// Copyright 2011 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#include "VideoCommon/VideoBackendBase.h"

#include <algorithm>
#include <cstring>
#include <memory>
#include <string>
#include <vector>

#include <fmt/format.h>

#include "Common/ChunkFile.h"
#include "Common/CommonTypes.h"
#include "Common/FileUtil.h"
#include "Common/Logging/Log.h"

#include "Core/Config/MainSettings.h"
#include "Core/ConfigManager.h"
#include "Core/Core.h"
#include "Core/CoreTiming.h"
#include "Core/DolphinAnalytics.h"
#include "Core/HW/SystemTimers.h"
#include "Core/HW/VideoInterface.h"
#include "Core/System.h"

// TODO: ugly
#ifdef _WIN32
#include "VideoBackends/D3D/VideoBackend.h"
#include "VideoBackends/D3D12/VideoBackend.h"
#endif
#include "VideoBackends/Null/VideoBackend.h"
#ifdef HAS_OPENGL
#include "VideoBackends/OGL/VideoBackend.h"
#include "VideoBackends/Software/VideoBackend.h"
#endif
#ifdef HAS_VULKAN
#include "VideoBackends/Vulkan/VideoBackend.h"
#endif
#if defined(__APPLE__) && !defined(__LIBRETRO__)
#include "VideoBackends/Metal/VideoBackend.h"
#endif

#include "VideoCommon/AbstractGfx.h"
#include "VideoCommon/AsyncRequests.h"
#include "VideoCommon/BPStructs.h"
#include "VideoCommon/BoundingBox.h"
#include "VideoCommon/CPMemory.h"
#include "VideoCommon/CommandProcessor.h"
#include "VideoCommon/EFBInterface.h"
#include "VideoCommon/Fifo.h"
#include "VideoCommon/FrameDumper.h"
#include "VideoCommon/FramebufferManager.h"
#include "VideoCommon/GeometryShaderManager.h"
#include "VideoCommon/GraphicsModSystem/Runtime/GraphicsModManager.h"
#include "VideoCommon/OnScreenDisplay.h"
#include "VideoCommon/PixelEngine.h"
#include "VideoCommon/PixelShaderManager.h"
#include "VideoCommon/Present.h"
#include "VideoCommon/Resources/CustomResourceManager.h"
#include "VideoCommon/TMEM.h"
#include "VideoCommon/TextureCacheBase.h"
#include "VideoCommon/VertexLoaderManager.h"
#include "VideoCommon/VertexManagerBase.h"
#include "VideoCommon/VertexShaderManager.h"
#include "VideoCommon/VideoConfig.h"
#include "VideoCommon/VideoState.h"
#include "VideoCommon/Widescreen.h"
#include "VideoCommon/XFStateManager.h"
#ifdef __LIBRETRO__
#include "DolphinLibretro/VideoContexts/ContextStatus.h"
#endif

VideoBackendBase* g_video_backend = nullptr;

#ifdef _WIN32
#include <windows.h>

// Nvidia drivers >= v302 will check if the application exports a global
// variable named NvOptimusEnablement to know if it should run the app in high
// performance graphics mode or using the IGP.
// AMD drivers >= 13.35 do the same, but for the variable
// named AmdPowerXpressRequestHighPerformance instead.
extern "C" {
__declspec(dllexport) DWORD NvOptimusEnablement = 1;
__declspec(dllexport) int AmdPowerXpressRequestHighPerformance = 1;
}
#endif

std::string VideoBackendBase::BadShaderFilename(const char* shader_stage, int counter)
{
  return fmt::format("{}bad_{}_{}_{}.txt", File::GetUserPath(D_DUMP_IDX), shader_stage,
                     g_video_backend->GetConfigName(), counter);
}

