package {
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    import flash.display.MovieClip;
    import flash.events.Event;
    import flash.geom.Point;
    import DriverBubble;
    import TweetBubble;

    public class DocumentMain extends MovieClip {
        public var collisionParticles:Array; // the array of main objects in frame
        public var wallBounce:Number = 0.7; // how much velocity is retained when bouncing off walls
        public var friction:Number = 0.97; // how quickly objects slow down
        public var boundaryWidth:Number = 50; // how far from stage sides the objects should stay
        public var boundaryHeight:Number = 30; // how far from the top and bottom objects should stay
        public var boundaryGravity:Number = 0.8; // how fast objects repel from the boundary

        public function DocumentMain() {
            init();
        }

        private function init() {
            stage.align = StageAlign.TOP_LEFT;
            stage.scaleMode = StageScaleMode.NO_SCALE;

            collisionParticles = new Array();

            // create the driver particles
            for(var i = 0; i < 2; i++) {
                var randX:Number = Math.floor(Math.random() * (stage.stageWidth - 210)) + 105;
                var randY:Number = Math.floor(Math.random() * (stage.stageHeight - 210)) + 105;
                var randSize:Number = Math.random() * 40 + 60;
                var myBubble:DriverBubble = new DriverBubble();
                myBubble.setSize(randSize);
                myBubble.x = randX;
                myBubble.y = randY;
                addChild(myBubble);
                collisionParticles.push(myBubble);

                var numTweets:Number = 20; //Math.floor(Math.random() * 20) +
                for(var j = 0; j < numTweets; j++) {
                    var tweetX:Number = Math.floor(Math.random() * (stage.stageWidth - 210)) + 105;
                    var tweetY:Number = Math.floor(Math.random() * (stage.stageHeight - 210)) + 105;
                    var tBubble:TweetBubble = new TweetBubble();
                    tBubble.setSize(4);
                    tBubble.x = tweetX;
                    tBubble.y = tweetY;
                    addChild(tBubble);
                    collisionParticles.push(tBubble);
                    myBubble.tweets.push(tBubble);
                }
            }
            addEventListener(Event.ENTER_FRAME, onEnterFrame);
        }

        private function onEnterFrame(event:Event) {
            // loop for movement
            for( var i:uint = 0; i < collisionParticles.length; i++ ) {
                var particle = collisionParticles[i];
                stayOnCanvas(particle);

                //friction
                particle.vx *= friction;
                particle.vy *= friction;

                //move
                particle.x += (particle.vx - particle.x) * .2;
                particle.y += (particle.vy - particle.y) * .2;

                if(particle.hasOwnProperty('tweets')) {
                    if(particle.tweets.length) {
                        // loop for gravity in groups
                        for( var k:uint = 0; k < particle.tweets.length; k++) {
                            gravitate(particle.tweets[k], particle);
                        }
                    }
                }
            }

            // loop for collision
            for( i=0; i < collisionParticles.length - 1; i++ ) {
                var partA:Bubble = collisionParticles[i];
                for(var j:uint = i+1; j < collisionParticles.length; j++) {
                    var partB:Bubble = collisionParticles[j];
                    checkCollision(partA, partB);
                    //gravitate(partA, partB);
                }
            }
        }
        private function gravitate(partA:Bubble, partB:Bubble):void {
            var dx:Number = partB.x - partA.x;
            var dy:Number = partB.y - partA.y;
            var distSQ:Number = dx * dx + dy * dy;
            var dist:Number = Math.sqrt(distSQ);
            var force:Number = partA.mass * partB.mass / distSQ;
            var ax:Number = force * dx / dist;
            var ay:Number = force * dy / dist;
            partA.vx += ax / partA.mass;
            partA.vy += ay / partA.mass;
            partB.vx -= ax / partB.mass;
            partB.vy -= ay / partB.mass;
        }
        private function checkCollision(ball0:Bubble, ball1:Bubble):void {
            var dx:Number = ball1.x - ball0.x;
            var dy:Number = ball1.y - ball0.y;
            var dist:Number = Math.sqrt(dx*dx + dy*dy);
            if(dist <= ball0.mySize + ball1.mySize) {
                //calculate angle, sine, and cosine
                var angle:Number = Math.atan2(dy, dx);
                var sin:Number = Math.sin(angle);
                var cos:Number = Math.cos(angle);

                //rotate ball0 position
                var pos0:Point = new Point(0,0);

                //rotate ball1 position
                var pos1:Point = rotate(dx, dy, sin, cos, true);

