/* This file is (c) 2017 Abs62
 * Part of GoldenDict. Licensed under GPLv3 or later, see the LICENSE file */

#include <QDebug>
#include <QApplication>
#include <QDockWidget>
#include <QKeyEvent>
#include <QClipboard>
#include <QDomDocument>
#include <QMessageBox>
#include <QtAlgorithms>
#include <QMap>
#include <algorithm>
#include <functional>

#include "favoritespanewidget.hh"
#include "gddebug.hh"
#include "atomic_rename.hh"

/************************************************** FavoritesPaneWidget *********************************************/

void FavoritesPaneWidget::setUp( Config::Class * cfg, QMenu * menu )
{
  m_cfg = cfg;
  m_favoritesTree = findChild< TreeView * >( "favoritesTree" );
  QDockWidget * favoritesPane = qobject_cast< QDockWidget * >( parentWidget() );
  m_favoritesTree->setHeaderHidden( true );

  // Delete selected items action
  m_deleteSelectedAction = new QAction( this );
  m_deleteSelectedAction->setText( tr( "&Delete Selected" ) );
  m_deleteSelectedAction->setShortcut( QKeySequence( QKeySequence::Delete ) );
  m_deleteSelectedAction->setShortcutContext( Qt::WidgetWithChildrenShortcut );
  addAction( m_deleteSelectedAction );
  connect( m_deleteSelectedAction, &QAction::triggered, this, &FavoritesPaneWidget::deleteSelectedItems );

  // Copy selected items to clipboard
  m_copySelectedToClipboard = new QAction( this );
  m_copySelectedToClipboard->setText( tr( "Copy Selected" ) );
  m_copySelectedToClipboard->setShortcut( QKeySequence( QKeySequence::Copy ) );
  m_copySelectedToClipboard->setShortcutContext( Qt::WidgetWithChildrenShortcut );
  addAction( m_copySelectedToClipboard );
  connect( m_copySelectedToClipboard, &QAction::triggered, this, &FavoritesPaneWidget::copySelectedItems );

  // Add folder to tree view
  m_addFolder = new QAction( this );
  m_addFolder->setText( tr( "Add folder" ) );
  addAction( m_addFolder );
  connect( m_addFolder, &QAction::triggered, this, &FavoritesPaneWidget::addFolder );


  // Handle context menu, reusing some of the top-level window's History menu
  m_favoritesMenu = new QMenu( this );
  m_separator = m_favoritesMenu->addSeparator();
  QListIterator< QAction * > actionsIter( menu->actions() );
  while ( actionsIter.hasNext() )
    m_favoritesMenu->addAction( actionsIter.next() );

  // Make the favorites pane's titlebar

  favoritesLabel.setText( tr( "Favorites:" ) );
  favoritesLabel.setObjectName( "favoritesLabel" );
  if ( layoutDirection() == Qt::LeftToRight )
  {
    favoritesLabel.setAlignment( Qt::AlignLeft );
  }
  else
  {
    favoritesLabel.setAlignment( Qt::AlignRight );
  }

  favoritesPaneTitleBarLayout.addWidget( &favoritesLabel );
  favoritesPaneTitleBarLayout.setContentsMargins(5, 5, 5, 5);
  favoritesPaneTitleBar.setLayout( &favoritesPaneTitleBarLayout );
  favoritesPaneTitleBar.setObjectName("favoritesPaneTitleBar");
  favoritesPane->setTitleBarWidget( &favoritesPaneTitleBar );

  // Favorites tree
  m_favoritesModel = new FavoritesModel( Config::getFavoritiesFileName(), this );

  listItemDelegate = new WordListItemDelegate( m_favoritesTree->itemDelegate() );
  m_favoritesTree->setItemDelegate( listItemDelegate );

