/*
    Copyright (c) 2008-2019 Jan W. Krieger (<jan@jkrieger.de>)

    

    This software is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License (LGPL) as published by
    the Free Software Foundation, either version 2.1 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License (LGPL) for more details.

    You should have received a copy of the GNU Lesser General Public License (LGPL)
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/



#include <QString>
#include <QPainter>
#include <QPair>
#include "jkqtplotter/jkqtpgraphsscatter.h"
#include "jkqtplotter/jkqtpgraphsbasestylingmixins.h"
#include "jkqtplottertools/jkqtp_imexport.h"
#include <functional>

#ifndef jkqtpgraphsevaluatedfunction_H
#define jkqtpgraphsevaluatedfunction_H




/*! \brief type of functions that may be plottet
    \ingroup jkqtplotter_functiongraphs

    This is the type of functions \f$ y=f(x, \vec{p}) \f$ that may be plottet by JKQTPXFunctionLineGraph
    and JKQTPYFunctionLineGraph. It is possible to supply parameters \f$ \vec{p} \f$ to the function that
    influence its result. Parameters are given as a pointer to some memory location. The function has to
    know on its own how to interpret these.
*/
typedef std::function<double(double, void*)> jkqtpPlotFunctionType;

/*! \brief simplified type of functions (without parameters) that may be plottet
    \ingroup jkqtplotter_functiongraphs

    This is the type of functions \f$ y=f(x) \f$ that may be plottet by JKQTPXFunctionLineGraph
    and JKQTPYFunctionLineGraph.
*/
typedef std::function<double(double)> jkqtpSimplePlotFunctionType;


/*! \brief This implements line plots where the data is taken from a user supplied function \f$ y=f(x) \f$
    \ingroup jkqtplotter_functiongraphs

    This class implements an intelligent plotting algorithm for functions. It starts by sampling
    the function at minSamples positions. Then each function interval is bisected recursively if
    necessary. To do so the function is evaluated at the mid point and the slopes \f$ \alpha_{\mbox{left}} \f$
    and \f$ \alpha_{\mbox{right}} \f$ of the two linear segments are compared. the midpoint is added
    to the graph if \f[ \left|\alpha_{\mbox{right}}-\alpha_{\mbox{left}}\right|>\mbox{slopeTolerance} \f]
    In addition all sampling points except minimum and maximum are beeing shifted by a random fraction their
    distance to the other points. This helps to prevent beats when sampling periodic functions.

    the following image
    \image html plot_functionplots.png
 */
class JKQTP_LIB_EXPORT JKQTPXFunctionLineGraph: public JKQTPGraph, public JKQTPGraphLineStyleMixin, public JKQTPGraphFillStyleMixin {
        Q_OBJECT
    public:

        enum SpecialFunction {
            Polynomial, /*!< \brief a polynomial \f$ f(x)=p_0+p_1x+p_2x^2+p_3x^3+... \f$ The parameters \a params have to be point to a QVector<double> and contain the parameters \f$ p_0, p_1, ... \f$ */
            Line=Polynomial, /*!< \brief a polynomial \f$ f(x)=p_0+p_1x \f$ The parameters \a params have to be point to a QVector<double> and contain the parameters \f$ p_0, p_1, ... \f$ */
            Exponential,  /*!< \brief an exponential function \f$ f(x)=p_0+p_1\cdot\exp(x/p_2) \f$ or \f$ f(x)=p_0\cdot\exp(x/p_1) \f$ (depending on the number of parameters). The parameters \a params have to be point to a QVector<double> and contain the parameters \f$ p_0, p_1, ... \f$ */
            PowerLaw,  /*!< \brief an exponential function \f$ f(x)=p_0+p_1\cdot x^{p_3} \f$ or \f$ f(x)=p_0\cdot x^{p_1} \f$ or \f$ f(x)= x^{p_0} \f$ (depending on the number of parameters) The parameters \a params have to be point to a QVector<double> and contain the parameters \f$ p_0, p_1, ... \f$ */

            UserFunction,  /*!< \brief no special function but the function is provided by the user */
        };

        /** \brief class constructor */
        JKQTPXFunctionLineGraph(JKQTBasePlotter* parent=nullptr);

        /** \brief class constructor */
        JKQTPXFunctionLineGraph(JKQTPlotter* parent);