// Run from the CPU thread (from VideoInterface.cpp)
void VideoBackendBase::Video_OutputXFB(u32 xfb_addr, u32 fb_width, u32 fb_stride, u32 fb_height,
                                       u64 ticks)
{
  if (!m_initialized || !g_presenter)
    return;

  auto& system = Core::System::GetInstance();
  auto& core_timing = system.GetCoreTiming();

  if (!g_ActiveConfig.bImmediateXFB)
  {
    system.GetFifo().SyncGPU(Fifo::SyncGPUReason::Swap);

    const TimePoint presentation_time = core_timing.GetTargetHostTime(ticks);
    AsyncRequests::GetInstance()->PushEvent([=] {
      g_presenter->ViSwap(xfb_addr, fb_width, fb_stride, fb_height, ticks, presentation_time);
    });
  }

  // Inform the Presenter of the next estimated swap time.

  auto& vi = system.GetVideoInterface();
  const s64 refresh_rate_den = vi.GetTargetRefreshRateDenominator();
  const s64 refresh_rate_num = vi.GetTargetRefreshRateNumerator();

  const auto next_swap_estimated_ticks =
      ticks + (system.GetSystemTimers().GetTicksPerSecond() * refresh_rate_den / refresh_rate_num);
  const auto next_swap_estimated_time = core_timing.GetTargetHostTime(next_swap_estimated_ticks);

  AsyncRequests::GetInstance()->PushEvent([=] {
    g_presenter->SetNextSwapEstimatedTime(next_swap_estimated_ticks, next_swap_estimated_time);
  });
}

u32 VideoBackendBase::Video_GetQueryResult(PerfQueryType type)
{
  if (!g_perf_query->ShouldEmulate())
  {
    return 0;
  }

  auto& system = Core::System::GetInstance();
  system.GetFifo().SyncGPU(Fifo::SyncGPUReason::PerfQuery);

  if (!g_perf_query->IsFlushed())
  {
    AsyncRequests::GetInstance()->PushBlockingEvent([] { g_perf_query->FlushResults(); });
  }

  return g_perf_query->GetQueryResult(type);
}

u16 VideoBackendBase::Video_GetBoundingBox(int index)
{
  DolphinAnalytics::Instance().ReportGameQuirk(GameQuirk::ReadsBoundingBox);

  if (!g_ActiveConfig.bBBoxEnable)
  {
    static bool warn_once = true;
    if (warn_once)
    {
      ERROR_LOG_FMT(VIDEO,
                    "BBox shall be used but it is disabled. Please use a gameini to enable it "
                    "for this game.");
    }
    warn_once = false;
  }
  else if (!g_backend_info.bSupportsBBox)
  {
    static bool warn_once = true;
    if (warn_once)
    {
      PanicAlertFmtT(
          "This game requires bounding box emulation to run properly but your graphics "
          "card or its drivers do not support it. As a result you will experience bugs or "
          "freezes while running this game.");
    }
    warn_once = false;
  }

  auto& system = Core::System::GetInstance();
  system.GetFifo().SyncGPU(Fifo::SyncGPUReason::BBox);

  return AsyncRequests::GetInstance()->PushBlockingEvent(
      [&] { return g_bounding_box->Get(index); });
}

static VideoBackendBase* GetDefaultVideoBackend()
{
  const auto& backends = VideoBackendBase::GetAvailableBackends();
  if (backends.empty())
    return nullptr;
  return backends.front().get();
}

std::string VideoBackendBase::GetDefaultBackendConfigName()
{
  auto* default_backend = GetDefaultVideoBackend();
  return default_backend ? default_backend->GetConfigName() : "";
}

std::string VideoBackendBase::GetDefaultBackendDisplayName()
{
  auto* const default_backend = GetDefaultVideoBackend();
  return default_backend ? default_backend->GetDisplayName() : "";
}

const std::vector<std::unique_ptr<VideoBackendBase>>& VideoBackendBase::GetAvailableBackends()
{
  static auto s_available_backends = [] {
    std::vector<std::unique_ptr<VideoBackendBase>> backends;

