/*
 * Strawberry Music Player
 * This file was part of Clementine.
 * Copyright 2010, David Sansome <me@davidsansome.com>
 *
 * Strawberry 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.
 *
 * Strawberry 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 Strawberry.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "config.h"

#include <algorithm>
#include <iterator>
#include <limits>

#include <QtGlobal>
#include <QtConcurrentRun>
#include <QFuture>
#include <QObject>
#include <QWidget>
#include <QDialog>
#include <QItemSelectionModel>
#include <QAbstractItemModel>
#include <QDir>
#include <QAction>
#include <QDateTime>
#include <QList>
#include <QVariant>
#include <QString>
#include <QStringBuilder>
#include <QUrl>
#include <QPixmap>
#include <QPalette>
#include <QColor>
#include <QFont>
#include <QLabel>
#include <QLineEdit>
#include <QListWidget>
#include <QLocale>
#include <QMenu>
#include <QMessageBox>
#include <QShortcut>
#include <QSize>
#include <QSpinBox>
#include <QSplitter>
#include <QTabWidget>
#include <QTextEdit>
#include <QPlainTextEdit>
#include <QKeySequence>
#include <QDialogButtonBox>
#include <QPushButton>
#include <QAbstractButton>
#include <QtEvents>
#include <QSettings>
#include <QtDebug>

#include "core/application.h"
#include "core/closure.h"
#include "core/iconloader.h"
#include "core/logging.h"
#include "core/tagreaderclient.h"
#include "core/utilities.h"
#include "widgets/busyindicator.h"
#include "widgets/lineedit.h"
#include "collection/collectionbackend.h"
#include "playlist/playlist.h"
#include "playlist/playlistdelegates.h"
#if defined(HAVE_GSTREAMER) && defined(HAVE_CHROMAPRINT)
#  include "musicbrainz/tagfetcher.h"
#endif
#include "covermanager/albumcoverchoicecontroller.h"
#include "covermanager/albumcoverloader.h"
#include "covermanager/coverproviders.h"
#include "edittagdialog.h"
#include "trackselectiondialog.h"
#include "ui_edittagdialog.h"

const char *EditTagDialog::kHintText = QT_TR_NOOP("(different across multiple songs)");
const char *EditTagDialog::kSettingsGroup = "EditTagDialog";

EditTagDialog::EditTagDialog(Application *app, QWidget *parent)
    : QDialog(parent),
      ui_(new Ui_EditTagDialog),
      app_(app),
      album_cover_choice_controller_(new AlbumCoverChoiceController(this)),
      loading_(false),
      ignore_edits_(false),
#if defined(HAVE_GSTREAMER) && defined(HAVE_CHROMAPRINT)
      tag_fetcher_(new TagFetcher(this)),
#endif
      cover_art_id_(0),
      cover_art_is_set_(false),
      results_dialog_(new TrackSelectionDialog(this)),
      pending_(0)
  {

  cover_options_.default_output_image_ = AlbumCoverLoader::ScaleAndPad(cover_options_, QImage(":/pictures/cdcase.png"));

  connect(app_->album_cover_loader(), SIGNAL(ImageLoaded(quint64,QImage,QImage)), SLOT(ArtLoaded(quint64,QImage,QImage)));

#if defined(HAVE_GSTREAMER) && defined(HAVE_CHROMAPRINT)
  connect(tag_fetcher_, SIGNAL(ResultAvailable(Song, SongList)), results_dialog_, SLOT(FetchTagFinished(Song, SongList)), Qt::QueuedConnection);
  connect(tag_fetcher_, SIGNAL(Progress(Song,QString)), results_dialog_, SLOT(FetchTagProgress(Song,QString)));
  connect(results_dialog_, SIGNAL(SongChosen(Song, Song)), SLOT(FetchTagSongChosen(Song, Song)));
  connect(results_dialog_, SIGNAL(finished(int)), tag_fetcher_, SLOT(Cancel()));
#endif

  album_cover_choice_controller_->SetApplication(app_);

  ui_->setupUi(this);
  ui_->splitter->setSizes(QList<int>() << 200 << width() - 200);
  ui_->loading_label->hide();

  ui_->fetch_tag->setIcon(QPixmap::fromImage(QImage(":/pictures/musicbrainz.png")));
#if defined(HAVE_GSTREAMER) && defined(HAVE_CHROMAPRINT)
  ui_->fetch_tag->setEnabled(true);
#else
  ui_->fetch_tag->setEnabled(false);
#endif

