#ifndef __OPENGLPLAYGROUND_TEXTURE_HH__
#define __OPENGLPLAYGROUND_TEXTURE_HH__

#include <string>
#include <cstdio>
#include <cassert>
#include <algorithm>

#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>

#define GL_GLEXT_PROTOTYPES
#include <GL/gl.h>

#include "common.hh"

static unsigned ilog2(unsigned in)
{
  unsigned ret = 0u;
  while (in >>= 1) ++ret;
  return ret;
}

class Texture2D {
public:
  Texture2D(unsigned width, unsigned height) {
    _glCreate(width, height);
  }

  Texture2D(std::string const& file) {
    SDL_Surface *surf = IMG_Load(file.c_str());
    if (!surf)
      throw SDLException();

    try {
      _glCreate(surf->w, surf->h);
      try {
	assert(surf->format->format == SDL_PIXELFORMAT_RGB24); // TODO: Proper support of many formats
	if (SDL_MUSTLOCK(surf))
	  SDL_LockSurface(surf);
	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, surf->w, surf->h, GL_RGB, GL_UNSIGNED_BYTE, surf->pixels);
	glGenerateMipmap(GL_TEXTURE_2D);
	checkGlError();
      } catch(...) {
	glDeleteTextures(1, &_texID);
	throw;
      }
    }
    catch(...) {
      SDL_FreeSurface(surf);
      throw;
    }
    SDL_FreeSurface(surf);
  }
  
  ~Texture2D() {
    glDeleteTextures(1, &_texID);
  }

  void bind() {
    glBindTexture(GL_TEXTURE_2D, _texID);
    checkGlError();
  }
  
private:

  void _glCreate(unsigned width, unsigned height) {
    glGenTextures(1, &_texID);
    checkGlError();
    try {
      glBindTexture(GL_TEXTURE_2D, _texID);
      unsigned logWidth = ilog2(width), logHeight = ilog2(height);
      unsigned levels = std::max(logWidth,logHeight)+1u;
      if(SDL_GL_ExtensionSupported("GL_ARB_texture_storage"))
	glTexStorage2D(GL_TEXTURE_2D, levels, GL_RGB8, width, height);
      else {
	std::printf("Warning: extension GL_ARB_texture_storage not supported!\n");
	for (unsigned i = 0u; i < levels; ++i)
	  {
	    glTexImage2D(GL_TEXTURE_2D, i, GL_RGB8, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
	    width = std::max(1u, (width / 2u));
	    height = std::max(1u, (height / 2u));
	  }
      }
      checkGlError();
    } catch(...) {
      glDeleteTextures(1, &_texID);
    }
  }
  
  GLuint _texID;
};


#endif