#include "host_interface.h"
#include "bios.h"
#include "cdrom.h"
#include "common/audio_stream.h"
#include "common/byte_stream.h"
#include "common/file_system.h"
#include "common/log.h"
#include "common/string_util.h"
#include "common/timer.h"
#include "dma.h"
#include "game_list.h"
#include "gpu.h"
#include "host_display.h"
#include "mdec.h"
#include "spu.h"
#include "system.h"
#include "timers.h"
#include <cmath>
#include <cstring>
#include <imgui.h>
Log_SetChannel(HostInterface);

#ifdef _WIN32
#include "common/windows_headers.h"
#else
#include <time.h>
#endif

#if defined(ANDROID) || (defined(__GNUC__) && __GNUC__ < 8)

static std::string GetRelativePath(const std::string& path, const char* new_filename)
{
  const char* last = std::strrchr(path.c_str(), '/');
  if (!last)
    return new_filename;

  std::string new_path(path.c_str(), last - path.c_str() + 1);
  new_path += new_filename;
  return new_path;
}

#else

#include <filesystem>

static std::string GetRelativePath(const std::string& path, const char* new_filename)
{
  return std::filesystem::path(path).replace_filename(new_filename).string();
}

#endif

HostInterface::HostInterface()
{
  SetUserDirectory();
  CreateUserDirectorySubdirectories();
  m_game_list = std::make_unique<GameList>();
  m_game_list->SetCacheFilename(GetGameListCacheFileName());
  m_game_list->SetDatabaseFilename(GetGameListDatabaseFileName());
  m_settings.SetDefaults();
  m_last_throttle_time = Common::Timer::GetValue();
}

HostInterface::~HostInterface() = default;

bool HostInterface::CreateSystem()
{
  m_system = System::Create(this);

  // Pull in any invalid settings which have been reset.
  m_settings = m_system->GetSettings();
  m_paused = true;
  UpdateSpeedLimiterState();
  return true;
}

bool HostInterface::BootSystem(const char* filename, const char* state_filename)
{
  if (!m_system->Boot(filename))
    return false;

  m_paused = m_settings.start_paused;
  UpdateSpeedLimiterState();

  if (state_filename && !LoadState(state_filename))
    return false;

  return true;
}

void HostInterface::ResetSystem()
{
  m_system->Reset();
  ResetPerformanceCounters();
  AddOSDMessage("System reset.");
}

void HostInterface::DestroySystem()
{
  m_system.reset();
  m_paused = false;
  UpdateSpeedLimiterState();
}

void HostInterface::ReportError(const char* message)
{
  Log_ErrorPrint(message);
}

void HostInterface::ReportMessage(const char* message)
{
  Log_InfoPrintf(message);
}

void HostInterface::ReportFormattedError(const char* format, ...)
{
  std::va_list ap;
  va_start(ap, format);
  std::string message = StringUtil::StdStringFromFormatV(format, ap);
  va_end(ap);

  ReportError(message.c_str());
}

void HostInterface::ReportFormattedMessage(const char* format, ...)
{
  std::va_list ap;
  va_start(ap, format);
  std::string message = StringUtil::StdStringFromFormatV(format, ap);
  va_end(ap);

  ReportMessage(message.c_str());
}

void HostInterface::DrawFPSWindow()
{
  const bool show_fps = true;
  const bool show_vps = true;
  const bool show_speed = true;

  if (!(show_fps | show_vps | show_speed))
    return;

  const ImVec2 window_size =
    ImVec2(175.0f * ImGui::GetIO().DisplayFramebufferScale.x, 16.0f * ImGui::GetIO().DisplayFramebufferScale.y);
  ImGui::SetNextWindowPos(ImVec2(ImGui::GetIO().DisplaySize.x - window_size.x, 0.0f), ImGuiCond_Always);
  ImGui::SetNextWindowSize(window_size);

  if (!ImGui::Begin("FPSWindow", nullptr,
                    ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoCollapse |
                      ImGuiWindowFlags_NoBackground | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoMouseInputs |
                      ImGuiWindowFlags_NoBringToFrontOnFocus))
  {
    ImGui::End();
    return;
  }

  bool first = true;
  if (show_fps)
  {
    ImGui::Text("%.2f", m_fps);
    first = false;
  }
  if (show_vps)
  {
    if (first)
    {
      first = false;
    }
    else
    {
      ImGui::SameLine();
      ImGui::Text("/");
      ImGui::SameLine();
    }