  // An editable field is one that has a label as a buddy.
  // The label is important because it gets turned bold when the field is changed.
  for (QLabel *label : findChildren<QLabel*>()) {
    QWidget *widget = label->buddy();
    if (widget) {
      // Store information about the field
      fields_ << FieldData(label, widget, widget->objectName());

      // Connect the Reset signal
      if (dynamic_cast<ExtendedEditor*>(widget)) {
        connect(widget, SIGNAL(Reset()), SLOT(ResetField()));
      }

      // Connect the edited signal
      if (qobject_cast<QLineEdit*>(widget)) {
        connect(widget, SIGNAL(textChanged(QString)), SLOT(FieldValueEdited()));
      }
      else if (qobject_cast<QPlainTextEdit*>(widget)) {
        connect(widget, SIGNAL(textChanged()), SLOT(FieldValueEdited()));
      }
      else if (qobject_cast<QSpinBox*>(widget)) {
        connect(widget, SIGNAL(valueChanged(int)), SLOT(FieldValueEdited()));
      }
    }
  }

  // Set the colour of all the labels on the summary page
  const bool light = palette().color(QPalette::Base).value() > 128;
  const QColor color = palette().color(QPalette::WindowText);
  QPalette summary_label_palette(palette());
  summary_label_palette.setColor(QPalette::WindowText, light ? color.lighter(150) : color.darker(150));

  for (QLabel *label : ui_->summary_tab->findChildren<QLabel*>()) {
    if (label->property("field_label").toBool()) {
      label->setPalette(summary_label_palette);
    }
  }

  // Pretend the summary text is just a label
  ui_->summary->setMaximumHeight(ui_->art->height() - ui_->summary_art_button->height() - 4);

  connect(ui_->song_list->selectionModel(), SIGNAL(selectionChanged(QItemSelection, QItemSelection)), SLOT(SelectionChanged()));
  connect(ui_->button_box, SIGNAL(clicked(QAbstractButton*)), SLOT(ButtonClicked(QAbstractButton*)));
  connect(ui_->playcount_reset, SIGNAL(clicked()), SLOT(ResetPlayCounts()));
#if defined(HAVE_GSTREAMER) && defined(HAVE_CHROMAPRINT)
  connect(ui_->fetch_tag, SIGNAL(clicked()), SLOT(FetchTag()));
#endif

  // Set up the album cover menu
  cover_menu_ = new QMenu(this);

  QList<QAction*> actions = album_cover_choice_controller_->GetAllActions();

  connect(album_cover_choice_controller_->cover_from_file_action(), SIGNAL(triggered()), this, SLOT(LoadCoverFromFile()));
  connect(album_cover_choice_controller_->cover_to_file_action(), SIGNAL(triggered()), this, SLOT(SaveCoverToFile()));
  connect(album_cover_choice_controller_->cover_from_url_action(), SIGNAL(triggered()), this, SLOT(LoadCoverFromURL()));
  connect(album_cover_choice_controller_->search_for_cover_action(), SIGNAL(triggered()), this, SLOT(SearchForCover()));
  connect(album_cover_choice_controller_->unset_cover_action(), SIGNAL(triggered()), this, SLOT(UnsetCover()));
  connect(album_cover_choice_controller_->show_cover_action(), SIGNAL(triggered()), this, SLOT(ShowCover()));

  cover_menu_->addActions(actions);

  ui_->summary_art_button->setMenu(cover_menu_);

  ui_->art->installEventFilter(this);
  ui_->art->setAcceptDrops(true);

  // Add the next/previous buttons
  previous_button_ = new QPushButton(IconLoader::Load("go-previous"), tr("Previous"), this);
  next_button_ = new QPushButton(IconLoader::Load("go-next"), tr("Next"), this);
  ui_->button_box->addButton(previous_button_, QDialogButtonBox::ResetRole);
  ui_->button_box->addButton(next_button_, QDialogButtonBox::ResetRole);

  connect(previous_button_, SIGNAL(clicked()), SLOT(PreviousSong()));
  connect(next_button_, SIGNAL(clicked()), SLOT(NextSong()));

