/* This file is part of Clementine.
   Copyright 2010, 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 "tagfetcher.h"

#include <QFuture>
#include <QFutureWatcher>
#include <QUrl>
#include <QtConcurrentMap>

#include "acoustidclient.h"
#include "chromaprinter.h"
#include "core/timeconstants.h"
#include "musicbrainzclient.h"

TagFetcher::TagFetcher(QObject* parent)
    : QObject(parent),
      fingerprint_watcher_(nullptr),
      acoustid_client_(new AcoustidClient(this)),
      musicbrainz_client_(new MusicBrainzClient(this)) {
  connect(acoustid_client_, SIGNAL(Finished(int, QStringList)),
          SLOT(PuidsFound(int, QStringList)));
  connect(musicbrainz_client_,
          SIGNAL(Finished(int, MusicBrainzClient::ResultList)),
          SLOT(TagsFetched(int, MusicBrainzClient::ResultList)));
}

QString TagFetcher::GetFingerprint(const Song& song) {
  return Chromaprinter(song.url().toLocalFile()).CreateFingerprint();
}

void TagFetcher::StartFetch(const SongList& songs) {
  Cancel();

  songs_ = songs;

  QFuture<QString> future = QtConcurrent::mapped(songs_, GetFingerprint);
  fingerprint_watcher_ = new QFutureWatcher<QString>(this);
  connect(fingerprint_watcher_, SIGNAL(resultReadyAt(int)),
          SLOT(FingerprintFound(int)));
  fingerprint_watcher_->setFuture(future);

  for (const Song& song : songs) {
    emit Progress(song, tr("Fingerprinting song"));
  }
}

void TagFetcher::Cancel() {
  if (fingerprint_watcher_) {
    fingerprint_watcher_->cancel();

    delete fingerprint_watcher_;
    fingerprint_watcher_ = nullptr;
  }

  acoustid_client_->CancelAll();
  musicbrainz_client_->CancelAll();
  songs_.clear();
}

void TagFetcher::FingerprintFound(int index) {
  QFutureWatcher<QString>* watcher =
      reinterpret_cast<QFutureWatcher<QString>*>(sender());
  if (!watcher || index >= songs_.count()) {
    return;
  }

  const QString fingerprint = watcher->resultAt(index);
  const Song& song = songs_[index];

  if (fingerprint.isEmpty()) {
    emit ResultAvailable(song, SongList());
    return;
  }

  emit Progress(song, tr("Identifying song"));
  acoustid_client_->Start(index, fingerprint,
                          song.length_nanosec() / kNsecPerMsec);
}

void TagFetcher::PuidsFound(int index, const QStringList& puid_list) {
  if (index >= songs_.count()) {
    return;
  }

  const Song& song = songs_[index];

  if (puid_list.isEmpty()) {
    emit ResultAvailable(song, SongList());
    return;
  }

  emit Progress(song, tr("Downloading metadata"));
  musicbrainz_client_->Start(index, puid_list);
}

void TagFetcher::TagsFetched(int index,
                             const MusicBrainzClient::ResultList& results) {
  if (index >= songs_.count()) {
    return;
  }

  const Song& original_song = songs_[index];
  SongList songs_guessed;

  for (const MusicBrainzClient::Result& result : results) {
    Song song;
    song.Init(result.title_, result.artist_, result.album_,
              result.duration_msec_ * kNsecPerMsec);
    song.set_track(result.track_);
    song.set_year(result.year_);
    songs_guessed << song;
  }

  emit ResultAvailable(original_song, songs_guessed);
}