import gintro/[gst,gobject,glib], os, strformat

# Structure to contain all our information, so we can pass it to callbacks 
type
  CustomData = object
    pipeline, source, convert, resample, sink: gst.Element 

#[
typedef struct _CustomData {
  GstElement *pipeline;
  GstElement *source;
  GstElement *convert;
  GstElement *resample;
  GstElement *sink;
} CustomData;
]#

#[
/* Handler for the pad-added signal */
static void pad_added_handler (GstElement *src, GstPad *pad, CustomData *data);
]#


#[ proc sourceName*(self: Message): string =
  let resul0 = gst_object_get_name(cast[ptr Object00](self.impl.src))
  if resul0.isNil:
    return
  result = $resul0
  cogfree(resul0) ]#


# This function will be called by the pad-added signal NOTA: cast[ptr Pad00](pad.impl)
proc padAddedHandler(src:ptr Element00; newPad:ptr Pad00; dataPtr:pointer) {.cdecl.} =
  var data = cast[CustomData](dataPtr)
  #var sinkPad:gst.Pad = gst_element_get_static_pad(data.convert, "sink")
  var sinkPad:gst.Pad = getRequestPad(data.convert, "sink")
  #GstPadLinkReturn ret;
  #GstCaps *new_pad_caps = NULL;
  #GstStructure *new_pad_struct = NULL;
  #const gchar *new_pad_type = NULL;
  echo "New pad"
  #echo("Received new pad '%s' from '%s':\n",  newPad.name,  src.name )  # GST_PAD_NAME, GST_ELEMENT_NAME

  #[ /* If our converter is already linked, we have nothing to do here */
  if (gst_pad_is_linked (sink_pad)) {
    g_print ("We are already linked. Ignoring.\n");
    goto exit;
  } ]#

 #[  /* Check the new pad's type */
  new_pad_caps = gst_pad_get_current_caps (new_pad);
  new_pad_struct = gst_caps_get_structure (new_pad_caps, 0);
  new_pad_type = gst_structure_get_name (new_pad_struct);
  if (!g_str_has_prefix (new_pad_type, "audio/x-raw")) {
    g_print ("It has type '%s' which is not raw audio. Ignoring.\n", new_pad_type);
    goto exit;
  } ]#

 #[  /* Attempt the link */
  ret = gst_pad_link (new_pad, sink_pad);
  if (GST_PAD_LINK_FAILED (ret)) {
    g_print ("Type is '%s' but link failed.\n", new_pad_type);
  } else {
    g_print ("Link succeeded (type '%s').\n", new_pad_type);
  }
 ]#
#[ exit:
  /* Unreference the new pad's caps, if we got them */
  if (new_pad_caps != NULL)
    gst_caps_unref (new_pad_caps);

  /* Unreference the sink pad */
  gst_object_unref (sink_pad); ]#




proc toBoolVal(b: bool): Value =
  let gtype = typeFromName("gboolean")
  discard init(result, gtype)
  setBoolean(result, b)

proc toUIntVal(i: int): Value =
  let gtype = typeFromName("guint")
  discard init(result, gtype)
  setUint(result, i)

proc toStringVal(i: string): Value =
  let gtype = typeFromName("gchararray")
  discard init(result, gtype)
  setString(result, i)
  echo repr result

converter toBin*(elem:gst.Element):gst.Bin =
  cast[gst.Bin](elem)

proc main =
  var data:CustomData
  #GstBus *bus;
  #GstMessage *msg;
  #GstStateChangeReturn ret;
  #gboolean terminate = FALSE;

  ##  Initialize GStreamer
  gst.init() 

  # Create the elements
  data.source   = make("uridecodebin", "source")
  data.convert  = make("audioconvert", "convert")
  data.resample = make("audioresample", "resample")
  data.sink     = make("autoaudiosink", "sink")

  # Create the empty pipeline
  data.pipeline = newPipeline("test-pipeline")

  # Check if the elements are empty
  if data.source.isNil or data.pipeline.isNil or data.convert.isNil or data.resample.isNil or data.sink.isNil:
    quit("Not all elements could be created.\n") # QuitFailure, 

