public class PartsBot extends AdvancedRobot
{
    Random rand = new Random();

    private AdvancedEnemyBot enemy = new AdvancedEnemyBot();

    private RobotPart[] parts = new RobotPart[3]; // make three parts

    private final static int RADAR = 0;

    private final static int GUN = 1;

    private final static int TANK = 2;


    /**
     * This runs all the methods in the code.
     */
    public void run()
    {
        parts[TANK] = new Tank();
        parts[GUN] = new Gun();
        parts[RADAR] = new Radar();

        // initialize each part
        for ( int i = 0; i < parts.length; i++ )
        {
            // behold, the magic of polymorphism
            parts[i].init();
        }

        // iterate through each part, moving them as we go
        for ( int i = 0; true; i = ( i + 1 ) % parts.length )
        {
            // polymorphism galore!
            parts[i].move();
            if ( i == 0 )
            {
                execute();
            }
        }
    }


    /**
     * This is the event depending on if it gets hit by a bullet.
     *
     * @param e
     *            This is the situation that it gets hit by a bullet.
     */
    public void onHitByBullet( HitByBulletEvent e )
    {

    }


    /**
     * This is the event depending on if it scans another robot.
     *
     * @param e
     *            This is the situation that it scanned a robot.
     */
    public void onScannedRobot( ScannedRobotEvent e )
    {
        Radar radar = (Radar)parts[RADAR];
        if ( radar.shouldTrack( e ) )
        {
            // This looks for a new target
            enemy.update( e, this );
        }
    }


    /**
     * This is the event depending on if it scans a dead robot.
     *
     * @param e
     *            This is the situation that it scanned a dead robot.
     */
    public void onRobotDeath( RobotDeathEvent e )
    {
        Radar radar = (Radar)parts[RADAR];
        if ( radar.wasTracking( e ) )
        {
            // This prints out Victory upon killing an enemy :)
            this.out.println( "VICTORY!!" );
            enemy.reset();
        }
    }


    /**
     * This is the event depending on if it hits the wall.
     *
     * @param e
     *            This is the situation that it hits the wall.
     */
    public void onHitWall( HitWallEvent e )
    {
        // This is if the robot hits a wall
        Tank tank = (Tank)parts[TANK];
        tank.hitWalls();
    }


    // ... put normalizeBearing and absoluteBearing methods here
    /**
     * computes the absolute bearing between two points
     *
     * @param x1
     *            This is the original x.
     * @param y1
     *            This is the original y.
     * @param x2
     *            This is the next x.
     * @param y2
     *            This is the next y
     * @return bearing This is the double that describes the bearing to enemy.
     */
    public double absoluteBearing( double x1, double y1, double x2, double y2 )
    {
        double xo = x2 - x1;
        double yo = y2 - y1;
        double hyp = Point2D.distance( x1, y1, x2, y2 );
        double arcSin = Math.toDegrees( Math.asin( xo / hyp ) );
        double bearing = 0;

        if ( xo > 0 && yo > 0 )
        { // both pos: lower-Left
            bearing = arcSin;
        }
        else if ( xo < 0 && yo > 0 )
        { // x neg, y pos: lower-right
            bearing = 360 + arcSin; // arcsin is negative here, actually 360
                                    // -
                                    // ang
        }
        else if ( xo > 0 && yo < 0 )
        { // x pos, y neg: upper-left
            bearing = 180 - arcSin;
        }
        else if ( xo < 0 && yo < 0 )
        { // both neg: upper-right
            bearing = 180 - arcSin; // arcsin is negative here, actually 180
                                    // +
                                    // ang
        }

        return bearing;
    }


    /**
     * normalizes a bearing to between +180 and -180
     *
     * @param angle
     *            This is the angle to turn the radar.
     * @return angle This is the smallest angle change.
     */
    public double normalizeBearing( double angle )
    {
        while ( angle > 180 )
        {
            angle -= 360;
        }
        while ( angle < -180 )
        {
            angle += 360;
        }
        return angle;
    }


    /**
     * ... declare the RobotPart interface and classes that implement it here
     * They will be _inner_ classes.
     */
    public interface RobotPart
    {
        /**
         * This initializes the bot.
         */
        public void init();


        /**
         * This moves the bot.
         */
        public void move();

    }


    /**
     * This class controls the radar.
     */
    public class Radar implements RobotPart
    {
        /**
         * This controls the radar.
         */
        public void init()
        {
            // initialize radar operation
            setAdjustRadarForGunTurn( true );
        }


