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

#include "VideoBackends/D3D12/XFBEncoder.h"
#include "Common/Align.h"
#include "Common/CommonTypes.h"
#include "Common/Logging/Log.h"
#include "Common/MsgHandler.h"
#include "VideoBackends/D3D12/D3DBase.h"
#include "VideoBackends/D3D12/D3DCommandListManager.h"
#include "VideoBackends/D3D12/D3DShader.h"
#include "VideoBackends/D3D12/D3DState.h"
#include "VideoBackends/D3D12/D3DUtil.h"
#include "VideoBackends/D3D12/FramebufferManager.h"
#include "VideoBackends/D3D12/Render.h"
#include "VideoBackends/D3D12/StaticShaderCache.h"

namespace DX12
{
// YUYV data is packed into half-width RGBA, with Y values in (R,B) and UV in (G,A)
constexpr size_t XFB_TEXTURE_WIDTH = MAX_XFB_WIDTH / 2;
constexpr size_t XFB_TEXTURE_HEIGHT = MAX_XFB_HEIGHT;

// Buffer enough space for 2 XFB buffers (our frame latency)
constexpr size_t XFB_UPLOAD_BUFFER_SIZE =
    Common::AlignUp(XFB_TEXTURE_WIDTH * sizeof(u32), D3D12_TEXTURE_DATA_PITCH_ALIGNMENT) *
    XFB_TEXTURE_HEIGHT * 2;
constexpr size_t XFB_ENCODER_PARAMS_BUFFER_SIZE = 64 * 1024;

std::unique_ptr<XFBEncoder> g_xfb_encoder;

XFBEncoder::XFBEncoder()
{
  ID3D12Resource* texture;

  CheckHR(D3D::device12->CreateCommittedResource(
      &CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_DEFAULT), D3D12_HEAP_FLAG_NONE,
      &CD3DX12_RESOURCE_DESC::Tex2D(DXGI_FORMAT_R8G8B8A8_UNORM, XFB_TEXTURE_WIDTH,
                                    XFB_TEXTURE_HEIGHT, 1, 1, 1, 0,
                                    D3D12_RESOURCE_FLAG_ALLOW_RENDER_TARGET),
      D3D12_RESOURCE_STATE_RENDER_TARGET, nullptr, IID_PPV_ARGS(&texture)));

  m_yuyv_texture =
      new D3DTexture2D(texture, TEXTURE_BIND_FLAG_SHADER_RESOURCE | TEXTURE_BIND_FLAG_RENDER_TARGET,
                       DXGI_FORMAT_R8G8B8A8_UNORM, DXGI_FORMAT_UNKNOWN, DXGI_FORMAT_R8G8B8A8_UNORM);
  SAFE_RELEASE(texture);

  CheckHR(D3D::device12->CreateCommittedResource(
      &CD3DX12_HEAP_PROPERTIES(D3D12_HEAP_TYPE_READBACK), D3D12_HEAP_FLAG_NONE,
      &CD3DX12_RESOURCE_DESC::Buffer(
          Common::AlignUp(XFB_TEXTURE_WIDTH * sizeof(u32), D3D12_TEXTURE_DATA_PITCH_ALIGNMENT) *
          MAX_XFB_HEIGHT),
      D3D12_RESOURCE_STATE_COPY_DEST, nullptr, IID_PPV_ARGS(&m_readback_buffer)));

  m_upload_buffer =
      std::make_unique<D3DStreamBuffer>(XFB_UPLOAD_BUFFER_SIZE, XFB_UPLOAD_BUFFER_SIZE, nullptr);
  m_encode_params_buffer = std::make_unique<D3DStreamBuffer>(
      XFB_ENCODER_PARAMS_BUFFER_SIZE, XFB_ENCODER_PARAMS_BUFFER_SIZE, nullptr);
}

