#include <SDL.h>
#define GL_GLEXT_PROTOTYPES
#include <SDL_opengl.h>

#include <string>
#include <iostream>

using namespace std;

SDL_GLContext glRenderContext;
SDL_Window *mainWindow;

string glErrorToString(GLenum e)
{
    switch (e) {
        case GL_NO_ERROR: return "GL_NO_ERROR";
        case GL_INVALID_ENUM: return "GL_INVALID_ENUM";
        case GL_INVALID_VALUE: return "GL_INVALID_VALUE";
        case GL_INVALID_OPERATION: return "GL_INVALID_OPERATION";
        case GL_INVALID_FRAMEBUFFER_OPERATION: return "GL_INVALID_FRAMEBUFFER_OPERATION";
        case GL_OUT_OF_MEMORY: return "GL_OUT_OF_MEMORY";
        case GL_STACK_UNDERFLOW: return "GL_STACK_UNDERFLOW";
        case GL_STACK_OVERFLOW: return "GL_STACK_OVERFLOW";
        default: return "unknown error";
    }
}

int main(int argc, char* argv[])
{
    if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER) != 0) {
        cout << "Unable to initialize SDL: " << SDL_GetError() << endl;
        return -1;
    }

    int resolutionX = 512;
    int resolutionY = 512;

    mainWindow = SDL_CreateWindow(
        "An SDL2 window",
        SDL_WINDOWPOS_UNDEFINED,
        SDL_WINDOWPOS_UNDEFINED,
        resolutionX,
        resolutionY,
        SDL_WINDOW_SHOWN | SDL_WINDOW_OPENGL
    );

    if(mainWindow==NULL){
        std::cout << "Could not create window: " << SDL_GetError() << std::endl;
        return -1;
    }

    //mesa/radeonsi only supports GL3.3 in Core
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
    glRenderContext = SDL_GL_CreateContext(mainWindow);
    
    int x = 512;
    int y = 512;
    GLenum internalformat = GL_RGBA8;
    int samples = 2;
    GLuint textureId;
    
    glGenTextures(1, &textureId);
    glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, textureId);
    glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, samples, internalformat, x, y, GL_TRUE);
  
    GLuint fboId;
    glGenFramebuffers(1, &fboId);
    glBindFramebuffer(GL_READ_FRAMEBUFFER, fboId);
    glFramebufferTexture(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, textureId, 0);
    
    //when trying to blit any kind of multi sample fbo, this will always cause an GL_INVALID_OPERATION
    //KHR_debug: "GL_INVALID_OPERATION in glBlitFramebufferEXT(bad src/dst multisample pixel formats)"
    glBlitFramebuffer(0, 0, 512, 512, 0, 0, 512, 512, GL_COLOR_BUFFER_BIT, GL_NEAREST);
    
    GLenum e = glGetError();
    if (e != GL_NO_ERROR) {
        cout << "glGetError = " << glErrorToString(e) << endl;
    }


    SDL_GL_DeleteContext(glRenderContext);
    SDL_DestroyWindow(mainWindow);
    SDL_Quit();
    return 0;
}