#include "gl3w.h"
#include "ruby.h"
#include "Window.h"
#include <SDL.h>

#define WIDTH   500
#define HEIGHT  500

typedef struct
{
    SDL_Window * sdl_window;
} Window;

static VALUE ruby_class;

static void Init_SDL(void)
{
    static bool initialized = false;

    if (initialized)
        return;

    if (SDL_Init(SDL_INIT_VIDEO))
    {
        rb_raise(rb_eRuntimeError, "Failed to initialize SDL");
    }

    atexit(SDL_Quit);

    initialized = true;
}

static void Init_OpenGL()
{
    static bool initialized = false;

    if (initialized)
        return;

    if (gl3wInit() != 0)
    {
        SDL_Quit();
        rb_raise(rb_eRuntimeError, "Failed to gl3wInit()");
    }

    if (!gl3wIsSupported(3, 0))
    {
        SDL_Quit();
        rb_raise(rb_eRuntimeError, "OpenGL 3.0 is not supported");
    }

    initialized = true;
}

static void Window_free(void * ptr)
{
    Window * window = (Window *)ptr;

    if (window->sdl_window)
        SDL_DestroyWindow(window->sdl_window);

    delete window;
}

static VALUE Window_new(VALUE klass)
{
    static bool one_created = false;

    if (one_created)
    {
        rb_raise(rb_eRuntimeError, "Only one Window for now");
    }

    Init_SDL();
    Window * window = new Window();
    window->sdl_window = SDL_CreateWindow("jes",
                                          SDL_WINDOWPOS_UNDEFINED,
                                          SDL_WINDOWPOS_UNDEFINED,
                                          WIDTH,
                                          HEIGHT,
                                          SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
    if (window->sdl_window == NULL)
    {
        free(window);
        rb_raise(rb_eRuntimeError, "Failed to create SDL window");
    }

    (void)SDL_GL_CreateContext(window->sdl_window);

    Init_OpenGL();

    one_created = true;

    return Data_Wrap_Struct(ruby_class, NULL, Window_free, window);
}

void Window_Init(void)
{
    ruby_class = rb_define_class("Window", rb_cObject);
    rb_define_singleton_method(ruby_class, "new", (VALUE(*)(...))Window_new, 0);
}