[DllImport ("libgobject-2.0-0.dll") ]
static extern IntPtr g_object_ref (IntPtr raw);
[DllImport ("gstreamer-0.10.dll") ]
static extern bool gst_element_add_pad (IntPtr raw, IntPtr pad);

public bool AddPad (Pad p) {
  bool ret = gst_element_add_pad (this.Handle, p == null ? IntPtr.Zero : p.Handle);
  if (ret)
    g_object_ref (p.Handle);
  return ret;
}

public static bool LinkMany (params Element [] elements) {
  for (int i = 0; i < elements.Length - 1; i++) {
    if (!elements[i].Link (elements[i+1]))
      return false;
  }

  return true;
}

public static void UnlinkMany (params Element [] elements) {
  for (int i = 0; i < elements.Length - 1; i++) {
    elements[i].Unlink (elements[i+1]);
  }
}

[DllImport ("gstreamer-0.10.dll") ]
static extern int gst_iterator_next (IntPtr iterator, out IntPtr elem);
[DllImport ("gstreamer-0.10.dll") ]
static extern void gst_iterator_resync (IntPtr iterator);
[DllImport ("gstreamer-0.10.dll") ]
static extern void gst_iterator_free (IntPtr iterator);
[DllImport ("gstreamer-0.10.dll") ]
static extern IntPtr gst_element_iterate_pads (IntPtr element);
[DllImport ("gstreamer-0.10.dll") ]
static extern IntPtr gst_element_iterate_src_pads (IntPtr element);
[DllImport ("gstreamer-0.10.dll") ]
static extern IntPtr gst_element_iterate_sink_pads (IntPtr element);

private class PadEnumerable : IEnumerable {
  private class PadEnumerator : IEnumerator {
    Hashtable seen = new Hashtable ();
    IntPtr iterator;

    private object current = null;
    public object Current {
      get {
        return current;
      }
    }

    public bool MoveNext () {
      IntPtr raw_ret;
      bool retry = false;

      if (iterator == IntPtr.Zero)
        return false;

      do {
        int ret = gst_iterator_next (iterator, out raw_ret);
        switch (ret) {
          case 0:
            return false;
          case 1:
            if (seen.Contains (raw_ret)) {
              retry = true;
              break;
            }

            seen.Add (raw_ret, null);
            current = GLib.Object.GetObject (raw_ret, true);
            return true;
          case 2:
            gst_iterator_resync (iterator);
            break;
          default:
          case 3:
            throw new Exception ("Error while iterating pads");
        }
      } while (retry);

      return false;
    }

    public void Reset () {
      seen.Clear ();
      if (iterator != IntPtr.Zero)
        gst_iterator_resync (iterator);
    }

    public PadEnumerator (IntPtr iterator) {
      this.iterator = iterator;
    }
  }

  private IntPtr iterator;
  private PadEnumerator enumerator;

  public PadEnumerable (IntPtr iterator) {
    this.iterator = iterator;
    this.enumerator = new PadEnumerator (iterator);
  }

  public IEnumerator GetEnumerator () {
    return enumerator;
  }

  ~PadEnumerable () {
    if (iterator != IntPtr.Zero)
      gst_iterator_free (iterator);
  }
}

public IEnumerable Pads {
  get {
    return new PadEnumerable (gst_element_iterate_pads (Handle));
  }
}

public IEnumerable SinkPads {
  get {
    return new PadEnumerable (gst_element_iterate_sink_pads (Handle));
  }
}

public IEnumerable SrcPads {
  get {
    return new PadEnumerable (gst_element_iterate_src_pads (Handle));
  }
}

public Gst.StateChangeReturn GetState (out Gst.State state, ulong timeout) {
  Gst.State pending;
  return GetState (out state, out pending, timeout);
}

[DllImport ("gstreamer-0.10.dll") ]
static extern void gst_element_found_tags (IntPtr raw, IntPtr list);
[DllImport ("gstreamer-0.10.dll") ]
static extern IntPtr gst_tag_list_copy (IntPtr raw);

public void FoundTags (Gst.TagList list) {
  gst_element_found_tags (Handle, list == null ? IntPtr.Zero : gst_tag_list_copy (list.Handle));
}

[DllImport ("gstreamer-0.10.dll") ]
static extern void gst_element_found_tags_for_pad (IntPtr raw, IntPtr pad, IntPtr list);

public void FoundTagsForPad (Gst.Pad pad, Gst.TagList list) {
  gst_element_found_tags_for_pad (Handle, pad == null ? IntPtr.Zero : pad.Handle, list == null ? IntPtr.Zero : gst_tag_list_copy (list.Handle));
}

