// Copyright(c) 2019, NVIDIA CORPORATION. All rights reserved.
//
// 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.
//
// VulkanHpp Samples : TexelBuffer
//                     Use a texel buffer to draw a green triangle.

#include "../utils/geometries.hpp"
#include "../utils/math.hpp"
#include "../utils/shaders.hpp"
#include "../utils/utils.hpp"
#include "SPIRV/GlslangToSpv.h"
#include "vulkan/vulkan.hpp"

#include <iostream>
#include <thread>

static char const * AppName    = "TexelBuffer";
static char const * EngineName = "Vulkan.hpp";

static const std::string vertexShaderText = R"(
#version 400

#extension GL_ARB_separate_shader_objects : enable
#extension GL_ARB_shading_language_420pack : enable

layout (binding = 0) uniform samplerBuffer texels;
layout (location = 0) out vec4 outColor;

vec2 vertices[3];

void main()
{
  float r = texelFetch(texels, 0).r;
  float g = texelFetch(texels, 1).r;
  float b = texelFetch(texels, 2).r;
  outColor = vec4(r, g, b, 1.0);

  vertices[0] = vec2(-1.0, -1.0);
  vertices[1] = vec2( 1.0, -1.0);
  vertices[2] = vec2( 0.0,  1.0);
  gl_Position = vec4(vertices[gl_VertexIndex % 3], 0.0, 1.0);
}
)";

int main( int /*argc*/, char ** /*argv*/ )
{
  const float texels[] = { 118.0f / 255.0f, 185.0f / 255.0f, 0.0f };

  try
  {
    vk::UniqueInstance instance = vk::su::createInstance( AppName, EngineName, {}, vk::su::getInstanceExtensions() );
#if !defined( NDEBUG )
    vk::UniqueDebugUtilsMessengerEXT debugUtilsMessenger = vk::su::createDebugUtilsMessenger( instance );
#endif

    vk::PhysicalDevice physicalDevice = instance->enumeratePhysicalDevices().front();

    vk::PhysicalDeviceProperties physicalDeviceProperties = physicalDevice.getProperties();
    if ( physicalDeviceProperties.limits.maxTexelBufferElements < 4 )
    {
      std::cout << "maxTexelBufferElements too small\n";
      exit( -1 );
    }

    vk::Format           texelFormat      = vk::Format::eR32Sfloat;
    vk::FormatProperties formatProperties = physicalDevice.getFormatProperties( texelFormat );
    if ( !( formatProperties.bufferFeatures & vk::FormatFeatureFlagBits::eUniformTexelBuffer ) )
    {
      std::cout << "R32_SFLOAT format unsupported for texel buffer\n";
      exit( -1 );
    }

    vk::su::SurfaceData surfaceData( instance, AppName, vk::Extent2D( 500, 500 ) );

    std::pair<uint32_t, uint32_t> graphicsAndPresentQueueFamilyIndex =
      vk::su::findGraphicsAndPresentQueueFamilyIndex( physicalDevice, *surfaceData.surface );
    vk::UniqueDevice device =
      vk::su::createDevice( physicalDevice, graphicsAndPresentQueueFamilyIndex.first, vk::su::getDeviceExtensions() );

    vk::UniqueCommandPool   commandPool = vk::su::createCommandPool( device, graphicsAndPresentQueueFamilyIndex.first );
    vk::UniqueCommandBuffer commandBuffer = std::move( device
                                                         ->allocateCommandBuffersUnique( vk::CommandBufferAllocateInfo(
                                                           commandPool.get(), vk::CommandBufferLevel::ePrimary, 1 ) )
                                                         .front() );

    vk::Queue graphicsQueue = device->getQueue( graphicsAndPresentQueueFamilyIndex.first, 0 );
    vk::Queue presentQueue  = device->getQueue( graphicsAndPresentQueueFamilyIndex.second, 0 );

    vk::su::SwapChainData swapChainData( physicalDevice,
                                         device,
                                         *surfaceData.surface,
                                         surfaceData.extent,
                                         vk::ImageUsageFlagBits::eColorAttachment |
                                           vk::ImageUsageFlagBits::eTransferSrc,
                                         vk::UniqueSwapchainKHR(),
                                         graphicsAndPresentQueueFamilyIndex.first,
                                         graphicsAndPresentQueueFamilyIndex.second );

    vk::su::BufferData texelBufferData(
      physicalDevice, device, sizeof( texels ), vk::BufferUsageFlagBits::eUniformTexelBuffer );
    texelBufferData.upload( device, texels );

    vk::UniqueBufferView texelBufferView = device->createBufferViewUnique(
      vk::BufferViewCreateInfo( {}, *texelBufferData.buffer, texelFormat, 0, sizeof( texels ) ) );

    vk::UniqueDescriptorSetLayout descriptorSetLayout = vk::su::createDescriptorSetLayout(
      device, { { vk::DescriptorType::eUniformTexelBuffer, 1, vk::ShaderStageFlagBits::eVertex } } );
    vk::UniquePipelineLayout pipelineLayout = device->createPipelineLayoutUnique(
      vk::PipelineLayoutCreateInfo( vk::PipelineLayoutCreateFlags(), *descriptorSetLayout ) );

    vk::UniqueRenderPass renderPass = vk::su::createRenderPass(
      device,
      vk::su::pickSurfaceFormat( physicalDevice.getSurfaceFormatsKHR( surfaceData.surface.get() ) ).format,
      vk::Format::eUndefined );

