qgsexpressiontreeview.h

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/***************************************************************************
    qgsexpressiontreeview.h
     --------------------------------------
    Date                 : march 2020 - quarantine day 9
    Copyright            : (C) 2020 by Denis Rouzaud
    Email                : [email protected]
 ***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef QGSEXPRESSIONTREEVIEW_H
#define QGSEXPRESSIONTREEVIEW_H
 
#include "qgis_gui.h"
#include "qgis_sip.h"
#include "qgsexpressioncontext.h"
#include "qgsproject.h"
 
#include <QPointer>
#include <QSortFilterProxyModel>
#include <QStandardItemModel>
#include <QTreeView>
 
class QgsVectorLayer;
 

class GUI_EXPORT QgsExpressionItem : public QStandardItem
{
  public:
    enum ItemType
    {
      Header,
      Field,
      ExpressionNode
    };
 
    QgsExpressionItem( const QString &label, const QString &expressionText, const QString &helpText, QgsExpressionItem::ItemType itemType = ExpressionNode )
      : QStandardItem( label )
    {
      mExpressionText = expressionText;
      mHelpText = helpText;
      mType = itemType;
      setData( itemType, ITEM_TYPE_ROLE );
    }
 
    QgsExpressionItem( const QString &label, const QString &expressionText, QgsExpressionItem::ItemType itemType = ExpressionNode )
      : QStandardItem( label )
    {
      mExpressionText = expressionText;
      mType = itemType;
      setData( itemType, ITEM_TYPE_ROLE );
    }
 
    QString getExpressionText() const { return mExpressionText; }

    QString getHelpText() const { return mHelpText; }

    void setHelpText( const QString &helpText ) { mHelpText = helpText; }

    QgsExpressionItem::ItemType getItemType() const { return mType; }

    static const int CUSTOM_SORT_ROLE = Qt::UserRole + 1;
    static const int ITEM_TYPE_ROLE = Qt::UserRole + 2;
    static const int SEARCH_TAGS_ROLE = Qt::UserRole + 3;
    static const int ITEM_NAME_ROLE = Qt::UserRole + 4;
    static const int LAYER_ID_ROLE = Qt::UserRole + 5;
 
  private:
    QString mExpressionText;
    QString mHelpText;
    QgsExpressionItem::ItemType mType;
};
 

class GUI_EXPORT QgsExpressionItemSearchProxy : public QSortFilterProxyModel
{
    Q_OBJECT
 
  public:
    QgsExpressionItemSearchProxy();
 
    bool filterAcceptsRow( int source_row, const QModelIndex &source_parent ) const override;

    void setFilterString( const QString &string );
 
  protected:
    bool lessThan( const QModelIndex &left, const QModelIndex &right ) const override;
 
  private:
    QString mFilterString;
};

class GUI_EXPORT QgsExpressionTreeView : public QTreeView
{
    Q_OBJECT
  public:
    class MenuProvider
    {
      public:
        explicit MenuProvider() = default;
        virtual ~MenuProvider() = default;

        virtual QMenu *createContextMenu( QgsExpressionItem *item ) SIP_FACTORY
        {
          Q_UNUSED( item )
          return nullptr;
        }
    };

    QgsExpressionTreeView( QWidget *parent = nullptr );

    void setLayer( QgsVectorLayer *layer );

    void loadFieldNames( const QgsFields &fields );

    void setExpressionContext( const QgsExpressionContext &context );

    QgsExpressionContext expressionContext() const { return mExpressionContext; }

    QgsProject *project();

    void setProject( QgsProject *project );

    void setMenuProvider( MenuProvider *provider );

    void refresh();

    QgsExpressionItem *currentItem() const;

    Q_DECL_DEPRECATED QStandardItemModel *model() SIP_SKIP; // TODO remove QGIS 4

    void loadRecent( const QString &collection = QStringLiteral( "generic" ) );

    void saveToRecent( const QString &expressionText, const QString &collection = "generic" );

    void saveToUserExpressions( const QString &label, const QString &expression, const QString &helpText );

    void removeFromUserExpressions( const QString &label );

    void loadUserExpressions();

    const QList<QgsExpressionItem *> findExpressions( const QString &label );

    QStringList userExpressionLabels() const SIP_SKIP;

    QJsonDocument exportUserExpressions();

    void loadExpressionsFromJson( const QJsonDocument &expressionsDocument );
 
  signals:
    void expressionItemDoubleClicked( const QString &text );

    void currentExpressionItemChanged( QgsExpressionItem *item );
 
  public slots:
    void setSearchText( const QString &text );
 
 
  private slots:
    void onDoubleClicked( const QModelIndex &index );
 
    void showContextMenu( QPoint pt );
 
    void currentItemChanged( const QModelIndex &index, const QModelIndex & );
 
  private:
    void updateFunctionTree();

    QgsExpressionItem *registerItem( const QString &group, const QString &label, const QString &expressionText, const QString &helpText = QString(), QgsExpressionItem::ItemType type = QgsExpressionItem::ExpressionNode, bool highlightedItem = false, int sortOrder = 1, const QIcon &icon = QIcon(), const QStringList &tags = QStringList(), const QString &name = QString() );

    void registerItemForAllGroups( const QStringList &groups, const QString &label, const QString &expressionText, const QString &helpText = QString(), QgsExpressionItem::ItemType type = QgsExpressionItem::ExpressionNode, bool highlightedItem = false, int sortOrder = 1, const QStringList &tags = QStringList() );
 
    void loadExpressionContext();
    void loadRelations();
    void loadLayers();
    void loadLayerFields( QgsVectorLayer *layer, QgsExpressionItem *parentItem );
    void loadFieldNames();

    void showMessageBoxConfirmExpressionOverwrite( bool &isApplyToAll, bool &isOkToOverwrite, const QString &label, const QString &oldExpression, const QString &newExpression );
 
 
    std::unique_ptr<QStandardItemModel> mModel;
    std::unique_ptr<QgsExpressionItemSearchProxy> mProxyModel;
    QMap<QString, QgsExpressionItem *> mExpressionGroups;
 
    MenuProvider *mMenuProvider = nullptr;
 
    QgsVectorLayer *mLayer = nullptr;
    QPointer<QgsProject> mProject;
    QgsExpressionContext mExpressionContext;
    QString mRecentKey;
 
    QStringList mUserExpressionLabels;
};
 
#endif // QGSEXPRESSIONTREEVIEW_H