// Copyright 2015 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include "Common/LinearDiskCache.h"

#include "Core/ConfigManager.h"

#include "VideoBackends/D3D12/D3DCommandListManager.h"
#include "VideoBackends/D3D12/D3DShader.h"
#include "VideoBackends/D3D12/ShaderCache.h"

#include "VideoCommon/Debugger.h"
#include "VideoCommon/Statistics.h"
#include "VideoCommon/VideoCommon.h"

namespace DX12
{
// Primitive topology type is always triangle, unless the GS stage is used. This is consumed
// by the PSO created in Renderer::ApplyState.
static D3D12_PRIMITIVE_TOPOLOGY_TYPE s_current_primitive_topology =
    D3D12_PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE;

using GsBytecodeCache = std::map<GeometryShaderUid, D3D12_SHADER_BYTECODE>;
using PsBytecodeCache = std::map<PixelShaderUid, D3D12_SHADER_BYTECODE>;
using VsBytecodeCache = std::map<VertexShaderUid, D3D12_SHADER_BYTECODE>;
GsBytecodeCache s_gs_bytecode_cache;
PsBytecodeCache s_ps_bytecode_cache;
VsBytecodeCache s_vs_bytecode_cache;

// Used to keep track of blobs to release at Shutdown time.
static std::vector<ID3DBlob*> s_shader_blob_list;

static LinearDiskCache<GeometryShaderUid, u8> s_gs_disk_cache;
static LinearDiskCache<PixelShaderUid, u8> s_ps_disk_cache;
static LinearDiskCache<VertexShaderUid, u8> s_vs_disk_cache;

static D3D12_SHADER_BYTECODE s_last_geometry_shader_bytecode;
static D3D12_SHADER_BYTECODE s_last_pixel_shader_bytecode;
static D3D12_SHADER_BYTECODE s_last_vertex_shader_bytecode;
static GeometryShaderUid s_last_geometry_shader_uid;
static PixelShaderUid s_last_pixel_shader_uid;
static VertexShaderUid s_last_vertex_shader_uid;

template <class UidType, class ShaderCacheType, ShaderCacheType* cache>
class ShaderCacheInserter final : public LinearDiskCacheReader<UidType, u8>
{
public:
  void Read(const UidType& key, const u8* value, u32 value_size)
  {
    ID3DBlob* blob = nullptr;
    CheckHR(d3d_create_blob(value_size, &blob));
    memcpy(blob->GetBufferPointer(), value, value_size);

    ShaderCache::InsertByteCode<UidType, ShaderCacheType>(key, cache, blob);
  }
};

void ShaderCache::Init()
{
  // This class intentionally shares its shader cache files with DX11, as the shaders are (right
  // now) identical.
  // Reduces unnecessary compilation when switching between APIs.

  s_last_geometry_shader_bytecode = {};
  s_last_pixel_shader_bytecode = {};
  s_last_vertex_shader_bytecode = {};
  s_last_geometry_shader_uid = {};
  s_last_pixel_shader_uid = {};
  s_last_vertex_shader_uid = {};

  if (g_ActiveConfig.bShaderCache)
  {
    // Ensure shader cache directory exists..
    std::string shader_cache_path = File::GetUserPath(D_SHADERCACHE_IDX);

    if (!File::Exists(shader_cache_path))
      File::CreateDir(File::GetUserPath(D_SHADERCACHE_IDX));

    const std::string& title_game_id = SConfig::GetInstance().GetGameID();

    std::string gs_cache_filename =
        StringFromFormat("%sdx11-%s-gs.cache", shader_cache_path.c_str(), title_game_id.c_str());
    std::string ps_cache_filename =
        StringFromFormat("%sdx11-%s-ps.cache", shader_cache_path.c_str(), title_game_id.c_str());
    std::string vs_cache_filename =
        StringFromFormat("%sdx11-%s-vs.cache", shader_cache_path.c_str(), title_game_id.c_str());

    ShaderCacheInserter<GeometryShaderUid, GsBytecodeCache, &s_gs_bytecode_cache> gs_inserter;
    s_gs_disk_cache.OpenAndRead(gs_cache_filename, gs_inserter);

    ShaderCacheInserter<PixelShaderUid, PsBytecodeCache, &s_ps_bytecode_cache> ps_inserter;
    s_ps_disk_cache.OpenAndRead(ps_cache_filename, ps_inserter);

    ShaderCacheInserter<VertexShaderUid, VsBytecodeCache, &s_vs_bytecode_cache> vs_inserter;
    s_vs_disk_cache.OpenAndRead(vs_cache_filename, vs_inserter);
  }