  // Set some shortcuts for the buttons
  new QShortcut(QKeySequence::Back, previous_button_, SLOT(click()));
  new QShortcut(QKeySequence::Forward, next_button_, SLOT(click()));
  new QShortcut(QKeySequence::MoveToPreviousPage, previous_button_, SLOT(click()));
  new QShortcut(QKeySequence::MoveToNextPage, next_button_, SLOT(click()));

  // Show the shortcuts as tooltips
  previous_button_->setToolTip(QString("%1 (%2 / %3)").arg(
      previous_button_->text(),
      QKeySequence(QKeySequence::Back).toString(QKeySequence::NativeText),
      QKeySequence(QKeySequence::MoveToPreviousPage).toString(QKeySequence::NativeText)));
  next_button_->setToolTip(QString("%1 (%2 / %3)").arg(
      next_button_->text(),
      QKeySequence(QKeySequence::Forward).toString(QKeySequence::NativeText),
      QKeySequence(QKeySequence::MoveToNextPage).toString(QKeySequence::NativeText)));

  new TagCompleter(app_->collection_backend(), Playlist::Column_Artist, ui_->artist);
  new TagCompleter(app_->collection_backend(), Playlist::Column_Album, ui_->album);
  new TagCompleter(app_->collection_backend(), Playlist::Column_AlbumArtist, ui_->albumartist);
  new TagCompleter(app_->collection_backend(), Playlist::Column_Genre, ui_->genre);
  new TagCompleter(app_->collection_backend(), Playlist::Column_Composer, ui_->composer);
  new TagCompleter(app_->collection_backend(), Playlist::Column_Performer, ui_->performer);
  new TagCompleter(app_->collection_backend(), Playlist::Column_Grouping, ui_->grouping);

}

EditTagDialog::~EditTagDialog() {
  delete ui_;
}

bool EditTagDialog::SetLoading(const QString &message) {

  const bool loading = !message.isEmpty();
  if (loading == loading_) return false;
  loading_ = loading;

  ui_->button_box->setEnabled(!loading);
  ui_->tab_widget->setEnabled(!loading);
  ui_->song_list->setEnabled(!loading);
#if defined(HAVE_GSTREAMER) && defined(HAVE_CHROMAPRINT)
  ui_->fetch_tag->setEnabled(!loading);
#endif
  ui_->loading_label->setVisible(loading);
  ui_->loading_label->set_text(message);
  return true;

}

QList<EditTagDialog::Data> EditTagDialog::LoadData(const SongList &songs) const {

  QList<Data> ret;

  for (const Song &song : songs) {
    if (song.IsEditable()) {
      // Try reloading the tags from file
      Song copy(song);
      TagReaderClient::Instance()->ReadFileBlocking(copy.url().toLocalFile(), &copy);

      if (copy.is_valid()) {
        copy.MergeUserSetData(song);
        ret << Data(copy);
      }
    }
  }

  return ret;
}

void EditTagDialog::SetSongs(const SongList &s, const PlaylistItemList &items) {

  // Show the loading indicator
  if (!SetLoading(tr("Loading tracks") + "...")) return;

  data_.clear();
  playlist_items_ = items;
  ui_->song_list->clear();

  // Reload tags in the background
  QFuture<QList<Data>> future = QtConcurrent::run(this, &EditTagDialog::LoadData, s);
  NewClosure(future, this, SLOT(SetSongsFinished(QFuture<QList<EditTagDialog::Data>>)), future);

}

void EditTagDialog::SetSongsFinished(QFuture<QList<Data>> future) {

  if (!SetLoading(QString())) return;

  data_ = future.result();
  if (data_.count() == 0) {
    // If there were no valid songs, disable everything
    ui_->song_list->setEnabled(false);
    ui_->tab_widget->setEnabled(false);

    // Show a summary with empty information
    UpdateSummaryTab(Song());
    ui_->tab_widget->setCurrentWidget(ui_->summary_tab);

    SetSongListVisibility(false);
    return;
  }

  // Add the filenames to the list
  for (const Data &data : data_) {
    ui_->song_list->addItem(data.current_.basefilename());
  }

  // Select all
  ui_->song_list->setCurrentRow(0);
  ui_->song_list->selectAll();

  // Hide the list if there's only one song in it
  SetSongListVisibility(data_.count() != 1);