    glslang::InitializeProcess();
    vk::UniqueShaderModule vertexShaderModule =
      vk::su::createShaderModule( device, vk::ShaderStageFlagBits::eVertex, vertexShaderText );
    vk::UniqueShaderModule fragmentShaderModule =
      vk::su::createShaderModule( device, vk::ShaderStageFlagBits::eFragment, fragmentShaderText_C_C );
    glslang::FinalizeProcess();

    std::vector<vk::UniqueFramebuffer> framebuffers = vk::su::createFramebuffers(
      device, renderPass, swapChainData.imageViews, vk::UniqueImageView(), surfaceData.extent );

    vk::UniqueDescriptorPool descriptorPool =
      vk::su::createDescriptorPool( device, { { vk::DescriptorType::eUniformTexelBuffer, 1 } } );
    vk::UniqueDescriptorSet descriptorSet = std::move(
      device->allocateDescriptorSetsUnique( vk::DescriptorSetAllocateInfo( *descriptorPool, *descriptorSetLayout ) )
        .front() );
    vk::su::updateDescriptorSets(
      device,
      descriptorSet,
      { { vk::DescriptorType::eUniformTexelBuffer, texelBufferData.buffer, texelBufferView } },
      {} );

    vk::UniquePipelineCache pipelineCache = device->createPipelineCacheUnique( vk::PipelineCacheCreateInfo() );
    vk::UniquePipeline      graphicsPipeline =
      vk::su::createGraphicsPipeline( device,
                                      pipelineCache,
                                      std::make_pair( *vertexShaderModule, nullptr ),
                                      std::make_pair( *fragmentShaderModule, nullptr ),
                                      0,
                                      {},
                                      vk::FrontFace::eClockwise,
                                      false,
                                      pipelineLayout,
                                      renderPass );

    /* VULKAN_KEY_START */

    // Get the index of the next available swapchain image:
    vk::UniqueSemaphore       imageAcquiredSemaphore = device->createSemaphoreUnique( vk::SemaphoreCreateInfo() );
    vk::ResultValue<uint32_t> currentBuffer          = device->acquireNextImageKHR(
      swapChainData.swapChain.get(), vk::su::FenceTimeout, imageAcquiredSemaphore.get(), nullptr );
    assert( currentBuffer.result == vk::Result::eSuccess );
    assert( currentBuffer.value < framebuffers.size() );

    commandBuffer->begin( vk::CommandBufferBeginInfo() );

    vk::ClearValue clearValue;
    clearValue.color = vk::ClearColorValue( std::array<float, 4>( { { 0.2f, 0.2f, 0.2f, 0.2f } } ) );
    vk::RenderPassBeginInfo renderPassBeginInfo( renderPass.get(),
                                                 framebuffers[currentBuffer.value].get(),
                                                 vk::Rect2D( vk::Offset2D( 0, 0 ), surfaceData.extent ),
                                                 clearValue );

    commandBuffer->beginRenderPass( renderPassBeginInfo, vk::SubpassContents::eInline );
    commandBuffer->bindPipeline( vk::PipelineBindPoint::eGraphics, graphicsPipeline.get() );
    commandBuffer->bindDescriptorSets(
      vk::PipelineBindPoint::eGraphics, pipelineLayout.get(), 0, descriptorSet.get(), nullptr );

    commandBuffer->setViewport( 0,
                                vk::Viewport( 0.0f,
                                              0.0f,
                                              static_cast<float>( surfaceData.extent.width ),
                                              static_cast<float>( surfaceData.extent.height ),
                                              0.0f,
                                              1.0f ) );
    commandBuffer->setScissor( 0, vk::Rect2D( vk::Offset2D( 0, 0 ), surfaceData.extent ) );

    commandBuffer->draw( 3, 1, 0, 0 );
    commandBuffer->endRenderPass();
    commandBuffer->end();

    vk::UniqueFence drawFence = device->createFenceUnique( vk::FenceCreateInfo() );

    vk::PipelineStageFlags waitDestinationStageMask( vk::PipelineStageFlagBits::eColorAttachmentOutput );
    vk::SubmitInfo         submitInfo( *imageAcquiredSemaphore, waitDestinationStageMask, *commandBuffer );
    graphicsQueue.submit( submitInfo, drawFence.get() );

    while ( vk::Result::eTimeout == device->waitForFences( drawFence.get(), VK_TRUE, vk::su::FenceTimeout ) )
      ;

    vk::Result result =
      presentQueue.presentKHR( vk::PresentInfoKHR( {}, *swapChainData.swapChain, currentBuffer.value ) );
    switch ( result )
    {
      case vk::Result::eSuccess: break;
      case vk::Result::eSuboptimalKHR: std::cout << "vk::Queue::presentKHR returned vk::Result::eSuboptimalKHR !\n";
      default: assert( false );  // an unexpected result is returned !
    }
    std::this_thread::sleep_for( std::chrono::milliseconds( 1000 ) );

    /* VULKAN_KEY_END */

    device->waitIdle();
  }
  catch ( vk::SystemError & err )
  {
    std::cout << "vk::SystemError: " << err.what() << std::endl;
    exit( -1 );
  }
  catch ( std::exception & err )
  {
    std::cout << "std::exception: " << err.what() << std::endl;
    exit( -1 );
  }
  catch ( ... )
  {
    std::cout << "unknown error\n";
    exit( -1 );
  }
  return 0;
}