// Copyright 2016 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <algorithm>
#include <cstring>

#include "Common/CommonFuncs.h"

#include "VideoBackends/Vulkan/CommandBufferManager.h"
#include "VideoBackends/Vulkan/FramebufferManager.h"
#include "VideoBackends/Vulkan/ObjectCache.h"
#include "VideoBackends/Vulkan/Renderer.h"
#include "VideoBackends/Vulkan/StagingTexture2D.h"
#include "VideoBackends/Vulkan/StateTracker.h"
#include "VideoBackends/Vulkan/StreamBuffer.h"
#include "VideoBackends/Vulkan/Texture2D.h"
#include "VideoBackends/Vulkan/TextureCache.h"
#include "VideoBackends/Vulkan/TextureEncoder.h"
#include "VideoBackends/Vulkan/Util.h"
#include "VideoBackends/Vulkan/VulkanContext.h"

#include "VideoCommon/TextureConversionShader.h"
#include "VideoCommon/TextureDecoder.h"

namespace Vulkan
{
TextureEncoder::TextureEncoder()
{
}

TextureEncoder::~TextureEncoder()
{
  if (m_encoding_render_pass != VK_NULL_HANDLE)
    vkDestroyRenderPass(g_vulkan_context->GetDevice(), m_encoding_render_pass, nullptr);

  if (m_encoding_texture_framebuffer != VK_NULL_HANDLE)
    vkDestroyFramebuffer(g_vulkan_context->GetDevice(), m_encoding_texture_framebuffer, nullptr);

  for (VkShaderModule shader : m_texture_encoding_shaders)
  {
    if (shader != VK_NULL_HANDLE)
      vkDestroyShaderModule(g_vulkan_context->GetDevice(), shader, nullptr);
  }
}

bool TextureEncoder::Initialize()
{
  if (!CompileShaders())
  {
    PanicAlert("Failed to compile shaders");
    return false;
  }

  if (!CreateEncodingRenderPass())
  {
    PanicAlert("Failed to create encode render pass");
    return false;
  }

  if (!CreateEncodingTexture())
  {
    PanicAlert("Failed to create encoding texture");
    return false;
  }

  if (!CreateDownloadTexture())
  {
    PanicAlert("Failed to create download texture");
    return false;
  }

  return true;
}

void TextureEncoder::EncodeTextureToRam(StateTracker* state_tracker, VkImageView src_texture,
                                        u8* dest_ptr, u32 format, u32 native_width,
                                        u32 bytes_per_row, u32 num_blocks_y, u32 memory_stride,
                                        PEControl::PixelFormat src_format, bool is_intensity,
                                        int scale_by_half, const EFBRectangle& src_rect)
{
  if (m_texture_encoding_shaders[format] == VK_NULL_HANDLE)
  {
    ERROR_LOG(VIDEO, "Missing encoding fragment shader for format %u", format);
    return;
  }

  // Can't do our own draw within a render pass.
  state_tracker->EndRenderPass();

  UtilityShaderDraw draw(g_command_buffer_mgr->GetCurrentCommandBuffer(),
                         g_object_cache->GetPushConstantPipelineLayout(), m_encoding_render_pass,
                         g_object_cache->GetScreenQuadVertexShader(), VK_NULL_HANDLE,
                         m_texture_encoding_shaders[format]);

  // Uniform - int4 of left,top,native_width,scale
  s32 position_uniform[4] = {src_rect.left, src_rect.top, static_cast<s32>(native_width),
                             scale_by_half ? 2 : 1};
  draw.SetPushConstants(position_uniform, sizeof(position_uniform));

  // Doesn't make sense to linear filter depth values
  draw.SetPSSampler(0, src_texture, (scale_by_half && src_format != PEControl::Z24) ?
                                        g_object_cache->GetLinearSampler() :
                                        g_object_cache->GetPointSampler());

  u32 render_width = bytes_per_row / sizeof(u32);
  u32 render_height = num_blocks_y;
  Util::SetViewportAndScissor(g_command_buffer_mgr->GetCurrentCommandBuffer(), 0, 0, render_width,
                              render_height);

  // TODO: We could use compute shaders here.
  VkRect2D render_region = {{0, 0}, {render_width, render_height}};
  draw.BeginRenderPass(m_encoding_texture_framebuffer, render_region);
  draw.DrawWithoutVertexBuffer(VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP, 4);
  draw.EndRenderPass();

  // Transition the image before copying
  m_encoding_texture->OverrideImageLayout(VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL);
  m_download_texture->CopyFromImage(g_command_buffer_mgr->GetCurrentCommandBuffer(),
                                    m_encoding_texture->GetImage(), VK_IMAGE_ASPECT_COLOR_BIT, 0, 0,
                                    render_width, render_height, 0, 0);

  // Block until the GPU has finished copying to the staging texture.
  g_command_buffer_mgr->ExecuteCommandBuffer(false, true);
  state_tracker->InvalidateDescriptorSets();
  state_tracker->SetPendingRebind();