}

void EditTagDialog::SetSongListVisibility(bool visible) {
  ui_->song_list->setVisible(visible);
  previous_button_->setEnabled(visible);
  next_button_->setEnabled(visible);
}

QVariant EditTagDialog::Data::value(const Song &song, const QString &id) {

  if (id == "title") return song.title();
  if (id == "artist") return song.artist();
  if (id == "album") return song.album();
  if (id == "albumartist") return song.albumartist();
  if (id == "composer") return song.composer();
  if (id == "performer") return song.performer();
  if (id == "grouping") return song.grouping();
  if (id == "genre") return song.genre();
  if (id == "comment") return song.comment();
  if (id == "track") return song.track();
  if (id == "disc") return song.disc();
  if (id == "year") return song.year();
  qLog(Warning) << "Unknown ID" << id;
  return QVariant();

}

void EditTagDialog::Data::set_value(const QString &id, const QVariant &value) {

  if (id == "title") current_.set_title(value.toString());
  else if (id == "artist") current_.set_artist(value.toString());
  else if (id == "album") current_.set_album(value.toString());
  else if (id == "albumartist") current_.set_albumartist(value.toString());
  else if (id == "composer") current_.set_composer(value.toString());
  else if (id == "performer") current_.set_performer(value.toString());
  else if (id == "grouping") current_.set_grouping(value.toString());
  else if (id == "genre") current_.set_genre(value.toString());
  else if (id == "comment") current_.set_comment(value.toString());
  else if (id == "track") current_.set_track(value.toInt());
  else if (id == "disc") current_.set_disc(value.toInt());
  else if (id == "year") current_.set_year(value.toInt());
  else qLog(Warning) << "Unknown ID" << id;

}

bool EditTagDialog::DoesValueVary(const QModelIndexList &sel, const QString &id) const {
  QVariant value = data_[sel.first().row()].current_value(id);
  for (int i = 1; i < sel.count(); ++i) {
    if (value != data_[sel[i].row()].current_value(id)) return true;
  }
  return false;
}

bool EditTagDialog::IsValueModified(const QModelIndexList &sel, const QString &id) const {

  for (const QModelIndex &i : sel) {
    if (data_[i.row()].original_value(id) != data_[i.row()].current_value(id))
      return true;
  }
  return false;

}

void EditTagDialog::InitFieldValue(const FieldData &field, const QModelIndexList &sel) {

  const bool varies = DoesValueVary(sel, field.id_);

  if (ExtendedEditor *editor = dynamic_cast<ExtendedEditor*>(field.editor_)) {
    editor->clear();
    editor->clear_hint();
    if (varies) {
      editor->set_hint(tr(EditTagDialog::kHintText));
    }
    else {
      editor->set_text(data_[sel[0].row()].current_value(field.id_).toString());
    }
  }

  UpdateModifiedField(field, sel);

}

void EditTagDialog::UpdateFieldValue(const FieldData &field, const QModelIndexList &sel) {

  // Get the value from the field
  QVariant value;
  if (ExtendedEditor *editor = dynamic_cast<ExtendedEditor*>(field.editor_)) {
    value = editor->text();
  }

  // Did we get it?
  if (!value.isValid()) {
    return;
  }

  // Set it in each selected song
  for (const QModelIndex &i : sel) {
    data_[i.row()].set_value(field.id_, value);
  }

  UpdateModifiedField(field, sel);

}

void EditTagDialog::UpdateModifiedField(const FieldData &field, const QModelIndexList &sel) {

  const bool modified = IsValueModified(sel, field.id_);

  // Update the boldness
  QFont new_font(font());
  new_font.setBold(modified);
  field.label_->setFont(new_font);
  field.editor_->setFont(new_font);

}

void EditTagDialog::ResetFieldValue(const FieldData &field, const QModelIndexList &sel) {

  // Reset each selected song
  for (const QModelIndex &i : sel) {
    Data &data = data_[i.row()];
    data.set_value(field.id_, data.original_value(field.id_));
  }

  // Reset the field
  InitFieldValue(field, sel);

}

void EditTagDialog::SelectionChanged() {

  const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();
  if (sel.isEmpty())
    return;

  // Set the editable fields
  UpdateUI(sel);