    ImGui::Text("%.2f", m_vps);
  }
  if (show_speed)
  {
    if (first)
    {
      first = false;
    }
    else
    {
      ImGui::SameLine();
      ImGui::Text("/");
      ImGui::SameLine();
    }

    const u32 rounded_speed = static_cast<u32>(std::round(m_speed));
    if (m_speed < 90.0f)
      ImGui::TextColored(ImVec4(1.0f, 0.4f, 0.4f, 1.0f), "%u%%", rounded_speed);
    else if (m_speed < 110.0f)
      ImGui::TextColored(ImVec4(1.0f, 1.0f, 1.0f, 1.0f), "%u%%", rounded_speed);
    else
      ImGui::TextColored(ImVec4(0.4f, 1.0f, 0.4f, 1.0f), "%u%%", rounded_speed);
  }

  ImGui::End();
}

void HostInterface::AddOSDMessage(const char* message, float duration /*= 2.0f*/)
{
  OSDMessage msg;
  msg.text = message;
  msg.duration = duration;

  std::unique_lock<std::mutex> lock(m_osd_messages_lock);
  m_osd_messages.push_back(std::move(msg));
}

void HostInterface::AddFormattedOSDMessage(float duration, const char* format, ...)
{
  std::va_list ap;
  va_start(ap, format);
  std::string message = StringUtil::StdStringFromFormatV(format, ap);
  va_end(ap);

  OSDMessage msg;
  msg.text = std::move(message);
  msg.duration = duration;

  std::unique_lock<std::mutex> lock(m_osd_messages_lock);
  m_osd_messages.push_back(std::move(msg));
}

void HostInterface::DrawOSDMessages()
{
  constexpr ImGuiWindowFlags window_flags = ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoInputs |
                                            ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoSavedSettings |
                                            ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoNav |
                                            ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoFocusOnAppearing;

  std::unique_lock<std::mutex> lock(m_osd_messages_lock);
  if (m_osd_messages.empty())
    return;

  const float scale = ImGui::GetIO().DisplayFramebufferScale.x;

  auto iter = m_osd_messages.begin();
  float position_x = 10.0f * scale;
  float position_y = (10.0f + (static_cast<float>(m_display->GetDisplayTopMargin()))) * scale;
  u32 index = 0;
  while (iter != m_osd_messages.end())
  {
    const OSDMessage& msg = *iter;
    const double time = msg.time.GetTimeSeconds();
    const float time_remaining = static_cast<float>(msg.duration - time);
    if (time_remaining <= 0.0f)
    {
      iter = m_osd_messages.erase(iter);
      continue;
    }

    const float opacity = std::min(time_remaining, 1.0f);
    ImGui::SetNextWindowPos(ImVec2(position_x, position_y));
    ImGui::SetNextWindowSize(ImVec2(0.0f, 0.0f));
    ImGui::PushStyleVar(ImGuiStyleVar_Alpha, opacity);

    char buf[64];
    std::snprintf(buf, sizeof(buf), "osd_%u", index++);

    if (ImGui::Begin(buf, nullptr, window_flags))
    {
      ImGui::TextUnformatted(msg.text.c_str());
      position_y += ImGui::GetWindowSize().y + (4.0f * scale);
    }

    ImGui::End();
    ImGui::PopStyleVar();
    ++iter;
  }
}

void HostInterface::DrawDebugWindows()
{
  const Settings::DebugSettings& debug_settings = m_system->GetSettings().debugging;

  if (debug_settings.show_gpu_state)
    m_system->GetGPU()->DrawDebugStateWindow();
  if (debug_settings.show_cdrom_state)
    m_system->GetCDROM()->DrawDebugWindow();
  if (debug_settings.show_timers_state)
    m_system->GetTimers()->DrawDebugStateWindow();
  if (debug_settings.show_spu_state)
    m_system->GetSPU()->DrawDebugStateWindow();
  if (debug_settings.show_mdec_state)
    m_system->GetMDEC()->DrawDebugStateWindow();
}

void HostInterface::ClearImGuiFocus()
{
  ImGui::SetWindowFocus(nullptr);
}

std::optional<std::vector<u8>> HostInterface::GetBIOSImage(ConsoleRegion region)
{
  // Try the other default filenames in the directory of the configured BIOS.
#define TRY_FILENAME(filename)                                                                                         \
  do                                                                                                                   \
  {                                                                                                                    \
    std::string try_filename = filename;                                                                               \
    std::optional<BIOS::Image> found_image = BIOS::LoadImageFromFile(try_filename);                                    \
    BIOS::Hash found_hash = BIOS::GetHash(*found_image);                                                               \
    Log_DevPrintf("Hash for BIOS '%s': %s", try_filename.c_str(), found_hash.ToString().c_str());                      \
    if (BIOS::IsValidHashForRegion(region, found_hash))                                                                \
    {                                                                                                                  \
      Log_InfoPrintf("Using BIOS from '%s'", try_filename.c_str());                                                    \
      return found_image;                                                                                              \
    }                                                                                                                  \
  } while (0)

  // Try the configured image.
  TRY_FILENAME(m_settings.bios_path);