#ifdef _WIN32
    backends.push_back(std::make_unique<DX11::VideoBackend>());
    backends.push_back(std::make_unique<DX12::VideoBackend>());
#endif
#ifdef HAS_OPENGL
    backends.push_back(std::make_unique<OGL::VideoBackend>());
#endif
#ifdef HAS_VULKAN
#ifdef __APPLE__
    // Emplace the Vulkan backend at the beginning so it takes precedence over OpenGL.
    // On macOS, we prefer Vulkan over OpenGL due to OpenGL support being deprecated by Apple.
    backends.emplace(backends.begin(), std::make_unique<Vulkan::VideoBackend>());
#else
    backends.push_back(std::make_unique<Vulkan::VideoBackend>());
#endif
#endif
#if defined(__APPLE__) && !defined(__LIBRETRO__)
    backends.emplace(backends.begin(), std::make_unique<Metal::VideoBackend>());
#endif
#ifdef HAS_OPENGL
    backends.push_back(std::make_unique<SW::VideoSoftware>());
#endif
    backends.push_back(std::make_unique<Null::VideoBackend>());

    if (!backends.empty())
      g_video_backend = backends.front().get();

    return backends;
  }();
  return s_available_backends;
}

void VideoBackendBase::ActivateBackend(const std::string& name)
{
  // If empty, set it to the default backend (expected behavior)
  if (name.empty())
    g_video_backend = GetDefaultVideoBackend();

  const auto& backends = GetAvailableBackends();
  const auto iter = std::ranges::find(backends, name, &VideoBackendBase::GetConfigName);

  if (iter == backends.end())
    return;

  g_video_backend = iter->get();
}

void VideoBackendBase::PopulateBackendInfo(const WindowSystemInfo& wsi)
{
  // If the core has been initialized, the backend info will have been populated already. Doing it
  // again would be unnecessary and could cause the UI thread to race with the GPU thread.
  if (!Core::IsUninitialized(Core::System::GetInstance()))
    return;

  g_Config.Refresh();
  // Reset backend_info so if the backend forgets to initialize something it doesn't end up using
  // a value from the previously used renderer
  g_backend_info = {};
  ActivateBackend(Config::Get(Config::MAIN_GFX_BACKEND));
  g_backend_info.DisplayName = g_video_backend->GetDisplayName();
  g_video_backend->InitBackendInfo(wsi);
  // We validate the config after initializing the backend info, as system-specific settings
  // such as anti-aliasing, or the selected adapter may be invalid, and should be checked.
  g_Config.VerifyValidity();
}

void VideoBackendBase::DoState(PointerWrap& p)
{
  auto& system = Core::System::GetInstance();
  if (!system.IsDualCoreMode())
  {
    VideoCommon_DoState(p);
    return;
  }

  AsyncRequests::GetInstance()->PushBlockingEvent([&] { VideoCommon_DoState(p); });

  // Let the GPU thread sleep after loading the state, so we're not spinning if paused after loading
  // a state. The next GP burst will wake it up again.
  system.GetFifo().GpuMaySleep();
}

bool VideoBackendBase::InitializeShared(std::unique_ptr<AbstractGfx> gfx,
                                        std::unique_ptr<VertexManagerBase> vertex_manager,
                                        std::unique_ptr<PerfQueryBase> perf_query,
                                        std::unique_ptr<BoundingBox> bounding_box)
{
  // All hardware backends use the default EFBInterface and TextureCacheBase.
  // Only Null and Software backends override them

  return InitializeShared(std::move(gfx), std::move(vertex_manager), std::move(perf_query),
                          std::move(bounding_box), std::make_unique<HardwareEFBInterface>(),
                          std::make_unique<TextureCacheBase>());
}

