#pragma once

#include <cstdint> // Para uint32_t
#include <cstring> // Para memcpy
#include <vector>

#define EXTENSION_INTRODUCER 0x21
#define IMAGE_DESCRIPTOR 0x2C
#define TRAILER 0x3B
#define GRAPHIC_CONTROL 0xF9
#define APPLICATION_EXTENSION 0xFF
#define COMMENT_EXTENSION 0xFE
#define PLAINTEXT_EXTENSION 0x01

#define READ(dst, size)        \
    memcpy(dst, buffer, size); \
    buffer += size

struct ScreenDescriptor
{
    uint16_t width;
    uint16_t height;
    uint8_t fields;
    uint8_t background_color_index;
    uint8_t pixel_aspect_ratio;
};

struct RGB
{
    uint8_t r, g, b;
};

struct ImageDescriptor
{
    uint16_t image_left_position;
    uint16_t image_top_position;
    uint16_t image_width;
    uint16_t image_height;
    uint8_t fields;
};

struct DictionaryEntry
{
    uint8_t byte;
    int prev;
    int len;
};

struct Extension
{
    uint8_t extension_code;
    uint8_t block_size;
};

struct GraphicControlExtension
{
    uint8_t fields;
    uint16_t delay_time;
    uint8_t transparent_color_index;
};

struct ApplicationExtension
{
    uint8_t application_id[8];
    uint8_t version[3];
};

struct PlaintextExtension
{
    uint16_t left, top, width, height;
    uint8_t cell_width, cell_height;
    uint8_t foreground_color, background_color;
};

class Gif
{
public:
    void uncompress(int code_length, const uint8_t *input, int input_length, uint8_t *out);
    uint32_t *LoadPalette(uint8_t *buffer);
    uint8_t *LoadGif(uint8_t *buffer, uint16_t *w, uint16_t *h);

private:
    int read_sub_blocks(uint8_t *buffer, uint8_t **data);
    uint8_t *process_image_descriptor(uint8_t *buffer, RGB *gct, int gct_size, int resolution_bits);
    uint8_t *process_gif_stream(uint8_t *buffer, uint16_t *w, uint16_t *h);
};