  // If we're editing multiple songs then we have to disable certain tabs
  const bool multiple = sel.count() > 1;
  ui_->tab_widget->setTabEnabled(ui_->tab_widget->indexOf(ui_->summary_tab), !multiple);

  if (!multiple) {
    const Song &song = data_[sel.first().row()].original_;
    UpdateSummaryTab(song);
    UpdateStatisticsTab(song);
  }

}

void EditTagDialog::UpdateUI(const QModelIndexList &sel){

  ignore_edits_ = true;
  for (const FieldData &field : fields_) {
    InitFieldValue(field, sel);
  }
  ignore_edits_ = false;

}

static void SetText(QLabel *label, int value, const QString &suffix, const QString &def = QString()) {
  label->setText(value <= 0 ? def : (QString::number(value) + " " + suffix));
}

static void SetDate(QLabel *label, uint time) {

  if (time == std::numeric_limits<uint>::max()) {  // -1
    label->setText(QObject::tr("Unknown"));
  }
  else {
    label->setText(QDateTime::fromTime_t(time).toString(QLocale::system().dateTimeFormat(QLocale::LongFormat)));
  }

}

void EditTagDialog::UpdateSummaryTab(const Song &song) {

  cover_art_id_ = app_->album_cover_loader()->LoadImageAsync(cover_options_, song);

  QString summary = "<b>" + song.PrettyTitleWithArtist().toHtmlEscaped() + "</b><br/>";

  bool art_is_set = true;
  if (song.has_manually_unset_cover()) {
    summary += tr("Cover art manually unset").toHtmlEscaped();
    art_is_set = false;
  }
  else if (!song.art_manual().isEmpty()) {
    summary += tr("Cover art set from %1").arg(song.art_manual()).toHtmlEscaped();
  }
  else if (song.has_embedded_cover()) {
    summary += tr("Cover art from embedded image");
  }
  else if (!song.art_automatic().isEmpty()) {
    summary += tr("Cover art loaded automatically from %1").arg(song.art_automatic()).toHtmlEscaped();
  }
  else {
    summary += tr("Cover art not set").toHtmlEscaped();
    art_is_set = false;
  }

  ui_->summary->setText(summary);

  album_cover_choice_controller_->unset_cover_action()->setEnabled(art_is_set);
  album_cover_choice_controller_->show_cover_action()->setEnabled(art_is_set);
  ui_->summary_art_button->setEnabled(song.id() != -1);

  ui_->length->setText(Utilities::PrettyTimeNanosec(song.length_nanosec()));

  SetText(ui_->samplerate, song.samplerate(), "Hz");
  SetText(ui_->bitdepth, song.bitdepth(), "Bit");
  SetText(ui_->bitrate, song.bitrate(), tr("kbps"));
  SetDate(ui_->mtime, song.mtime());
  SetDate(ui_->ctime, song.ctime());

  if (song.filesize() == -1) {
    ui_->filesize->setText(tr("Unknown"));
  }
  else {
    ui_->filesize->setText(Utilities::PrettySize(song.filesize()));
  }

  ui_->filetype->setText(song.TextForFiletype());

  if (song.url().scheme() == "file")
    ui_->filename->setText(QDir::toNativeSeparators(song.url().toLocalFile()));
  else
    ui_->filename->setText(song.url().toString());

  album_cover_choice_controller_->search_for_cover_action()->setEnabled(app_->cover_providers()->HasAnyProviders());

}

void EditTagDialog::UpdateStatisticsTab(const Song &song) {

  ui_->playcount->setText(QString::number(qMax(0, song.playcount())));
  ui_->skipcount->setText(QString::number(qMax(0, song.skipcount())));

  ui_->lastplayed->setText(song.lastplayed() <= 0 ? tr("Never") : QDateTime::fromTime_t(song.lastplayed()).toString(QLocale::system().dateTimeFormat(QLocale::LongFormat)));

}

void EditTagDialog::ArtLoaded(quint64 id, const QImage &scaled, const QImage &original) {

  if (id == cover_art_id_) {
    ui_->art->setPixmap(QPixmap::fromImage(scaled));
    original_ = original;
  }

}

void EditTagDialog::FieldValueEdited() {

  if (ignore_edits_) return;

  const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();
  if (sel.isEmpty())
    return;

  QWidget *w = qobject_cast<QWidget*>(sender());

  // Find the field
  for (const FieldData &field : fields_) {
    if (field.editor_ == w) {
      UpdateFieldValue(field, sel);
      return;
    }
  }

