/*
    Copyright (c) 2008-2018 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 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/>.
*/



/**
 * \defgroup jkqtplotter_elements Plot Elements
 * \ingroup jkqtplotter
 * \defgroup jkqtplotter_plots Graphs
 * \ingroup jkqtplotter_elements
 */

/** \file jkqtpgraphs.h
  * \ingroup jkqtplotter
  */

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

#ifndef jkqtpgraphsevaluatedfunction_H
#define jkqtpgraphsevaluatedfunction_H




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

    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_plots

    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_plots

    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 LIB_EXPORT JKQTPxFunctionLineGraph: public JKQTPgraph {
        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();

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

        /** \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);
        /** \brief get the maximum and minimum y-value of the graph
         */
        virtual bool getYMinMax(double& miny, double& maxy, double& smallestGreaterZero);

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

        JKQTPGET_SET_MACRO(QColor, color)
        JKQTPGET_SET_MACRO(QColor, fillColor)
        JKQTPGET_SET_MACRO(Qt::BrushStyle, fillStyle)
        JKQTPGET_SET_MACRO(Qt::PenStyle, style)
        JKQTPGET_SET_MACRO(double, lineWidth)
        JKQTPGET_SET_MACRO(bool, drawLine)

        /** \brief sets the property plotFunction to the specified \a __value.
         *
         *  \details Description of the parameter varname is: <CENTER>\copybrief plotFunction.</CENTER>
         * \see plotFunction for more information */
        virtual void set_plotFunction (jkqtpPlotFunctionType && __value);
        /** \brief sets the property plotFunction to the specified \a __value.
         *
         *  \details Description of the parameter varname is: <CENTER>\copybrief plotFunction.</CENTER>
         * \see plotFunction for more information */
        virtual void set_plotFunction (const jkqtpPlotFunctionType & __value);
        /** \brief sets the property plotFunction to the specified \a __value.
         *
         *  \details Description of the parameter plotFunction is: <CENTER>\copybrief plotFunction.</CENTER>
         * \see plotFunction for more information */
        virtual void set_plotFunction (jkqtpSimplePlotFunctionType && __value);
        /** \brief sets the property plotFunction to the specified \a __value.
         *
         *  \details Description of the parameter plotFunction is: <CENTER>\copybrief plotFunction.</CENTER>
         * \see plotFunction for more information */
        virtual void set_plotFunction (const jkqtpSimplePlotFunctionType & __value);
        /** \brief returns the property plotFunction. \see plotFunction for more information */ \
        virtual jkqtpPlotFunctionType get_plotFunction () const;
        /** \brief returns the property simplePlotFunction. \see simplePlotFunction for more information */ \
        virtual jkqtpSimplePlotFunctionType get_simplePlotFunction () const;

        JKQTPGET_SET_MACRO_I(void*, params, clearData())
        /** \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!!!) */
        void set_params(const QVector<double>& params);
        /** \brief sets the params from a copy of the given array of length \a N */
        void set_copiedParams(const double* params, int N);
        /** \brief set an internal parameter vector as function parameters, initialized with {p1} */
        void set_paramsV(double p1);
        /** \brief set an internal parameter vector as function parameters, initialized with {p1,p2} */
        void set_paramsV(double p1, double p2);
        /** \brief set an internal parameter vector as function parameters, initialized with {p1,p2,p3} */
        void set_paramsV(double p1, double p2, double p3);
        /** \brief set an internal parameter vector as function parameters, initialized with {p1,p2,p3,p4} */
        void set_paramsV(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 set_paramsV(double p1, double p2, double p3, double p4, double p5);

