// 1bpp packed
u32 gba_btn_a_data[] = {
    0xc0300804, 0x844242c2, 0x030c1020, 0x21424243,
    0x42440408, 0x30c00000, 0x42222010, 0x0c030000,
};

u32 gba_btn_b_data[] = {
    0xc0300804, 0xc442c242, 0x030c1020, 0x21424142,
    0x42c40408, 0x30c00000, 0x42212010, 0x0c030000,
};

u32 gba_btn_updown_data[] = {
    0x00f01010, 0x90d01010, 0x001f1011, 0x13171111,
    0x101020c0, 0x00000000, 0x11110807, 0x00000000,
};

u32 gba_btn_leftright_data[] = {
    0x000000f8, 0x0888c8e8, 0x0000000f, 0x1020202f,
    0xc88808f8, 0x00000000, 0x2020100f, 0x00000000,
};

u32 gba_btn_l_data[] = {
    0xfc028181, 0x818101ff, 0xff808080, 0x808380ff,
};

u32 gba_btn_r_data[] = {
    0xff018181, 0x818101ff, 0x3f408182, 0x818280ff,
};

u32 gba_btn_ab_shadow_data[] = {
    0x00020204, 0x040830c0, 0x00404020, 0x20100c03,
};

u32 gba_btn_up_shadow_data[] = {
    0x00000010, 0x1020c000, 0x00000010, 0x10080700,
};

u32 gba_btn_down_shadow_data[] = {
    0x00000000, 0x10f00000, 0x00000000, 0x101f0000,
};

u32 gba_btn_leftright_shadow_data[] = {
    0x00000000, 0x000008f8, 0x00000000, 0x2020100f,
};

u32 gba_btn_lr_shadow_data[] = {
    0x00000000, 0x000001ff, 0x00000000, 0x000080ff,
};

u32 gba_btn_startselect_data[] = {
    0x0000f804, 0xfcf80000, 0x00001f20, 0x3f1f0000,
    0x000000f8, 0x04f80000, 0x0000001f, 0x201f0000,
};

u32 gba_btn_fx_downup[] = {
    0x00000000, 0x00000000, 0x04000000, 0x00000000,
    0x40000100, 0x00000000, 0x00000000, 0x00000000,
    0x00000000, 0x00000000, 0x00000201, 0x00000000,
    0x00008000, 0x01010000, 0x00000001, 0x00000000,
    0x00000000, 0x80000000, 0x00000001, 0x00000000,
    0x00000000, 0x00010100, 0x00000001, 0x02000000,
    0x00000000, 0x00400000, 0x00000000, 0x00000000,
    0x00000000, 0x00000001, 0x00000000, 0x00040000,
};

typedef struct SpriteAnimation {
    size_t *tile_offsets;
    size_t n_frames;
} SpriteAnimation;

typedef enum {BTN_STATE_IDLE, BTN_STATE_PRESSED, BTN_STATE_RELEASED, BTN_STATE_HOLD} BtnState;

static size_t btn_state_idle[] = {0};
// static size_t btn_state_pressed[] = {16, 16, 32, 32, 48, 48, 64, 64, 80, 96};
static size_t btn_state_pressed[] = {0};

static SpriteAnimation *animation_states[] = {
    &(SpriteAnimation){
        .tile_offsets = &btn_state_idle,
        .n_frames = sizeof(btn_state_idle) / sizeof(size_t),
    },
    &(SpriteAnimation){
        .tile_offsets = &btn_state_pressed,
        .n_frames = sizeof(btn_state_pressed) / sizeof(size_t),
    },
};

typedef struct AnimationEntry {
    int x_offset;
    int y_offset;
    int tile_offset;
    // NOTE: Maybe this should be a part of an animation?
    // For example, hidden state, h/v flip.
    u16 hidden;
    // u16 obj_attr_1;
    // u16 obj_attr_2;
} AnimationEntry;

typedef struct ObjState {
    size_t id;
    int x;
    int y;
    u32 *data;
    size_t base_tile;
    size_t n_tiles;
    size_t frames;
    u16 obj_attr_0;
    u16 obj_attr_1;
    u16 obj_attr_2;
} ObjState;

AnimationEntry *btn_down_animation[] = {
    &(AnimationEntry[]){
        {0, 0, 0, 0},
        {0, 0, 0, 0},
        {0, 1, 0, 0},
        {0, 1, 0, 0},
        {0, 2, 0, 0},
        {0, 2, 0, 0},
        {0, 2, 0, 0},
        {0, 2, 0, 0},
    },
    &(AnimationEntry[]){
        {0, 11, 0, 0},
        {0, 11, 0, 0},
        {0, 11, 0, 0},
        {0, 11, 0, 0},
        {0, 11, 0, 0},
        {0, 11, 0, 0},
        {0, 11, 0, 0},
        {0, 11, 0, 0},
    },
    &(AnimationEntry[]){
        {-8, 17, 0,  1},
        {-8, 17, 0,  0},
        {-8, 17, 4,  0},
        {-8, 17, 4,  0},
        {-8, 17, 8,  0},
        {-8, 17, 8,  0},
        {-8, 17, 12, 0},
        {-8, 17, 12, 1},
    },
};