/***************************************************************************
  qgslayertreegroup.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 QGSLAYERTREEGROUP_H
#define QGSLAYERTREEGROUP_H

#include "qgis_core.h"
#include "qgis.h"
#include "qgslayertreenode.h"

class QgsMapLayer;
class QgsLayerTreeLayer;

/**
 * \ingroup core
 * Layer tree group node serves as a container for layers and further groups.
 *
 * Group names do not need to be unique within one tree nor within one parent.
 *
 * \since QGIS 2.4
 */
class CORE_EXPORT QgsLayerTreeGroup : public QgsLayerTreeNode
{
    Q_OBJECT
  public:

    /**
     * Constructor
     */
    QgsLayerTreeGroup( const QString &name = QString(), bool checked = true );

#ifndef SIP_RUN
    QgsLayerTreeGroup( const QgsLayerTreeGroup &other );
#endif

    /**
     * Returns the group's name.
     */
    QString name() const override;

    /**
     * Sets the group's name.
     */
    void setName( const QString &n ) override;

    /**
     * Insert a new group node with given name at specified position. The newly created node is owned by this group.
     */
    QgsLayerTreeGroup *insertGroup( int index, const QString &name );

    /**
     * Append a new group node with given name. Newly created node is owned by this group.
     */
    QgsLayerTreeGroup *addGroup( const QString &name );

    /**
     * Insert a new layer node for given map layer at specified position. The newly created node is owned by this group.
     */
    QgsLayerTreeLayer *insertLayer( int index, QgsMapLayer *layer );

    /**
     * Append a new layer node for given map layer. The newly created node is owned by this group.
     */
    QgsLayerTreeLayer *addLayer( QgsMapLayer *layer );

    /**
     * Insert existing nodes at specified position. The nodes must not have a parent yet. The nodes will be owned by this group.
     */
    void insertChildNodes( int index, const QList<QgsLayerTreeNode *> &nodes SIP_TRANSFER );

    /**
     * Insert existing node at specified position. The node must not have a parent yet. The node will be owned by this group.
     */
    void insertChildNode( int index, QgsLayerTreeNode *node SIP_TRANSFER );

    /**
     * Append an existing node. The node must not have a parent yet. The node will be owned by this group.
     */
    void addChildNode( QgsLayerTreeNode *node SIP_TRANSFER );

    /**
     * Remove a child node from this group. The node will be deleted.
     */
    void removeChildNode( QgsLayerTreeNode *node );

    /**
     * Remove map layer's node from this group. The node will be deleted.
     */
    void removeLayer( QgsMapLayer *layer );

    /**
     * Remove child nodes from index "from". The nodes will be deleted.
     */
    void removeChildren( int from, int count );

    /**
     * Remove all child group nodes without layers. The groupnodes will be deleted.
     */
    void removeChildrenGroupWithoutLayers();

    /**
     * Remove all child nodes. The nodes will be deleted.
     */
    void removeAllChildren();

    /**
     * Find layer node representing the map layer. Searches recursively the whole sub-tree.
     * \since QGIS 3.0
     */
    QgsLayerTreeLayer *findLayer( QgsMapLayer *layer ) const;

    /**
     * Find layer node representing the map layer specified by its ID. Searches recursively the whole sub-tree.
     */
    QgsLayerTreeLayer *findLayer( const QString &layerId ) const;

    /**
     * Find all layer nodes. Searches recursively the whole sub-tree.
     */
    QList<QgsLayerTreeLayer *> findLayers() const;

    /**
     * Find layer IDs used in all layer nodes. Searches recursively the whole sub-tree.
     */
    QStringList findLayerIds() const;

    /**
     * Find group node with specified name. Searches recursively the whole sub-tree.
     */
    QgsLayerTreeGroup *findGroup( const QString &name );

    /**
     * Read group (tree) from XML element <layer-tree-group> and return the newly created group (or null on error).
     * Does not resolve textual references to layers. Call resolveReferences() afterwards to do it.
     */
    static QgsLayerTreeGroup *readXml( QDomElement &element, const QgsReadWriteContext &context ) SIP_FACTORY;

    /**
     * Read group (tree) from XML element <layer-tree-group> and return the newly created group (or null on error).
     * Also resolves textual references to layers from the project (calls resolveReferences() internally).
     * \since QGIS 3.0
     */
    static QgsLayerTreeGroup *readXml( QDomElement &element, const QgsProject *project, const QgsReadWriteContext &context ) SIP_FACTORY;

    /**
     * Write group (tree) as XML element <layer-tree-group> and add it to the given parent element
     */
    void writeXml( QDomElement &parentElement, const QgsReadWriteContext &context ) override;

    /**
     * Read children from XML and append them to the group.
     * Does not resolve textual references to layers. Call resolveReferences() afterwards to do it.
     */
    void readChildrenFromXml( QDomElement &element, const QgsReadWriteContext &context );

    /**
     * Return text representation of the tree. For debugging purposes only.
     */
    QString dump() const override;

    /**
     * Return a clone of the group. The children are cloned too.
     */
    QgsLayerTreeGroup *clone() const override SIP_FACTORY;

    /**
     * Calls resolveReferences() on child tree nodes
     * \since QGIS 3.0
     */
    void resolveReferences( const QgsProject *project, bool looseMatching = false ) override;

    /**
     * Check or uncheck a node and all its children (taking into account exclusion rules)
     */
    void setItemVisibilityCheckedRecursive( bool checked ) override;

    /**
     * Return whether the group is mutually exclusive (only one child can be checked at a time)
     * \since QGIS 2.12
     */
    bool isMutuallyExclusive() const;

    /**
     * Set whether the group is mutually exclusive (only one child can be checked at a time).
     * The initial child index determines which child should be initially checked. The default value
     * of -1 will determine automatically (either first one currently checked or none)
     * \since QGIS 2.12
     */
    void setIsMutuallyExclusive( bool enabled, int initialChildIndex = -1 );

  protected slots:
    void nodeVisibilityChanged( QgsLayerTreeNode *node );

  protected:

    /**
     * Set check state of children - if mutually exclusive
     */
    void updateChildVisibilityMutuallyExclusive();

    QString mName;

    bool mChangingChildVisibility = false;

    //! Whether the group is mutually exclusive (i.e. only one child can be checked at a time)
    bool mMutuallyExclusive = false;

    /**
     * Keeps track which child has been most recently selected
     * (so if the whole group is unchecked and checked again, we know which child to check)
     */
    int mMutuallyExclusiveChildIndex = -1;

  private:

#ifdef SIP_RUN

    /**
     * Copies are not allowed
     */
    QgsLayerTreeGroup( const QgsLayerTreeGroup &other );
#endif

};


#endif // QGSLAYERTREEGROUP_H