[DllImport ("gstreamer-0.10.dll") ]
static extern bool gst_element_post_message (IntPtr raw, IntPtr message);
[DllImport ("gstreamer-0.10.dll") ]
static extern IntPtr gst_mini_object_ref (IntPtr raw);

public bool PostMessage (Gst.Message message) {
  bool raw_ret = gst_element_post_message (Handle, message == null ? IntPtr.Zero : gst_mini_object_ref (message.Handle));
  bool ret = raw_ret;
  return ret;
}

[DllImport ("gstreamer-0.10.dll") ]
static extern IntPtr gst_element_get_query_types (IntPtr raw);

public Gst.QueryType[] GetQueryTypes () {
  IntPtr raw_ret = gst_element_get_query_types (Handle);
  if (raw_ret == IntPtr.Zero)
    return new Gst.QueryType[] {};

  ArrayList result = new ArrayList ();
  bool term = false;
  int ofs = 0;
  while (!term) {
    Gst.QueryType t = (Gst.QueryType) Marshal.ReadInt32 (raw_ret, ofs);
    if (t == Gst.QueryType.None) {
      term = true;
    } else {
      result.Add (t);
      ofs += 4;
    }
  }

  return (Gst.QueryType[]) result.ToArray (typeof (Gst.QueryType));
}


[DllImport ("gstreamer-0.10.dll") ]
static extern bool gst_element_send_event (IntPtr raw, IntPtr evnt);

public bool SendEvent (Gst.Event evnt) {
  bool raw_ret = gst_element_send_event (Handle, evnt == null ? IntPtr.Zero : gst_mini_object_ref (evnt.Handle));
  bool ret = raw_ret;
  return ret;
}

[DllImport ("gstreamer-0.10.dll") ]
static extern void gst_element_class_add_pad_template (IntPtr klass, IntPtr templ);

protected static void AddPadTemplate (GLib.GType gtype, Gst.PadTemplate templ) {
  IntPtr class_ptr = new IntPtr (gtype.ClassPtr.ToInt64 ());
  gst_element_class_add_pad_template (class_ptr, templ.Handle);
}

[DllImport ("gstreamer-0.10.dll") ]
static extern IntPtr gst_element_class_get_pad_template (IntPtr klass, IntPtr name);

public Gst.PadTemplate GetPadTemplate (string name) {
  GLib.GType gtype = this.LookupGType ();
  IntPtr class_ptr = new IntPtr (gtype.ClassPtr.ToInt64 ());
  IntPtr native_name = GLib.Marshaller.StringToPtrGStrdup (name);
  IntPtr raw_ret = gst_element_class_get_pad_template (class_ptr, native_name);
  GLib.Marshaller.Free (native_name);

  return GLib.Object.GetObject (raw_ret, false) as Gst.PadTemplate;
}

[DllImport ("gstreamer-0.10.dll") ]
static extern IntPtr gst_element_class_get_pad_template_list (IntPtr klass);

public Gst.PadTemplate[] PadTemplates {
  get {
    GLib.GType gtype = this.LookupGType ();
    IntPtr class_ptr = new IntPtr (gtype.ClassPtr.ToInt64 ());
    IntPtr raw_ret = gst_element_class_get_pad_template_list (class_ptr);

    return (Gst.PadTemplate[]) GLib.Marshaller.ListPtrToArray (raw_ret, typeof (GLib.List), false, false, typeof (Gst.PadTemplate));
  }
}

[DllImport ("gstreamer-0.10.dll") ]
static extern void gst_element_class_set_details_simple (IntPtr klass, IntPtr longname, IntPtr classification, IntPtr desc, IntPtr author);

protected static void SetDetails (GLib.GType gtype, string longname, string klass, string description, string author) {
  IntPtr class_ptr = new IntPtr (gtype.ClassPtr.ToInt64 ());
  IntPtr native_longname = GLib.Marshaller.StringToPtrGStrdup (longname);
  IntPtr native_klass = GLib.Marshaller.StringToPtrGStrdup (klass);
  IntPtr native_desc = GLib.Marshaller.StringToPtrGStrdup (description);
  IntPtr native_author = GLib.Marshaller.StringToPtrGStrdup (author);
  gst_element_class_set_details_simple (class_ptr, native_longname, native_klass, native_desc, native_author);

  GLib.Marshaller.Free (native_longname);
  GLib.Marshaller.Free (native_klass);
  GLib.Marshaller.Free (native_desc);
  GLib.Marshaller.Free (native_author);
}