        /** \brief class destructor */
        virtual ~JKQTPXFunctionLineGraph() override;

        /** \brief plots the graph to the plotter object specified as parent */
        virtual void draw(JKQTPEnhancedPainter& painter) override;
        /** \brief plots a key marker inside the specified rectangle \a rect */
        virtual void drawKeyMarker(JKQTPEnhancedPainter& painter, QRectF& rect) override;
        /** \brief returns the color to be used for the key label */
        virtual QColor getKeyLabelColor() const override;

        /** \brief get the maximum and minimum x-value of the graph
         *
         * This functions returns 0 for both parameters, so that the plotter uses the predefined
         * min and max values.
         */
        virtual bool getXMinMax(double& minx, double& maxx, double& smallestGreaterZero) override;
        /** \brief get the maximum and minimum y-value of the graph
         */
        virtual bool getYMinMax(double& miny, double& maxy, double& smallestGreaterZero) override;

        /** \brief clear the data sampled from the function. */
        void clearData();

        /*! \brief set color, fill color and error color at the same time */
        void setColor(QColor c);

        /*! \copydoc drawLine
            \see see drawLine for details */ 
        void setDrawLine(bool __value);
        /*! \copydoc drawLine
            \see see drawLine for details */ 
        bool getDrawLine() const;

        /** \brief sets the property plotFunction ( \copybrief plotFunction ) to the specified \a __value.
         *
         *  \details Description of the parameter plotFunction is: <BLOCKQUOTE>\copydoc plotFunction </BLOCKQUOTE>
         * \see plotFunction for more information */
        virtual void setPlotFunctionFunctor (jkqtpPlotFunctionType && __value);
        /** \brief sets the property plotFunction ( \copybrief plotFunction ) to the specified \a __value.
         *
         *  \details Description of the parameter plotFunction is: <BLOCKQUOTE>\copydoc plotFunction </BLOCKQUOTE>
         * \see plotFunction for more information */
        virtual void setPlotFunctionFunctor (const jkqtpPlotFunctionType & __value);
        /** \brief sets the property plotFunction ( \copybrief plotFunction ) to the specified \a __value.
         *
         *  \details Description of the parameter plotFunction is: <BLOCKQUOTE>\copydoc plotFunction </BLOCKQUOTE>
         * \see plotFunction for more information */
        virtual void setPlotFunctionFunctor (jkqtpSimplePlotFunctionType && __value);
        /** \brief sets the property plotFunction ( \copybrief plotFunction ) to the specified \a __value.
         *
         *  \details Description of the parameter plotFunction is: <BLOCKQUOTE>\copydoc plotFunction </BLOCKQUOTE>
         * \see plotFunction for more information */
        virtual void setPlotFunctionFunctor (const jkqtpSimplePlotFunctionType & __value);
        /*! \brief returns the property plotFunction ( \copybrief plotFunction ). \see plotFunction for more information */ \
        virtual jkqtpPlotFunctionType getPlotFunctionFunctor () const;
        /*! \brief returns the property simplePlotFunction ( \copybrief simplePlotFunction ). \see simplePlotFunction for more information */ \
        virtual jkqtpSimplePlotFunctionType getSimplePlotFunction () const;

        /*! \copydoc params
            \see see params for details */ 
        virtual void setParams(void* __value);
        /*! \copydoc params
            \see see params for details */ 
        void* getParams() const;
        /** \brief sets the params as a pointer to an internal COPY of the given vector (not the data of the vector, as then the size would be unknown!!!) */
        virtual void setParams(const QVector<double>& params);
        /** \brief sets the params from a copy of the given array of length \a N */
        void setCopiedParams(const double* params, int N);
        /** \brief set an internal parameter vector as function parameters, initialized with {p1} */
        void setParamsV(double p1);
        /** \brief set an internal parameter vector as function parameters, initialized with {p1,p2} */
        void setParamsV(double p1, double p2);
        /** \brief set an internal parameter vector as function parameters, initialized with {p1,p2,p3} */
        void setParamsV(double p1, double p2, double p3);
        /** \brief set an internal parameter vector as function parameters, initialized with {p1,p2,p3,p4} */
        void setParamsV(double p1, double p2, double p3, double p4);
        /** \brief set an internal parameter vector as function parameters, initialized with {p1,p2,p3,p4,p5} */
        void setParamsV(double p1, double p2, double p3, double p4, double p5);

