package {
    import flash.display.Bitmap;
    import flash.display.BitmapData;
    import flash.display.BlendMode;
    import flash.display.Shape;
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.filters.BitmapFilterQuality;
    import flash.filters.BlurFilter;
    import flash.geom.ColorTransform;
    import flash.geom.Matrix;
    import flash.geom.Point;

    public class Beginner extends Sprite {
        /**
         * Overwrite this update function.
         * Every frame the function is invoked with two bitmaps.
         * First one contains reference to the stage bitmap.
         * Second one contains static copy of stage.
         */

        public var canvas:BitmapData;
        public var drawHere:BitmapData;
        public var mat:Matrix;

        private const FADE:ColorTransform = new ColorTransform(1, 1, 1, 1, 2, 2, 2, 0);
        private const BLUR:BlurFilter = new BlurFilter(2, 2, BitmapFilterQuality.LOW);

        private var ballCanvas:Shape = new Shape();
        private var radian:Number = 0;

        private var ballBuideX:Number = 240;
        private var ballBuideY:Number = 240;
        private var vX:Number = 0;
        private var vY:Number = 0;
        private const SPRING:Number = 0.012;
        private const FRICTION:Number = 0.89;

        private var hFlg:Number = 0;


        public function update():void {
            hFlg = -(stage.mouseX - 240) / 240;

            fadeStep();
            drawStep();
            transformStep();
            renderStep();
        }


        public function drawStep():void {
            calcPoint();
            drawBall();
            drawHere.draw(ballCanvas);
        }
        private function calcPoint():void {
            var nowX:Number = stage.mouseX;
            var nowY:Number = stage.mouseY;
            vX += (nowX - ballBuideX) * SPRING;
            vY += (nowY - ballBuideY) * SPRING;
            vX *= FRICTION;
            vY *= FRICTION;
            ballBuideX += vX;
            ballBuideY += vY;
        }
        private function drawBall():void {
            var radiusOffset:Number = Math.sqrt(vX * vX + vY * vY);
            var radius:Number = Math.min(40, 360 / radiusOffset);

            ballCanvas.graphics.clear();
            ballCanvas.graphics.beginFill(0x000000);
            ballCanvas.graphics.drawCircle(ballBuideX, ballBuideY, radius);
            ballCanvas.graphics.endFill();
        }


        public function transformStep():void {
            mat = new Matrix();
            mat.translate(-240,-240);
            mat.scale(1.005,1.005);
            mat.rotate(Math.PI / 180 * hFlg);
            mat.translate(240,240);
        }


        public function renderStep():void {
            canvas.draw(drawHere, mat);
        }


        public function fadeStep():void {
            drawHere.colorTransform(drawHere.rect, FADE);
            drawHere.applyFilter(drawHere, drawHere.rect, new Point(), BLUR);
        }


        /**
         * ---------------------------------------
         * DO NOT CHANGE FOLLOWING CODES
         * DO NOT ACCESS FOLLOWING PROPERTIES DIRECTLY
         * ---------------------------------------
        */


        private var bitmap:Bitmap;


        public function Beginner() {
            canvas = new BitmapData(480,480,false,0x000000);
            bitmap = new Bitmap(canvas);
            addChild(bitmap);
            addEventListener(Event.ENTER_FRAME, _update);
        }

        public function _update(e:Event):void{
            if(drawHere)
                drawHere.dispose();
            drawHere = canvas.clone();
            update();
        }
    }
}