/*
 * 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 "rectangle.hpp"

#include <array>

#include "../core.hpp"
#include "graphics_pipeline_2d_wired_layout.hpp"

namespace
{

void
load_mesh(void *obj)
{
  auto self = static_cast<VK::Rectangle*>(obj);

  self->queue_family =
    cg_core.vk_device_with_swapchain->get_queue_family_with_graphics();

  glm::vec2 rect[4]{
    glm::vec2{self->x, self->y},
    glm::vec2{self->x, self->y + self->height},
    glm::vec2{self->x + self->width, self->y},
    glm::vec2{self->x + self->width, self->y + self->height}
  };

  void *vertexes_data{&rect};
  static const size_t vertexes_size =
    sizeof(glm::vec2) * VK::Rectangle::vertex_count;
  self->source_buffers.reserve(cg_core.vk_swapchain->images_count);
  self->vertex_buffers.reserve(cg_core.vk_swapchain->images_count);
  for(int i{0}; i < cg_core.vk_swapchain->images_count; i++)
  {
    self->source_buffers.emplace_back(
      self->queue_family->device, vertexes_data, vertexes_size);
    self->vertex_buffers.emplace_back(
      self->queue_family, &self->source_buffers[i],
      VK_BUFFER_USAGE_VERTEX_BUFFER_BIT);
  }
}

void
unload_mesh(void *obj)
{
  auto self = static_cast<VK::Rectangle*>(obj);

  self->vertex_buffers.clear();
  self->source_buffers.clear();
}

void
load_uniform_buffer(void *obj)
{
  auto self = static_cast<VK::Rectangle*>(obj);

  self->ub_rectangle.reserve(cg_core.vk_swapchain->images_count);
  for(auto i{0}; i < cg_core.vk_swapchain->images_count; i++)
    self->ub_rectangle.emplace_back(
      cg_core.vk_device_with_swapchain, sizeof(VK::UBOModel2D));
}

void
unload_uniform_buffer(void *obj)
{
  auto self = static_cast<VK::Rectangle*>(obj);

  self->ub_rectangle.clear();
}

void
load_descriptor_set_pool(void *obj)
{
  auto self = static_cast<VK::Rectangle*>(obj);

  std::array<VkDescriptorPoolSize, 1> descriptor_pool_sizes{};
  descriptor_pool_sizes[0].type = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
  descriptor_pool_sizes[0].descriptorCount = self->ub_rectangle.size();

  VkDescriptorPoolCreateInfo pool_info{};
  pool_info.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO;
  pool_info.pNext = nullptr;
  pool_info.flags = 0;
  pool_info.maxSets = self->ub_rectangle.size();
  pool_info.poolSizeCount = descriptor_pool_sizes.size();
  pool_info.pPoolSizes = descriptor_pool_sizes.data();

  if(vkCreateDescriptorPool(
       self->queue_family->device->device, &pool_info, nullptr,
       &self->descriptor_pool) != VK_SUCCESS)
    throw CommandError{"Failed to create a Vulkan descriptor pool."};
}

void
unload_descriptor_set_pool(void *obj)
{
  auto self = static_cast<VK::Rectangle*>(obj);

  vkDestroyDescriptorPool(
    self->queue_family->device->device, self->descriptor_pool, nullptr);
}

void
load_descriptor_sets(void *obj)
{
  auto self = static_cast<VK::Rectangle*>(obj);

  std::vector<VkDescriptorSetLayout> layouts(
    cg_core.vk_swapchain->images_count,
    cg_core.vk_graphics_pipeline_2d_wired_layout->descriptor_set_instance);

  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.resize(layouts.size());
  if(vkAllocateDescriptorSets(
       self->queue_family->device->device, &alloc_info,
       self->descriptor_sets.data()) != VK_SUCCESS)
    CommandError{"Failed to create Vulkan descriptor set."};
}

void
load_data_to_descriptor_sets(void *obj)
{
  auto self = static_cast<VK::Rectangle*>(obj);

  for(auto i{0}; i < self->ub_rectangle.size(); i++)
  {
    VkDescriptorBufferInfo buffer_info{};
    buffer_info.buffer = self->ub_rectangle[i].buffer;
    buffer_info.offset = 0;
    buffer_info.range = sizeof(VK::UBOModel2D);

    std::array<VkWriteDescriptorSet, 1> write_descriptors{};
    write_descriptors[0].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
    write_descriptors[0].dstSet = self->descriptor_sets[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 = &buffer_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);
  }
}

static const CommandChain loader{
  {&load_mesh, &unload_mesh},
  {&load_uniform_buffer, &unload_uniform_buffer},
  {&load_descriptor_set_pool, &unload_descriptor_set_pool},
  {&load_descriptor_sets, nullptr},
  {&load_data_to_descriptor_sets, nullptr},
};

constexpr bool
_align_vertically(const float a_x, const float a_width,
                 const float b_x, const float b_width)
{
  return a_x <= b_x + b_width && a_x + a_width >= b_x;
}

constexpr bool
_align_horizontally(const float a_y, const float a_height,
                   const float b_y, const float b_height)
{
  return a_y <= b_y + b_height && a_y + a_height >= b_y;
}

}

namespace VK
{

Rectangle::Rectangle(float x, float y, float width, float height):
  x{x},
  y{y},
  width{width},
  height{height}
{
  loader.execute(this);
}

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

bool
Rectangle::align_vertically(const Rectangle &that) const
{
  return _align_vertically(this->x, this->width, that.x, that.width);
}

bool
Rectangle::align_horizontally(const Rectangle &that) const
{
  return _align_horizontally(this->y, this->height, that.y, that.height);
}

bool
Rectangle::collide(const Rectangle &that) const
{
  return
    _align_vertically(this->x, this->width, that.x, that.width) &&
    _align_horizontally(this->y, this->height, that.y, that.height);
}

void
Rectangle::update_vertex_buffer()
{
  glm::vec2 rect[4]{
    glm::vec2{this->x, this->y},
    glm::vec2{this->x, this->y + this->height},
    glm::vec2{this->x + this->width, this->y},
    glm::vec2{this->x + this->width, this->y + this->height}
  };

  void *vertexes_data{&rect};
  this->source_buffers[cg_core.vk_swapchain->current_frame].copy_data(
    vertexes_data);
  this->vertex_buffers[cg_core.vk_swapchain->current_frame].copy_data();
}

}