/* GStreamer GES plugin
 *
 * Copyright (C) 2019 Igalia S.L
 *     Author: 2019 Thibault Saunier <tsaunier@igalia.com>
 *
 * gesdemux.c
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

 /**
 * SECTION:gstdemux
 * @short_description: A GstBin subclasses use to use GESTimeline
 * as demux inside any GstPipeline.
 * @see_also: #GESTimeline
 *
 * The gstdemux is a bin that will simply expose the track source pads
 * and implements the GstUriHandler interface using a custom ges://0Xpointer
 * uri scheme.
 **/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "gesbasebin.h"

#include <gst/gst.h>
#include <glib/gstdio.h>
#include <gst/pbutils/pbutils.h>
#include <gst/base/gstadapter.h>
#include <ges/ges.h>

GST_DEBUG_CATEGORY_STATIC (gesdemux);
#define GST_CAT_DEFAULT gesdemux

static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("application/xges"));

G_DECLARE_FINAL_TYPE (GESDemux, ges_demux, GES, Demux, GESBaseBin);

struct _GESDemux
{
  GESBaseBin parent;

  GESTimeline *timeline;
  GstPad *sinkpad;

  GstAdapter *input_adapter;
};

G_DEFINE_TYPE (GESDemux, ges_demux, ges_base_bin_get_type ());
#define GES_DEMUX(obj) ((GESDemux*)obj)

enum
{
  PROP_0,
  PROP_TIMELINE,
  PROP_LAST
};

static GParamSpec *properties[PROP_LAST];

static void
ges_demux_get_property (GObject * object, guint property_id,
    GValue * value, GParamSpec * pspec)
{
  GESDemux *self = GES_DEMUX (object);

  switch (property_id) {
    case PROP_TIMELINE:
      g_value_set_object (value,
          ges_base_bin_get_timeline (GES_BASE_BIN (self)));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
  }
}

static void
ges_demux_set_property (GObject * object, guint property_id,
    const GValue * value, GParamSpec * pspec)
{
  switch (property_id) {
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
  }
}

static void
ges_demux_class_init (GESDemuxClass * self_class)
{
  GObjectClass *gclass = G_OBJECT_CLASS (self_class);
  GstElementClass *gstelement_klass = GST_ELEMENT_CLASS (self_class);

  GST_DEBUG_CATEGORY_INIT (gesdemux, "gesdemux", 0, "ges demux element");

  gclass->get_property = ges_demux_get_property;
  gclass->set_property = ges_demux_set_property;

  /**
   * GESDemux:timeline:
   *
   * Timeline to use in this source.
   */
  properties[PROP_TIMELINE] = g_param_spec_object ("timeline", "Timeline",
      "Timeline to use in this source.",
      GES_TYPE_TIMELINE, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);
  g_object_class_override_property (gclass, PROP_TIMELINE, "timeline");

  gst_element_class_add_pad_template (gstelement_klass,
      gst_static_pad_template_get (&sink_template));
  gst_element_class_set_static_metadata (gstelement_klass,
      "GStreamer Editing Services based 'demuxer'",
      "Codec/Demux/Editing",
      "Demuxer for complex timeline file formats using GES.",
      "Thibault Saunier <tsaunier@igalia.com");
}

typedef struct
{
  GESTimeline *timeline;
  GMainLoop *ml;
  GError *error;
  gulong loaded_sigid;
  gulong error_sigid;
} TimelineConstructionData;

static void
project_loaded_cb (GESProject * project, GESTimeline * timeline,
    TimelineConstructionData * data)
{
  data->timeline = timeline;
  g_signal_handler_disconnect (project, data->loaded_sigid);
  data->loaded_sigid = 0;

  g_main_loop_quit (data->ml);
}

static void
error_loading_asset_cb (GESProject * project, GError * error, gchar * id,
    GType extractable_type, TimelineConstructionData * data)
{
  data->error = g_error_copy (error);
  g_signal_handler_disconnect (project, data->error_sigid);
  data->error_sigid = 0;

  g_main_loop_quit (data->ml);
}

static gboolean
ges_demux_create_timeline (GESDemux * self, gchar * uri, GError ** error)
{
  GESProject *project = ges_project_new (uri);
  G_GNUC_UNUSED void *unused;
  TimelineConstructionData data = { 0, };
  GMainContext *ctx = g_main_context_new ();