}

void EditTagDialog::ResetField() {

  const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();
  if (sel.isEmpty())
    return;

  QWidget *w = qobject_cast<QWidget*>(sender());

  // Find the field
  for (const FieldData &field : fields_) {
    if (field.editor_ == w) {
      ignore_edits_ = true;
      ResetFieldValue(field, sel);
      ignore_edits_ = false;
      return;
    }
  }

}

Song *EditTagDialog::GetFirstSelected() {

  const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();
  if (sel.isEmpty()) return nullptr;
  return &data_[sel.first().row()].original_;

}

void EditTagDialog::LoadCoverFromFile() {

  Song *song = GetFirstSelected();
  if (!song) return;

  const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();

  QString cover = album_cover_choice_controller_->LoadCoverFromFile(song);

  if (!cover.isEmpty()) UpdateCoverOf(*song, sel, cover);

}

void EditTagDialog::SaveCoverToFile() {

  Song *song = GetFirstSelected();
  if (!song) return;

  album_cover_choice_controller_->SaveCoverToFile(*song, original_);

}

void EditTagDialog::LoadCoverFromURL() {

  Song *song = GetFirstSelected();
  if (!song) return;

  const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();

  QString cover = album_cover_choice_controller_->LoadCoverFromURL(song);

  if (!cover.isEmpty()) UpdateCoverOf(*song, sel, cover);
}

void EditTagDialog::SearchForCover() {

  Song *song = GetFirstSelected();
  if (!song) return;

  const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();

  QString cover = album_cover_choice_controller_->SearchForCover(song);

  if (!cover.isEmpty()) UpdateCoverOf(*song, sel, cover);
}

void EditTagDialog::UnsetCover() {

  Song *song = GetFirstSelected();
  if (!song) return;

  const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();

  QString cover = album_cover_choice_controller_->UnsetCover(song);
  UpdateCoverOf(*song, sel, cover);
}

void EditTagDialog::ShowCover() {

  Song *song = GetFirstSelected();
  if (!song) {
    return;
  }

  album_cover_choice_controller_->ShowCover(*song);
}

void EditTagDialog::UpdateCoverOf(const Song &selected, const QModelIndexList &sel, const QString &cover) {

  if (!selected.is_valid() || selected.id() == -1) return;

  UpdateSummaryTab(selected);

  // Now check if we have any other songs cached that share that artist and album (and would therefore be changed as well)
  for (int i = 0; i < data_.count(); ++i) {
    if (i == sel.first().row())  // Already changed this one
      continue;

    Song *other_song = &data_[i].original_;
    if (selected.artist() == other_song->artist() && selected.album() == other_song->album()) {
      other_song->set_art_manual(cover);
    }
  }

}

void EditTagDialog::NextSong() {

  if (ui_->song_list->count() == 0) {
    return;
  }

  int row = (ui_->song_list->currentRow() + 1) % ui_->song_list->count();
  ui_->song_list->setCurrentRow(row);
}

void EditTagDialog::PreviousSong() {

  if (ui_->song_list->count() == 0) {
    return;
  }

  int row = (ui_->song_list->currentRow() - 1 + ui_->song_list->count()) % ui_->song_list->count();
  ui_->song_list->setCurrentRow(row);
}

void EditTagDialog::ButtonClicked(QAbstractButton *button) {
  if (button == ui_->button_box->button(QDialogButtonBox::Discard)) {
    reject();
  }
}

void EditTagDialog::SaveData(const QList<Data> &data) {

  for (int i = 0; i < data.count(); ++i) {
    const Data &ref = data[i];
    if (ref.current_.IsMetadataEqual(ref.original_)) continue;

    pending_++;
    TagReaderReply *reply = TagReaderClient::Instance()->SaveFile(ref.current_.url().toLocalFile(), ref.current_);
    NewClosure(reply, SIGNAL(Finished(bool)), this, SLOT(SongSaveComplete(TagReaderReply*, QString, Song)), reply, ref.current_.url().toLocalFile(), ref.current_);

  }

  if (pending_ <= 0) AcceptFinished();

}

void EditTagDialog::accept() {

  // Show the loading indicator
  if (!SetLoading(tr("Saving tracks") + "...")) return;

  SaveData(data_);

