/*
 * Copyright 2022 Frederico de Oliveira Linhares
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "view_2d.hpp"

#include <array>

#include "../core.hpp"

namespace
{

void
load_2d_uniform_buffer(void *obj)
{
  auto self = static_cast<VK::View2D*>(obj);

  try
  {
    self->ub_2d.reserve(cg_core.vk_swapchain->images_count);
    for(auto i{0}; i < cg_core.vk_swapchain->images_count; i++)
      self->ub_2d.emplace_back(
	cg_core.vk_device_with_swapchain, sizeof(VK::UBOView2D));
  }
  catch(const std::exception& e)
  {
    throw CommandError{e.what()};
  }
}

void
unload_2d_uniform_buffer(void *obj)
{
  auto self = static_cast<VK::View2D*>(obj);

  self->ub_2d.clear();
}

void
load_descriptor_sets_2d(void *obj)
{
  auto self = static_cast<VK::View2D*>(obj);

  std::vector<VkDescriptorSetLayout> layouts(
    cg_core.vk_swapchain->images_count,
    cg_core.vk_graphics_pipeline_2d_solid_layout->descriptor_set_view);

  VkDescriptorSetAllocateInfo alloc_info{};
  alloc_info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
  alloc_info.descriptorPool = self->descriptor_pool;
  alloc_info.descriptorSetCount = layouts.size();
  alloc_info.pSetLayouts = layouts.data();

  self->descriptor_sets_2d.resize(layouts.size());
  if(vkAllocateDescriptorSets(
       cg_core.vk_device_with_swapchain->device, &alloc_info,
       self->descriptor_sets_2d.data()) != VK_SUCCESS)
    throw CommandError{"Failed to create Vulkan descriptor sets for view."};
}

void
load_resources_to_descriptor_sets_2d(void *obj)
{
  auto self = static_cast<VK::View2D*>(obj);

  for(auto i{0}; i < self->ub_2d.size(); i++)
  {
    VkDescriptorBufferInfo view_2d_info{};
    view_2d_info.buffer = self->ub_2d[i].buffer;
    view_2d_info.offset = 0;
    view_2d_info.range = sizeof(VK::UBOView2D);

    std::array<VkWriteDescriptorSet, 1> write_descriptors{};
    write_descriptors[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
    write_descriptors[0].dstSet = self->descriptor_sets_2d[i];
    write_descriptors[0].dstBinding = 0;
    write_descriptors[0].dstArrayElement = 0;
    write_descriptors[0].descriptorCount = 1;
    write_descriptors[0].descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
    write_descriptors[0].pBufferInfo = &view_2d_info;
    write_descriptors[0].pImageInfo = nullptr;
    write_descriptors[0].pTexelBufferView = nullptr;

    vkUpdateDescriptorSets(
      cg_core.vk_device_with_swapchain->device, write_descriptors.size(),
      write_descriptors.data(), 0, nullptr);

    VK::UBOView2D ubo_view_2d;
    ubo_view_2d.proj = glm::ortho(
      0.0f, self->region.z,
      0.0f, self->region.w,
      0.0f, 100.0f);
    self->ub_2d[i].copy_data(&ubo_view_2d);
  }
}

}

namespace VK
{

const CommandChain View2D::loader{
  {&load_2d_uniform_buffer, &unload_2d_uniform_buffer}
};

const CommandChain View2D::descriptor_sets_loader{
  {&load_descriptor_sets_2d, nullptr},
  {&load_resources_to_descriptor_sets_2d, nullptr}
};

View2D::View2D(glm::vec4 region):
  region{region},
  descriptor_pool{VK_NULL_HANDLE},
  rectangles_to_draw{cg_core.vk_swapchain->images_count},
  sprites_to_draw{cg_core.vk_swapchain->images_count}
{
  loader.execute(this);
}

View2D::~View2D()
{
  loader.revert(this);
}

void
View2D::load_descriptor_sets(VkDescriptorPool descriptor_pool)
{
  if(this->descriptor_pool != VK_NULL_HANDLE) return;

  this->descriptor_pool = descriptor_pool;
  descriptor_sets_loader.execute(this);
}

void
View2D::unload_descriptor_sets()
{
  if(this->descriptor_pool == VK_NULL_HANDLE) return;

  this->descriptor_pool = VK_NULL_HANDLE;
  descriptor_sets_loader.revert(this);
}

}