  QAbstractItemModel * oldModel = m_favoritesTree->model();
  m_favoritesTree->setModel( m_favoritesModel );
  if( oldModel )
    oldModel->deleteLater();

  connect( m_favoritesTree, &QTreeView::expanded, m_favoritesModel, &FavoritesModel::itemExpanded );

  connect( m_favoritesTree, &QTreeView::collapsed, m_favoritesModel, &FavoritesModel::itemCollapsed );

  connect( m_favoritesModel, &FavoritesModel::expandItem, m_favoritesTree, &QTreeView::expand );

  m_favoritesModel->checkAllNodesForExpand();
  m_favoritesTree->viewport()->setAcceptDrops( true );
  m_favoritesTree->setDragEnabled( true );
//  m_favoritesTree->setDragDropMode( QAbstractItemView::InternalMove );
  m_favoritesTree->setDragDropMode( QAbstractItemView::DragDrop );
  m_favoritesTree->setDefaultDropAction( Qt::MoveAction );

  m_favoritesTree->setRootIsDecorated( true );

  m_favoritesTree->setContextMenuPolicy( Qt::CustomContextMenu );
  m_favoritesTree->setSelectionMode( QAbstractItemView::ExtendedSelection );

  m_favoritesTree->setEditTriggers( QAbstractItemView::SelectedClicked | QAbstractItemView::EditKeyPressed );

  m_favoritesTree->installEventFilter( this );
  m_favoritesTree->viewport()->installEventFilter( this );

  // list selection and keyboard navigation
  connect( m_favoritesTree, &QAbstractItemView::clicked, this, &FavoritesPaneWidget::onItemClicked );

  connect( m_favoritesTree->selectionModel(),
    SIGNAL( selectionChanged( QItemSelection const &, QItemSelection const & ) ),
    this,
    SLOT( onSelectionChanged( QItemSelection const & ) ) );

  connect( m_favoritesTree, &QWidget::customContextMenuRequested, this, &FavoritesPaneWidget::showCustomMenu );
}

FavoritesPaneWidget::~FavoritesPaneWidget()
{
  if( listItemDelegate )
    delete listItemDelegate;
}

bool FavoritesPaneWidget::eventFilter( QObject * obj, QEvent * ev )
{
  // unused for now

  return QWidget::eventFilter( obj, ev );
}

void FavoritesPaneWidget::copySelectedItems()
{
  QModelIndexList selectedIdxs = m_favoritesTree->selectionModel()->selectedIndexes();

  if ( selectedIdxs.isEmpty() )
  {
    // nothing to do
    return;
  }

  QStringList selectedStrings = m_favoritesModel->getTextForIndexes( selectedIdxs );

  QApplication::clipboard()->setText( selectedStrings.join( QString::fromLatin1( "\n" ) ) );
}

void FavoritesPaneWidget::deleteSelectedItems()
{
  QModelIndexList selectedIdxs = m_favoritesTree->selectionModel()->selectedIndexes();

  if ( selectedIdxs.isEmpty() )
  {
    // nothing to do
    return;
  }

  if( m_cfg->preferences.confirmFavoritesDeletion )
  {
    QMessageBox mb( QMessageBox::Warning, "GoldenDict",
                    tr( "All selected items will be deleted. Continue?" ),
                    QMessageBox::Yes | QMessageBox::No );
    mb.exec();
    if( mb.result() != QMessageBox::Yes )
      return;
  }

  m_favoritesModel->removeItemsForIndexes( selectedIdxs );
}

void FavoritesPaneWidget::showCustomMenu(QPoint const & pos)
{
  QModelIndexList selectedIdxs = m_favoritesTree->selectionModel()->selectedIndexes();

  m_favoritesMenu->removeAction( m_copySelectedToClipboard );
  m_favoritesMenu->removeAction( m_deleteSelectedAction );
  m_favoritesMenu->removeAction( m_addFolder );

  m_separator->setVisible( !selectedIdxs.isEmpty() );

  if ( !selectedIdxs.isEmpty() )
  {
    m_favoritesMenu->insertAction( m_separator, m_copySelectedToClipboard );
    m_favoritesMenu->insertAction( m_separator, m_deleteSelectedAction );
  }

  if( selectedIdxs.size() <= 1 )
  {
    m_favoritesMenu->insertAction( m_separator, m_addFolder );
    m_separator->setVisible( true );
  }

  m_favoritesMenu->exec( m_favoritesTree->mapToGlobal( pos ) );
}

void FavoritesPaneWidget::onSelectionChanged( QItemSelection const & selection )
{
  if ( m_favoritesTree->selectionModel()->selectedIndexes().size() != 1
       || selection.indexes().isEmpty() )
    return;

  itemSelectionChanged = true;
  emitFavoritesItemRequested( selection.indexes().front() );
}

void FavoritesPaneWidget::onItemClicked( QModelIndex const & idx )
{
  if ( !itemSelectionChanged && m_favoritesTree->selectionModel()->selectedIndexes().size() == 1 )
  {
    emitFavoritesItemRequested( idx );
  }
  itemSelectionChanged = false;
}

void FavoritesPaneWidget::emitFavoritesItemRequested( QModelIndex const & idx )
{
  if( m_favoritesModel->itemType( idx ) != TreeItem::Word )
  {
    // Item is not headword
    return;
  }

