////////////////////////////////////////////////////////////
//~ Track types

Enum(MIX_TrackFlag)
{
  MIX_TrackFlag_None        = 0,
  MIX_TrackFlag_Spatialize  = (1 << 0)
};

Struct(MIX_Handle)
{
  u64 gen;
  void *data;
};

Struct(MIX_TrackDesc)
{
  MIX_TrackFlag flags;
  f32 volume; // 0 -> 1.0+
  f32 speed;  // 0 -> 1.0+
  b32 looping;

  Vec2 pos;
};
#define MIX_TRACKDESC(...) ((MIX_TrackDesc) { \
  .flags      = 0,                            \
  .volume     = 1.0,                          \
  .speed      = 1.0,                          \
  .looping    = 0,                            \
  .pos        = VEC2(0, 0),                   \
  __VA_ARGS__                                 \
})

////////////////////////////////////////////////////////////
//~ Mix types

// Stereo mix of 32 bit float samples
Struct(MIX_PcmF32)
{
  u64 count;
  f32 *samples;
};

Struct(MIX_EffectData)
{
  // Spatialization
  f32 spatial_volume;
  f32 spatial_pan;
};

Struct(MIX_MixData)
{
  MIX_Handle track_handle;
  b32 track_finished;

  MIX_TrackDesc desc;
  MIX_EffectData effect_data;
  SND_Sound *source;
  u64 source_pos;
};

Struct(MIX_Track){
  u64 gen;

  // Controlled via interface
  SND_Sound *sound;
  MIX_TrackDesc desc;

  // Internal
  MIX_MixData mix;

  MIX_Track *next;
  MIX_Track *prev;
};

////////////////////////////////////////////////////////////
//~ State types

Struct(MIX_Ctx)
{
  Mutex mutex;

  // Listener
  Vec2 listener_pos;
  Vec2 listener_dir;

  // Track list
  Arena *track_arena;
  MIX_Track *track_first_playing;
  MIX_Track *track_last_playing;
  u64 track_playing_count;
  MIX_Track *track_first_free;
};

extern MIX_Ctx MIX;

////////////////////////////////////////////////////////////
//~ Bootstrap

void MIX_Bootstrap(void);

////////////////////////////////////////////////////////////
//~ Track

MIX_Handle MIX_HandleFromTrack(MIX_Track *track);
MIX_Track *MIX_TrackFromHandle(MIX_Handle handle);
MIX_Track *MIX_AcquireTrackLocked(Lock *lock, SND_Sound *sound);
void MIX_ReleaseTrackLocked(Lock *lock, MIX_Track *track);

MIX_Handle MIX_PlaySound(SND_Sound *sound);
MIX_Handle MIX_PlaySoundEx(SND_Sound *sound, MIX_TrackDesc desc);
MIX_TrackDesc MIX_TrackDescFromHandle(MIX_Handle handle);
void MIX_UpdateTrack(MIX_Handle handle, MIX_TrackDesc desc);
void MIX_UpdateListener(Vec2 pos, Vec2 dir);

////////////////////////////////////////////////////////////
//~ Mix

i16 MIX_SampleSound(SND_Sound *sound, u64 sample_pos, b32 wrap);
MIX_PcmF32 MIX_MixAllTracks(Arena *arena, u64 frame_count);