        /** \brief returns the currently set internal parameter vector */
        QVector<double> getInternalParams() const;
        /** \brief returns the currently set internal parameter vector */
        QVector<double> getInternalErrorParams() const;
        /*! \copydoc minSamples
            \see see minSamples for details */ 
        void setMinSamples(const unsigned int & __value);
        /*! \copydoc minSamples
            \see see minSamples for details */ 
        unsigned int getMinSamples() const;
        /*! \copydoc maxRefinementDegree
            \see see maxRefinementDegree for details */ 
        void setMaxRefinementDegree(const unsigned int & __value);
        /*! \copydoc maxRefinementDegree
            \see see maxRefinementDegree for details */ 
        unsigned int getMaxRefinementDegree() const;
        /*! \copydoc slopeTolerance
            \see see slopeTolerance for details */ 
        void setSlopeTolerance(double __value);
        /*! \copydoc slopeTolerance
            \see see slopeTolerance for details */ 
        double getSlopeTolerance() const;
        /*! \copydoc minPixelPerSample
            \see see minPixelPerSample for details */ 
        void setMinPixelPerSample(double __value);
        /*! \copydoc minPixelPerSample
            \see see minPixelPerSample for details */ 
        double getMinPixelPerSample() const;
        /*! \copydoc plotRefinement
            \see see plotRefinement for details */ 
        void setPlotRefinement(bool __value);
        /*! \copydoc plotRefinement
            \see see plotRefinement for details */ 
        bool getPlotRefinement() const;
        /*! \copydoc displaySamplePoints
            \see see displaySamplePoints for details */ 
        void setDisplaySamplePoints(bool __value);
        /*! \copydoc displaySamplePoints
            \see see displaySamplePoints for details */ 
        bool getDisplaySamplePoints() const;
        /*! \copydoc drawErrorPolygons
            \see see drawErrorPolygons for details */ 
        void setDrawErrorPolygons(bool __value);
        /*! \copydoc drawErrorPolygons
            \see see drawErrorPolygons for details */ 
        bool getDrawErrorPolygons() const;
        /*! \copydoc drawErrorLines
            \see see drawErrorLines for details */ 
        void setDrawErrorLines(bool __value);
        /*! \copydoc drawErrorLines
            \see see drawErrorLines for details */ 
        bool getDrawErrorLines() const;
        /** \brief sets the property errorPlotFunction ( \copybrief errorPlotFunction ) to the specified \a __value.
         *
         *  \details Description of the parameter errorPlotFunction is: <BLOCKQUOTE>\copydoc errorPlotFunction </BLOCKQUOTE>
         * \see errorPlotFunction for more information */
        virtual void setErrorPlotFunction (jkqtpPlotFunctionType && __value);
        /** \brief sets the property errorPlotFunction ( \copybrief errorPlotFunction ) to the specified \a __value.
         *
         *  \details Description of the parameter errorPlotFunction is: <BLOCKQUOTE>\copydoc errorPlotFunction </BLOCKQUOTE>
         * \see errorPlotFunction for more information */
        virtual void setErrorPlotFunction (const jkqtpPlotFunctionType & __value);
        /*! \brief returns the property errorPlotFunction ( \copybrief errorPlotFunction ). \see errorPlotFunction for more information */ \
        virtual jkqtpPlotFunctionType getErrorPlotFunction () const;
        /** \brief sets the property errorPlotFunction ( \copybrief errorPlotFunction ) to the specified \a __value.
         *
         *  \details Description of the parameter errorPlotFunction is: <BLOCKQUOTE>\copydoc errorPlotFunction </BLOCKQUOTE>
         * \see errorPlotFunction for more information */
        virtual void setErrorPlotFunction (jkqtpSimplePlotFunctionType && __value);
        /** \brief sets the property errorPlotFunction ( \copybrief errorPlotFunction ) to the specified \a __value.
         *
         *  \details Description of the parameter errorPlotFunction is: <BLOCKQUOTE>\copydoc errorPlotFunction </BLOCKQUOTE>
         * \see errorPlotFunction for more information */
        virtual void setErrorPlotFunction (const jkqtpSimplePlotFunctionType & __value);
        /*! \brief returns the property errorSimplePlotFunction ( \copybrief errorSimplePlotFunction ). \see errorSimplePlotFunction for more information */ \
        virtual jkqtpSimplePlotFunctionType getErrorSimplePlotFunction () const;
        /*! \copydoc errorParams
            \see see errorParams for details */ 
        virtual void setErrorParams(void* __value);
        /*! \copydoc errorParams
            \see see errorParams for details */ 
        void *getErrorParams() const;
        /** \brief sets the error params as a pointer to an internal COPY of the given vector (not the data of the vector, as then the size would be unknown!!!) */
        void setErrorParams(const QVector<double>& errorParams);

