/***************************************************************************
                              qgsinterpolator.h
                              ------------------------
  begin                : March 10, 2008
  copyright            : (C) 2008 by Marco Hugentobler
  email                : marco dot hugentobler at karto dot baug dot ethz dot ch
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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 QGSINTERPOLATOR_H
#define QGSINTERPOLATOR_H

#include <QVector>

class QgsVectorLayer;
class QgsGeometry;

struct ANALYSIS_EXPORT vertexData
{
  double x;
  double y;
  double z;
};

/**Interface class for interpolations. Interpolators take
the vertices of a vector layer as base data. The z-Value
can be an attribute or the z-coordinates in case of 25D types*/
class ANALYSIS_EXPORT QgsInterpolator
{
  public:
    /**Describes the type of input data*/
    enum InputType
    {
      POINTS,
      STRUCTURE_LINES,
      BREAK_LINES
    };

    /**A layer together with the information about interpolation attribute / z-coordinate interpolation and the type (point, structure line, breakline)*/
    struct LayerData
    {
      QgsVectorLayer* vectorLayer;
      bool zCoordInterpolation;
      int interpolationAttribute;
      InputType mInputType;
    };

    QgsInterpolator( const QList<LayerData>& layerData );

    virtual ~QgsInterpolator();

    /**Calculates interpolation value for map coordinates x, y
       @param x x-coordinate (in map units)
       @param y y-coordinate (in map units)
       @param result out: interpolation result
       @return 0 in case of success*/
    virtual int interpolatePoint( double x, double y, double& result ) = 0;

    /**Use a vector attribute as interpolation value*/
    void enableAttributeValueInterpolation( int attribute );

  protected:
    /**Caches the vertex and value data from the provider. All the vertex data
     will be held in virtual memory
    @return 0 in case of success*/
    int cacheBaseData();

    QVector<vertexData> mCachedBaseData;

    /**Flag that tells if the cache already has been filled*/
    bool mDataIsCached;

    //Information about the input vector layers and the attributes (or z-values) that are used for interpolation
    QList<LayerData> mLayerData;

  private:
    QgsInterpolator(); //forbidden
    /**Helper method that adds the vertices of a geometry to the mCachedBaseData
       @param geom the geometry
       @param zCoord true if the z-coordinate of the geometry is to be interpolated
       @param attributeValue the attribute value for interpolation (if not interpolated from z-coordinate)
     @return 0 in case of success*/
    int addVerticesToCache( QgsGeometry* geom, bool zCoord, double attributeValue );


};

#endif
