/***********************************************************
Description	: This Indicator plots the Trend Detection Index
Provided By	: TS Support, LLC for eSignal                   
Modified by : Alexis C. Montenegro 08/04/2006               
              - converted to efs2 syntax                    
              - added multiple time frame/symbol capability 
              - added moving average                        
 ***********************************************************/

var fpArray = new Array();

function preMain(){
	setStudyTitle("Trend Detection Index");
	setCursorLabelName("TDI",0);
	setCursorLabelName("MAofTDI",1);
	setDefaultBarFgColor(Color.blue, 0);
    setDefaultBarFgColor(Color.red, 1);
    setDefaultBarThickness(1,0);
    setDefaultBarThickness(1,1);
	var x=0;
    fpArray[x] = new FunctionParameter("Length", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(1);		
        setDefault(12);
    }
	fpArray[x] = new FunctionParameter("Source", FunctionParameter.STRING);
	with(fpArray[x++]){
        addOption("open"); 
        addOption("high");
        addOption("low");
        addOption("close");
        addOption("hl2");
        addOption("hlc3");
        addOption("ohlc4"); 
        setDefault("close"); 
    }
    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("MAType", FunctionParameter.STRING);
    with(fpArray[x++]){
        addOption("sma");
        addOption("ema");
        addOption("wma");
        setDefault("sma");
    }
	fpArray[x] = new FunctionParameter("MALength", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(1);		
        setDefault(3);
    }
    fpArray[x] = new FunctionParameter("LineColor1", FunctionParameter.COLOR);
	with(fpArray[x++]){
        setName("Color1");
        setDefault(Color.blue);
    }
	fpArray[x] = new FunctionParameter("LineColor2", FunctionParameter.COLOR);
	with(fpArray[x++]){
        setName("Color2");
        setDefault(Color.red);
    }
	fpArray[x] = new FunctionParameter("Params", FunctionParameter.BOOLEAN);
	with(fpArray[x++]){
        setName("Show Parameters");
        setDefault(false);
    }
}

var bInit = false;
var xTDI  = null;
var xMATDI = null;

function main(Length,Source,Symbol,Interval,MAType,MALength,LineColor1,LineColor2,Params){
    if(bInit==false){
        if(Symbol == null) Symbol = getSymbol();
        if(Interval == null) Interval = getInterval();
        var vSymbol = Symbol+","+Interval;
        xTDI = getSeries(efsInternal("calcTDI", Length,eval(Source)(vSymbol)));
        xMATDI = getSeries(eval(MAType)(MALength,xTDI));
        setDefaultBarFgColor(LineColor1,0);
        setDefaultBarFgColor(LineColor2,1);
        addBand(0,PS_SOLID,1,Color.lightgrey,"0");
        setShowTitleParameters(eval(Params));
        bInit = true;
    }
    return new Array (xTDI, xMATDI);
}

xMOM = null;

function calcTDI(period, source){
	if (xMOM == null) xMOM = mom(period,source);
	var MomSum     = 0;
    var MomSumAbs  = 0; 
    var MomAbsSum  = 0;
    var MomAbsSum2 = 0;
    for (var i=0; i<period-1; i++){
        MomSum += xMOM.getValue(-i);
    }
	MomSumAbs = Math.abs(MomSum);
	for (var i=0; i<period-1; i++){
        MomAbsSum += Math.abs(xMOM.getValue(-i));
    }
	for (var i=0; i<period*2-1; i++){
        MomAbsSum2 += Math.abs(xMOM.getValue(-i));
    }
	var ret = MomSumAbs - (MomAbsSum2 - MomAbsSum);	
	return ret;
}