package 
{
	import flash.display.DisplayObject;
	import flash.display.MovieClip;
	import flash.events.KeyboardEvent;
	import flash.events.TimerEvent;
	import flash.geom.ColorTransform;
	import flash.geom.Point;
	import flash.geom.Transform;
	import flash.utils.Timer;
	

	public class Car extends MovieClip
	{
		private var steerSpeed:Number = 2.5;
		private var accelerateSpeed:Number = 0.14;
		private var brakeSpeed:Number = -0.06;
		private var coastSpeed:Number = 0.975;
		private var intertiaRotationProportion:Number = 0.20;
		private var skidLossFactor:Number = 3.5;

		var steerAway:Number = 2;
		
		var prop0:Number = 0.970;
		var prop1:Number = 0.030;

		
		private var deltaX:Number = 0;
		private var deltaY:Number = 0;


		// keeps a record of the track for collision
		private var track:Track = null; 
		
		private var keys:Object = new Object();

		public function Car():void
		{

			stage.addEventListener(KeyboardEvent.KEY_DOWN, KeyDown);
			stage.addEventListener(KeyboardEvent.KEY_UP, KeyUp);
		}

		public function set Track(value:Track):void
		{
			this.track = value;
		}
		
		private function KeyDown(event:KeyboardEvent):void
		{
			keys[event.keyCode] = true;
			
			switch (event.keyCode)
			{
				case 16:
					var testGraphic:TestGraphic = new TestGraphic();
					var trackPosition:Point = track.globalToLocal(localToGlobal(new Point(0, 0)));
					
					testGraphic.x = trackPosition.x;
					testGraphic.y = trackPosition.y;
					track.addChild(testGraphic);

					break;
			}
		}

		private function KeyUp(event:KeyboardEvent):void
		{
			keys[event.keyCode] = false;
		}
	
		public function Process():void
		{
			var deltaRotation:Number = 0;
			
			if (keys[37])
			{
				// left
				deltaRotation = -steerSpeed;
			}
			
			if (keys[39])
			{
				// right 
				deltaRotation = steerSpeed;
			}

			if (deltaRotation != 0)
			{
				var inertiaRotation = deltaRotation / 180 * Math.PI * intertiaRotationProportion;
				
				var newDeltaX = Math.cos(inertiaRotation) * deltaX - Math.sin(inertiaRotation) * deltaY;
				var newDeltaY = Math.sin(inertiaRotation) * deltaX + Math.cos(inertiaRotation) * deltaY;

				deltaX = newDeltaX;
				deltaY = newDeltaY;
				
				rotation += deltaRotation;
			}
			
			
			
			if (keys[38])
			{
				// up
				deltaX += Math.cos(rotation / 180 * Math.PI) * accelerateSpeed;
				
				deltaY += Math.sin(rotation / 180 * Math.PI) * accelerateSpeed;

			}

			if (keys[40])
			{
				// down
				deltaX += Math.cos(rotation / 180 * Math.PI) * brakeSpeed;
				deltaY += Math.sin(rotation / 180 * Math.PI) * brakeSpeed;
			}

			
			
			x += deltaX;
			y += deltaY;

			var maxTurns:int = 5;
			
			while (maxTurns > 0 && !track.CheckPoint(localToGlobal(new Point(collisionPointFrontRight.x, collisionPointFrontRight.y))))
			{
				var newDeltaX = deltaX * prop0 + deltaY * prop1;
				var newDeltaY = deltaY * prop0 - deltaX * prop1;

				deltaX = newDeltaX;
				deltaY = newDeltaY;

				rotation -= steerAway;
				maxTurns--;
			}

			while (maxTurns > 0 && !track.CheckPoint(localToGlobal(new Point(collisionPointFrontLeft.x, collisionPointFrontLeft.y))))
			{
				var newDeltaX = deltaX * prop0 - deltaY * prop1;
				var newDeltaY = deltaY * prop0 + deltaX * prop1;

				deltaX = newDeltaX;
				deltaY = newDeltaY;

				rotation += steerAway;
				maxTurns--;
			}

			var inertiaDirection = Math.atan2(deltaY, deltaX);
			
			// use  dot product of direction and inertia to calculate skid factor
			
			var skidding:Number = Math.cos(rotation / 180 * Math.PI) * Math.cos(inertiaDirection) +
					Math.sin(rotation / 180 * Math.PI) * Math.sin(inertiaDirection);
			if (skidding < 0)
			{
				skidding = -skidding;
			}
			
			var adjustedSkidding:Number = 1 - Math.pow(1 - skidding, skidLossFactor);
			var speedLoss:Number = coastSpeed * adjustedSkidding;
	
	
			deltaX *= speedLoss;
			deltaY *= speedLoss;

		}
	}
}