}

void EditTagDialog::AcceptFinished() {
  if (!SetLoading(QString())) return;
  QDialog::accept();
}

bool EditTagDialog::eventFilter(QObject *o, QEvent *e) {

  if (o == ui_->art) {
    switch (e->type()) {
      case QEvent::MouseButtonRelease:
        cover_menu_->popup(static_cast<QMouseEvent*>(e)->globalPos());
        break;

      case QEvent::DragEnter: {
        QDragEnterEvent *event = static_cast<QDragEnterEvent*>(e);
        if (AlbumCoverChoiceController::CanAcceptDrag(event)) {
          event->acceptProposedAction();
        }
        break;
      }

      case QEvent::Drop: {
        const QDropEvent *event = static_cast<QDropEvent*>(e);
        const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();
        Song *song = GetFirstSelected();

        const QString cover = album_cover_choice_controller_->SaveCover(song, event);
        if (!cover.isEmpty()) {
          UpdateCoverOf(*song, sel, cover);
        }

        break;
      }

      default:
        break;
    }
  }
  return false;
}

void EditTagDialog::showEvent(QShowEvent *e) {

  // Set the dialog's height to the smallest possible
  resize(width(), sizeHint().height());

  // Restore the tab that was current last time.
  QSettings s;
  s.beginGroup(kSettingsGroup);
  ui_->tab_widget->setCurrentIndex(s.value("current_tab").toInt());

  QDialog::showEvent(e);
}

void EditTagDialog::hideEvent(QHideEvent *e) {

  // Save the current tab
  QSettings s;
  s.beginGroup(kSettingsGroup);
  s.setValue("current_tab", ui_->tab_widget->currentIndex());

  QDialog::hideEvent(e);
}

void EditTagDialog::ResetPlayCounts() {

  const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();
  if (sel.isEmpty())
    return;
  Song *song = &data_[sel.first().row()].original_;
  if (!song->is_valid() || song->id() == -1) return;

  if (QMessageBox::question(this, tr("Reset play counts"), tr("Are you sure you want to reset this song's statistics?"), QMessageBox::Reset, QMessageBox::Cancel) != QMessageBox::Reset) {
    return;
  }

  song->set_playcount(0);
  song->set_skipcount(0);
  song->set_lastplayed(-1);

  app_->collection_backend()->ResetStatisticsAsync(song->id());
  UpdateStatisticsTab(*song);
}

#if defined(HAVE_GSTREAMER) && defined(HAVE_CHROMAPRINT)
void EditTagDialog::FetchTag() {

  const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();

  SongList songs;

  for (const QModelIndex &index : sel) {
    Song song = data_[index.row()].original_;
    if (!song.is_valid()) {
      continue;
    }

    songs << song;
  }

  if (songs.isEmpty()) return;

  results_dialog_->Init(songs);
  tag_fetcher_->StartFetch(songs);

  results_dialog_->show();

}

void EditTagDialog::FetchTagSongChosen(const Song &original_song, const Song &new_metadata) {

  const QString filename = original_song.url().toLocalFile();

  // Find the song with this filename
  auto data_it = std::find_if(data_.begin(), data_.end(), [&filename](const Data &d) {
    return d.original_.url().toLocalFile() == filename;
  });
  if (data_it == data_.end()) {
    qLog(Warning) << "Could not find song to filename: " << filename;
    return;
  }

  // Update song data
  data_it->current_.set_title(new_metadata.title());
  data_it->current_.set_artist(new_metadata.artist());
  data_it->current_.set_album(new_metadata.album());
  data_it->current_.set_track(new_metadata.track());
  data_it->current_.set_year(new_metadata.year());

  // Is it currently being displayed in the UI?
  if (ui_->song_list->currentRow() == std::distance(data_.begin(), data_it)) {
    // Yes! Additionally update UI
    const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();
    UpdateUI(sel);
  }

}
#endif

void EditTagDialog::SongSaveComplete(TagReaderReply *reply, const QString filename, const Song song) {

  reply->deleteLater();

  pending_--;

  if (!reply->message().save_file_response().success()) {
    QString message = tr("An error occurred writing metadata to '%1'").arg(filename);
    emit Error(message);
  }
  else if (song.directory_id() != -1) {
    SongList songs;
    songs << song;
    app_->collection_backend()->AddOrUpdateSongs(songs);
  }

  if (pending_ <= 0) AcceptFinished();

}