                //rotate ball0 velocity
                var vel0:Point = rotate(ball0.vx, ball0.vy, sin, cos, true);

                //rotate ball1 velocity
                var vel1:Point = rotate(ball1.vx, ball1.vy, sin, cos, true);

                //collision reaction
                var vxTotal:Number = vel0.x - vel1.x;
                vel0.x = ((ball0.mass - ball1.mass) * vel0.x +
                    2 * ball1.mass * vel1.x) /
                    (ball0.mass + ball1.mass);
                vel1.x = vxTotal + vel0.x;

                //update position
                var absV:Number = Math.abs(vel0.x) + Math.abs(vel1.x);
                var overlap:Number = (ball0.mySize + ball1.mySize)
                        - Math.abs(pos0.x - pos1.x);
                pos0.x += vel0.x / absV * overlap;
                pos1.x += vel1.x / absV * overlap;

                //rotate positions back
                var pos0F:Object = rotate(pos0.x, pos0.y, sin, cos, false);
                var pos1F:Object = rotate(pos1.x, pos1.y, sin, cos, false);

                //adjust positions to actual screen positions
                ball1.x = ball0.x + pos1F.x;
                ball1.y = ball0.y + pos1F.y;
                ball0.x = ball0.x + pos0F.x;
                ball0.y = ball0.y + pos0F.y;

                //rotate velocities back
                var vel0F:Object = rotate(vel0.x, vel0.y, sin, cos, false);
                var vel1F:Object = rotate(vel1.x, vel1.y, sin, cos, false);

                ball0.vx = vel0F.x;
                ball0.vy = vel0F.y;
                ball1.vx = vel1F.x;
                ball1.vy = vel1F.y;
            }
        }

        private function rotate(x:Number, y:Number, sin:Number, cos:Number, reverse:Boolean):Point {
            var result:Point = new Point();

            if(reverse) {
                result.x = x * cos + y * sin;
                result.y = y * cos - x * sin;
            }
            else {
                result.x = x * cos - y * sin;
                result.y = y * cos + x * sin;
            }
            return result;
        }
        /*
        private function checkCollision(partA:Bubble, partB:Bubble):void {
            var dx:Number = partB.x - partA.x;
            var dy:Number = partB.y - partA.y;
            var dist:Number = Math.sqrt(dx *  dx + dy * dy);
            var hitDistance:Number = partA.mySize + partB.mySize;
            if(dist <= hitDistance) {
                var angle:Number = Math.atan2(dy, dx);
                var tx:Number = partA.x + Math.cos(angle) * hitDistance;
                var ty:Number = partA.y + Math.sin(angle) * hitDistance;
                var ax:Number = (tx - partB.x) * 0.5;
                var ay:Number = (ty - partB.y) * 0.5;
                partA.vx -= ax;
                partA.vy -= ay;
                partB.vx += ax;
                partB.vy += ay;
            }
        }
        */

        private function stayOnCanvas(partA:Bubble):void {
            var minx:Number = 0;
            var miny:Number = 0;
            var maxx:Number = stage.stageWidth;
            var maxy:Number = stage.stageHeight;

            if(partA.x + partA.mySize > maxx) {
                partA.x = maxx - partA.mySize;
                partA.vx *= -wallBounce;
            }
            else if(partA.x - partA.mySize < minx) {
                partA.x = minx + partA.mySize;
                partA.vx *= -wallBounce;
            }

            if(partA.y + partA.mySize > maxy) {
                partA.y = maxy - partA.mySize;
                partA.vy *= -wallBounce;
            }
            else if(partA.y - partA.mySize < miny) {
                partA.y = miny + partA.mySize;
                partA.vy *= -wallBounce;
            }

            // boundary gravity
            var mincomfortablex:Number = partA.mySize + boundaryWidth;
            var maxcomfortablex:Number = stage.stageWidth - (partA.mySize + boundaryWidth);
            var mincomfortabley:Number = partA.mySize + boundaryHeight;
            var maxcomfortabley:Number = stage.stageHeight - (partA.mySize + boundaryHeight);

            if(partA.x > maxcomfortablex) {
                partA.vx -= boundaryGravity;
            }
            else if(partA.x < mincomfortablex) {
                partA.vx += boundaryGravity;
            }

            if(partA.y > maxcomfortabley) {
                partA.vy -= boundaryGravity;
            }
            else if(partA.y < mincomfortabley) {
                partA.vy += boundaryGravity;
            }
        }
    }
}