/***************************************************************************
  qgslayertreeregistrybridge.h
  --------------------------------------
  Date                 : May 2014
  Copyright            : (C) 2014 by Martin Dobias
  Email                : wonder dot sk at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   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 QGSLAYERTREEREGISTRYBRIDGE_H
#define QGSLAYERTREEREGISTRYBRIDGE_H

#include <QObject>
#include <QStringList>
#include <QPointer>

#include "qgis_core.h"
#include "qgis_sip.h"
#include "qgis.h"
#include "qgslayertreegroup.h"

class QgsLayerTreeNode;
class QgsMapLayer;
class QgsProject;


/**
 * \ingroup core
 * \brief Listens to layer changes from a QgsProject and applies changes to a QgsLayerTree.
 *
 * When connected to a layer tree, any layers added to the map layer registry
 * will be also added to the layer tree. Similarly, map layers that are removed
 * from registry will be removed from the layer tree.
 *
 * If a layer is completely removed from the layer tree, it will be also removed
 * from the map layer registry.
 *
 */
class CORE_EXPORT QgsLayerTreeRegistryBridge : public QObject
{
    Q_OBJECT
  public:

    /**
     * A structure to define the insertion point to the layer tree.
     * This represents the current layer tree group and index where newly added map layers should be inserted into.
     * \since QGIS 3.10
     */
    struct InsertionPoint
    {
      //! Constructs an insertion point as layer tree group with its corresponding position.
      InsertionPoint( QgsLayerTreeGroup *group, int position )
        : group( group ), position( position ) {}

      QgsLayerTreeGroup *group;
      int position = 0;
    };

    //! Create the instance that synchronizes given project with a layer tree root
    explicit QgsLayerTreeRegistryBridge( QgsLayerTreeGroup *root, QgsProject *project, QObject *parent SIP_TRANSFERTHIS = nullptr );

    void setEnabled( bool enabled ) { mEnabled = enabled; }
    bool isEnabled() const { return mEnabled; }

    void setNewLayersVisible( bool enabled ) { mNewLayersVisible = enabled; }
    bool newLayersVisible() const { return mNewLayersVisible; }

    /**
     * Set where the new layers should be inserted - can be used to follow current selection.
     * By default it is root group with zero index.
     * \deprecated QGIS 3.10. Use setLayerInsertionPoint( const InsertionPoint &insertionPoint ) instead.
     */
    Q_DECL_DEPRECATED void setLayerInsertionPoint( QgsLayerTreeGroup *parentGroup, int index ) SIP_DEPRECATED;

    /**
     * Set where the new layers should be inserted - can be used to follow current selection.
     * By default it is root group with zero index.
     * \since QGIS 3.10
     */
    void setLayerInsertionPoint( const InsertionPoint &insertionPoint );

    /**
     * Returns the insertion point used to add layers to the tree
     * \since QGIS 3.42
     */
    InsertionPoint layerInsertionPoint() const;

    /**
     * Sets the insertion \a method used to add layers to the tree
     * \since QGIS 3.30
     */
    void setLayerInsertionMethod( Qgis::LayerTreeInsertionMethod method ) { mInsertionMethod = method; }

    /**
     * Returns the insertion method used to add layers to the tree
     * \since QGIS 3.30
     */
    Qgis::LayerTreeInsertionMethod layerInsertionMethod() const { return mInsertionMethod; }

  signals:

    /**
     * Tell others we have just added layers to the tree (used in QGIS to auto-select first newly added layer)
     */
    void addedLayersToLayerTree( const QList<QgsMapLayer *> &layers );

  protected slots:
    void layersAdded( const QList<QgsMapLayer *> &layers );
    void layersWillBeRemoved( const QStringList &layerIds );

    void groupWillRemoveChildren( QgsLayerTreeNode *node, int indexFrom, int indexTo );
    void groupRemovedChildren();

    void removeLayersFromRegistry( const QStringList &layerIds );

  protected:
    QgsLayerTreeGroup *mRoot = nullptr;
    QgsProject *mProject = nullptr;
    QStringList mLayerIdsForRemoval;
    bool mRegistryRemovingLayers;
    bool mEnabled;
    bool mNewLayersVisible;

    QPointer< QgsLayerTreeGroup > mInsertionPointGroup;
    int mInsertionPointPosition = 0;

    Qgis::LayerTreeInsertionMethod mInsertionMethod = Qgis::LayerTreeInsertionMethod::AboveInsertionPoint;
};

#endif // QGSLAYERTREEREGISTRYBRIDGE_H
