
/*** block a  from ../../../docs/manual/advanced-buffering.xml ***/
#include <gst/gst.h>

GstState target_state;
static gboolean is_live;
static gboolean is_buffering;

static gboolean
buffer_timeout (gpointer data)
{
  GstElement *pipeline = data;
  GstQuery *query;
  gboolean busy;
  gint percent;
  gint64 estimated_total;
  gint64 position, duration;
  guint64 play_left;

  query = gst_query_new_buffering (GST_FORMAT_TIME);

  if (!gst_element_query (pipeline, query))
    return TRUE;

  gst_query_parse_buffering_percent (query, &busy, &percent);
  gst_query_parse_buffering_range (query, NULL, NULL, NULL, &estimated_total);

  if (estimated_total == -1)
    estimated_total = 0;

  /* calculate the remaining playback time */
  if (!gst_element_query_position (pipeline, GST_FORMAT_TIME, &position))
    position = -1;
  if (!gst_element_query_duration (pipeline, GST_FORMAT_TIME, &duration))
    duration = -1;

  if (duration != -1 && position != -1)
    play_left = GST_TIME_AS_MSECONDS (duration - position);
  else
    play_left = 0;

  g_message ("play_left %" G_GUINT64_FORMAT", estimated_total %" G_GUINT64_FORMAT
      ", percent %d", play_left, estimated_total, percent);

  /* we are buffering or the estimated download time is bigger than the
   * remaining playback time. We keep buffering. */
  is_buffering = (busy || estimated_total * 1.1 > play_left);

  if (!is_buffering)
    gst_element_set_state (pipeline, target_state);

  return is_buffering;
}

static void
on_message_buffering (GstBus *bus, GstMessage *message, gpointer user_data)
{
  GstElement *pipeline = user_data;
  gint percent;

  /* no state management needed for live pipelines */
  if (is_live)
    return;

  gst_message_parse_buffering (message, &percent);

  if (percent < 100) {
    /* buffering busy */
    if (is_buffering == FALSE) {
      is_buffering = TRUE;
      if (target_state == GST_STATE_PLAYING) {
        /* we were not buffering but PLAYING, PAUSE  the pipeline. */
        gst_element_set_state (pipeline, GST_STATE_PAUSED);
      }
    }
  }
}

static void
on_message_async_done (GstBus *bus, GstMessage *message, gpointer user_data)
{
  GstElement *pipeline = user_data;

  if (is_buffering == FALSE)
    gst_element_set_state (pipeline, target_state);
  else
    g_timeout_add (500, buffer_timeout, pipeline);
}

gint
main (gint   argc,
      gchar *argv[])
{
  GstElement *pipeline;
  GMainLoop *loop;
  GstBus *bus;
  GstStateChangeReturn ret;

  /* init GStreamer */
  gst_init (&argc, &argv);
  loop = g_main_loop_new (NULL, FALSE);

  /* make sure we have a URI */
  if (argc != 2) {
    g_print ("Usage: %s <URI>\n", argv[0]);
    return -1;
  }

  /* set up */
  pipeline = gst_element_factory_make ("playbin", "pipeline");
  g_object_set (G_OBJECT (pipeline), "uri", argv[1], NULL);
  g_object_set (G_OBJECT (pipeline), "flags", 0x697 , NULL);

  bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
  gst_bus_add_signal_watch (bus);

  g_signal_connect (bus, "message::buffering",
    (GCallback) on_message_buffering, pipeline);
  g_signal_connect (bus, "message::async-done",
    (GCallback) on_message_async_done, pipeline);
  gst_object_unref (bus);

  is_buffering = FALSE;
  target_state = GST_STATE_PLAYING;
  ret = gst_element_set_state (pipeline, GST_STATE_PAUSED);

  switch (ret) {
    case GST_STATE_CHANGE_SUCCESS:
      is_live = FALSE;
      break;

    case GST_STATE_CHANGE_FAILURE:
      g_warning ("failed to PAUSE");
      return -1;

    case GST_STATE_CHANGE_NO_PREROLL:
      is_live = TRUE;
      break;

    default:
      break;
  }

  /* now run */
  g_main_loop_run (loop);

  /* also clean up */
  gst_element_set_state (pipeline, GST_STATE_NULL);
  gst_object_unref (GST_OBJECT (pipeline));
  g_main_loop_unref (loop);

  return 0;
}