  // Try searching in the same folder for other region's images.
  switch (region)
  {
    case ConsoleRegion::NTSC_J:
      TRY_FILENAME(GetRelativePath(m_settings.bios_path, "scph1000.bin"));
      TRY_FILENAME(GetRelativePath(m_settings.bios_path, "scph5500.bin"));
      break;

    case ConsoleRegion::NTSC_U:
      TRY_FILENAME(GetRelativePath(m_settings.bios_path, "scph1001.bin"));
      TRY_FILENAME(GetRelativePath(m_settings.bios_path, "scph5501.bin"));
      break;

    case ConsoleRegion::PAL:
      TRY_FILENAME(GetRelativePath(m_settings.bios_path, "scph1002.bin"));
      TRY_FILENAME(GetRelativePath(m_settings.bios_path, "scph5502.bin"));
      break;

    default:
      break;
  }

#undef RELATIVE_PATH
#undef TRY_FILENAME

  // Fall back to the default image.
  Log_WarningPrintf("No suitable BIOS image for region %s could be located, using configured image '%s'. This may "
                    "result in instability.",
                    Settings::GetConsoleRegionName(region), m_settings.bios_path.c_str());
  return BIOS::LoadImageFromFile(m_settings.bios_path);
}

void HostInterface::Throttle()
{
  // Allow variance of up to 40ms either way.
  constexpr s64 MAX_VARIANCE_TIME = INT64_C(40000000);

  // Don't sleep for <1ms or >=period.
  constexpr s64 MINIMUM_SLEEP_TIME = INT64_C(1000000);

  // Use unsigned for defined overflow/wrap-around.
  const u64 time = static_cast<u64>(m_throttle_timer.GetTimeNanoseconds());
  const s64 sleep_time = static_cast<s64>(m_last_throttle_time - time);
  if (std::abs(sleep_time) >= MAX_VARIANCE_TIME)
  {
#ifdef Y_BUILD_CONFIG_RELEASE
    // Don't display the slow messages in debug, it'll always be slow...
    // Limit how often the messages are displayed.
    if (m_speed_lost_time_timestamp.GetTimeSeconds() >= 1.0f)
    {
      Log_WarningPrintf("System too %s, lost %.2f ms", sleep_time < 0 ? "slow" : "fast",
                        static_cast<double>(std::abs(sleep_time) - MAX_VARIANCE_TIME) / 1000000.0);
      m_speed_lost_time_timestamp.Reset();
    }
#endif
    m_last_throttle_time = 0;
    m_throttle_timer.Reset();
  }
  else if (sleep_time >= MINIMUM_SLEEP_TIME && sleep_time <= m_throttle_period)
  {
#ifdef WIN32
    Sleep(static_cast<u32>(sleep_time / 1000000));
#else
    const struct timespec ts = {0, static_cast<long>(sleep_time)};
    nanosleep(&ts, nullptr);
#endif
  }

  m_last_throttle_time += m_throttle_period;
}

bool HostInterface::LoadState(const char* filename)
{
  std::unique_ptr<ByteStream> stream = FileSystem::OpenFile(filename, BYTESTREAM_OPEN_READ | BYTESTREAM_OPEN_STREAMED);
  if (!stream)
    return false;

  AddFormattedOSDMessage(2.0f, "Loading state from %s...", filename);

  const bool result = m_system->LoadState(stream.get());
  if (!result)
  {
    ReportFormattedError("Loading state from %s failed. Resetting.", filename);
    m_system->Reset();
  }

  return result;
}

bool HostInterface::SaveState(const char* filename)
{
  std::unique_ptr<ByteStream> stream =
    FileSystem::OpenFile(filename, BYTESTREAM_OPEN_CREATE | BYTESTREAM_OPEN_WRITE | BYTESTREAM_OPEN_TRUNCATE |
                                     BYTESTREAM_OPEN_ATOMIC_UPDATE | BYTESTREAM_OPEN_STREAMED);
  if (!stream)
    return false;

  const bool result = m_system->SaveState(stream.get());
  if (!result)
  {
    ReportFormattedError("Saving state to %s failed.", filename);
    stream->Discard();
  }
  else
  {
    AddFormattedOSDMessage(2.0f, "State saved to %s.", filename);
    stream->Commit();
  }

  return result;
}

void HostInterface::UpdateSpeedLimiterState()
{
  m_speed_limiter_enabled = m_settings.speed_limiter_enabled && !m_speed_limiter_temp_disabled;

  const bool audio_sync_enabled = !m_system || m_paused || (m_speed_limiter_enabled && m_settings.audio_sync_enabled);
  const bool video_sync_enabled = !m_system || m_paused || (m_speed_limiter_enabled && m_settings.video_sync_enabled);
  Log_InfoPrintf("Syncing to %s%s", audio_sync_enabled ? "audio" : "",
                 (audio_sync_enabled && video_sync_enabled) ? " and video" : (video_sync_enabled ? "video" : ""));

