#include <glib.h>
#include <cairo.h>
#include <moz-headless.h>
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>

static MozHeadless *headless;
static GMainLoop *mainloop;
static gboolean resized = FALSE;
static cairo_surface_t *surface;

static void
net_stop_cb (MozHeadless *headless)
{
  gint width, height;
  moz_headless_get_document_size (headless, &width, &height);
  surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, width, height);
  moz_headless_set_surface (headless, cairo_image_surface_get_data (surface),
                            width, height, width * 4);
  moz_headless_set_size (headless, width, height);
  resized = TRUE;
}

static void
updated_cb (MozHeadless *headless, gint x, gint y, gint width, gint height)
{
  if (resized) g_main_loop_quit (mainloop);
}

static void
leave (int sig)
{
  net_stop_cb (headless);
}

int
main (int argc, char **argv)
{
  gint width, height;

  if (argc < 4) {
    printf ("Usage: %s <url> <width> <height> <output.png>", argv[0]);
    return 1;
  }

  width = atoi (argv[2]);
  height = atoi (argv[3]);

  g_type_init ();
  mainloop = g_main_loop_new (NULL, FALSE);
  headless = moz_headless_new ();
  moz_headless_set_size (headless, width, height);
  
  g_signal_connect (headless, "net-stop",
                    G_CALLBACK (net_stop_cb), NULL);
  g_signal_connect (headless, "updated",
                    G_CALLBACK (updated_cb), NULL);
  
  moz_headless_load_url (headless, argv[1]);
  signal (SIGINT, leave);
  g_main_loop_run (mainloop);
  
  cairo_surface_write_to_png (surface, argv[4]);
  return 0;
}