  SETSTAT(stats.numPixelShadersAlive, static_cast<int>(s_ps_bytecode_cache.size()));
  SETSTAT(stats.numPixelShadersCreated, static_cast<int>(s_ps_bytecode_cache.size()));
  SETSTAT(stats.numVertexShadersAlive, static_cast<int>(s_vs_bytecode_cache.size()));
  SETSTAT(stats.numVertexShadersCreated, static_cast<int>(s_vs_bytecode_cache.size()));
}

void ShaderCache::Clear()
{
  for (auto& iter : s_shader_blob_list)
    SAFE_RELEASE(iter);

  s_shader_blob_list.clear();

  s_gs_bytecode_cache.clear();
  s_ps_bytecode_cache.clear();
  s_vs_bytecode_cache.clear();

  s_last_geometry_shader_bytecode = {};
  s_last_geometry_shader_uid = {};

  s_last_pixel_shader_bytecode = {};
  s_last_pixel_shader_uid = {};

  s_last_vertex_shader_bytecode = {};
  s_last_vertex_shader_uid = {};
}

void ShaderCache::Shutdown()
{
  Clear();

  s_gs_disk_cache.Sync();
  s_gs_disk_cache.Close();
  s_ps_disk_cache.Sync();
  s_ps_disk_cache.Close();
  s_vs_disk_cache.Sync();
  s_vs_disk_cache.Close();
}

void ShaderCache::LoadAndSetActiveShaders(u32 gs_primitive_type)
{
  SetCurrentPrimitiveTopology(gs_primitive_type);

  GeometryShaderUid gs_uid = GetGeometryShaderUid(gs_primitive_type);
  PixelShaderUid ps_uid = GetPixelShaderUid();
  VertexShaderUid vs_uid = GetVertexShaderUid();

  bool gs_changed = gs_uid != s_last_geometry_shader_uid;
  bool ps_changed = ps_uid != s_last_pixel_shader_uid;
  bool vs_changed = vs_uid != s_last_vertex_shader_uid;

  if (!gs_changed && !ps_changed && !vs_changed)
  {
    return;
  }

  if (gs_changed)
  {
    HandleGSUIDChange(gs_uid, gs_primitive_type);
  }

  if (ps_changed)
  {
    HandlePSUIDChange(ps_uid);
  }

  if (vs_changed)
  {
    HandleVSUIDChange(vs_uid);
  }

  // A Uid has changed, so the PSO will need to be reset at next ApplyState.
  D3D::command_list_mgr->SetCommandListDirtyState(COMMAND_LIST_STATE_PSO, true);
}

void ShaderCache::SetCurrentPrimitiveTopology(u32 gs_primitive_type)
{
  switch (gs_primitive_type)
  {
  case PRIMITIVE_TRIANGLES:
    s_current_primitive_topology = D3D12_PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE;
    break;
  case PRIMITIVE_LINES:
    s_current_primitive_topology = D3D12_PRIMITIVE_TOPOLOGY_TYPE_LINE;
    break;
  case PRIMITIVE_POINTS:
    s_current_primitive_topology = D3D12_PRIMITIVE_TOPOLOGY_TYPE_POINT;
    break;
  default:
    CHECK(0, "Invalid primitive type.");
    break;
  }
}

void ShaderCache::HandleGSUIDChange(GeometryShaderUid gs_uid, u32 gs_primitive_type)
{
  s_last_geometry_shader_uid = gs_uid;

  if (gs_uid.GetUidData()->IsPassthrough())
  {
    s_last_geometry_shader_bytecode = {};
    return;
  }

  auto gs_iterator = s_gs_bytecode_cache.find(gs_uid);
  if (gs_iterator != s_gs_bytecode_cache.end())
  {
    s_last_geometry_shader_bytecode = gs_iterator->second;
  }
  else
  {
    ShaderCode gs_code = GenerateGeometryShaderCode(APIType::D3D, gs_uid.GetUidData());
    ID3DBlob* gs_bytecode = nullptr;

    if (!D3D::CompileGeometryShader(gs_code.GetBuffer(), &gs_bytecode))
    {
      GFX_DEBUGGER_PAUSE_AT(NEXT_ERROR, true);
      return;
    }

    s_last_geometry_shader_bytecode = InsertByteCode(gs_uid, &s_gs_bytecode_cache, gs_bytecode);
    s_gs_disk_cache.Append(gs_uid, reinterpret_cast<u8*>(gs_bytecode->GetBufferPointer()),
                           static_cast<u32>(gs_bytecode->GetBufferSize()));
  }
}

void ShaderCache::HandlePSUIDChange(PixelShaderUid ps_uid)
{
  s_last_pixel_shader_uid = ps_uid;

  auto ps_iterator = s_ps_bytecode_cache.find(ps_uid);
  if (ps_iterator != s_ps_bytecode_cache.end())
  {
    s_last_pixel_shader_bytecode = ps_iterator->second;
    GFX_DEBUGGER_PAUSE_AT(NEXT_PIXEL_SHADER_CHANGE, true);
  }
  else
  {
    ShaderCode ps_code = GeneratePixelShaderCode(APIType::D3D, ps_uid.GetUidData());
    ID3DBlob* ps_bytecode = nullptr;

    if (!D3D::CompilePixelShader(ps_code.GetBuffer(), &ps_bytecode))
    {
      GFX_DEBUGGER_PAUSE_AT(NEXT_ERROR, true);
      return;
    }

    s_last_pixel_shader_bytecode = InsertByteCode(ps_uid, &s_ps_bytecode_cache, ps_bytecode);
    s_ps_disk_cache.Append(ps_uid, reinterpret_cast<u8*>(ps_bytecode->GetBufferPointer()),
                           static_cast<u32>(ps_bytecode->GetBufferSize()));