XFBEncoder::~XFBEncoder()
{
  SAFE_RELEASE(m_yuyv_texture);
  SAFE_RELEASE(m_readback_buffer);
}

void XFBEncoder::EncodeTextureToRam(u8* dst, u32 dst_pitch, u32 dst_height,
                                    D3DTexture2D* src_texture, const TargetRectangle& src_rect,
                                    u32 src_width, u32 src_height, float gamma)
{
  // src_rect is in native coordinates
  // dst_pitch is in words
  u32 dst_width = dst_pitch / 2;
  u32 dst_texture_width = dst_width / 2;
  _assert_msg_(VIDEO, dst_width <= MAX_XFB_WIDTH && dst_height <= MAX_XFB_HEIGHT,
               "XFB destination does not exceed maximum size");

  // Encode parameters constant buffer used by shader
  struct EncodeParameters
  {
    float srcRect[4];
    float texelSize[2];
    float pad[2];
  };
  EncodeParameters parameters = {
      {static_cast<float>(src_rect.left) / static_cast<float>(src_width),
       static_cast<float>(src_rect.top) / static_cast<float>(src_height),
       static_cast<float>(src_rect.right) / static_cast<float>(src_width),
       static_cast<float>(src_rect.bottom) / static_cast<float>(src_height)},
      {1.0f / EFB_WIDTH, 1.0f / EFB_HEIGHT},
      {0.0f, 0.0f}};
  m_encode_params_buffer->AllocateSpaceInBuffer(sizeof(parameters),
                                                D3D12_CONSTANT_BUFFER_DATA_PLACEMENT_ALIGNMENT);
  memcpy(m_encode_params_buffer->GetCPUAddressOfCurrentAllocation(), &parameters,
         sizeof(parameters));

  // Convert RGBA texture to YUYV intermediate texture.
  // Performs downscaling through a linear filter. Probably not ideal, but it's not going to look
  // perfect anyway.
  CD3DX12_RECT src_texture_rect(src_rect.left, src_rect.top, src_rect.right, src_rect.bottom);
  D3D12_RESOURCE_STATES src_texture_state = src_texture->GetResourceUsageState();
  m_yuyv_texture->TransitionToResourceState(D3D::current_command_list,
                                            D3D12_RESOURCE_STATE_RENDER_TARGET);
  D3D::current_command_list->OMSetRenderTargets(1, &m_yuyv_texture->GetRTV12(), FALSE, nullptr);
  D3D::current_command_list->SetGraphicsRootConstantBufferView(
      DESCRIPTOR_TABLE_PS_CBVONE, m_encode_params_buffer->GetGPUAddressOfCurrentAllocation());
  D3D::command_list_mgr->SetCommandListDirtyState(COMMAND_LIST_STATE_PS_CBV, true);
  D3D::SetViewportAndScissor(0, 0, dst_texture_width, dst_height);
  D3D::SetLinearCopySampler();
  D3D::DrawShadedTexQuad(src_texture, &src_texture_rect, src_rect.GetWidth(), src_rect.GetHeight(),
                         StaticShaderCache::GetXFBEncodePixelShader(),
                         StaticShaderCache::GetSimpleVertexShader(),
                         StaticShaderCache::GetSimpleVertexShaderInputLayout(), {}, gamma, 0,
                         DXGI_FORMAT_R8G8B8A8_UNORM, false, false);

  src_texture->TransitionToResourceState(D3D::current_command_list, src_texture_state);

  // Copy from YUYV intermediate texture to readback buffer. It's likely the pitch here is going to
  // be different to dst_pitch.
  u32 readback_pitch = static_cast<u32>(
      Common::AlignUp(dst_width * sizeof(u16), D3D12_TEXTURE_DATA_PITCH_ALIGNMENT));
  D3D12_PLACED_SUBRESOURCE_FOOTPRINT dst_footprint = {
      0, {DXGI_FORMAT_R8G8B8A8_UNORM, dst_texture_width, dst_height, 1, readback_pitch}};
  CD3DX12_TEXTURE_COPY_LOCATION dst_location(m_readback_buffer, dst_footprint);
  CD3DX12_TEXTURE_COPY_LOCATION src_location(m_yuyv_texture->GetTex12(), 0);
  CD3DX12_BOX src_box(0, 0, dst_texture_width, dst_height);
  m_yuyv_texture->TransitionToResourceState(D3D::current_command_list,
                                            D3D12_RESOURCE_STATE_COPY_SOURCE);
  D3D::current_command_list->CopyTextureRegion(&dst_location, 0, 0, 0, &src_location, &src_box);

