/***************************************************************************
  qgsterrainentity.h
  --------------------------------------
  Date                 : July 2017
  Copyright            : (C) 2017 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 QGSTERRAINENTITY_H
#define QGSTERRAINENTITY_H

///@cond PRIVATE

//
//  W A R N I N G
//  -------------
//
// This file is not part of the QGIS API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//

#define SIP_NO_FILE

#include "qgschunkedentity.h"
#include "qgschunkqueuejob.h"

#include <memory>


namespace Qt3DCore
{
  class QTransform;
}

class Qgs3DMapSettings;
class QgsTerrainTextureGenerator;
class QgsCoordinateTransform;
class QgsMapLayer;
class QgsTerrainGenerator;
class TerrainMapUpdateJobFactory;

/**
 * \ingroup qgis_3d
 * \brief Controller for terrain - decides on what terrain tiles to show based on camera position
 * and creates them using map's terrain tile generator.
 */
class QgsTerrainEntity : public QgsChunkedEntity
{
    Q_OBJECT
  public:
    //! Constructs terrain entity. The argument maxLevel determines how deep the tree of tiles will be
    explicit QgsTerrainEntity( Qgs3DMapSettings *map, Qt3DCore::QNode *parent = nullptr );

    ~QgsTerrainEntity() override;

    //! Returns pointer to the generator of textures for terrain tiles
    QgsTerrainTextureGenerator *textureGenerator() { return mTextureGenerator; }

    //! Returns the transform attached to the terrain entity
    Qt3DCore::QTransform *transform() const { return mTerrainTransform; }
    //! Returns the terrain elevation offset (adjusts the terrain position up and down)
    float terrainElevationOffset() const;

    QVector<QgsRayCastingUtils::RayHit> rayIntersection( const QgsRayCastingUtils::Ray3D &ray, const QgsRayCastingUtils::RayCastContext &context ) const override;

  private slots:
    void onShowBoundingBoxesChanged();
    void invalidateMapImages();
    void onLayersChanged();
    void onTerrainElevationOffsetChanged();

  private:
    void connectToLayersRepaintRequest();

    QgsTerrainTextureGenerator *mTextureGenerator = nullptr;
    Qt3DCore::QTransform *mTerrainTransform = nullptr;

    std::unique_ptr<TerrainMapUpdateJobFactory> mUpdateJobFactory;

    //! layers that are currently being used for map rendering (and thus being watched for renderer updates)
    QList<QgsMapLayer *> mLayers;
};


//! Handles asynchronous updates of terrain's map images when layers change
class TerrainMapUpdateJob : public QgsChunkQueueJob
{
    Q_OBJECT
  public:
    TerrainMapUpdateJob( QgsTerrainTextureGenerator *textureGenerator, QgsChunkNode *mNode );

    void cancel() override;

  private slots:
    void onTileReady( int jobId, const QImage &image );

  private:
    QgsTerrainTextureGenerator *mTextureGenerator = nullptr;
    int mJobId;
};

/// @endcond

#endif // QGSTERRAINENTITY_H