        /*! \copydoc parameterColumn
            \see see parameterColumn for details */ 
        void setParameterColumn(int __value);
        /*! \copydoc parameterColumn
            \see see parameterColumn for details */ 
        int getParameterColumn() const;
        /*! \brief sets the property parameterColumn ( \copybrief parameterColumn ) to the specified \a __value, where __value is static_cast'ed from size_t to int. 
            \details Description of the parameter parameterColumn is:  <BLOCKQUOTE>\copydoc parameterColumn </BLOCKQUOTE> 
            \see parameterColumn for more information */ 
        void setParameterColumn (size_t __value);
        /*! \copydoc errorParameterColumn
            \see see errorParameterColumn for details */ 
        void setErrorParameterColumn(int __value);
        /*! \copydoc errorParameterColumn
            \see see errorParameterColumn for details */ 
        int getErrorParameterColumn() const;
        /*! \brief sets the property errorParameterColumn ( \copybrief errorParameterColumn ) to the specified \a __value, where __value is static_cast'ed from size_t to int. 
            \details Description of the parameter errorParameterColumn is:  <BLOCKQUOTE>\copydoc errorParameterColumn </BLOCKQUOTE> 
            \see errorParameterColumn for more information */ 
        void setErrorParameterColumn (size_t __value);

        /*! \copydoc errorColor
            \see see errorColor for details */ 
        inline virtual void setErrorColor(const QColor & __value)  
        {
            this->errorColor = __value;
        } 
        /*! \copydoc errorColor
            \see see errorColor for details */ 
        inline virtual QColor getErrorColor() const  
        {
            return this->errorColor; 
        }
        /*! \copydoc errorFillColor
            \see see errorFillColor for details */ 
        inline virtual void setErrorFillColor(const QColor & __value)  
        {
            this->errorFillColor = __value;
        } 
        /*! \copydoc errorFillColor
            \see see errorFillColor for details */ 
        inline virtual QColor getErrorFillColor() const  
        {
            return this->errorFillColor; 
        }
        /*! \copydoc errorFillStyle
            \see see errorFillStyle for details */ 
        inline virtual void setErrorFillStyle(const Qt::BrushStyle & __value)  
        {
            this->errorFillStyle = __value;
        } 
        /*! \copydoc errorFillStyle
            \see see errorFillStyle for details */ 
        inline virtual Qt::BrushStyle getErrorFillStyle() const  
        {
            return this->errorFillStyle; 
        }
        /*! \copydoc errorStyle
            \see see errorStyle for details */ 
        inline virtual void setErrorStyle(const Qt::PenStyle & __value)  
        {
            this->errorStyle = __value;
        } 
        /*! \copydoc errorStyle
            \see see errorStyle for details */ 
        inline virtual Qt::PenStyle getErrorStyle() const  
        {
            return this->errorStyle; 
        }
        /*! \copydoc errorLineWidth
            \see see errorLineWidth for details */ 
        inline virtual void setErrorLineWidth(double __value)
        {
            this->errorLineWidth = __value;
        } 
        /*! \copydoc errorLineWidth
            \see see errorLineWidth for details */ 
        inline virtual double getErrorLineWidth() const  
        {
            return this->errorLineWidth; 
        }

        /** \copydoc JKQTPGraph::usesColumn() */
        virtual bool usesColumn(int c) const override;


