#include <gst/gst.h>
#include <string.h>

#define GRAPH_LENGTH 80

/* playbin2 flags */
typedef enum {
  GST_PLAY_FLAG_DOWNLOAD      = (1 << 7) /* Enable progressive download buffering for selected formats. */
} GstPlayFlags;
  
typedef struct _CustomData {
  gboolean is_live;
  GstElement *pipeline;
  GMainLoop *loop;
  gint buffering_level;
} CustomData;
  
static void cb_message (GstBus *bus, GstMessage *msg, CustomData *data) {
  
  switch (GST_MESSAGE_TYPE (msg)) {
    case GST_MESSAGE_ERROR: {
      GError *err;
      gchar *debug;
      
      gst_message_parse_error (msg, &err, &debug);
      g_print ("Error: %s\n", err->message);
      g_error_free (err);
      g_free (debug);
      
      gst_element_set_state (data->pipeline, GST_STATE_READY);
      g_main_loop_quit (data->loop);
      break;
    }
    case GST_MESSAGE_EOS:
      /* end-of-stream */
      gst_element_set_state (data->pipeline, GST_STATE_READY);
      g_main_loop_quit (data->loop);
      break;
    case GST_MESSAGE_BUFFERING:
      /* If the stream is live, we do not care about buffering. */
      if (data->is_live) break;
      
      gst_message_parse_buffering (msg, &data->buffering_level);
      
      /* Wait until buffering is complete before start/resume playing */
      if (data->buffering_level < 100)
        gst_element_set_state (data->pipeline, GST_STATE_PAUSED);
      else
        gst_element_set_state (data->pipeline, GST_STATE_PLAYING);
      break;
    case GST_MESSAGE_CLOCK_LOST:
      /* Get a new clock */
      gst_element_set_state (data->pipeline, GST_STATE_PAUSED);
      gst_element_set_state (data->pipeline, GST_STATE_PLAYING);
      break;
    default:
      /* Unhandled message */
      break;
    }
}
  
static gboolean refresh_ui (CustomData *data) {
  GstQuery *query;
  gboolean result;

  query = gst_query_new_buffering (GST_FORMAT_PERCENT);
  result = gst_element_query (data->pipeline, query);
  if (result) {
    gint n_ranges, range, i;
    gchar graph[GRAPH_LENGTH + 1];
    GstFormat format = GST_FORMAT_TIME;
    gint64 position = 0, duration = 0;

    memset (graph, ' ', GRAPH_LENGTH);
    graph[GRAPH_LENGTH] = '\0';

    n_ranges = gst_query_get_n_buffering_ranges (query);
    for (range = 0; range < n_ranges; range++) {
      gint64 start, stop;
      gst_query_parse_nth_buffering_range (query, range, &start, &stop);
      start = start * GRAPH_LENGTH / 100;
      stop = stop * GRAPH_LENGTH / 100;
      for (i = (gint)start; i < stop; i++)
        graph [i] = '-';
    }
    if (gst_element_query_position (data->pipeline, &format, &position) &&
        GST_CLOCK_TIME_IS_VALID (position) &&
        gst_element_query_duration (data->pipeline, &format, &duration) &&
        GST_CLOCK_TIME_IS_VALID (duration)) {
      i = (gint)(GRAPH_LENGTH * (double)position / (double)(duration + 1));
      graph [i] = data->buffering_level < 100 ? 'X' : '>';
    }
    g_print ("[%s]", graph);
    if (data->buffering_level < 100) {
      g_print (" Buffering: %3d%%", data->buffering_level);
    } else {
      g_print ("                ");
    }
    g_print ("\r");
  }

  return TRUE;

}
  
int main(int argc, char *argv[]) {
  GstElement *pipeline;
  GstBus *bus;
  GstStateChangeReturn ret;
  GMainLoop *main_loop;
  CustomData data;
  guint flags;
  
  /* Initialize GStreamer */
  gst_init (&argc, &argv);
  
  /* Initialize our data structure */
  memset (&data, 0, sizeof (data));
  data.buffering_level = 100;
  
  /* Build the pipeline */
  pipeline = gst_parse_launch ("playbin2 uri=http://docs.gstreamer.com/media/sintel_trailer-480p.webm", NULL);
//  pipeline = gst_parse_launch ("playbin2 uri=http://micro.autom.teithe.gr/~vivia/oldmovies/peta.mp4", NULL);
  bus = gst_element_get_bus (pipeline);
  
  /* Set the download flag */
  g_object_get (pipeline, "flags", &flags, NULL);
  flags |= GST_PLAY_FLAG_DOWNLOAD;
  g_object_set (pipeline, "flags", flags, NULL);
  
  /* Start playing */
  ret = gst_element_set_state (pipeline, GST_STATE_PLAYING);
  if (ret == GST_STATE_CHANGE_FAILURE) {
    g_printerr ("Unable to set the pipeline to the playing state.\n");
    gst_object_unref (pipeline);
    return -1;
  } else if (ret == GST_STATE_CHANGE_NO_PREROLL) {
    data.is_live = TRUE;
  }
  
  main_loop = g_main_loop_new (NULL, FALSE);
  data.loop = main_loop;
  data.pipeline = pipeline;
  
  gst_bus_add_signal_watch (bus);
  g_signal_connect (bus, "message", G_CALLBACK (cb_message), &data);
  
  /* Register a function that GLib will call every second */
  g_timeout_add_seconds (1, (GSourceFunc)refresh_ui, &data);
  
  g_main_loop_run (main_loop);
  
  /* Free resources */
  g_main_loop_unref (main_loop);
  gst_object_unref (bus);
  gst_element_set_state (pipeline, GST_STATE_NULL);
  gst_object_unref (pipeline);

  g_print ("\n");
  return 0;
}