  QString headword = m_favoritesModel->data( idx, Qt::DisplayRole ).toString();
  QString path = m_favoritesModel->pathToItem( idx );

  if( !headword.isEmpty() )
    emit favoritesItemRequested( headword, path );
}

void FavoritesPaneWidget::addFolder()
{
  QModelIndexList selectedIdx = m_favoritesTree->selectionModel()->selectedIndexes();
  if( selectedIdx.size() > 1 )
    return;

  QModelIndex folderIdx;
  if( selectedIdx.size() )
    folderIdx = m_favoritesModel->addNewFolder( selectedIdx.front() );
  else
    folderIdx = m_favoritesModel->addNewFolder( QModelIndex() );

  if( folderIdx.isValid() )
    m_favoritesTree->edit( folderIdx );
}

void FavoritesPaneWidget::addHeadword( QString const & path, QString const & headword )
{
  m_favoritesModel->addNewHeadword( path, headword );
}

bool FavoritesPaneWidget::removeHeadword( QString const & path, QString const & headword )
{
  return m_favoritesModel->removeHeadword( path, headword );
}

bool FavoritesPaneWidget::isHeadwordPresent( const QString & path, const QString & headword )
{
  return m_favoritesModel->isHeadwordPresent( path, headword );
}

void FavoritesPaneWidget::getDataInXml( QByteArray & dataStr )
{
  m_favoritesModel->getDataInXml( dataStr );
}

void FavoritesPaneWidget::getDataInPlainText( QString & dataStr )
{
  m_favoritesModel->getDataInPlainText( dataStr );
}

bool FavoritesPaneWidget::setDataFromXml( QString const & dataStr )
{
  return m_favoritesModel->setDataFromXml( dataStr );
}

bool FavoritesPaneWidget::setDataFromTxt( QString const & dataStr )
{
  return m_favoritesModel->setDataFromTxt( dataStr );
}

void FavoritesPaneWidget::setSaveInterval( unsigned interval )
{
  if( timerId )
  {
    killTimer( timerId );
    timerId = 0;
  }
  if( interval )
  {
    m_favoritesModel->saveData();
    timerId = startTimer( interval * 60000 );
  }
}

void FavoritesPaneWidget::timerEvent( QTimerEvent * ev )
{
  Q_UNUSED( ev )
  m_favoritesModel->saveData();
}

void FavoritesPaneWidget::saveData()
{
  m_favoritesModel->saveData();
}

/************************************************** TreeItem *********************************************/

TreeItem::TreeItem( const QVariant &data, TreeItem *parent, Type type ) :
  itemData( data ),
  parentItem( parent ),
  m_type( type ),
  m_expanded( false )
{
}

TreeItem::~TreeItem()
{
  qDeleteAll( childItems );
}

void TreeItem::appendChild( TreeItem *item )
{
  childItems.append( item );
}

void TreeItem::insertChild( int row, TreeItem * item )
{
  if( row > childItems.count() )
    row = childItems.count();
  childItems.insert( row, item );
}

TreeItem *TreeItem::child( int row ) const
{
  return childItems.value( row );
}

void TreeItem::deleteChild( int row )
{
  if( row < 0 || row >= childItems.count() )
    return;

