/* This file is part of Clementine.
   Copyright 2014, David Sansome <me@davidsansome.com>

   Clementine is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Clementine 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Clementine.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "cddasongloader.h"

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

#include <QtConcurrentRun>

#include "cddadevice.h"
#include "core/logging.h"
#include "core/timeconstants.h"

CddaSongLoader::CddaSongLoader(const QUrl& url, QObject* parent)
    : QObject(parent), url_(url), cdda_(nullptr), cdio_(nullptr) {
  connect(this, SIGNAL(MusicBrainzDiscIdLoaded(const QString&)),
          SLOT(LoadAudioCDTags(const QString&)));
}

CddaSongLoader::~CddaSongLoader() {
  if (cdio_) cdio_destroy(cdio_);
}

QUrl CddaSongLoader::GetUrlFromTrack(int track_number) const {
  QString track;
  if (url_.isEmpty()) {
    track = QString("cdda://%1").arg(track_number);
  } else {
    track = QString("cdda://%1/%2").arg(url_.path()).arg(track_number);
  }
  return CddaDevice::TrackStrToUrl(track);
}

void CddaSongLoader::LoadSongs() {
  QtConcurrent::run(this, &CddaSongLoader::LoadSongsFromCdda);
}
void CddaSongLoader::LoadSongsFromCdda() {
  QMutexLocker locker(&mutex_load_);
  cdio_ = cdio_open(url_.path().toLocal8Bit().constData(), DRIVER_DEVICE);
  if (cdio_ == nullptr) {
    return;
  }
  // Create gstreamer cdda element
  GError* error = nullptr;
  cdda_ = gst_element_make_from_uri(GST_URI_SRC, "cdda://", nullptr, &error);
  if (error) {
    qLog(Error) << error->code << QString::fromLocal8Bit(error->message);
  }
  if (cdda_ == nullptr) {
    return;
  }

  if (!url_.isEmpty()) {
    g_object_set(cdda_, "device",
                 g_strdup(url_.path().toLocal8Bit().constData()), nullptr);
  }
  if (g_object_class_find_property(G_OBJECT_GET_CLASS(cdda_),
                                   "paranoia-mode")) {
    g_object_set(cdda_, "paranoia-mode", 0, NULL);
  }

  // Change the element's state to ready and paused, to be able to query it
  if (gst_element_set_state(cdda_, GST_STATE_READY) ==
          GST_STATE_CHANGE_FAILURE ||
      gst_element_set_state(cdda_, GST_STATE_PAUSED) ==
          GST_STATE_CHANGE_FAILURE) {
    gst_element_set_state(cdda_, GST_STATE_NULL);
    gst_object_unref(GST_OBJECT(cdda_));
    return;
  }

  // Get number of tracks
  GstFormat fmt = gst_format_get_by_nick("track");
  GstFormat out_fmt = fmt;
  gint64 num_tracks = 0;
  if (!gst_element_query_duration(cdda_, out_fmt, &num_tracks) ||
      out_fmt != fmt) {
    qLog(Error) << "Error while querying cdda GstElement";
    gst_object_unref(GST_OBJECT(cdda_));
    return;
  }

  SongList songs;
  for (int track_number = 1; track_number <= num_tracks; track_number++) {
    // Init song
    Song song;
    song.set_id(track_number);
    song.set_valid(true);
    song.set_filetype(Song::Type_Cdda);
    song.set_url(GetUrlFromTrack(track_number));
    song.set_title(QString("Track %1").arg(track_number));
    song.set_track(track_number);
    songs << song;
  }
  emit SongsLoaded(songs);

  gst_tag_register_musicbrainz_tags();

  GstElement* pipeline = gst_pipeline_new("pipeline");
  GstElement* sink = gst_element_factory_make("fakesink", NULL);
  gst_bin_add_many(GST_BIN(pipeline), cdda_, sink, NULL);
  gst_element_link(cdda_, sink);
  gst_element_set_state(pipeline, GST_STATE_READY);
  gst_element_set_state(pipeline, GST_STATE_PAUSED);

