/********************************************************************
Title:		Hull MA Script for eSignal 7.x
By:         Chris D. Kryza (Divergence Software, Inc.)
Email:      ckryza@verizon.net; ckryza@sr-analyst.com
Incept:     01/13/2006
Version:    1.0.0

=====================================================================
Fix History:

01/13/2006 -   	Initial Release
1.0.0

=====================================================================
Project Description:   

Hull Moving Average.

Dislaimer: For educational purposes only! Obviously, no guarantees 
whatsoever and use at your own risk.

**********************************************************************/


//External Variables
var nBarCounter			= 0;
var nStudy1				= null;
var nStudy2				= null;
var nPlot				= null;
var nPlot_1				= null;
var aFPArray			= new Array();
var bInitialized		= false;

//== PreMain function required by eSignal to set things up
function preMain() {
var x;

    setPriceStudy(true);
    setStudyTitle("Hull MA");
    setCursorLabelName("HullMA", 0);
    setDefaultBarFgColor( Color.blue, 0 );
    setShowTitleParameters( false );

    
    //initialize formula parameters
	x=0; 
	aFPArray[x] = new FunctionParameter( "Period", FunctionParameter.NUMBER);
	with( aFPArray[x] ) {
		setName( "Hull MA Period" );
		setLowerLimit( 2 );
		setUpperLimit( 9999 );
		setDefault( 15 );
	}  
	x++;
	aFPArray[x] = new FunctionParameter( "Price", FunctionParameter.STRING);
	with( aFPArray[x] ) {
		setName( "Hull MA Price Source" );
		addOption( "close" );
		addOption( "open" );		
		addOption( "high" );
		addOption( "low" );
		addOption( "hl2" );
		addOption( "hlc3" );
		addOption( "ohlc4" );
		setDefault( "close" );
	}  	
	x++; 
	aFPArray[x] = new FunctionParameter( "UpColor", FunctionParameter.COLOR);
	with( aFPArray[x] ) {
		setName( "Up Color" );
		setDefault( Color.green );
	}      
	x++; 
	aFPArray[x] = new FunctionParameter( "DnColor", FunctionParameter.COLOR);
	with( aFPArray[x] ) {
		setName( "Dn Color" );
		setDefault( Color.red );
	} 
	x++; 
	aFPArray[x] = new FunctionParameter( "Type", FunctionParameter.STRING);
	with( aFPArray[x] ) {
		setName( "Plot Type" );
		addOption( "Solid" );
		addOption( "Dot" );
		addOption( "Dash" );
		addOption( "DashDot" );
		addOption( "DashDotDot" );
		setDefault( "Solid" );
	}      	  	     
	x++;
	aFPArray[x] = new FunctionParameter( "Thickness", FunctionParameter.NUMBER);
	with( aFPArray[x] ) {
		setName( "Plot Thickness" );
		setLowerLimit( 1 );
		setUpperLimit( 10 );
		setDefault( 3 );
	}  

}

//== Main processing function
function main( Period, Price, UpColor, DnColor, Type, Thickness ) {
var x;
	
	//script is initializing
    if ( getBarState() == BARSTATE_ALLBARS ) {
        return null;
    }

	if ( bInitialized == false ) {
	
		setDefaultBarThickness( Math.round( Thickness ), 0 );
		setDefaultBarStyle( eval( "PS_"+Type.toUpperCase() ), 0 );

		nSrc = eval( Price )();		
		nStudy1 = efsInternal( "custSeriesFunc", Period, nSrc );
		nStudy2 = wma( Math.floor( Math.sqrt( Period ) ), nStudy1 );
		
		
		bInitialized = true;
	}

	//called on each new bar
	if ( getBarState() == BARSTATE_NEWBAR ) {
		
		nPlot_1 = nPlot;
		
		nBarCounter++;
	}


	nPlot = nStudy2.getValue(0);
	
	if ( nPlot>nPlot_1 ) {
		setBarFgColor( UpColor, 0 );	
		setDefaultBarFgColor( UpColor, 0 );
	}
	if ( nPlot<nPlot_1 ) {
		setBarFgColor( DnColor, 0 );
		setDefaultBarFgColor( DnColor, 0 );
	}
	

	
	return( nPlot );

}


/*************************************************
             SUPPORT FUNCTIONS                    
**************************************************/    

var _study1 = null;
var _study2 = null;
var bInit = false;
function custSeriesFunc( _len, _src ) {

	if ( bInit==false ) {
		_study1 = wma( Math.floor( _len/2 ), _src );
		_study2 = wma( _len, _src );
		bInit = true;
	}
	
	return( 2 * _study1.getValue(0)-_study2.getValue(0) );
	
}
    
//== gID function assigns unique identifier to graphic/text routines
function gID() {
    grID ++;
    return( grID );
}