QGIS/src/gui/qgsorderbydialog.cpp

/***************************************************************************
 qgosorderbydialog.cpp

 ---------------------
 begin                : 20.12.2015
 copyright            : (C) 2015 by Matthias Kuhn
 email                : matthias@opengis.ch
 ***************************************************************************
 *                                                                         *
 *   This program 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 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#include "qgsorderbydialog.h"

#include "qgsexpressionbuilderdialog.h"
#include "qgsfieldexpressionwidget.h"
#include "qgsvectorlayer.h"

#include <QTableWidget>
#include <QKeyEvent>

QgsOrderByDialog::QgsOrderByDialog( QgsVectorLayer *layer, QWidget *parent )
  : QDialog( parent )
  , mLayer( layer )
{
  setupUi( this );

  mOrderByTableWidget->horizontalHeader()->setSectionResizeMode( QHeaderView::Stretch );
  mOrderByTableWidget->horizontalHeader()->setSectionResizeMode( 1, QHeaderView::ResizeToContents );
  mOrderByTableWidget->horizontalHeader()->setSectionResizeMode( 2, QHeaderView::ResizeToContents );

  mOrderByTableWidget->installEventFilter( this );

  connect( buttonBox, &QDialogButtonBox::helpRequested, this, &QgsOrderByDialog::showHelp );
}

void QgsOrderByDialog::setOrderBy( const QgsFeatureRequest::OrderBy &orderBy )
{
  mOrderByTableWidget->setRowCount( orderBy.length() + 1 );

  int i = 0;
  Q_FOREACH ( const QgsFeatureRequest::OrderByClause &orderByClause, orderBy )
  {
    setRow( i, orderByClause );

    ++i;
  }

  // Add an empty widget at the end
  setRow( i, QgsFeatureRequest::OrderByClause( QLatin1String( "" ) ) );
}

QgsFeatureRequest::OrderBy QgsOrderByDialog::orderBy()
{
  QgsFeatureRequest::OrderBy orderBy;

  for ( int i = 0; i < mOrderByTableWidget->rowCount(); ++i )
  {
    QString expressionText = static_cast<QgsFieldExpressionWidget *>( mOrderByTableWidget->cellWidget( i, 0 ) )->currentText();
    bool isExpression = static_cast<QgsFieldExpressionWidget *>( mOrderByTableWidget->cellWidget( i, 0 ) )->isExpression();

    if ( ! expressionText.isEmpty() )
    {
      bool asc = true;
      int ascIndex = static_cast<QComboBox *>( mOrderByTableWidget->cellWidget( i, 1 ) )->currentIndex();
      if ( ascIndex == 1 )
        asc = false;

      bool nullsFirst = false;
      int nullsFirstIndex = static_cast<QComboBox *>( mOrderByTableWidget->cellWidget( i, 2 ) )->currentIndex();
      if ( nullsFirstIndex == 1 )
        nullsFirst = true;

      if ( !isExpression )
        expressionText = QgsExpression::quotedColumnRef( expressionText );

      QgsFeatureRequest::OrderByClause orderByClause( expressionText, asc, nullsFirst );

      orderBy << orderByClause;
    }
  }

  return orderBy;
}

void QgsOrderByDialog::onExpressionChanged( const QString &expression )
{
  // The sender() is the field widget which is the cell widget of the first column
  int row;
  for ( row = 0; row < mOrderByTableWidget->rowCount(); ++row )
  {
    if ( mOrderByTableWidget->cellWidget( row, 0 ) == sender() )
    {
      break;
    }
  }

  if ( expression.isEmpty() && row != mOrderByTableWidget->rowCount() - 1 )
  {
    mOrderByTableWidget->removeRow( row );
  }
  else if ( !expression.isEmpty() && row == mOrderByTableWidget->rowCount() - 1 )
  {
    mOrderByTableWidget->insertRow( mOrderByTableWidget->rowCount() );
    setRow( row + 1, QgsFeatureRequest::OrderByClause( QLatin1String( "" ) ) );
  }
}

void QgsOrderByDialog::setRow( int row, const QgsFeatureRequest::OrderByClause &orderByClause )
{
  QgsFieldExpressionWidget *fieldExpression = new QgsFieldExpressionWidget();
  fieldExpression->setLayer( mLayer );
  fieldExpression->setField( orderByClause.expression().expression() );
  connect( fieldExpression, static_cast < void ( QgsFieldExpressionWidget::* )( const QString & ) >( &QgsFieldExpressionWidget::fieldChanged ), this, &QgsOrderByDialog::onExpressionChanged );

  QComboBox *ascComboBox = new QComboBox();
  ascComboBox->addItem( tr( "Ascending" ) );
  ascComboBox->addItem( tr( "Descending" ) );
  ascComboBox->setCurrentIndex( orderByClause.ascending() ? 0 : 1 );

  QComboBox *nullsFirstComboBox = new QComboBox();
  nullsFirstComboBox->addItem( tr( "NULLs last" ) );
  nullsFirstComboBox->addItem( tr( "NULLs first" ) );
  nullsFirstComboBox->setCurrentIndex( orderByClause.nullsFirst() ? 1 : 0 );

  mOrderByTableWidget->setCellWidget( row, 0, fieldExpression );
  mOrderByTableWidget->setCellWidget( row, 1, ascComboBox );
  mOrderByTableWidget->setCellWidget( row, 2, nullsFirstComboBox );
}

bool QgsOrderByDialog::eventFilter( QObject *obj, QEvent *e )
{
  Q_UNUSED( obj )
  Q_ASSERT( obj == mOrderByTableWidget );

  if ( e->type() == QEvent::KeyPress )
  {
    QKeyEvent *keyEvent = static_cast<QKeyEvent *>( e );

    if ( keyEvent->key() == Qt::Key_Delete )
    {
      if ( mOrderByTableWidget->currentRow() != mOrderByTableWidget->rowCount() - 1 )
        mOrderByTableWidget->removeRow( mOrderByTableWidget->currentRow() );
      return true;
    }
  }

  return false;
}

void QgsOrderByDialog::showHelp()
{
  QgsHelp::openHelp( QStringLiteral( "working_with_vector/vector_properties.html#layer-rendering" ) );
}