  TreeItem *it = childItems.at( row );
  childItems.removeAt( row );
  delete it;
}

int TreeItem::childCount() const
{
  return childItems.count();
}

QVariant TreeItem::data() const
{
  return itemData;
}

void TreeItem::setData( const QVariant & newData )
{
  itemData = newData;
}

int TreeItem::row() const
{
  if( parentItem )
      return parentItem->childItems.indexOf( const_cast< TreeItem * >( this ) );

  return 0;
}

TreeItem *TreeItem::parent()
{
  return parentItem;
}

Qt::ItemFlags TreeItem::flags() const
{
  Qt::ItemFlags f = Qt::ItemIsEnabled | Qt::ItemIsSelectable |
                    Qt::ItemIsDragEnabled;
  if( m_type == Folder )
    f |= Qt::ItemIsEditable | Qt::ItemIsDropEnabled;
  else
  if( m_type == Root )
    f |= Qt::ItemIsDropEnabled;

  return f;
}

QString TreeItem::fullPath() const
{
  // Get full path from root item
  QString path;
  TreeItem * par = parentItem;
  for( ; ; )
  {
    if( !par )
      break;
    path = par->data().toString() + "/" + path;
    par = par->parentItem;
  }
  return path;
}

TreeItem * TreeItem::duplicateItem( TreeItem * newParent ) const
{
  TreeItem * newItem = new TreeItem( itemData, newParent, m_type );
  if( m_type == Folder )
  {
    QList< TreeItem * >::const_iterator it = childItems.begin();
    for( ; it != childItems.end(); ++it )
      newItem->appendChild( (*it)->duplicateItem( newItem ) );
  }
  return newItem;
}

bool TreeItem::haveAncestor( TreeItem * item )
{
  TreeItem *par = parentItem;
  for( ; ; )
  {
    if( !par )
      break;
    if( par == item )
      return true;
    par = par->parent();
  }
  return false;
}

bool TreeItem::haveSameItem( TreeItem * item, bool allowSelf )
{
  QList< TreeItem * >::const_iterator it = childItems.begin();
  QString name = item->data().toString();
  for( ; it != childItems.end(); ++it )
  {
    if( *it == item && !allowSelf )
      return true;
    if( (*it)->data().toString() == name && (*it)->type() == item->type() && (*it) != item )
      return true;
  }

  return false;
}

QStringList TreeItem::getTextFromAllChilds() const
{
  QStringList list;
  QList< TreeItem * >::const_iterator it = childItems.begin();
  for( ; it != childItems.end(); ++it )
  {
    if( (*it)->type() == Word )
    {
      QString txt = (*it)->data().toString();
      list.append( txt );
    }
    else // Folder
    {
      QStringList childList = (*it)->getTextFromAllChilds();
      list.append( childList );
    }
  }
  return list;
}

/************************************************** FavoritesModel *********************************************/

FavoritesModel::FavoritesModel( QString favoritesFilename, QObject * parent ) :
  QAbstractItemModel( parent ),
  m_favoritesFilename( favoritesFilename ),
  rootItem( 0 ),
  dirty( false )
{
  readData();
  dirty = false;
}

FavoritesModel::~FavoritesModel()
{
  if( rootItem )
    delete rootItem;
}

Qt::ItemFlags FavoritesModel::flags( const QModelIndex &idx ) const
{
  TreeItem * item = getItem( idx );
  return item->flags();
}

QVariant FavoritesModel::headerData( int , Qt::Orientation,
                                     int ) const
{
  return QVariant();
}

QModelIndex FavoritesModel::index( int row, int column, const QModelIndex &parentIdx ) const
{
//  if(!hasIndex(row, column, parent))
//    return QModelIndex();

  TreeItem *parentItem = getItem( parentIdx );

  TreeItem *childItem = parentItem->child(row);
  if( childItem )
    return createIndex( row, column, childItem );

  return QModelIndex();
}

QModelIndex FavoritesModel::parent( const QModelIndex &index ) const
{
  if ( !index.isValid() )
    return QModelIndex();

  TreeItem *childItem = getItem( index );
  if( childItem == rootItem )
    return QModelIndex();

  TreeItem *parentItem = childItem->parent();

  if( parentItem == rootItem )
    return QModelIndex();

  return createIndex( parentItem->row(), 0, parentItem );
}

int FavoritesModel::rowCount(const QModelIndex &parent) const
{
  if ( parent.column() > 0 )
    return 0;

  TreeItem *parentItem = getItem( parent );

  return parentItem->childCount();
}

int FavoritesModel::columnCount(const QModelIndex & ) const
{
  return 1;
}

bool FavoritesModel::removeRows( int row, int count, const QModelIndex &parent )
{
  TreeItem * parentItem = getItem( parent );

  beginRemoveRows( parent, row, row + count - 1 );

  for( int i = 0; i < count; i++ )
    parentItem->deleteChild( row );

  endRemoveRows();

  dirty = true;

  return true;
}

bool FavoritesModel::setData( const QModelIndex & index, const QVariant & value, int role )
{
  if( role != Qt::EditRole || !index.isValid() || value.toString().isEmpty() )
    return false;

