/*       /\         +--------------------------------------------------------------+ 
    ____/  \____   /| - zlib/MIT/Unlicenced game framework licensed to freely use, |
    \          /  / |   copy, modify and sell without restriction                  |
  +--\ ^__^   /--+  |                                                              |
  | ~/        \~ |  | - originally created at [http://nugget.fun]                  |
  | ~~~~~~~~~~~~ |  +--------------------------------------------------------------+
  | SPACE ~~~~~  | /
  |  ~~~~~~~ BOX |/
  +--------------+

  [Texture.hpp]

  The Texture class abstracts the file opening, data loading and binding steps of Open GL
  texture creation. Currently it only supports loading GL_TEXTURE_2D with GL_RGB8 pixels
  and automatic GL_NEAREST mipmapping. Support may be added for users to pass in their own
  pixel data, to customize mipmapping, and more. The class can also be used in a custom
  way by passing the Texture ID to GL functions instead of using the class's member
  functions.
  
*/

#ifndef SB_TEXTURE_H_
#define SB_TEXTURE_H_

#include <sstream>
#include <stdexcept>
#include "glm/vec2.hpp"
#include "SDL.h"
#include "SDL_image.h"
#include "sdl2-gfx/SDL2_rotozoom.h"
#include "filesystem.hpp"
#include "GLObject.hpp"
#include "Log.hpp"

namespace sb
{
    
    class Texture : public GLObject
    {

    private:

        fs::path path = "";

    public:

        Texture();
        Texture(fs::path);
        void associate(fs::path);
        void generate();
        void generate(glm::vec2);
        void load();
        void load(fs::path);
        void load(SDL_RWops*);
        void load(SDL_Surface*);
        void load(void* pixels, glm::vec2 size, GLenum format = GL_RGBA, GLenum type = GL_UNSIGNED_BYTE);

#ifndef __EMSCRIPTEN__
        /*!
         * @overload load(void* pixels, glm::vec2 size, GLenum format, GLenum type)
         * 
         * The texture must have been previously generated with a size to use this generic pixel data load function. The size is
         * determined with `glGetTexLevelParameter`, which is only available to OpenGL ES 3.1+, so this overload is not available
         * for Emscripten builds.
         *
         * see OpenGL's `glTexSubImage2D`
         *
         * @param pixels   pointer to pixel data
         * @param format   GL format of pixel data (for example, GL_RGBA)
         * @param type     data type of the pixel data (for example, GL_UNSIGNED_BYTE if each byte is one of the RGBA values)
         */
        void load(void* pixels, GLenum format = GL_RGBA, GLenum type = GL_UNSIGNED_BYTE);

        /*!
         * Return the size in pixels of mipmap level 0 (the only mipmap level supported by this class). If the texture hasn't been,
         * generated, return {0, 0}. `glGetTexLevelParameter` is only available in OpenGL ES 3.1+, so this function is removed from
         * Emscripten builds.
         *
         * @return glm::vec2    A vector consisting of {TEXTURE_MIPMAP_WIDTH, TEXTURE_MIPMAP_HEIGHT}
         */
        glm::vec2 size() const;
#endif
        
        void bind() const override;
        bool operator==(const Texture&) const;

    };

    void texture_deleter(GLuint*);

}

#endif