  // Wait until the GPU completes the copy. Resets back to known state automatically.
  D3D::command_list_mgr->ExecuteQueuedWork(true);

  // Copy from the readback buffer to dst.
  // Can't be done as one memcpy due to pitch difference.
  void* readback_texture_map;
  D3D12_RANGE read_range = {0, readback_pitch * dst_height};
  CheckHR(m_readback_buffer->Map(0, &read_range, &readback_texture_map));

  for (u32 row = 0; row < dst_height; row++)
  {
    const u8* row_src = reinterpret_cast<u8*>(readback_texture_map) + readback_pitch * row;
    u8* row_dst = dst + dst_pitch * row;
    memcpy(row_dst, row_src, std::min(dst_pitch, readback_pitch));
  }

  D3D12_RANGE write_range = {};
  m_readback_buffer->Unmap(0, &write_range);
}

void XFBEncoder::DecodeToTexture(D3DTexture2D* dst_texture, const u8* src, u32 src_width,
                                 u32 src_height)
{
  _assert_msg_(VIDEO, src_width <= MAX_XFB_WIDTH && src_height <= MAX_XFB_HEIGHT,
               "XFB source does not exceed maximum size");

  // Copy to XFB upload buffer. Each row has to be done separately due to pitch differences.
  u32 buffer_pitch = static_cast<u32>(
      Common::AlignUp(src_width / 2 * sizeof(u32), D3D12_TEXTURE_DATA_PITCH_ALIGNMENT));
  m_upload_buffer->AllocateSpaceInBuffer(buffer_pitch * src_height,
                                         D3D12_TEXTURE_DATA_PLACEMENT_ALIGNMENT);
  for (u32 row = 0; row < src_height; row++)
  {
    const u8* row_src = src + (src_width * 2) * row;
    u8* row_dst = reinterpret_cast<u8*>(m_upload_buffer->GetCPUAddressOfCurrentAllocation()) +
                  buffer_pitch * row;
    memcpy(row_dst, row_src, src_width * 2);
  }

  // Copy from upload buffer to intermediate YUYV texture.
  D3D12_PLACED_SUBRESOURCE_FOOTPRINT src_footprint = {
      m_upload_buffer->GetOffsetOfCurrentAllocation(),
      {DXGI_FORMAT_R8G8B8A8_UNORM, src_width / 2, src_height, 1, buffer_pitch}};
  CD3DX12_TEXTURE_COPY_LOCATION src_location(m_upload_buffer->GetBuffer(), src_footprint);
  CD3DX12_TEXTURE_COPY_LOCATION dst_location(m_yuyv_texture->GetTex12(), 0);
  CD3DX12_BOX src_box(0, 0, src_width / 2, src_height);
  m_yuyv_texture->TransitionToResourceState(D3D::current_command_list,
                                            D3D12_RESOURCE_STATE_COPY_DEST);
  D3D::current_command_list->CopyTextureRegion(&dst_location, 0, 0, 0, &src_location, &src_box);

  // Convert YUYV texture to RGBA texture with pixel shader.
  CD3DX12_RECT src_texture_rect(0, 0, src_width / 2, src_height);
  dst_texture->TransitionToResourceState(D3D::current_command_list,
                                         D3D12_RESOURCE_STATE_RENDER_TARGET);
  D3D::current_command_list->OMSetRenderTargets(1, &dst_texture->GetRTV12(), FALSE, nullptr);
  D3D::SetViewportAndScissor(0, 0, src_width, src_height);
  D3D::DrawShadedTexQuad(m_yuyv_texture, &src_texture_rect, XFB_TEXTURE_WIDTH, XFB_TEXTURE_HEIGHT,
                         StaticShaderCache::GetXFBDecodePixelShader(),
                         StaticShaderCache::GetSimpleVertexShader(),
                         StaticShaderCache::GetSimpleVertexShaderInputLayout(), {}, 1.0f, 0,
                         DXGI_FORMAT_R8G8B8A8_UNORM, false, false);

  // XFB source textures are expected to be in shader resource state.
  dst_texture->TransitionToResourceState(D3D::current_command_list,
                                         D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE);
}
}