  QModelIndex parentIdx = parent( index );
  if( findItemInFolder( value.toString(), TreeItem::Folder, parentIdx ).isValid() )
  {
    // Such folder is already presented in parent folder
    return false;
  }

  TreeItem * item = getItem( index );
  item->setData( value );

  dirty = true;

  return true;
}

QVariant FavoritesModel::data( QModelIndex const & index, int role ) const
{
  if( !index.isValid() )
    return QVariant();

  TreeItem *item = getItem( index );
  if( item == rootItem )
    return QVariant();

  if ( role == Qt::DisplayRole || role == Qt::ToolTipRole )
  {
    return item->data();
  }
  else
  if( role == Qt::DecorationRole )
  {
    if( item->type() == TreeItem::Folder || item->type() == TreeItem::Root )
      return QIcon( ":/icons/folder.svg" );

    return QVariant();
  }
  if( role == Qt::EditRole )
  {
    if( item->type() == TreeItem::Folder )
      return item->data();

    return QVariant();
  }

  return QVariant();
}

Qt::DropActions FavoritesModel::supportedDropActions() const
{
  return Qt::MoveAction | Qt::CopyAction;
}

void FavoritesModel::readData()
{
  // Read data from "favorities" file

  beginResetModel();

  if( rootItem )
    delete rootItem;

  rootItem = new TreeItem( QVariant(), 0, TreeItem::Root );

  QFile favoritesFile( m_favoritesFilename );
  if( !favoritesFile.open( QFile::ReadOnly ) )
  {
    gdDebug( "No favorites file found" );
    return;
  }

  QString errorStr;
  int errorLine, errorColumn;
  dom.clear();

  if ( !dom.setContent( &favoritesFile, false, &errorStr, &errorLine, &errorColumn  ) )
  {
    // Mailformed file
    gdWarning( "Favorites file parsing error: %s at %d,%d\n", errorStr.toUtf8().data(),  errorLine,  errorColumn );

    QMessageBox mb( QMessageBox::Warning, "GoldenDict",
                      tr( "Error in favorities file" ),
                      QMessageBox::Ok );
    mb.exec();

    dom.clear();
    favoritesFile.close();
    renameAtomically( m_favoritesFilename, m_favoritesFilename + ".bak" );
  }
  else
    favoritesFile.close();

  QDomNode rootNode = dom.documentElement();
  addFolder( rootItem, rootNode );
  dom.clear();

  endResetModel();
  dirty = false;
}

void FavoritesModel::saveData()
{
  if( !dirty )
    return;

  QFile tmpFile( m_favoritesFilename + ".tmp" );
  if( !tmpFile.open( QFile::WriteOnly ) )
  {
    gdWarning( "Can't write favorites file, error: %s", tmpFile.errorString().toUtf8().data() );
    return;
  }

  dom.clear();

  QDomElement el = dom.createElement( "root" );
  dom.appendChild( el );
  storeFolder( rootItem, el );

  QByteArray result( dom.toByteArray() );

  if ( tmpFile.write( result ) != result.size() )
  {
    gdWarning( "Can't write favorites file, error: %s", tmpFile.errorString().toUtf8().data() );
    return;
  }

  tmpFile.close();

  if( renameAtomically( tmpFile.fileName(), m_favoritesFilename ) )
    dirty = false;

  dom.clear();
}

void FavoritesModel::addFolder( TreeItem *parent, QDomNode &node )
{
  QDomNodeList nodes = node.childNodes();
  for( int i = 0; i < nodes.count(); i++ )
  {
    QDomElement el = nodes.at( i ).toElement();
    if( el.nodeName() == "folder" )
    {
      // New subfolder
      QString name = el.attribute( "name", "" );
      TreeItem *item = new TreeItem( name, parent, TreeItem::Folder );
      item->setExpanded( el.attribute( "expanded", "0" ) == "1" );
      parent->appendChild( item );
      addFolder( item, el );
    }
    else
    {
      QString word = el.text();
      parent->appendChild( new TreeItem( word, parent, TreeItem::Word ) );
    }
  }
  dirty = true;
}