        /** \brief sets function to the given special function */
        void setSpecialFunction(SpecialFunction function);
        /** \brief returns, which special function is set (or if any is set) */
        SpecialFunction getFunctionType() const;
    protected:


        struct doublePair {
            double x;
            double f;
            doublePair* next;
        };
        /** \brief a linked list holding the datapoints \f$ \left(x, y=f(x, \vec{p})\right) \f$ to be plotted */
        doublePair* data;

        /** \brief fill the data array with data from the function plotFunction */
        virtual void createPlotData( bool collectParams=true);

        virtual void collectParameters();
        /** \brief refine datapoints on the function graph between two evaluations \a a and \a b */
        void refine(doublePair* a, doublePair* b, unsigned int degree=0);

        /** \brief if set, the values from this datatsore column are used for the parameters \c p1 , \c p2 , \c p3 , ...  of the plot function */
        int parameterColumn;
        /** \brief if set, the values from this datatsore column are used for the parameters \c p1 , \c p2 , \c p3 , ...  of the error plot function */
        int errorParameterColumn;

        /** \brief indicates whether to draw a line or not */
        bool drawLine;
        /** \brief indicates whether to fill the space between the curve and the x-axis */
        bool fillCurve;
        /** \brief the function to be plotted */
        jkqtpPlotFunctionType plotFunction;
        /** \brief a simple function to be plotted, simplified form without parameters */
        jkqtpSimplePlotFunctionType simplePlotFunction;
        /** \brief indicates whether a special function is set (and if so, which one), or a user-supplied function */
        SpecialFunction functionType;
        /** \brief pointer to the parameters supplied to the plotting funtion */
        void* params;
        /** \brief the minimum number of points to evaluate the function at */
        unsigned int minSamples;
        /** \brief the maximum number of recursive refinement steps
         *
         * each step bisects the interval \f$ [a, b] \f$ into two halfes. So the maximum number
         * of points plotted at all are thus:
         *  \f[ \mbox{minSamples} \cdot 2^{\mbox{maxRefinementDegree}} \f]
         */
        unsigned int maxRefinementDegree;
        /** \brief the tolerance for the difference of two subsequent slopes */
        double slopeTolerance;
        /** \brief create one sample at least every \a minPixelPerSample pixels */
        double minPixelPerSample;
        /** \brief switch on or off [default: on] the plot refinement algorithm */
        bool plotRefinement;
        /** \brief if true [default: off] display the points where the function has been sampled */
        bool displaySamplePoints;
        /** \brief indicates whether an error polygon should be drawn */
        bool drawErrorPolygons;
        /** \brief indicates whether error lines should be drawn */
        bool drawErrorLines;
        /** \brief this function calculates the error at a given position */
        jkqtpPlotFunctionType errorPlotFunction;
        /** \brief this function calculates the error at a given position, simplified form without parameters */
        jkqtpSimplePlotFunctionType errorSimplePlotFunction;
        /** \brief parameters for errorFunction */
        void* errorParams;


        /** \brief color of the error graph */
        QColor errorColor;
        /** \brief color of the error graph fill */
        QColor errorFillColor;
        /** \brief linestyle of the error graph lines */
        Qt::PenStyle errorStyle;
        /** \brief width (pixels) of the error graph */
        double errorLineWidth;
        /** \brief fill style, if the error curve should be filled */
        Qt::BrushStyle errorFillStyle;


        QBrush getErrorBrush(JKQTPEnhancedPainter& painter) const;
        QPen getErrorLinePen(JKQTPEnhancedPainter &painter) const;

        QVector<double> iparams, ierrorparams;
};

/*! \brief This implements line plots where the data is taken from a user supplied function \f$ x=f(y) \f$
    \ingroup jkqtplotter_functiongraphs

 */
class JKQTP_LIB_EXPORT JKQTPYFunctionLineGraph: public JKQTPXFunctionLineGraph {
        Q_OBJECT
    public:
        /** \brief class constructor */
        JKQTPYFunctionLineGraph(JKQTBasePlotter* parent=nullptr);
        /** \brief class constructor */
        JKQTPYFunctionLineGraph(JKQTPlotter* parent);

        /** \brief plots the graph to the plotter object specified as parent */
        virtual void draw(JKQTPEnhancedPainter& painter) override;
    protected:

        /** \brief fill the data array with data from the function plotFunction */
        virtual void createPlotData( bool collectParams=true) override;

};




#endif // jkqtpgraphsevaluatedfunction_H