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

Struct(ASE_Slice)
{
    u32 start;
    Rng2I32 rect;
    ASE_Slice *next;
};

Struct(ASE_Span)
{
    String name;
    u32 start;
    u32 end;
    ASE_Span *next;
};

Struct(ASE_Frame)
{
    u32 index;
    Rng2I32 rect;
    f64 duration;
    ASE_Frame *next;
};

Struct(ASE_SliceKey)
{
    String name;
    u32 num_slices;
    ASE_Slice *first_slice;
    ASE_SliceKey *next;
};

////////////////////////////////////////////////////////////
//~ Decoder result types

Struct(ASE_Error)
{
    String msg;
    ASE_Error *next;
};

Struct(ASE_ErrorList)
{
    u64 count;
    ASE_Error *first;
    ASE_Error *last;
};

Struct(ASE_DecodedImage)
{
    u32 width;
    u32 height;
    u32 *pixels;  /* Array of [width * height] pixels */
    ASE_ErrorList errors;
    b32 ok;
};

Struct(ASE_DecodedSheet)
{
    Vec2 image_size;
    Vec2 frame_size;
    u32 num_frames;
    u32 num_spans;
    u32 num_slice_keys;
    ASE_Frame *first_frame;
    ASE_Span *first_span;
    ASE_SliceKey *first_slice_key;
    ASE_ErrorList errors;
    b32 ok;
};

////////////////////////////////////////////////////////////
//~ Inflator types

#define ASE_HuffBitCount 16

Struct(ASE_Bitbuff)
{
    u8 *data;
    u64 cur_bit;
};

Enum(ASE_BlockType)
{
    ASE_BlockType_Uncompressed          = 0,
    ASE_BlockType_CompressedFixed       = 1,
    ASE_BlockType_CompressedDynamic     = 2,
    ASE_BlockType_Reserved              = 3
};

Struct(ASE_HuffEntry)
{
    u16 symbol;
    u16 bits_used;
};

Struct(ASE_HuffDict)
{
    u32 max_code_bits;
    u32 entries_count;
    ASE_HuffEntry *entries;
};

////////////////////////////////////////////////////////////
//~ Header types

Packed(Struct(ASE_Header)
{
    u32 file_size;
    u16 magic;
    u16 frames;
    u16 width;
    u16 height;
    u16 color_depth;
    u32 flags;
    u16 speed;
    u32 _1;
    u32 _2;
    u8 palette_entry;
    u8 _3[3];
    u16 num_colors;
    u8 pixel_width;
    u8 pixel_height;
    i16 grid_x;
    i16 grid_y;
    u16 grid_width;
    u16 grid_height;
    u8 _4[84];
});

Packed(Struct(ASE_FrameHeader)
{
    u32 bytes;
    u16 magic;
    u16 chunks_old;
    u16 frame_duration_ms;
    u8 _[2];
    u32 chunks_new;
});

////////////////////////////////////////////////////////////
//~ Image decoder types

Enum(ASE_ChunkKind)
{
    ASE_ChunkKind_OldPalette1       = 0x0004,
    ASE_ChunkKind_OldPalette2       = 0x0011,
    ASE_ChunkKind_Layer             = 0x2004,
    ASE_ChunkKind_Cel               = 0x2005,
    ASE_ChunkKind_CelExtra          = 0x2006,
    ASE_ChunkKind_ColorProfile      = 0x2007,
    ASE_ChunkKind_ExternalFiles     = 0x2008,
    ASE_ChunkKind_Mask              = 0x2016,
    ASE_ChunkKind_Path              = 0x2017,
    ASE_ChunkKind_Tags              = 0x2018,
    ASE_ChunkKind_Palette           = 0x2019,
    ASE_ChunkKind_Userdata          = 0x2020,
    ASE_ChunkKind_Slice             = 0x2022,
    ASE_ChunkKind_Tileset           = 0x2023
};

Enum(ASE_CelKind)
{
    ASE_CelKind_RawImage            = 0,
    ASE_CelKind_Linked              = 1,
    ASE_CelKind_CompressedImage     = 2,
    ASE_CelKind_CompressedTilemap   = 3
};

Struct(ASE_Layer)
{
    u16 flags;
    u16 type;
    u16 child_level;
    u16 blend_mode;
    u8 opacity;
    String name;
    u32 tileset_index;

    u32 index;
    ASE_Layer *next;
};

Struct(Ace_Cel)
{
    u16 layer_index;
    i16 x_pos;
    i16 y_pos;
    u8 opacity;
    ASE_CelKind type;
    i16 z_index;

    /* Linked cel */
    u16 frame_pos;

    /* Compressed image */
    u32 width;
    u32 height;
    u32 *pixels;

    u16 frame_index;
    Ace_Cel *next;
};

////////////////////////////////////////////////////////////
//~ Ase bitbuff helpers

u32 ASE_PeekBits(ASE_Bitbuff *bb, u32 nbits);
u32 ASE_ConsumeBits(ASE_Bitbuff *bb, u32 nbits);
void ASE_SkipBits(ASE_Bitbuff *bb, u32 nbits);

////////////////////////////////////////////////////////////
//~ Inflate

u32 ASE_ReverseBits(u32 v, u32 bit_count);
ASE_HuffDict ASE_InitHuffDict(Arena *arena, u32 max_code_bits, u32 *bl_counts, u32 bl_counts_count);
u16 ASE_DecodeHuffDict(ASE_HuffDict *huffman, ASE_Bitbuff *bb);
void ASE_Inflate(u8 *dst, u8 *encoded);

////////////////////////////////////////////////////////////
//~ Error helpers

void ASE_PushError(Arena *arena, ASE_ErrorList *list, String msg_src);

////////////////////////////////////////////////////////////
//~ Decode helpers

u32 ASE_BlendMulU8(u32 a, u32 b);
u32 ASE_Blend(u32 src, u32 dst, u8 opacity);
void ASE_MakeDimensionsSquareish(ASE_Header *header, u32 *frames_x, u32 *frames_y, u64 *image_width, u64 *image_height);

////////////////////////////////////////////////////////////
//~ Decode image

ASE_DecodedImage ASE_DecodeImage(Arena *arena, String encoded);

////////////////////////////////////////////////////////////
//~ Decode sheet

ASE_DecodedSheet ASE_DecodeSheet(Arena *arena, String encoded);