        /**
         * This moves the radar and turns it.
         */
        public void move()
        {

                // Absolute angle towards target
                double angleToEnemy = getHeading() + enemy.getBearing();

                // Subtract current radar heading to get the turn required to
                // face
                // the enemy, be sure it is normalized
                double radarTurn = normalizeBearing(angleToEnemy - getRadarHeading() );

                // Distance we want to scan from middle of enemy to either side
                // The 36.0 is how many units from the center of the enemy
                // robot it scans.
                if (radarTurn > 0) {
                    radarTurn += 10.0;
                }
                else {
                    radarTurn -= 10.0;
                }

                // Adjust the radar turn so it goes that much further in the
                // direction it is going to turn
                // Basically if we were going to turn it left, turn it even
                // more left, if right, turn more right.
                // This allows us to overshoot our enemy so that we get a good
                // sweep
                // that will not slip.


                // Turn the radar
                setTurnRadarRightRadians( radarTurn );


        }


        /**
         * This is the boolean statement
         *
         * @param e
         *            This is the event of scanning a robot.
         *
         * @return ( enemy.none() || e.getDistance() < enemy.getDistance() - 70
         *         || e.getName().equals( enemy.getName() ) ) This determines
         *         whether the enemy should be tracked.
         */
        public boolean shouldTrack( ScannedRobotEvent e )
        {
            // track if we have no enemy, the one we found is significantly
            // closer, or we scanned the one we've been tracking.
            return ( enemy.none() || e.getDistance() < enemy.getDistance()
                            - 100
                || e.getName().equals( enemy.getName() ) );
        }


        /**
         * This controls the radar.
         *
         * @param e
         *            This is the event of scanning a dead robot.
         *
         * @return e.getName().equals( enemy.getName() ) If enemy is dead, the
         *         robot finds another target.
         */
        public boolean wasTracking( RobotDeathEvent e )
        {
            // if enemy is dead, the robot finds another target.
            return e.getName().equals( enemy.getName() );
        }
    }


    /**
     * This is the class that controls the gun.
     */
    public class Gun implements RobotPart
    {
        /**
         * This is the initialization method.
         */
        public void init()
        {
            // initialize gun operation
            setAdjustGunForRobotTurn( true );
        }

        public void onScannedRobot( ScannedRobotEvent e )
        {
           // track if we have no enemy, the one we found is significantly
           // closer, or we scanned the one we've been tracking.
           if ( enemy.none() || e.getDistance() < enemy.getDistance() - 70
              || e.getName().equals( enemy.getName() ) )
           {

              // track him using the NEW update method
              enemy.update( e );
           }
        }

        public void move()
        {
            // TODO: gun implementation
            if ( enemy.none() )
                return;

         // calculate firepower based on distance
            double firePower = Math.min( 500 / enemy.getDistance(), 3 );
            // calculate speed of bullet
            double bulletSpeed = 20 - firePower * 3;
            // distance = rate * time, solved for time
            long time = (long)( enemy.getDistance() / bulletSpeed );

            // calculate gun turn to predicted x,y location
            double futureX = enemy.getFutureX( time );
            double futureY = enemy.getFutureY( time );
            double absDeg = absoluteBearing( getX(), getY(), futureX, futureY );
            // non-predictive firing can be done like this:
            // double absDeg = absoluteBearing(getX(), getY(), enemy.getX(),
            // enemy.getY());

            // turn the gun to the predicted x,y location
            setTurnGunRight( normalizeBearing( absDeg - getGunHeading() ) );

            // if the gun is cool and we're pointed in the right direction, shoot!
            if ( getGunHeat() == 0 && Math.abs( getGunTurnRemaining() ) < 10 )
            {
               setFire( firePower );
            }

        }


    }


    /**
     * This moves the tanks and turns it.
     */
    public class Tank implements RobotPart
    {
        /**
         * This is the initialization for the tank.
         */
        public void init()
        {
            // this is the initial color.
            setColors( Color.white, Color.white, Color.red, Color.white,
                Color.white );
        }

        // this is used when strafing
        private byte moveDirection = 1;

        public void move()
        {

            setTurnRight( normalizeBearing( enemy.getBearing() + 90 ) );
            setAhead(100 * moveDirection);

        }


        public void hitWalls( ) {
            setMaxVelocity( 10 );
            moveDirection *= -1;
        }

    }
}