        /** \brief returns the currently set internal parameter vector */
        QVector<double> get_internalParams() const;
        /** \brief returns the currently set internal parameter vector */
        QVector<double> get_internalErrorParams() const;
        JKQTPGET_SET_MACRO(unsigned int, minSamples)
        JKQTPGET_SET_MACRO(unsigned int, maxRefinementDegree)
        JKQTPGET_SET_MACRO(double, slopeTolerance)
        JKQTPGET_SET_MACRO(double, minPixelPerSample)
        JKQTPGET_SET_MACRO(bool, plotRefinement)
        JKQTPGET_SET_MACRO(bool, displaySamplePoints)
        JKQTPGET_SET_MACRO(bool, drawErrorPolygons)
        JKQTPGET_SET_MACRO(bool, drawErrorLines)
        /** \brief sets the property errorPlotFunction to the specified \a __value.
         *
         *  \details Description of the parameter varname is: <CENTER>\copybrief errorPlotFunction.</CENTER>
         * \see errorPlotFunction for more information */
        virtual void set_errorPlotFunction (jkqtpPlotFunctionType && __value);
        /** \brief sets the property errorPlotFunction to the specified \a __value.
         *
         *  \details Description of the parameter varname is: <CENTER>\copybrief errorPlotFunction.</CENTER>
         * \see errorPlotFunction for more information */
        virtual void set_errorPlotFunction (const jkqtpPlotFunctionType & __value);
        /** \brief returns the property varname. \see varname for more information */ \
        virtual jkqtpPlotFunctionType get_errorPlotFunction () const;
        /** \brief sets the property errorPlotFunction to the specified \a __value.
         *
         *  \details Description of the parameter varname is: <CENTER>\copybrief errorPlotFunction.</CENTER>
         * \see errorPlotFunction for more information */
        virtual void set_errorPlotFunction (jkqtpSimplePlotFunctionType && __value);
        /** \brief sets the property errorPlotFunction to the specified \a __value.
         *
         *  \details Description of the parameter varname is: <CENTER>\copybrief errorPlotFunction.</CENTER>
         * \see errorPlotFunction for more information */
        virtual void set_errorPlotFunction (const jkqtpSimplePlotFunctionType & __value);
        /** \brief returns the property varname. \see varname for more information */ \
        virtual jkqtpSimplePlotFunctionType get_errorSimplePlotFunction () const;
        JKQTPGET_SET_MACRO(void*, errorParams)
        /** \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 set_errorParams(const QVector<double>& errorParams);

        JKQTPGET_SET_MACRO(int, parameterColumn)
        JKQTPSET_CAST_MACRO(size_t, int, parameterColumn)
        JKQTPGET_SET_MACRO(int, errorParameterColumn)
        JKQTPSET_CAST_MACRO(size_t, int, errorParameterColumn)

        JKQTPGET_SET_MACRO(QColor, errorColor)
        JKQTPGET_SET_MACRO(QColor, errorFillColor)
        JKQTPGET_SET_MACRO(Qt::BrushStyle, errorFillStyle)
        JKQTPGET_SET_MACRO(Qt::PenStyle, errorStyle)
        JKQTPGET_SET_MACRO(double, errorLineWidth)

        /** \copydoc JKQTPgraph::usesColumn() */
        virtual bool usesColumn(int c);


        /** \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:
        /** \brief which plot style to use from the parent plotter (via JKQtPlotterBase::getPlotStyle() and JKQtPlotterBase::getNextStyle() ) */
        int parentPlotStyle;

        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 color of the graph */
        QColor color;
        /** \brief color of the graph fill */
        QColor fillColor;
        /** \brief linestyle of the graph lines */
        Qt::PenStyle style;
        /** \brief width (pixels) of the graph */
        double lineWidth;
        /** \brief fill style, if the curve should be filled */
        Qt::BrushStyle fillStyle;
        /** \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 getBrush(JKQTPEnhancedPainter& painter) const;
        QPen getLinePen(JKQTPEnhancedPainter& painter) const;

        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_plots

 */
class LIB_EXPORT JKQTPyFunctionLineGraph: public JKQTPxFunctionLineGraph {
        Q_OBJECT
    public:
        /** \brief class constructor */
        inline JKQTPyFunctionLineGraph(JKQtBasePlotter* parent=nullptr):JKQTPxFunctionLineGraph(parent) {}
        /** \brief class constructor */
        inline JKQTPyFunctionLineGraph(JKQtPlotter* parent):JKQTPxFunctionLineGraph(parent) {}

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

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

};




#endif // jkqtpgraphsevaluatedfunction_H