void FavoritesModel::storeFolder( TreeItem * folder, QDomNode & node )
{
  int n = folder->childCount();
  for( int i = 0; i < n; i++ )
  {
    TreeItem * child = folder->child( i );
    QString name = child->data().toString();
    if( child->type() == TreeItem::Folder )
    {
      QDomElement el = dom.createElement( "folder" );
      el.setAttribute( "name", name );
      el.setAttribute( "expanded", child->isExpanded() ? "1" : "0" );
      node.appendChild( el );
      storeFolder( child, el );
    }
    else
    {
      QDomElement el = dom.createElement( "headword" );
      el.appendChild( dom.createTextNode( name ) );
      node.appendChild( el );
    }
  }
}

void FavoritesModel::itemExpanded( const QModelIndex & index )
{
  if( index.isValid() )
  {
    TreeItem *item = getItem( index );
    item->setExpanded( true );
  }
}

void FavoritesModel::itemCollapsed( const QModelIndex & index )
{
  if( index.isValid() )
  {
    TreeItem *item = getItem( index );
    item->setExpanded( false );
  }
}

void FavoritesModel::checkAllNodesForExpand()
{
  checkNodeForExpand( rootItem, QModelIndex() );
}

void FavoritesModel::checkNodeForExpand( const TreeItem * item, const QModelIndex & parent )
{
  for( int i = 0; i < item->childCount(); i++ )
  {
    TreeItem * ch = item->child( i );
    if( ch->type() == TreeItem::Folder && ch->isExpanded() )
    {
      // We need to expand this node...
      QModelIndex idx = index( i, 0, parent );
      emit expandItem( idx );

      // ...and check it for children nodes
      checkNodeForExpand( item->child( i ), idx );
    }
  }
}

QStringList FavoritesModel::mimeTypes() const
{
  return QStringList( QString::fromLatin1( FAVORITES_MIME_TYPE ) );
}

QMimeData *FavoritesModel::mimeData( const QModelIndexList & indexes ) const
{
  FavoritesMimeData *data = new FavoritesMimeData();
  data->setIndexesList( indexes );
  return data;
}

bool FavoritesModel::dropMimeData( const QMimeData *data, Qt::DropAction action,
                                   int row, int, const QModelIndex &par )
{
  if( action == Qt::MoveAction || action == Qt::CopyAction )
  {
    if( data->hasFormat( FAVORITES_MIME_TYPE ) )
    {
      FavoritesMimeData const * mimeData = qobject_cast< FavoritesMimeData const * >( data );
      if( mimeData )
      {
        QModelIndexList const & list = mimeData->getIndexesList();

        if( list.isEmpty() )
          return false;

        TreeItem * parentItem = getItem( par );
        QModelIndex parentIdx = par;

        if( row < 0 )
          row = 0;

        QList< QModelIndex >::const_iterator it = list.begin();
        QList< TreeItem * > movedItems;
        for( ; it != list.end(); ++it )
        {
          TreeItem * item = getItem( *it );

          // Check if we can copy/move this item
          if( parentItem->haveAncestor( item ) || parentItem->haveSameItem( item, action == Qt::MoveAction ) )
            return false;

          movedItems.append( item );
        }

        // Insert items to new place

        beginInsertRows( parentIdx, row, row + movedItems.count() - 1 );
        for( int i = 0; i < movedItems.count(); i++ )
        {
          TreeItem * item = movedItems.at( i );
          TreeItem *newItem = item->duplicateItem( parentItem );
          parentItem->insertChild( row + i, newItem );
        }
        endInsertRows();

        dirty = true;

        return true;
      }
    }
  }
  return false;
}

QModelIndex FavoritesModel::findItemInFolder( const QString & itemName, int itemType,
                                              const QModelIndex & parentIdx )
{
  TreeItem * parentItem = getItem( parentIdx );
  for( int i = 0; i < parentItem->childCount(); i++ )
  {
    TreeItem * item = parentItem->child( i );
    if( item->data().toString() == itemName && item->type() == itemType )
      return createIndex( i, 0, item );
  }
  return QModelIndex();
}

TreeItem *FavoritesModel::getItem( const QModelIndex &index ) const
{
  if( index.isValid() )
  {
    TreeItem *item = static_cast< TreeItem * >( index.internalPointer() );
    if (item)
      return item;
  }
  return rootItem;
}

