#include <SDL2/SDL_events.h>
#include <SDL2/SDL_render.h>
#include <SDL2/SDL_video.h>
#include <cstdio>
#include <SDL2/SDL.h>
#include <GL/glew.h>
#include <SDL2/SDL_opengl.h>
#include <GL/glut.h>

const GLchar* vertexShaderSource[] ={
  "#version 460 core\nin vec3 pos; void main() {gl_Position = vec4(pos, 1.0); }"
};

const GLchar* fragShaderSource[] = {
  "#version 460 core\n out vec4 FragColor; void main() { FragColor = vec4(1.0);}"
};

int main(){

  bool running = true;

  SDL_GL_SetAttribute( SDL_GL_CONTEXT_MAJOR_VERSION, 3 );
  SDL_GL_SetAttribute( SDL_GL_CONTEXT_MINOR_VERSION, 1 );
  SDL_GL_SetAttribute( SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE );


  SDL_Window* window;
  SDL_Renderer* renderer;

  SDL_CreateWindowAndRenderer(600, 400, SDL_WINDOW_RESIZABLE, &window, &renderer);

  SDL_GLContext gl_context = SDL_GL_CreateContext(window);

  if (gl_context == NULL){
    printf("Failed to create OpenGL context\n");
    return -1;
  }

  glewExperimental = true;

  GLenum glewError = glewInit();
  if (glewError != GLEW_OK){
    printf("Failed to init glew\n");
    return -1;
  }

  GLuint vsShader = glCreateShader(GL_VERTEX_SHADER);
  glShaderSource(vsShader, 1, vertexShaderSource, NULL);
  glCompileShader(vsShader);

  GLuint fsShader = glCreateShader(GL_FRAGMENT_SHADER);
  glShaderSource(fsShader, 1, fragShaderSource, NULL);
  glCompileShader(fsShader);

  GLuint program = glCreateProgram();
  glAttachShader(program, vsShader);
  glAttachShader(program, fsShader);
  glLinkProgram(program);

  float vertices[] ={
    0.0f, 0.5f, 0.0f,
    -0.5f, -0.5f, 0.0f,
    0.5f, -0.5f, 0.0f,
  };

  GLuint VAO, VBO;
  glGenVertexArrays(1, &VAO);
  glGenBuffers(1, &VBO);

  glBindVertexArray(VAO);
  glBindBuffer(GL_ARRAY_BUFFER, VBO);

  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
  glEnableVertexAttribArray(0);

  glClear(GL_COLOR_BUFFER_BIT);

  SDL_Event event;

  while(running){
    while(SDL_PollEvent(&event)){
      if (event.type == SDL_QUIT){
        running = false;
      }
    }

    //glClear(GL_COLOR_BUFFER_BIT);


    /*glDrawArrays(GL_TRIANGLES, 0, 9);*/

    SDL_GL_SwapWindow(window);
  }


  return 0;
}