    SETSTAT(stats.numPixelShadersAlive, static_cast<int>(s_ps_bytecode_cache.size()));
    INCSTAT(stats.numPixelShadersCreated);
  }
}

void ShaderCache::HandleVSUIDChange(VertexShaderUid vs_uid)
{
  s_last_vertex_shader_uid = vs_uid;

  auto vs_iterator = s_vs_bytecode_cache.find(vs_uid);
  if (vs_iterator != s_vs_bytecode_cache.end())
  {
    s_last_vertex_shader_bytecode = vs_iterator->second;
    GFX_DEBUGGER_PAUSE_AT(NEXT_VERTEX_SHADER_CHANGE, true);
  }
  else
  {
    ShaderCode vs_code = GenerateVertexShaderCode(APIType::D3D, vs_uid.GetUidData());
    ID3DBlob* vs_bytecode = nullptr;

    if (!D3D::CompileVertexShader(vs_code.GetBuffer(), &vs_bytecode))
    {
      GFX_DEBUGGER_PAUSE_AT(NEXT_ERROR, true);
      return;
    }

    s_last_vertex_shader_bytecode = InsertByteCode(vs_uid, &s_vs_bytecode_cache, vs_bytecode);
    s_vs_disk_cache.Append(vs_uid, reinterpret_cast<u8*>(vs_bytecode->GetBufferPointer()),
                           static_cast<u32>(vs_bytecode->GetBufferSize()));

    SETSTAT(stats.numVertexShadersAlive, static_cast<int>(s_vs_bytecode_cache.size()));
    INCSTAT(stats.numVertexShadersCreated);
  }
}

template <class UidType, class ShaderCacheType>
D3D12_SHADER_BYTECODE ShaderCache::InsertByteCode(const UidType& uid, ShaderCacheType* shader_cache,
                                                  ID3DBlob* bytecode_blob)
{
  // Note: Don't release the incoming bytecode, we need it to stick around, since in D3D12
  // the raw bytecode itself is bound. It is released at Shutdown() time.

  s_shader_blob_list.push_back(bytecode_blob);

  D3D12_SHADER_BYTECODE shader_bytecode;
  shader_bytecode.pShaderBytecode = bytecode_blob->GetBufferPointer();
  shader_bytecode.BytecodeLength = bytecode_blob->GetBufferSize();

  (*shader_cache)[uid] = shader_bytecode;

  return shader_bytecode;
}

D3D12_PRIMITIVE_TOPOLOGY_TYPE ShaderCache::GetCurrentPrimitiveTopology()
{
  return s_current_primitive_topology;
}

D3D12_SHADER_BYTECODE ShaderCache::GetActiveGeometryShaderBytecode()
{
  return s_last_geometry_shader_bytecode;
}
D3D12_SHADER_BYTECODE ShaderCache::GetActivePixelShaderBytecode()
{
  return s_last_pixel_shader_bytecode;
}
D3D12_SHADER_BYTECODE ShaderCache::GetActiveVertexShaderBytecode()
{
  return s_last_vertex_shader_bytecode;
}

const GeometryShaderUid* ShaderCache::GetActiveGeometryShaderUid()
{
  return &s_last_geometry_shader_uid;
}
const PixelShaderUid* ShaderCache::GetActivePixelShaderUid()
{
  return &s_last_pixel_shader_uid;
}
const VertexShaderUid* ShaderCache::GetActiveVertexShaderUid()
{
  return &s_last_vertex_shader_uid;
}

D3D12_SHADER_BYTECODE ShaderCache::GetGeometryShaderFromUid(const GeometryShaderUid* uid)
{
  auto bytecode = s_gs_bytecode_cache.find(*uid);
  if (bytecode != s_gs_bytecode_cache.end())
    return bytecode->second;

  return D3D12_SHADER_BYTECODE();
}

D3D12_SHADER_BYTECODE ShaderCache::GetPixelShaderFromUid(const PixelShaderUid* uid)
{
  auto bytecode = s_ps_bytecode_cache.find(*uid);
  if (bytecode != s_ps_bytecode_cache.end())
    return bytecode->second;

  return D3D12_SHADER_BYTECODE();
}

D3D12_SHADER_BYTECODE ShaderCache::GetVertexShaderFromUid(const VertexShaderUid* uid)
{
  auto bytecode = s_vs_bytecode_cache.find(*uid);
  if (bytecode != s_vs_bytecode_cache.end())
    return bytecode->second;

  return D3D12_SHADER_BYTECODE();
}
}