QStringList FavoritesModel::getTextForIndexes( const QModelIndexList & idxList ) const
{
  QStringList list;
  QModelIndexList::const_iterator it = idxList.begin();
  for( ; it != idxList.end(); ++it )
  {
    TreeItem *item = getItem( *it );
    if( item->type() == TreeItem::Word )
      list.append( item->data().toString() );
    else
      list.append( item->getTextFromAllChilds() );
  }
  return list;
}

void FavoritesModel::removeItemsForIndexes( const QModelIndexList & idxList )
{
  // We should delete items from lowest tree level and in decreasing order
  // so that first deletions won't affect the indexes for subsequent deletions.

  QMap< int, QModelIndexList > itemsToDelete;
  int lowestLevel = 0;

  QModelIndexList::const_iterator it = idxList.begin();
  for( ; it != idxList.end(); ++it )
  {
    int n = level( *it );
    if( n > lowestLevel )
      lowestLevel = n;
    itemsToDelete[ n ].append( *it );
  }

  for( int i = lowestLevel; i >= 0; i-- )
  {
    QModelIndexList idxSublist = itemsToDelete[ i ];
    // std::greater does not work as operator < not implemented
    #if __cplusplus >= 201703L
    std::sort( idxSublist.begin(), idxSublist.end(), std::not_fn( std::less< QModelIndex >() ) );
    #else
    std::sort( idxSublist.begin(), idxSublist.end(), std::not2( std::less< QModelIndex >() ) );
    #endif

    it = idxSublist.begin();
    for( ; it != idxSublist.end(); ++it )
    {
      QModelIndex parentIdx = parent( *it );
      removeRows( (*it).row(), 1, parentIdx );
    }
  }
}

QModelIndex FavoritesModel::addNewFolder( const QModelIndex & idx )
{
  QModelIndex parentIdx;
  if( idx.isValid() )
    parentIdx = parent( idx );
  else
    parentIdx = idx;

  QString baseName = QString::fromLatin1( "New folder" );

  // Create unique name

  QString name = baseName;
  if( findItemInFolder( name, TreeItem::Folder, parentIdx ).isValid() )
  {
    int i;
    for( i = 1; i < 1000; i++ )
    {
      name = baseName + QString::number( i );
      if( !findItemInFolder( name, TreeItem::Folder, parentIdx ).isValid() )
        break;
    }
    if( i >= 1000 )
      return QModelIndex();
  }

  // Create folder with unique name

  TreeItem *parentItem = getItem( parentIdx );
  int row;

  if( idx.isValid() )
  {
    // Insert after selected element
    row = idx.row() + 1;
  }
  else
  {
    // No selected element - add to end of root folder
    row = parentItem->childCount();
  }

  beginInsertRows( parentIdx, row, row );
  TreeItem * newFolder = new TreeItem( name, parentItem, TreeItem::Folder );
  parentItem->insertChild( row, newFolder );
  endInsertRows();

  dirty = true;

  return createIndex( row, 0, newFolder );
}

bool FavoritesModel::addNewHeadword( const QString & path, const QString & headword )
{
  QModelIndex parentIdx;

  // Find or create target folder

  QStringList folders = path.split( "/", Qt::SkipEmptyParts );
  QStringList::const_iterator it = folders.begin();
  for( ; it != folders.end(); ++it )
    parentIdx = forceFolder( *it, parentIdx );

  // Add headword

  return addHeadword( headword, parentIdx );
}

bool FavoritesModel::removeHeadword( const QString & path, const QString & headword )
{
  QModelIndex idx;

  // Find target folder

  QStringList folders = path.split( "/", Qt::SkipEmptyParts );
  QStringList::const_iterator it = folders.begin();
  for( ; it != folders.end(); ++it )
  {
    idx = findItemInFolder( *it, TreeItem::Folder, idx );
    if( !idx.isValid() )
      break;
  }

  if( path.isEmpty() || idx.isValid() )
  {
    idx = findItemInFolder( headword, TreeItem::Word, idx );
    if( idx.isValid() )
    {
      QModelIndexList list;
      list.append( idx );
      removeItemsForIndexes( list );
      return true;
    }
  }

  return false;
}

bool FavoritesModel::isHeadwordPresent( const QString & path, const QString & headword )
{
  QModelIndex idx;

