/*********************************************************
Alexis C. Montenegro © January 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("Chaikin Money Flow");
    setCursorLabelName("CMF");
    setDefaultBarFgColor(Color.blue);
    setDefaultBarThickness(1);
	setPlotType(PLOTTYPE_LINE);
	var x=0;
    fpArray[x] = new FunctionParameter("Length", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(1);		
        setDefault(21);
    }
    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("Hist", FunctionParameter.BOOLEAN);
	with(fpArray[x++]){
        setName("Plot as Histogram");
        setDefault(false);
    }
    fpArray[x] = new FunctionParameter("Params", FunctionParameter.BOOLEAN);
	with(fpArray[x++]){
        setName("Show Parameters");
        setDefault(false);
    }
}

var bInit = false;
var xCMF  = null;

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

    if(bInit == false){
        if(Symbol == null) Symbol = getSymbol();
        if(Interval == null) Interval = getInterval();
        var vSymbol = Symbol+","+Interval;
        xCMF = getSeries(efsInternal("calcCMF",Length,(sym(vSymbol))));
        if(Hist == true) setPlotType(PLOTTYPE_HISTOGRAM);
        addBand(0, PS_SOLID, 1, Color.black,"0");
        setShowTitleParameters(eval(Params));
        bInit = true;
    }
    return xCMF;
}

var xInit = false;
var xClose = null;
var xHigh  = null;
var xLow   = null;
var xVol   = null;

function calcCMF(length,source){
    if(xInit == false){
        xClose = close();
        xHigh  = high();
        xLow   = low();
        xVol   = volume();
        xInit = true;
    }
    if(getCurrentBarCount()<length) return;
    var Sum = 0;
	var SumVol = 0;
	for(var i=0; i<length; i++) {
        if (xHigh.getValue(-i)-xLow.getValue(-i) > 0) {
            Sum += (((xClose.getValue(-i)-xLow.getValue(-i))-(xHigh.getValue(-i)-xClose.getValue(-i)))/(xHigh.getValue(-i)-xLow.getValue(-i)))*xVol.getValue(-i);
        }
		SumVol += xVol.getValue(-i);
	}
	if(SumVol==0) return;
	return (Sum/SumVol);
}