  // Get TOC and TAG messages
  GstMessage* msg = nullptr;
  GstMessage* msg_toc = nullptr;
  GstMessage* msg_tag = nullptr;
  while ((msg = gst_bus_timed_pop_filtered(
              GST_ELEMENT_BUS(pipeline), 2 * GST_SECOND,
              (GstMessageType)(GST_MESSAGE_TOC | GST_MESSAGE_TAG)))) {
    if (GST_MESSAGE_TYPE(msg) == GST_MESSAGE_TOC) {
      if (msg_toc)
        gst_message_unref(msg_toc);  // Shouldn't happen, but just in case
      msg_toc = msg;
    } else if (GST_MESSAGE_TYPE(msg) == GST_MESSAGE_TAG) {
      if (msg_tag) gst_message_unref(msg_tag);
      msg_tag = msg;
    }
  }

  // Handle TOC message: get tracks duration
  if (msg_toc) {
    GstToc* toc;
    gst_message_parse_toc(msg_toc, &toc, nullptr);
    if (toc) {
      GList* entries = gst_toc_get_entries(toc);
      if (entries && songs.size() <= g_list_length(entries)) {
        int i = 0;
        for (GList* node = entries; node != nullptr; node = node->next) {
          GstTocEntry* entry = static_cast<GstTocEntry*>(node->data);
          quint64 duration = 0;
          gint64 start, stop;
          if (gst_toc_entry_get_start_stop_times(entry, &start, &stop))
            duration = stop - start;
          songs[i++].set_length_nanosec(duration);
        }
      }
    }
    gst_message_unref(msg_toc);
  }
  emit SongsDurationLoaded(songs);

  // Handle TAG message: generate MusicBrainz DiscId
  if (msg_tag) {
    GstTagList* tags = nullptr;
    gst_message_parse_tag(msg_tag, &tags);
    char* string_mb = nullptr;
    if (gst_tag_list_get_string(tags, GST_TAG_CDDA_MUSICBRAINZ_DISCID,
                                &string_mb)) {
      QString musicbrainz_discid(string_mb);
      qLog(Info) << "MusicBrainz discid: " << musicbrainz_discid;
      emit MusicBrainzDiscIdLoaded(musicbrainz_discid);

      g_free(string_mb);
      gst_message_unref(msg_tag);
      gst_tag_list_free(tags);
    }
  }

  gst_element_set_state(pipeline, GST_STATE_NULL);
  // This will also cause cdda_ to be unref'd.
  gst_object_unref(pipeline);
}

void CddaSongLoader::LoadAudioCDTags(const QString& musicbrainz_discid) const {
  MusicBrainzClient* musicbrainz_client = new MusicBrainzClient;
  connect(musicbrainz_client,
          SIGNAL(Finished(const QString&, const QString&,
                          MusicBrainzClient::ResultList)),
          SLOT(AudioCDTagsLoaded(const QString&, const QString&,
                                 MusicBrainzClient::ResultList)));

  musicbrainz_client->StartDiscIdRequest(musicbrainz_discid);
}

void CddaSongLoader::AudioCDTagsLoaded(
    const QString& artist, const QString& album,
    const MusicBrainzClient::ResultList& results) {
  MusicBrainzClient* musicbrainz_client =
      qobject_cast<MusicBrainzClient*>(sender());
  musicbrainz_client->deleteLater();
  SongList songs;
  if (results.empty()) return;
  int track_number = 1;
  for (const MusicBrainzClient::Result& ret : results) {
    Song song;
    song.set_artist(artist);
    song.set_album(album);
    song.set_title(ret.title_);
    song.set_length_nanosec(ret.duration_msec_ * kNsecPerMsec);
    song.set_track(track_number);
    song.set_year(ret.year_);
    song.set_id(track_number);
    song.set_filetype(Song::Type_Cdda);
    song.set_valid(true);
    // We need to set url: that's how playlist will find the correct item to
    // update
    song.set_url(GetUrlFromTrack(track_number++));
    songs << song;
  }
  emit SongsMetadataLoaded(songs);
}

bool CddaSongLoader::HasChanged() {
  if ((cdio_ && cdda_) && cdio_get_media_changed(cdio_) != 1) {
    return false;
  }
  // Check if mutex is already token (i.e. init is already taking place)
  if (!mutex_load_.tryLock()) {
    return false;
  }
  mutex_load_.unlock();
  return true;
}