  m_audio_stream->SetSync(audio_sync_enabled);
  m_display->SetVSync(video_sync_enabled);
  m_throttle_timer.Reset();
  m_last_throttle_time = 0;
}

void HostInterface::OnPerformanceCountersUpdated() {}

void HostInterface::OnRunningGameChanged() {}

void HostInterface::SetUserDirectory()
{
#ifdef WIN32
  // On Windows, use the path to the program.
  // We might want to use My Documents in the future.
  const std::string program_path = FileSystem::GetProgramPath();
  Log_InfoPrintf("Program path: %s", program_path.c_str());

  m_user_directory = FileSystem::GetPathDirectory(program_path.c_str());
#else
#endif

  Log_InfoPrintf("User directory: %s", m_user_directory.c_str());

  // Change to the user directory so that all default/relative paths in the config are after this.
  if (!m_user_directory.empty())
  {
    if (!FileSystem::SetWorkingDirectory(m_user_directory.c_str()))
      Log_ErrorPrintf("Failed to set working directory to '%s'", m_user_directory.c_str());
  }
}

void HostInterface::CreateUserDirectorySubdirectories()
{
  bool result = true;

  result &= FileSystem::CreateDirectory(GetUserDirectoryRelativePath("cache").c_str(), false);

  if (!result)
    ReportError("Failed to create one or more user directories. This may cause issues at runtime.");
}

std::string HostInterface::GetUserDirectoryRelativePath(const char* format, ...) const
{
  std::va_list ap;
  va_start(ap, format);
  std::string formatted_path = StringUtil::StdStringFromFormatV(format, ap);
  va_end(ap);

  if (m_user_directory.empty())
  {
    return formatted_path;
  }
  else
  {
    return StringUtil::StdStringFromFormat("%s%c%s", m_user_directory.c_str(), FS_OSPATH_SEPERATOR_CHARACTER,
                                           formatted_path.c_str());
  }
}

std::string HostInterface::GetSettingsFileName() const
{
  return GetUserDirectoryRelativePath("settings.ini");
}

std::string HostInterface::GetGameListCacheFileName() const
{
  return GetUserDirectoryRelativePath("cache/gamelist.cache");
}

std::string HostInterface::GetGameListDatabaseFileName() const
{
  return GetUserDirectoryRelativePath("cache/redump.dat");
}

void HostInterface::RunFrame()
{
  m_frame_timer.Reset();
  m_system->RunFrame();
  UpdatePerformanceCounters();
}

void HostInterface::UpdatePerformanceCounters()
{
  const float frame_time = static_cast<float>(m_frame_timer.GetTimeMilliseconds());
  m_average_frame_time_accumulator += frame_time;
  m_worst_frame_time_accumulator = std::max(m_worst_frame_time_accumulator, frame_time);

  // update fps counter
  const float time = static_cast<float>(m_fps_timer.GetTimeSeconds());
  if (time < 1.0f)
    return;

  const float frames_presented = static_cast<float>(m_system->GetFrameNumber() - m_last_frame_number);

  m_worst_frame_time = m_worst_frame_time_accumulator;
  m_worst_frame_time_accumulator = 0.0f;
  m_average_frame_time = m_average_frame_time_accumulator / frames_presented;
  m_average_frame_time_accumulator = 0.0f;
  m_vps = static_cast<float>(frames_presented / time);
  m_last_frame_number = m_system->GetFrameNumber();
  m_fps = static_cast<float>(m_system->GetInternalFrameNumber() - m_last_internal_frame_number) / time;
  m_last_internal_frame_number = m_system->GetInternalFrameNumber();
  m_speed = static_cast<float>(static_cast<double>(m_system->GetGlobalTickCounter() - m_last_global_tick_counter) /
                               (static_cast<double>(MASTER_CLOCK) * time)) *
            100.0f;
  m_last_global_tick_counter = m_system->GetGlobalTickCounter();
  m_fps_timer.Reset();

  OnPerformanceCountersUpdated();
}

void HostInterface::ResetPerformanceCounters()
{
  if (m_system)
  {
    m_last_frame_number = m_system->GetFrameNumber();
    m_last_internal_frame_number = m_system->GetInternalFrameNumber();
    m_last_global_tick_counter = m_system->GetGlobalTickCounter();
  }
  else
  {
    m_last_frame_number = 0;
    m_last_internal_frame_number = 0;
    m_last_global_tick_counter = 0;
  }
  m_average_frame_time_accumulator = 0.0f;
  m_worst_frame_time_accumulator = 0.0f;
  m_fps_timer.Reset();
}