#include <SDL.h>
#include <cairo/cairo.h>

#include "khepcc.h"
#include "display.h"
#include "render.h"
#include "events.h"

/* Surface constructed from pixel data */
SDL_Surface *displaySurface = NULL;

/* Shows how to draw with Cairo on SDL surfaces */
void draw_screen(khep_state_t *st, SDL_Surface * screen)
{
  /* The drawing will exactly fit in the screen. */
  int width = screen->w;
  int height = screen->h;

  /* The number of bytes used for every scanline. */
  int stride = width * 4;

  /* Free old pixel data and allocate new space */
  free(displayData);
  displayData = (unsigned char *) calloc(stride * height, 1);

  /* Create a cairo surface for our allocated image. */
  /* We use the CAIRO_FORMAT_ARGB32 to support transparancy. */
  cairo_surface_t *cairo_surface =
    cairo_image_surface_create_for_data(displayData,
					CAIRO_FORMAT_ARGB32, width,
					height, stride);

  /* Create a cairo drawing context, normalize it and draw. */
  /* Delete the context afterwards. */
  cairo_t *cr = cairo_create(cairo_surface);
  cairo_scale(cr, width, height);
  draw_scene(cr);
  cairo_destroy(cr);

  /* We stored our image in ARGB32 format. We have to create a mask */
  /* for this format to tell SDL about our data layout. */
  Uint32 rmask = 0x00ff0000;
  Uint32 gmask = 0x0000ff00;
  Uint32 bmask = 0x000000ff;
  Uint32 amask = 0xff000000;

  /* Free old surface and create a new one from our pixel data. */
  SDL_FreeSurface(displaySurface);
  displaySurface =
    SDL_CreateRGBSurfaceFrom((void *) displayData, width, height, 32,
			     stride, rmask, gmask, bmask, amask);

  /* Blit the rendering to the screen and refresh */
  SDL_BlitSurface(displaySurface, NULL, screen, NULL);
  SDL_UpdateRect(screen, 0, 0, 0, 0);
}

Uint32 callback_draw(Uint32 interval, void *param)
{
  SDL_Event event;
  event.type = SDL_USEREVENT;
  event.user.code = REDRAW_SCREEN;
  SDL_PushEvent(&event);
  
  /* We want the callback function to be called again in 100 ms. */
  return 100;
}