geometry *geom = object->get_geometry();

  if (geometry_motion_synced.contains(geom) || geometry_motion_attribute_synced.contains(geom)) {
    return;
  }

  geometry_motion_synced.insert(geom);

  /* Ensure we only motion sync geometry that also had geometry synced, to avoid
   * unnecessary work and to ensure that its attributes were clear. */
  if (!geometry_synced.contains(geom)) {
    return;
  }

  /* Nothing to do for lights. */
  if (geom->is_light()) {
    return;
  }

  /* If the geometry already has motion blur from a velocity attribute, don't
   * set the geometry motion steps again.
   *
   * Otherwise, setting geometry motion steps is done here to avoid concurrency issues.
   * - It can't be done earlier in sync_object_motion_init because sync_geometry
   *   runs in parallel, and has_motion_blur would check attributes while
   *   sync_geometry is potentially creating the attribute from velocity.
   * - It needs to happen before the parallel motion sync that happens right after
   *   this, because that can create the attribute from neighboring frames.
   * Copying the motion steps from the object here solves this. */
  if (!geom->has_motion_blur()) {
    geom->set_motion_steps(object->get_motion().size());
  }

  /* Find time matching motion step required by geometry. */
  const int motion_step = geom->motion_step(motion_time);
  if (motion_step < 0) {
    return;
  }

  auto sync_func = [this, b_ob_info, use_particle_hair, motion_step, geom]() mutable {
    if (progress.get_cancel()) {
      return;
    }

    if (GS(b_ob_info.object_data->name) == blender::ID_CV || use_particle_hair) {
      Hair *hair = static_cast<Hair *>(geom);
      sync_hair_motion(b_ob_info, hair, motion_step);
    }
    else if (GS(b_ob_info.object_data->name) == blender::ID_VO ||
             object_fluid_gas_domain_find(*b_ob_info.real_object))
    {
      /* No volume motion blur support yet. */
    }
    else if (GS(b_ob_info.object_data->name) == blender::ID_PT) {
      PointCloud *pointcloud = static_cast<PointCloud *>(geom);
      sync_pointcloud_motion(pointcloud, b_ob_info, motion_step);
    }
    else {
      Mesh *mesh = static_cast<Mesh *>(geom);
      sync_mesh_motion(b_ob_info, mesh, motion_step);
    }
  };

  /* Defer the actual geometry sync to the task_pool for multithreading */
  if (task_pool) {
    task_pool->push(sync_func);
  }
  else {
    sync_func();
  }
}

CCL_NAMESPACE_END