  // Copy from staging texture to the final destination, adjusting pitch if necessary.
  m_download_texture->ReadTexels(0, 0, render_width, render_height, dest_ptr, memory_stride);
}

bool TextureEncoder::CompileShaders()
{
  // Texture encoding shaders
  static const u32 texture_encoding_shader_formats[] = {
      GX_TF_I4,   GX_TF_I8,   GX_TF_IA4,  GX_TF_IA8,  GX_TF_RGB565, GX_TF_RGB5A3, GX_TF_RGBA8,
      GX_CTF_R4,  GX_CTF_RA4, GX_CTF_RA8, GX_CTF_A8,  GX_CTF_R8,    GX_CTF_G8,    GX_CTF_B8,
      GX_CTF_RG8, GX_CTF_GB8, GX_CTF_Z8H, GX_TF_Z8,   GX_CTF_Z16R,  GX_TF_Z16,    GX_TF_Z24X8,
      GX_CTF_Z4,  GX_CTF_Z8M, GX_CTF_Z8L, GX_CTF_Z16L};
  for (u32 format : texture_encoding_shader_formats)
  {
    const char* shader_source =
        TextureConversionShader::GenerateEncodingShader(format, APIType::Vulkan);
    m_texture_encoding_shaders[format] = Util::CompileAndCreateFragmentShader(shader_source);
    if (m_texture_encoding_shaders[format] == VK_NULL_HANDLE)
      return false;
  }

  return true;
}

bool TextureEncoder::CreateEncodingRenderPass()
{
  VkAttachmentDescription attachments[] = {
      {0, ENCODING_TEXTURE_FORMAT, VK_SAMPLE_COUNT_1_BIT, VK_ATTACHMENT_LOAD_OP_DONT_CARE,
       VK_ATTACHMENT_STORE_OP_STORE, VK_ATTACHMENT_LOAD_OP_DONT_CARE,
       VK_ATTACHMENT_STORE_OP_DONT_CARE, VK_IMAGE_LAYOUT_UNDEFINED,
       VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL}};

  VkAttachmentReference color_attachment_references[] = {
      {0, VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL}};

  VkSubpassDescription subpass_descriptions[] = {{0, VK_PIPELINE_BIND_POINT_GRAPHICS, 0, nullptr, 1,
                                                  color_attachment_references, nullptr, nullptr, 0,
                                                  nullptr}};

  VkSubpassDependency dependancies[] = {
      {0, VK_SUBPASS_EXTERNAL, VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
       VK_PIPELINE_STAGE_TRANSFER_BIT,
       VK_ACCESS_COLOR_ATTACHMENT_READ_BIT | VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
       VK_ACCESS_TRANSFER_READ_BIT, VK_DEPENDENCY_BY_REGION_BIT}};

  VkRenderPassCreateInfo pass_info = {VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO,
                                      nullptr,
                                      0,
                                      static_cast<u32>(ArraySize(attachments)),
                                      attachments,
                                      static_cast<u32>(ArraySize(subpass_descriptions)),
                                      subpass_descriptions,
                                      static_cast<u32>(ArraySize(dependancies)),
                                      dependancies};

  VkResult res = vkCreateRenderPass(g_vulkan_context->GetDevice(), &pass_info, nullptr,
                                    &m_encoding_render_pass);
  if (res != VK_SUCCESS)
  {
    LOG_VULKAN_ERROR(res, "vkCreateRenderPass (Encode) failed: ");
    return false;
  }

  return true;
}

bool TextureEncoder::CreateEncodingTexture()
{
  // From OGL: Why do we create a 1024 height texture?
  m_encoding_texture = Texture2D::Create(
      ENCODING_TEXTURE_WIDTH, ENCODING_TEXTURE_HEIGHT, 1, 1, ENCODING_TEXTURE_FORMAT,
      VK_SAMPLE_COUNT_1_BIT, VK_IMAGE_VIEW_TYPE_2D, VK_IMAGE_TILING_OPTIMAL,
      VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_SRC_BIT);
  if (!m_encoding_texture)
    return false;

  VkImageView framebuffer_attachments[] = {m_encoding_texture->GetView()};
  VkFramebufferCreateInfo framebuffer_info = {VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO,
                                              nullptr,
                                              0,
                                              m_encoding_render_pass,
                                              static_cast<u32>(ArraySize(framebuffer_attachments)),
                                              framebuffer_attachments,
                                              m_encoding_texture->GetWidth(),
                                              m_encoding_texture->GetHeight(),
                                              m_encoding_texture->GetLayers()};

  VkResult res = vkCreateFramebuffer(g_vulkan_context->GetDevice(), &framebuffer_info, nullptr,
                                     &m_encoding_texture_framebuffer);
  if (res != VK_SUCCESS)
  {
    LOG_VULKAN_ERROR(res, "vkCreateFramebuffer failed: ");
    return false;
  }

  return true;
}

bool TextureEncoder::CreateDownloadTexture()
{
  m_download_texture =
      StagingTexture2D::Create(STAGING_BUFFER_TYPE_READBACK, ENCODING_TEXTURE_WIDTH,
                               ENCODING_TEXTURE_HEIGHT, ENCODING_TEXTURE_FORMAT);

  if (!m_download_texture || !m_download_texture->Map())
    return false;

  return true;
}

}  // namespace Vulkan