package
{
    import flash.display.Bitmap;
    import flash.display.BitmapData;
    import flash.display.BlendMode;
    import flash.display.DisplayObject;
    import flash.display.Sprite;
    import org.flixel.FlxG;
    import org.flixel.FlxPoint;
    import org.flixel.FlxSprite;
    import org.flixel.FlxU;

    import flash.geom.ColorTransform;
    import flash.geom.Matrix;
    import flash.geom.Point;
    import flash.geom.Rectangle;

    public class FlxHitTest
    {
        public static function complexHitTestObject( target1:FlxSprite, target2:FlxSprite,  accurracy:Number = 1 ):Boolean
        {
            var bitmap1:Bitmap = flxspriteToBitmap(target1);
            var bitmap2:Bitmap = flxspriteToBitmap(target2);

            FlxG.state.addChild(bitmap1);
            FlxG.state.addChild(bitmap2);

            var result:Boolean = complexIntersectionRectangle( bitmap1, bitmap2, accurracy ).width != 0;

            FlxG.state.removeChild(bitmap1);
            FlxG.state.removeChild(bitmap2);

            return result;
        }

        public static function intersectionRectangle( target1:DisplayObject, target2:DisplayObject ):Rectangle
        {
            // If either of the items don't have a reference to stage, then they are not in a display list
            // or if a simple hitTestObject is false, they cannot be intersecting.
            if( !target1.root || !target2.root || !target1.hitTestObject( target2 ) ) return new Rectangle();

            // Get the bounds of each DisplayObject.
            var bounds1:Rectangle = target1.getBounds( target1.root );
            var bounds2:Rectangle = target2.getBounds( target2.root );

            // Determine test area boundaries.
            var intersection:Rectangle = new Rectangle();
            intersection.x      = Math.max( bounds1.x, bounds2.x );
            intersection.y      = Math.max( bounds1.y, bounds2.y );
            intersection.width  = Math.min( ( bounds1.x + bounds1.width ) - intersection.x, ( bounds2.x + bounds2.width ) - intersection.x );
            intersection.height = Math.min( ( bounds1.y + bounds1.height ) - intersection.y, ( bounds2.y + bounds2.height ) - intersection.y );

            return intersection;
        }

        public static function complexIntersectionRectangle( target1:DisplayObject, target2:DisplayObject, accurracy:Number = 1 ):Rectangle
        {

            // If a simple hitTestObject is false, they cannot be intersecting.
            if( !target1.hitTestObject( target2 ) ) return new Rectangle();

            var hitRectangle:Rectangle = intersectionRectangle( target1, target2 );
            // If their boundaries are no interesecting, they cannot be intersecting.
            if( hitRectangle.width * accurracy < 1 || hitRectangle.height * accurracy < 1 ) return new Rectangle();

            var bitmapData:BitmapData = new BitmapData( hitRectangle.width * accurracy, hitRectangle.height * accurracy, false, 0x000000 );

            // Draw the first target.
            bitmapData.draw( target1, FlxHitTest.getDrawMatrix( target1, hitRectangle, accurracy ), new ColorTransform( 1, 1, 1, 1, 255, -255, -255, 255 ) );
            // Overlay the second target.
            bitmapData.draw( target2, FlxHitTest.getDrawMatrix( target2, hitRectangle, accurracy ), new ColorTransform( 1, 1, 1, 1, 255, 255, 255, 255 ), BlendMode.DIFFERENCE );

            // Find the intersection.
            var intersection:Rectangle = bitmapData.getColorBoundsRect( 0xFFFFFFFF,0xFF00FFFF );

            bitmapData.dispose();

            // Alter width and positions to compensate for accurracy
            if( accurracy != 1 )
            {
                intersection.x /= accurracy;
                intersection.y /= accurracy;
                intersection.width /= accurracy;
                intersection.height /= accurracy;
            }

            intersection.x += hitRectangle.x;
            intersection.y += hitRectangle.y;

            return intersection;
        }

        public static function flxspriteToBitmap(Graphic:FlxSprite):Bitmap
        {
            var bitmap:Bitmap = new Bitmap(Graphic._framePixels);

            var mtx:Matrix = new Matrix();
            mtx.translate( -Graphic.origin.x, -Graphic.origin.y);
            mtx.scale(Graphic.scale.x, Graphic.scale.y);
            mtx.rotate(Math.PI * 2 * Graphic.angle / 360);
            mtx.translate(Graphic.x - Graphic.offset.x + Graphic.origin.x, Graphic.y - Graphic.offset.y + Graphic.origin.y);

            bitmap.transform.matrix = mtx;

            return bitmap;
        }

        protected static function getDrawMatrix( target:DisplayObject, hitRectangle:Rectangle, accurracy:Number ):Matrix
        {
            var localToGlobal:Point;;
            var matrix:Matrix;

            var rootConcatenatedMatrix:Matrix = target.root.transform.concatenatedMatrix;

            localToGlobal = target.localToGlobal( new Point( ) );
            matrix = target.transform.concatenatedMatrix;
            matrix.tx = localToGlobal.x - hitRectangle.x;
            matrix.ty = localToGlobal.y - hitRectangle.y;

            matrix.a = matrix.a / rootConcatenatedMatrix.a;
            matrix.d = matrix.d / rootConcatenatedMatrix.d;
            if( accurracy != 1 ) matrix.scale( accurracy, accurracy );

            return matrix;
        }

    }

}