package temple.utils 
{
	import flash.display.Stage;
	import flash.events.Event;
	import flash.events.MouseEvent;
	import flash.text.TextField;

	/**
	 * This class prevends the mouse-wheel scrolling the page in the browser if the page is larger than the browsers window.
	 * 
	 * Just call
	 * 
	 * MouseWheelBlocker.init(this.stage);
	 * 
	 * In the document class
	 * 
	 * @author Thijs Broerse
	 */
	public class MouseWheelBlocker 
	{
		private static var _initialized:Boolean;
		private static var _stage:Stage;
		private static var _textfield:TextField;
		private static var _enabled:Boolean;

		public static function init(stage:Stage):void
		{
			if(stage == null) throw new Error("stage can not be null");
			
			if(MouseWheelBlocker._initialized) return;
			
			MouseWheelBlocker._stage = stage;
			MouseWheelBlocker._textfield = new TextField();
			MouseWheelBlocker._textfield.width = MouseWheelBlocker._textfield.height = 100;
			MouseWheelBlocker._textfield.visible = false;
			MouseWheelBlocker._textfield.alpha = 0;
			MouseWheelBlocker._textfield.text = "";
			// add lots of new lines into the textfield
			for(var i:int = 0; i<100; i++)
			{
				MouseWheelBlocker._textfield.appendText("\n");
			}
			MouseWheelBlocker._textfield.addEventListener(Event.SCROLL, MouseWheelBlocker.handleScroll);
			MouseWheelBlocker._stage.addChild(MouseWheelBlocker._textfield);
			
			MouseWheelBlocker.enable();
		}
		
		public static function get enabled():Boolean
		{
			return MouseWheelBlocker._enabled;
		}

		public static function set enabled(value:Boolean):void
		{
			if(value)
			{
				MouseWheelBlocker.enable();
			}
			else
			{
				MouseWheelBlocker.disable();
			}
		}

		public static function enable():void
		{
			if(!MouseWheelBlocker._enabled)
			{
				MouseWheelBlocker._stage.addEventListener(MouseEvent.MOUSE_WHEEL, MouseWheelBlocker.handleMouseWheel);
				MouseWheelBlocker._stage.addEventListener(MouseEvent.MOUSE_MOVE, MouseWheelBlocker.handleMouseMove);
				MouseWheelBlocker._enabled = true;
			}
		}

		public static function disable():void
		{
			if(MouseWheelBlocker._enabled)
			{
				MouseWheelBlocker._stage.removeEventListener(MouseEvent.MOUSE_WHEEL, MouseWheelBlocker.handleMouseWheel);
				MouseWheelBlocker._stage.removeEventListener(MouseEvent.MOUSE_MOVE, MouseWheelBlocker.handleMouseMove);
				MouseWheelBlocker._enabled = false;
			}
		}
		
		private static function handleMouseWheel(event:MouseEvent):void
		{
			MouseWheelBlocker._textfield.x = MouseWheelBlocker._stage.mouseX- MouseWheelBlocker._textfield.width * .5;
			MouseWheelBlocker._textfield.y = MouseWheelBlocker._stage.mouseY- MouseWheelBlocker._textfield.height * .5;
			MouseWheelBlocker._textfield.visible = true;
			new FrameDelay(MouseWheelBlocker.hide);
		}

		private static function handleMouseMove(event:MouseEvent):void
		{
			MouseWheelBlocker._textfield.x = MouseWheelBlocker._stage.mouseX- MouseWheelBlocker._textfield.width * .5;
			MouseWheelBlocker._textfield.y = MouseWheelBlocker._stage.mouseY- MouseWheelBlocker._textfield.height * .5;
		}

		private static function hide():void
		{
			MouseWheelBlocker._textfield.visible = false;
		}
		
		private static function handleScroll(event:Event):void
		{
			MouseWheelBlocker._textfield.scrollV = MouseWheelBlocker._textfield.maxScrollV * .5;
		}
	}
}