/*********************************************************
Alexis C. Montenegro © June 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 amFunctions.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("Chande Adaptive Stochastic");
    setCursorLabelName("Stoch",0);
    setCursorLabelName("StochMA",1);
    setDefaultBarFgColor(Color.blue,0);
    setDefaultBarFgColor(Color.red,1);
    var x=0;
    fpArray[x] = new FunctionParameter("MaxLen", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setName("Max Length");
        setLowerLimit(1);		
        setDefault(28);
    }
	fpArray[x] = new FunctionParameter("MinLen", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setName("Min Length");
        setLowerLimit(1);		
        setDefault(7);
    }
    fpArray[x] = new FunctionParameter("StdDevLen", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setName("Std Dev Length");
        setLowerLimit(1);		
        setDefault(20);
    }
    fpArray[x] = new FunctionParameter("AvgLen", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setName("Average Length");
        setLowerLimit(1);		
        setDefault(3);
    }
    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("Upper", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(0);
        setDefault(80); 
    }
	fpArray[x] = new FunctionParameter("Lower", FunctionParameter.NUMBER);
	with(fpArray[x++]){
        setLowerLimit(0);
        setDefault(20); 
	}
	fpArray[x] = new FunctionParameter("Params", FunctionParameter.BOOLEAN);
	with(fpArray[x++]){
        setName("Show Parameters");
        setDefault(false);
    }
}

var xStoch = null;
var xStochMA = null;
var bInit = false;

function main(MaxLen,MinLen,StdDevLen,AvgLen,Symbol,Interval,Upper,Lower,Params){
    if(bInit==false){
        if(Symbol == null) Symbol = getSymbol();
        if(Interval == null) Interval = getInterval();
        var vSymbol = Symbol+","+Interval;
        xStoch = getSeries(efsInternal("calctemp",MaxLen,MinLen,StdDevLen,sym(vSymbol)));
        xStochMA = getSeries(ema(AvgLen,xStoch));
        addBand( Upper, PS_SOLID, 1, Color.black,"Upper");
        addBand( Lower, PS_SOLID, 1, Color.black,"Lower");
        bInit = true;
    }
    return new Array (xStoch, xStochMA);
}

var amLib = addLibrary("amFunctions.efsLib");
var xStdDev = null;
var xHHStdDev = null;
var xLLStdDev = null;
var xInit = false;

function calctemp(_maxLen,_minLen,_stddevLen,_source){
    if(xInit==false){
        xStdDev = amLib.amStdDev(_stddevLen);
        xHHStdDev = upperDonchian(_stddevLen, xStdDev);
        xLLStdDev = lowerDonchian(_stddevLen, xStdDev);
        xInit = true;
    }
    var nStdDev = xStdDev.getValue(0);
    var nHHStdDev = xHHStdDev.getValue(0);
    var nLLStdDev = xLLStdDev.getValue(0);
    if(nStdDev==null || nHHStdDev==null || nLLStdDev==null) return;
    if((nHHStdDev-nLLStdDev) > 0){
        var temp = ((nStdDev - nLLStdDev)/(nHHStdDev-nLLStdDev));
    }else{
        var temp = 0 ;
    }
    var adaptiveLength = parseInt(_minLen + (_maxLen-_minLen)*(1-temp)) ;
    var vHH = upperDonchian(adaptiveLength,0);
    var vLL = lowerDonchian(adaptiveLength,0);
    if(vHH==null || vLL==null) return;
    if ((vHH-vLL) > 0){
        var stoch = ((close(0) - vLL)/(vHH - vLL)) * 100 ;
    }
    return stoch;
}