/***************************************************************************
                              qgstininterpolator.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 QGSTININTERPOLATOR_H
#define QGSTININTERPOLATOR_H

#include "qgsinterpolator.h"
#include <QString>
#include "qgis_analysis.h"

class QgsFeatureSink;
class Triangulation;
class TriangleInterpolator;
class QgsFeature;
class QgsFeedback;
class QgsFields;

/**
 * \ingroup analysis
 *  Interpolation in a triangular irregular network
 * \since QGIS 3.0
*/
class ANALYSIS_EXPORT QgsTinInterpolator: public QgsInterpolator
{
  public:

    //! Indicates the type of interpolation to be performed
    enum TinInterpolation
    {
      Linear, //!< Linear interpolation
      CloughTocher, //!< Clough-Tocher interpolation
    };

    /**
     * Constructor for QgsTinInterpolator.
     * The \a feedback object specifies an optional QgsFeedback object for progress reports and cancelation support.
     * Ownership of \a feedback is not transferred and callers must ensure that it exists for the lifetime of this object.
     */
    QgsTinInterpolator( const QList<QgsInterpolator::LayerData> &inputData, TinInterpolation interpolation = Linear, QgsFeedback *feedback = nullptr );
    ~QgsTinInterpolator() override;

    int interpolatePoint( double x, double y, double &result SIP_OUT, QgsFeedback *feedback ) override;

    /**
     * Returns the fields output by features when saving the triangulation.
     * These fields should be used when creating
     * a suitable feature sink for setTriangulationSink()
     * \see setTriangulationSink()
     * \since QGIS 3.0
     */
    static QgsFields triangulationFields();

    /**
     * Sets the optional \a sink for saving the triangulation features.
     *
     * The sink must be setup to accept LineString features, with fields matching
     * those returned by triangulationFields().
     *
     * \see triangulationFields()
     *  \since QGIS 3.0
     */
    void setTriangulationSink( QgsFeatureSink *sink );

  private:
    Triangulation *mTriangulation = nullptr;
    TriangleInterpolator *mTriangleInterpolator = nullptr;
    bool mIsInitialized;
    QgsFeedback *mFeedback = nullptr;

    //! Feature sink for triangulation
    QgsFeatureSink *mTriangulationSink = nullptr;
    //! Type of interpolation
    TinInterpolation mInterpolation;

    //! Create dual edge triangulation
    void initialize();

    /**
     * Inserts the vertices of a feature into the triangulation
     * \param f the feature
     * \param source source for feature values to interpolate
     * \param attr interpolation attribute index (if zCoord is false)
     * \param type point/structure line, break line
     * \returns 0 in case of success, -1 if the feature could not be inserted because of numerical problems
    */
    int insertData( const QgsFeature &f, QgsInterpolator::ValueSource source, int attr, SourceType type );

    int addPointsFromGeometry( const QgsGeometry &g, ValueSource source, double attributeValue );
};

#endif
