/*
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 * and open the template in the editor.
 */

package mn;


import com.bestcode.mathparser.IMathParser;
import com.bestcode.mathparser.MathParserFactory;
import java.util.Observable;
import org.jfree.data.function.Function2D;
import org.jfree.data.general.DatasetUtilities;
import org.jfree.data.xy.XYDataset;






/**
 *
 * @author viroos
 */

public class Function  extends Observable implements Function2D{
    IMathParser parser;
    int samplesNumber;
    XYDataset samples;
    


    class Pair{
        private double low;
        private double hi;
        public void setLow(double l){
            low=l;
        }
        public void setHi(double h){
            hi=h;
        }
        public double getLow(){
            return low;
        }
        public double getHi(){
            return hi;
        }

    }
    private Pair range;
    private Pair markers;

    public void setFunction(String f){
        parser=MathParserFactory.create();
        parser.setExpression(f);
    }
    public void setRange(double l, double h){
        range.setLow(l);
        range.setHi(h);
        samplesNumber=(int)(range.hi-range.low)*constants.density;
        if(samplesNumber<constants.x_width*constants.density)
            samplesNumber=(int)constants.x_width*constants.density;
        samples=DatasetUtilities.sampleFunction2D(this, range.low, range.hi, samplesNumber, "f(x)");
        
        setChanged();
        notifyObservers(samples);
        notifyObservers(range);
        
    }
    public double getRangeMin(){
        return range.low;
    }
    public double getRangeMax(){
        return range.hi;
    }
    public void setRangeMin(double m){
        setRange(m,range.hi);
    }
    public void setRangeMax(double m){
        setRange(range.low,m);
    }
    public double getValue(double x) {
            parser.setX(x);
            double y;
            try {
            y=parser.getValue();
            }
            catch (Exception ex){
            y=0;
            }
            return y;
    }
    Function(double l,double h, String f){
        range=new Pair();
        markers=new Pair();
        setFunction(f);
        range.low=l;
        range.hi=h;
        samplesNumber=(int)(range.hi-range.low)*constants.density;
        samples=DatasetUtilities.sampleFunction2D(this, range.low, range.hi, samplesNumber, "f(x)");
    }
    Function(String f){
        range=new Pair();
        markers=new Pair();
        setFunction(f);
        range.low=-constants.x_width/2;
        range.hi=constants.x_width/2;
        samplesNumber=(int)constants.x_width*constants.density;
        samples=DatasetUtilities.sampleFunction2D(this, range.low, range.hi, samplesNumber, "f(x)");
    }
    @Override
    public String toString(){
        String s=new String();
        for(int i=0;i<samples.getItemCount(0);++i){
            s+="f("+samples.getXValue(0, i)+")="+samples.getYValue(0, i)+"\n";
        }
        return s;
    }
}