////////////////////////////////////////////////////////////
//~ Key types

Struct(SPR_SpanKey)
{
    u64 hash;
};

Struct(SPR_SliceKey)
{
    u64 hash;
};

////////////////////////////////////////////////////////////
//~ Texture types

Struct(SPR_Texture)
{
    b32 valid;
    b32 loaded;
    GPU_Resource *gpu_texture;
    u32 width;
    u32 height;
};

extern Readonly SPR_Texture SPR_NilTexture;

////////////////////////////////////////////////////////////
//~ Sheet types

Struct(SPR_Frame)
{
    u32 index;
    f64 duration;
    ClipRect clip;
};

Struct(SPR_Span)
{
    SPR_Span *next_in_bin;
    u64 hash;
    String name;
    u32 start;
    u32 end;
};

Struct(SPR_SpanBin)
{
    SPR_Span *first;
    SPR_Span *last;
};

Struct(SPR_Slice)
{
    /* If 1, this slice was not copied over from another frame in the sprite sheet */
    b32 is_original;

    /* If 1, the slice has a corresponding '.ray' slice affecting the 'dir' fields */
    b32 has_dir;

    /* Values are in the range -0.5 (top / left edge) -> +0.5 (bottom / right edge) */
    Rect rect;
    Vec2 center;
    Vec2 dir;

    /* '_px' values retain the original sprite pixel dimensions */
    Rect rect_px;
    Vec2 center_px;
    Vec2 dir_px;
};

Struct(SPR_SliceGroup)
{
    SPR_SliceGroup *next_in_bin;
    u64 hash;
    String name;
    SPR_Slice *slices;
};

Struct(SPR_SliceGroupBin)
{
    SPR_SliceGroup *first;
    SPR_SliceGroup *last;
};

Struct(SPR_Sheet)
{
    b32 valid;
    b32 loaded;
    Vec2 image_size;
    Vec2 frame_size;

    u32 frames_count;
    SPR_Frame *frames;

    u32 spans_count;
    SPR_Span *spans;

    u32 slice_groups_count;
    SPR_SliceGroup *slice_groups;

    u32 span_bins_count;
    SPR_SpanBin *span_bins;

    u32 slice_group_bins_count;
    SPR_SliceGroupBin *slice_group_bins;
};

extern Readonly SPR_Sheet SPR_NilSheet;

////////////////////////////////////////////////////////////
//~ Cache types

Struct(SPR_Entry)
{
    SPR_Entry *next_in_bin;

    SPR_Texture texture;
    SPR_Sheet sheet;

    Atomic32 texture_touched;
    Atomic32 sheet_touched;

    ResourceKey resource;
    Fence texture_ready_fence;
    Fence sheet_ready_fence;
};

Struct(SPR_EntryBin)
{
    SPR_Entry *first;
    SPR_Entry *last;
    Mutex mutex;
};

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

#define SPR_EntryBinsCount 1024

Struct(SPR_SharedState)
{
    SPR_EntryBin entry_bins[SPR_EntryBinsCount];
} extern SPR_shared_state;

////////////////////////////////////////////////////////////
//~ Load jobs

JobDecl(SPR_LoadTexture, { SPR_Entry *entry; });
JobDecl(SPR_LoadSheet, { SPR_Entry *entry; });

////////////////////////////////////////////////////////////
//~ Cache operations

Enum(SPR_FetchFlag)
{
    SPR_FetchFlag_None    = 0,
    SPR_FetchFlag_Texture = (1 << 0),
    SPR_FetchFlag_Sheet   = (1 << 1),
};

SPR_Entry *SPR_FetchEntry(ResourceKey resource, JobPoolId pool, SPR_FetchFlag flags);

////////////////////////////////////////////////////////////
//~ Sprite data retrieval operations

SPR_Texture *SPR_TextureFromResource(ResourceKey resource);
SPR_Texture *SPR_TextureFromResourceAsync(ResourceKey resource);

SPR_Sheet *SPR_SheetFromResource(ResourceKey resource);
SPR_Sheet *SPR_SheetFromResourceAsync(ResourceKey resource);

////////////////////////////////////////////////////////////
//~ Key helpers

SPR_SpanKey SPR_SpanKeyFromName(String name);
SPR_SliceKey SPR_SliceKeyFromName(String name);

////////////////////////////////////////////////////////////
//~ Sheet access operations

SPR_Span SPR_SpanFromKey(SPR_Sheet *sheet, SPR_SpanKey key);
SPR_Frame SPR_FrameFromIndex(SPR_Sheet *sheet, u64 index);
SPR_Slice SPR_SliceFromKey(SPR_Sheet *sheet, SPR_SliceKey key, u64 frame_index);