  // Find target folder

  QStringList folders = path.split( "/", Qt::SkipEmptyParts );
  QStringList::const_iterator it = folders.begin();
  for( ; it != folders.end(); ++it )
  {
    idx = findItemInFolder( *it, TreeItem::Folder, idx );
    if( !idx.isValid() )
      break;
  }

  if( path.isEmpty() || idx.isValid() )
  {
    idx = findItemInFolder( headword, TreeItem::Word, idx );
    return idx.isValid();
  }

  return false;
}

QModelIndex FavoritesModel::forceFolder( QString const & name, const QModelIndex & parentIdx )
{
  QModelIndex idx = findItemInFolder( name, TreeItem::Folder, parentIdx );
  if( idx.isValid() )
    return idx;

  // Folder not found, create it
  TreeItem * parentItem = getItem( parentIdx );
  TreeItem * newItem = new TreeItem( name, parentItem, TreeItem::Folder );
  int row = parentItem->childCount();

  beginInsertRows( parentIdx, row, row );
  parentItem->appendChild( newItem );
  endInsertRows();

  dirty = true;

  return createIndex( row, 0, newItem );
}

bool FavoritesModel::addHeadword( const QString & word, const QModelIndex & parentIdx )
{
  QModelIndex idx = findItemInFolder( word, TreeItem::Word, parentIdx );
  if( idx.isValid() )
    return false;

  // Headword not found, append it
  TreeItem * parentItem = getItem( parentIdx );
  TreeItem * newItem = new TreeItem( word, parentItem, TreeItem::Word );
  int row = parentItem->childCount();

  beginInsertRows( parentIdx, row, row );
  parentItem->appendChild( newItem );
  endInsertRows();

  dirty = true;

  return true;
}

int FavoritesModel::level( QModelIndex const & idx )
{
  int n = 0;
  QModelIndex parentIdx = parent( idx );
  while( parentIdx.isValid() )
  {
    n++;
    parentIdx = parent( parentIdx );
  }
  return n;
}

QString FavoritesModel::pathToItem( QModelIndex const & idx )
{
  QString path;
  QModelIndex parentIdx = parent( idx );
  while( parentIdx.isValid() )
  {
    if( !path.isEmpty() )
      path = "/" + path;

    path = data( parentIdx, Qt::DisplayRole ).toString() + path;

    parentIdx = parent( parentIdx );
  }
  return path;
}

void FavoritesModel::getDataInXml( QByteArray & dataStr )
{
  dom.clear();

  QDomElement el = dom.createElement( "root" );
  dom.appendChild( el );
  storeFolder( rootItem, el );

  dataStr = dom.toByteArray();
  dom.clear();
}

void FavoritesModel::getDataInPlainText( QString & dataStr )
{
  QModelIndexList list;
  list.append( QModelIndex() );
  dataStr = getTextForIndexes( list ).join( QString::fromLatin1( "\n" ) );
}

bool FavoritesModel::setDataFromXml( QString const & dataStr )
{
  QString errorStr;
  int errorLine, errorColumn;
  dom.clear();

  if ( !dom.setContent( dataStr, false, &errorStr, &errorLine, &errorColumn  ) )
  {
    // Mailformed data
    gdWarning( "XML parsing error: %s at %d,%d\n", errorStr.toUtf8().data(),  errorLine,  errorColumn );
    dom.clear();
    return false;
  }

  beginResetModel();

  if( rootItem )
    delete rootItem;

  rootItem = new TreeItem( QVariant(), 0, TreeItem::Root );

  QDomNode rootNode = dom.documentElement();
  addFolder( rootItem, rootNode );

  endResetModel();

  dom.clear();
  dirty = true;
  return true;
}

bool FavoritesModel::setDataFromTxt( QString const & dataStr )
{
  auto words = dataStr.split('\n',Qt::SkipEmptyParts);

  beginResetModel();

  if( rootItem )
    delete rootItem;

  rootItem = new TreeItem( QVariant(), 0, TreeItem::Root );

  for(auto const & word : words){
    rootItem->appendChild( new TreeItem( word, rootItem, TreeItem::Word ) );
  }
  endResetModel();

  dirty = true;
  return true;
}