  g_main_context_push_thread_default (ctx);
  data.ml = g_main_loop_new (ctx, TRUE);

  data.loaded_sigid =
      g_signal_connect (project, "loaded", G_CALLBACK (project_loaded_cb),
      &data);
  data.error_sigid =
      g_signal_connect_after (project, "error-loading-asset",
      G_CALLBACK (error_loading_asset_cb), &data);

  unused = GES_TIMELINE (ges_asset_extract (GES_ASSET (project), &data.error));
  if (data.error) {
    *error = data.error;

    goto done;
  }

  g_main_loop_run (data.ml);
  g_main_loop_unref (data.ml);

done:
  if (data.loaded_sigid)
    g_signal_handler_disconnect (project, data.loaded_sigid);

  if (data.error_sigid)
    g_signal_handler_disconnect (project, data.error_sigid);

  g_clear_object (&project);

  GST_INFO_OBJECT (self, "Timeline properly loaded: %" GST_PTR_FORMAT,
      data.timeline);
  ges_base_bin_set_timeline (GES_BASE_BIN (self), data.timeline);

  g_main_context_pop_thread_default (ctx);

  return G_SOURCE_REMOVE;
}

static gboolean
ges_demux_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
{
  GESDemux *self = GES_DEMUX (parent);

  switch (event->type) {
    case GST_EVENT_EOS:{
      GstMapInfo map;
      GstBuffer *xges_buffer;
      gboolean ret = TRUE;
      gsize available;

      available = gst_adapter_available (self->input_adapter);
      if (available == 0) {
        GST_WARNING_OBJECT (self,
            "Received EOS without any serialized timeline.");

        return gst_pad_event_default (pad, parent, event);
      }

      xges_buffer = gst_adapter_take_buffer (self->input_adapter, available);
      if (gst_buffer_map (xges_buffer, &map, GST_MAP_READ)) {
        GError *err = NULL;
        gchar *filename = NULL, *uri = NULL;
        GError *error = NULL;
        gint f = g_file_open_tmp (NULL, &filename, &err);

        if (err) {
          GST_ELEMENT_ERROR (self, RESOURCE, OPEN_WRITE,
              ("Could not open temporary file to write timeline description"),
              ("%s", err->message));

          goto error;
        }

        g_file_set_contents (filename, (gchar *) map.data, map.size, &err);
        if (err) {
          GST_ELEMENT_ERROR (self, RESOURCE, WRITE,
              ("Could not write temporary timeline description file"),
              ("%s", err->message));

          goto error;
        }

        uri = gst_filename_to_uri (filename, NULL);
        GST_INFO_OBJECT (self, "Pre loading the timeline.");

        ges_demux_create_timeline (self, uri, &error);
        if (error)
          goto error;

      done:
        g_free (filename);
        g_free (uri);
        g_close (f, NULL);
        return ret;

      error:
        ret = FALSE;
        gst_element_post_message (GST_ELEMENT (self),
            gst_message_new_error (parent, error,
                "Could not create timeline from description"));
        g_clear_error (&error);

        goto done;
      } else {
        GST_ELEMENT_ERROR (self, RESOURCE, READ,
            ("Could not map buffer containing timeline description"),
            ("Not info"));
      }
    }
    default:
      break;
  }

  return gst_pad_event_default (pad, parent, event);
}

static GstFlowReturn
ges_demux_sink_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
{
  GESDemux *self = GES_DEMUX (parent);

  gst_adapter_push (self->input_adapter, buffer);

  GST_INFO_OBJECT (self, "Received buffer, total size is %i bytes",
      (gint) gst_adapter_available (self->input_adapter));

  return GST_FLOW_OK;
}

static void
ges_demux_init (GESDemux * self)
{
  ges_init ();
  self->sinkpad = gst_pad_new_from_static_template (&sink_template, "sink");
  gst_element_add_pad (GST_ELEMENT (self), self->sinkpad);

  self->input_adapter = gst_adapter_new ();

  gst_pad_set_chain_function (self->sinkpad,
      GST_DEBUG_FUNCPTR (ges_demux_sink_chain));

  gst_pad_set_event_function (self->sinkpad,
      GST_DEBUG_FUNCPTR (ges_demux_sink_event));
}