/*********************************************************
Alexis C. Montenegro © March 2006                         
Use and/or modify this code freely. If you redistribute it
please include this and/or any other comment blocks and a 
description of any changes you make.                      
**********************************************************/

// NOTE:                                                                          
// This efs requires Parabolic.efsLib in the FunctionLibrary folder.              
// If you do not have this file you can download it at the link below.            
// http://share.esignal.com/groupcontents.jsp?folder=Formulas-Libraries&groupid=10

var fpArray = new Array();

function preMain(){
    setPriceStudy(false);
    setStudyTitle("Parabolic Osc")
    setCursorLabelName("ParOsc");
    setPlotType(PLOTTYPE_HISTOGRAM);
    setDefaultBarThickness(2);
    var x=0;
    fpArray[x] = new FunctionParameter("AF", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(0);		
        setDefault(0.02);
    }
    fpArray[x] = new FunctionParameter("AFMax", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(0);		
        setDefault(0.2);
    }
	fpArray[x] = new FunctionParameter("Interval", FunctionParameter.STRING);
	with(fpArray[x++]){
        setDefault();
    }
    fpArray[x] = new FunctionParameter("Params", FunctionParameter.BOOLEAN);
	with(fpArray[x++]){
        setName("Show Parameters");
        setDefault(false);
    }
}

var amLib = addLibrary("Parabolic.efsLib");
var bInit = false;
var xPAROSC = null;

function main(AF,AFMax,Interval,Params){
    if(bInit==false){
        if(Interval == null) Interval = getInterval();
        var vInterval = Interval;
        xPAROSC = getSeries(efsInternal("calcOsc",AF,AFMax,inv(vInterval)));
        setShowTitleParameters(eval(Params));
        bInit=true;
    }

    return xPAROSC;
}

var xInit = false;
var xParabolic = null;
var xClose = null;

function calcOsc(_af,_afmax,_source){
    if(xInit==false){
        with ( amLib ){
            xParabolic = amParabolic(_af,_afmax);
            xClose = close()
            xInit=true;
        }
    }
    var nClose     = xClose.getValue(0);
    var nParabolic = xParabolic.getValue(-1);//see Note below
    if(nClose==null||nParabolic==null) return;
    return (nClose-nParabolic);
}
//Note:
//Replace xParabolic.getValue(-1) with xParabolic.getValue(0) 
//to plot the current value of the Parabolic study