/*********************************************************
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.                      
**********************************************************/

var fpArray = new Array();

function preMain() {

    setPriceStudy(false);
    setStudyTitle("Relative Vigor Index");
    setCursorLabelName("RVI", 0);
    setCursorLabelName("Signal", 0);
    setDefaultBarFgColor(Color.blue, 0);
    setPlotType(PLOTTYPE_LINE,0);
    setDefaultBarThickness(1,0);
    setDefaultBarFgColor(Color.red, 1);
    setPlotType(PLOTTYPE_LINE,1);
    setDefaultBarThickness(1,1);
    askForInput();

    var x=0;
    fpArray[x] = new FunctionParameter("Length", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setName("Length");
        setLowerLimit(1);		
        setDefault(10);
    }
    fpArray[x] = new FunctionParameter("Symbol", FunctionParameter.STRING);
    with(fpArray[x++]){
        setDefault();
	}
	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 bInit = false;
var xTemp = null;
var xRVI = null;
var xRVISig = null;

function main(Length,Symbol,Interval,Params){

    if(bInit==false){
        if(Symbol == null) Symbol = getSymbol();
        if(Interval == null) Interval = getInterval();
        var vSymbol = Symbol+","+Interval;
        xTemp = efsInternal("calcRVI",Length,sym(vSymbol));
        xRVI = getSeries(xTemp,0)
        xRVISig = getSeries(xTemp,1)
        setShowTitleParameters(eval(Params));
        bInit=true;
    }
    
    return new Array (xRVI,xRVISig);
}

var xInit = false;
var xOpen = null;
var xHigh = null;
var xLow = null;
var xClose = null;
var RVI = 0;
var RVI_1 = 0;
var RVI_2 = 0;
var RVI_3 = 0;

function calcRVI(Length){ 
    if(getBarState()==BARSTATE_ALLBARS){
        RVI_3 = 0;
        RVI_2 = 0;
        RVI_1 = 0;
        RVI = 0;
    }
    if(xInit==false){
        xOpen = open();
        xHigh = high();
        xLow = low();
        xClose = close();
        xInit = true;
    }
    if(xClose.getValue(-Length)==null) return;        
    var SumNum = 0;
    var SumDen = 0;
    for (var i=0; i<Length; i++){
        SumNum += ((xClose.getValue(-i)-xOpen.getValue(-i))+2*(xClose.getValue(-i-1)-xOpen.getValue(-i-1))+2*(xClose.getValue(-i-2)-xOpen.getValue(-i-2))+(xClose.getValue(-i-3)-xOpen.getValue(-i-3)))/6;
        SumDen += ((xHigh.getValue(-i)-xLow.getValue(-i))+2*(xHigh.getValue(-i-1)-xLow.getValue(-i-1))+2*(xHigh.getValue(-i-2)-xLow.getValue(-i-2))+ (xHigh.getValue(-i-3)-xLow.getValue(-i-3)))/6;
    }
    if(getBarState()==BARSTATE_NEWBAR){
        RVI_3 = RVI_2;
        RVI_2 = RVI_1;
        RVI_1 = RVI;
    }
    RVI = SumNum/SumDen;
    var RVISig = (RVI+2*RVI_1+2*RVI_2+RVI_3)/6;
    return new Array (RVISig, RVI);
}