/***************************************************************************
    qgsmaphittest.h
    ---------------------
    begin                : September 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 QGSMAPHITTEST_H
#define QGSMAPHITTEST_H

#include "qgsmapsettings.h"
#include "qgsgeometry.h"

#include <QSet>

class QgsRenderContext;
class QgsSymbolV2;
class QgsVectorLayer;
class QgsExpression;

/**
 * Class that runs a hit test with given map settings. Based on the hit test it returns which symbols
 * will be visible on the map - this is useful for content based legend.
 *
 * @note added in 2.6
 */
class CORE_EXPORT QgsMapHitTest
{
  public:
    //! Maps an expression string to a layer id
    typedef QMap<QString, QString> LayerFilterExpression;

    //! @param settings Map settings used to evaluate symbols
    //! @param polygon Polygon geometry to refine the hit test
    //! @param layerFilterExpression Expression string for each layer id to evaluate in order to refine the symbol selection
    QgsMapHitTest( const QgsMapSettings& settings, const QgsGeometry& polygon = QgsGeometry(), const LayerFilterExpression& layerFilterExpression = LayerFilterExpression() );

    //! Constructor version used with only expressions to filter symbols (no extent or polygon intersection)
    QgsMapHitTest( const QgsMapSettings& settings, const LayerFilterExpression& layerFilterExpression );

    //! Runs the map hit test
    void run();

    /** Tests whether a symbol is visible for a specified layer.
     * @param symbol symbol to find
     * @param layer vector layer
     * @note added in QGIS 2.12
     * @see legendKeyVisible()
     */
    bool symbolVisible( QgsSymbolV2* symbol, QgsVectorLayer* layer ) const;

    /** Tests whether a given legend key is visible for a specified layer.
     * @param ruleKey legend rule key
     * @param layer vector layer
     * @note added in QGIS 2.14
     * @see symbolVisible()
     */
    bool legendKeyVisible( const QString& ruleKey, QgsVectorLayer* layer ) const;

  protected:

    //! @note not available in Python bindings
    typedef QSet<QString> SymbolV2Set;

    //! @note not available in Python bindings
    typedef QMap<QgsVectorLayer*, SymbolV2Set> HitTest;

    /** Runs test for visible symbols within a layer
     * @param vl vector layer
     * @param usedSymbols set for storage of visible symbols
     * @param usedSymbolsRuleKey set of storage of visible legend rule keys
     * @param context render context
     * @note added in QGIS 2.12
     * @note not available in Python bindings
     */
    void runHitTestLayer( QgsVectorLayer* vl, SymbolV2Set& usedSymbols, SymbolV2Set& usedSymbolsRuleKey, QgsRenderContext& context );

    //! The initial map settings
    QgsMapSettings mSettings;

    //! The hit test
    HitTest mHitTest;

    //! The hit test, using legend rule keys
    HitTest mHitTestRuleKey;

    //! List of expression filter for each layer
    LayerFilterExpression mLayerFilterExpression;

    //! Polygon used for filtering items. May be empty
    QgsGeometry mPolygon;

    //! Whether to use only expressions during the filtering
    bool mOnlyExpressions;
};

#endif // QGSMAPHITTEST_H