bool VideoBackendBase::InitializeShared(std::unique_ptr<AbstractGfx> gfx,
                                        std::unique_ptr<VertexManagerBase> vertex_manager,
                                        std::unique_ptr<PerfQueryBase> perf_query,
                                        std::unique_ptr<BoundingBox> bounding_box,
                                        std::unique_ptr<EFBInterfaceBase> efb_interface,
                                        std::unique_ptr<TextureCacheBase> texture_cache)
{
#ifdef __LIBRETRO__
  const bool is_initialized = g_context_status.IsInitialized();
  if(!is_initialized)
  {
#endif
    memset(reinterpret_cast<u8*>(&g_main_cp_state), 0, sizeof(g_main_cp_state));
    memset(reinterpret_cast<u8*>(&g_preprocess_cp_state), 0, sizeof(g_preprocess_cp_state));
    s_tex_mem.fill(0);
#ifdef __LIBRETRO__
  }
#endif
  // do not initialize again for the config window
  m_initialized = true;

  g_gfx = std::move(gfx);
  g_vertex_manager = std::move(vertex_manager);
  g_perf_query = std::move(perf_query);
  g_bounding_box = std::move(bounding_box);

  // Null and Software Backends supply their own derived EFBInterface and TextureCache
  g_texture_cache = std::move(texture_cache);
  g_efb_interface = std::move(efb_interface);

  g_presenter = std::make_unique<VideoCommon::Presenter>();
  g_frame_dumper = std::make_unique<FrameDumper>();
  g_framebuffer_manager = std::make_unique<FramebufferManager>();
  g_shader_cache = std::make_unique<VideoCommon::ShaderCache>();
  g_graphics_mod_manager = std::make_unique<GraphicsModManager>();
  g_widescreen = std::make_unique<WidescreenManager>();

  if (!g_vertex_manager->Initialize() || !g_shader_cache->Initialize() ||
      !g_perf_query->Initialize() || !g_presenter->Initialize() ||
      !g_framebuffer_manager->Initialize(g_ActiveConfig.iEFBScale) ||
      !g_texture_cache->Initialize() ||
      (g_backend_info.bSupportsBBox && !g_bounding_box->Initialize()) ||
      !g_graphics_mod_manager->Initialize())
  {
    PanicAlertFmtT("Failed to initialize renderer classes");
    Shutdown();
    return false;
  }

#ifdef __LIBRETRO__
  if(is_initialized)
    return true;
#endif
  auto& system = Core::System::GetInstance();
  auto& command_processor = system.GetCommandProcessor();
  command_processor.Init();
  system.GetFifo().Init();
  system.GetPixelEngine().Init();
  BPInit();
  VertexLoaderManager::Init();
  system.GetVertexShaderManager().Init();
  system.GetGeometryShaderManager().Init();
  system.GetPixelShaderManager().Init();
  system.GetXFStateManager().Init();
  TMEM::Init();

  g_Config.VerifyValidity();
  UpdateActiveConfig();

  if (g_Config.bDumpTextures)
  {
    OSD::AddMessage(fmt::format("Texture Dumping is enabled. This will reduce performance."),
                    OSD::Duration::NORMAL);
  }

  g_shader_cache->InitializeShaderCache();
  system.GetCustomResourceManager().Initialize();

  return true;
}

void VideoBackendBase::ShutdownShared()
{
  auto& system = Core::System::GetInstance();
  system.GetCustomResourceManager().Shutdown();
  g_frame_dumper.reset();
  g_presenter.reset();

  if (g_shader_cache)
    g_shader_cache->Shutdown();
  if (g_texture_cache)
    g_texture_cache->Shutdown();

  g_bounding_box.reset();
  g_perf_query.reset();
  g_graphics_mod_manager.reset();
  g_texture_cache.reset();
  g_framebuffer_manager.reset();
  g_shader_cache.reset();
  g_vertex_manager.reset();
  g_efb_interface.reset();
  g_widescreen.reset();
  g_gfx.reset();

  m_initialized = false;

  VertexLoaderManager::Clear();
#ifndef __LIBRETRO__
  system.GetFifo().Shutdown();
#endif
}