  # Build the pipeline 
  # 1. Add the elements
  discard data.pipeline.add(data.source)
  discard data.pipeline.add(data.convert)
  discard data.pipeline.add(data.resample)
  discard data.pipeline.add(data.sink)

  # 2. Linking
  discard data.source.link(data.convert)  
  discard data.convert.link(data.resample)
  discard data.resample.link(data.sink)

  #[
  /* Build the pipeline. Note that we are NOT linking the source at this
   * point. We will do it later. */
  gst_bin_add_many (GST_BIN (data.pipeline), data.source, data.convert, data.resample, data.sink, NULL);
  if (!gst_element_link_many (data.convert, data.resample, data.sink, NULL)) {
    g_printerr ("Elements could not be linked.\n");
    gst_object_unref (data.pipeline);
    return -1;
  }
  ]#

  # Set the URI to play
  var uri = toStringVal("https://www.freedesktop.org/software/gstreamer-sdk/data/media/sintel_trailer-480p.webm")
  data.source.setProperty("uri", uri)

  # Connect to the pad-added signal
  #g_signal_connect (data.source, "pad-added", G_CALLBACK (pad_added_handler), &data);
  #var flag:ConnectFlag = 0
  #discard scPadAdded( data.source, padAddedHandler, cast[pointer](data.unsafeAddr), {0.ConnectFlag})


  # Start playing
  discard gst.setState(data.pipeline, gst.State.playing) 


  ##  Wait until error or EOS
  var bus:gst.Bus     = gst.getBus(data.pipeline)
  var msg:gst.Message = gst.timedPopFiltered(bus, gst.Clock_Time_None, {gst.MessageFlag.error, gst.MessageFlag.eos})
  var tmp = msg.getType
  discard gst.setState(data.pipeline, gst.State.null) # is this necessary?

  #var msgFlag:MessageFlag = msg.getType
  var msgType = msg.getType
  #echo msg.impl.src.getName
  echo msg.getStructure.getName

  if gst.MessageFlag.error in msgType:
    var err:ptr glib.Error
    var debugInfo:string
    msg.parseError(err, debugInfo)

    #echo typeof(msg.src)
    echo &"Error received from element {gst_object_get_name(msg.impl.src)}: {err.message}"
    #echo cast[ptr gst.Object00](msg.impl).name
    if debugInfo == "":
      debugInfo = "none"
    echo &"Debugging information: {debugInfo}\n"
    #echo "Error received from element %s: %s", msg.src.name, err.message

#[


  /* Listen to the bus */
  bus = gst_element_get_bus (data.pipeline);
  do {
    msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE,
        GST_MESSAGE_STATE_CHANGED | GST_MESSAGE_ERROR | GST_MESSAGE_EOS);

    /* Parse message */
    if (msg != NULL) {
      GError *err;
      gchar *debug_info;

      switch (GST_MESSAGE_TYPE (msg)) {
        case GST_MESSAGE_ERROR:
          gst_message_parse_error (msg, &err, &debug_info);
          g_printerr ("Error received from element %s: %s\n", GST_OBJECT_NAME (msg->src), err->message);
          g_printerr ("Debugging information: %s\n", debug_info ? debug_info : "none");
          g_clear_error (&err);
          g_free (debug_info);
          terminate = TRUE;
          break;
        case GST_MESSAGE_EOS:
          g_print ("End-Of-Stream reached.\n");
          terminate = TRUE;
          break;
        case GST_MESSAGE_STATE_CHANGED:
          /* We are only interested in state-changed messages from the pipeline */
          if (GST_MESSAGE_SRC (msg) == GST_OBJECT (data.pipeline)) {
            GstState old_state, new_state, pending_state;
            gst_message_parse_state_changed (msg, &old_state, &new_state, &pending_state);
            g_print ("Pipeline state changed from %s to %s:\n",
                gst_element_state_get_name (old_state), gst_element_state_get_name (new_state));
          }
          break;
        default:
          /* We should not reach here */
          g_printerr ("Unexpected message received.\n");
          break;
      }
      gst_message_unref (msg);
    }
  } while (!terminate);

  /* Free resources */
  gst_object_unref (bus);
  gst_element_set_state (data.pipeline, GST_STATE_NULL);
  gst_object_unref (data.pipeline);
  return 0;
}


]#
main()