if( typeof com == "undefined" ) com = {};
if( typeof com.rozengain == "undefined" ) com.rozengain = {};
if( typeof com.rozengain.silverlight == "undefined" ) com.rozengain.silverlight = {};

com.rozengain.silverlight.whirl = {
	strokeColor : "#990000",
	strokeThickness : 1,
	control : null,
	rootElement : null,
	numSides : 3,
	
	/**
	 * Silverlight initialisation
	 */
	createSilverlight: function()
	{
		Silverlight.createObjectEx({
			source: "xml/Whirl.xaml",
			parentElement: document.getElementById("SilverlightControlHost"),
			id: "SilverlightControl",
			properties: {
				width: "100%",
				height: "100%",
				version: "1.0"
			},
			events: {
				onLoad: com.rozengain.silverlight.whirl.handleLoad
			}
		});
	},
	
	/**
	 * Onload event handler
	 */
	handleLoad: function( cntrl, usrContext, rootElem )
	{
		var self = com.rozengain.silverlight.whirl;
		
		self.control = cntrl;
		self.rootElement = rootElem;
		
		self.drawWhirl();
	},
	
	/**
	 * Draws a whirl shape with n sides
	 * 
	 * @param {Object} numSides
	 */
	drawWhirl: function()
	{
		var x = [];
		var y = [];
		var startTime = ( new Date() ).getTime();
		var scaleFactor = 275;
		var self = com.rozengain.silverlight.whirl;
		var centerX = self.rootElement.width * .5;
		var centerY = self.rootElement.height * .5;
		var rotAngle = .05;
		var numSides = self.numSides;
		var numLinesDrawn = 0;
		var rotAngleSin = Math.sin( rotAngle );
		var rotAngleCos = Math.cos( rotAngle );
		var a = Math.PI * ( 1 - 2 / numSides );
		var c = Math.sin( a ) / ( rotAngleSin + Math.sin( a + rotAngle ));
		
		self.rootElement.children.clear();		
		
		for( var k = 0; k <= numSides; k++ )
		{
			var t = ( 2 * k + 1 ) * Math.PI / numSides;
			x[ k ] = Math.sin( t );
			y[ k ] = Math.cos( t );
		}
		
		for (var n = 1; n < 64; n++) 
		{
			var previousPoint = {
				x: ( x[ 0 ] * scaleFactor ) + centerX,
				y: ( y[ 0 ] * scaleFactor ) + centerY
			};
			
			for( var l = 0; l <= numSides; l++ )
			{
				var newPoint = {
					x: ( x[ l ] * scaleFactor ) + centerX,
					y: ( y[ l ] * scaleFactor ) + centerY				
				};
				self.drawLine( previousPoint.x, previousPoint.y, newPoint.x, newPoint.y );
				numLinesDrawn++;
				previousPoint = newPoint;		
			}
			
			for( var m = 0; m <= numSides; m++ )
			{
				var z = x[ m ];
				x[ m ] = ( x[ m ] * rotAngleCos - y[ m ] * rotAngleSin ) * c;
				y[ m ] = ( z * rotAngleSin + y[ m ] * rotAngleCos ) * c;
			}
		}
		
		document.getElementById( "divInfo" ).innerHTML = 
			"<strong>Number of sides:</strong> " + numSides + "<br>" +
			"<strong>Number of lines drawn:</strong> " + numLinesDrawn + "<br>" +
			"<strong>Time:</strong> " + ( ( new Date() ).getTime() - startTime ) + " milliseconds";
	},
	
	/**
	 * Draw a line between the given points
	 * 
	 * @param {Object} control
	 * @param {Object} rootElement
	 * @param {Object} x1
	 * @param {Object} y1
	 * @param {Object} x2
	 * @param {Object} y2
	 */
	drawLine : function( x1, y1, x2, y2 )
	{
		var self = com.rozengain.silverlight.whirl;
		var line = self.control.content.CreateFromXaml( '<Line X1="'+x1+'" Y1="'+y1+'" X2="'+x2+'" Y2="'+y2+'" Stroke="'+self.strokeColor+'" StrokeThickness="'+self.strokeThickness+'"/> ');
		self.rootElement.children.add(line);
	},
	
	/**
	 * Decreases the number of sides
	 */
	decreaseNumSides : function()
	{
		var self = com.rozengain.silverlight.whirl;
		if ( self.numSides <= 3 )
		{
			alert( "The minimum number of sides is 3" );
		}
		else
		{
			self.numSides--;
			self.drawWhirl();
		} 
	},
	
	/**
	 * Increases the number of sides
	 */
	increaseNumSides : function()
	{
		var self = com.rozengain.silverlight.whirl;
		if( self.numSides >= 25 )
		{
			alert( "The maximum number of sides is 25" );
		}
		else
		{
			self.numSides++;
			self.drawWhirl();
		} 
	}
};