#pragma once
#include "common/timer.h"
#include "settings.h"
#include "types.h"
#include <chrono>
#include <deque>
#include <functional>
#include <memory>
#include <mutex>
#include <optional>
#include <string>
#include <vector>

class AudioStream;
class CDImage;
class HostDisplay;
class GameList;

class System;

class HostInterface
{
  friend System;

public:
  HostInterface();
  virtual ~HostInterface();

  /// Access to host display.
  ALWAYS_INLINE HostDisplay* GetDisplay() const { return m_display.get(); }

  /// Access to host audio stream.
  AudioStream* GetAudioStream() const { return m_audio_stream.get(); }

  /// Returns a settings object which can be modified.
  Settings& GetSettings() { return m_settings; }

  /// Returns the game list.
  const GameList* GetGameList() const { return m_game_list.get(); }

  bool CreateSystem();
  bool BootSystem(const char* filename, const char* state_filename);
  void ResetSystem();
  void DestroySystem();

  virtual void ReportError(const char* message);
  virtual void ReportMessage(const char* message);

  void ReportFormattedError(const char* format, ...);
  void ReportFormattedMessage(const char* format, ...);

  /// Adds OSD messages, duration is in seconds.
  void AddOSDMessage(const char* message, float duration = 2.0f);
  void AddFormattedOSDMessage(float duration, const char* format, ...);

  /// Loads the BIOS image for the specified region.
  virtual std::optional<std::vector<u8>> GetBIOSImage(ConsoleRegion region);


  /// Returns the base user directory path.
  const std::string& GetUserDirectory() const { return m_user_directory; }

  /// Returns a path relative to the user directory.
  std::string GetUserDirectoryRelativePath(const char* format, ...) const;

protected:
  enum : u32
  {
    AUDIO_SAMPLE_RATE = 44100,
    AUDIO_CHANNELS = 2,
    AUDIO_BUFFER_SIZE = 2048,
    AUDIO_BUFFERS = 2,
    PER_GAME_SAVE_STATE_SLOTS = 10,
    GLOBAL_SAVE_STATE_SLOTS = 10
  };

  struct OSDMessage
  {
    std::string text;
    Common::Timer time;
    float duration;
  };

  struct SaveStateInfo
  {
    std::string path;
    u64 timestamp;
    s32 slot;
    bool global;
  };

  virtual void SwitchGPURenderer();
  virtual void OnSystemPerformanceCountersUpdated();
  virtual void OnRunningGameChanged();

  void SetUserDirectory();

  /// Ensures all subdirectories of the user directory are created.
  void CreateUserDirectorySubdirectories();

  /// Returns the path of the settings file.
  std::string GetSettingsFileName() const;

  /// Returns the path of the game list cache file.
  std::string GetGameListCacheFileName() const;

  /// Returns the path of the game database cache file.
  std::string GetGameListDatabaseFileName() const;

  /// Returns the path to a save state file. Specifying an index of -1 is the "resume" save state.
  std::string GetGameSaveStateFileName(const char* game_code, s32 slot) const;

  /// Returns the path to a save state file. Specifying an index of -1 is the "resume" save state.
  std::string GetGlobalSaveStateFileName(s32 slot) const;

  /// Returns the default path to a memory card.
  std::string GetSharedMemoryCardPath(u32 slot) const;

  /// Returns the default path to a memory card for a specific game.
  std::string GetGameMemoryCardPath(const char* game_code, u32 slot) const;

  /// Returns a list of save states for the specified game code.
  std::vector<SaveStateInfo> GetAvailableSaveStates(const char* game_code) const;

  /// Loads the current emulation state from file. Specifying a slot of -1 loads the "resume" game state.
  bool LoadState(bool global, u32 slot);
  bool LoadState(const char* filename);

  /// Saves the current emulation state to a file. Specifying a slot of -1 saves the "resume" save state.
  bool SaveState(bool global, u32 slot);
  bool SaveState(const char* filename);

  /// Restores all settings to defaults.
  void SetDefaultSettings();

  /// Applies new settings, updating internal state as needed. apply_callback should call m_settings.Load() after
  /// locking any required mutexes.
  void UpdateSettings(const std::function<void()>& apply_callback);

  /// Quick switch between software and hardware rendering.
  void ToggleSoftwareRendering();

  /// Adjusts the internal (render) resolution of the hardware backends.
  void ModifyResolutionScale(s32 increment);

  void UpdateSpeedLimiterState();

  void DrawFPSWindow();
  void DrawOSDMessages();
  void DrawDebugWindows();
  void ClearImGuiFocus();

  std::unique_ptr<HostDisplay> m_display;
  std::unique_ptr<AudioStream> m_audio_stream;
  std::unique_ptr<System> m_system;
  std::unique_ptr<GameList> m_game_list;
  Settings m_settings;
  std::string m_user_directory;

  bool m_paused = false;
  bool m_speed_limiter_temp_disabled = false;
  bool m_speed_limiter_enabled = false;

  std::deque<OSDMessage> m_osd_messages;
  std::mutex m_osd_messages_lock;
};