package KinematicSimulator;

import java.util.Vector;

/**
 * This is the basic Physics Strategy.  It implements gravity, friction,
 * and elasticity.
 *
 * @author Steve
 */

public class NewtonianPhysicsStrategy extends PhysicsStrategy
{

    double m_gravity = 60;
    double m_elastic = 0;
    double m_friction = 3;
    int m_radius = 20;

    double m_width = 500;
    double m_height = 500;

    public NewtonianPhysicsStrategy(
        int gravity,
        int elastic,
        int friction,
        int radius)
    {
        m_gravity = gravity;
        m_elastic = elastic;
        m_friction = friction;
        m_radius = radius;
    }

    public NewtonianPhysicsStrategy()
    {
        this(60, 0, 3, 20);
    }

    public void setSize(int w, int h)
    {
        m_width = (double) w;

        m_height = (double) h;
    }

    public int getRadius()
    {
        return m_radius;
    }

    public void applyPhysics(Vector balls)
    {
        double d = m_gravity * 0.01D;
        double d1 = m_friction / 500D;
        double d2 = 0.01D * (double) (100F - m_elastic);
        double d3 = 0.01D * (double) (100F - m_elastic / 4F);
        for (int i = 0; i < balls.size(); i++)
        {
            Ball ball = (Ball) balls.elementAt(i);
            ball.move();
            ball.accelerate(0.0D, d);
            ball.accelerate(d1 * -ball.momentum_x(), d1 * -ball.momentum_y());

            if (ball.pos_y() > m_height - ball.radius()
                || ball.pos_y() < ball.radius())
                ball.accelerate(0.0D, -2D * ball.momentum_y() * d2);
            if (ball.pos_x() < ball.radius()
                || ball.pos_x() > m_width - ball.radius())
                ball.accelerate(-2D * ball.momentum_x() * d2, 0.0D);

            for (int j = i + 1; j < balls.size(); j++)
            {
                Ball ball1 = (Ball) balls.elementAt(j);
                if (ball.collision(ball1))
                {
                    Vector2D vector2d =
                        new Vector2D(
                            ball1.pos_x() - ball.pos_x(),
                            ball1.pos_y() - ball.pos_y());
                    Vector2D vector2d1 =
                        new Vector2D(ball.momentum_x(), ball.momentum_y());
                    Vector2D vector2d2 = vector2d.projection(vector2d1);
                    Vector2D vector2d3 =
                        new Vector2D(ball1.momentum_x(), ball1.momentum_y());
                    Vector2D vector2d4 = vector2d.projection(vector2d3);
                    Vector2D vector2d5 = vector2d4.add(vector2d2.negative());
                    vector2d =
                        new Vector2D(
                            ball.pos_x() - ball1.pos_x(),
                            ball.pos_y() - ball1.pos_y());
                    vector2d4 = vector2d.projection(vector2d1);
                    vector2d2 = vector2d.projection(vector2d3);
                    Vector2D vector2d6 = vector2d4.add(vector2d2.negative());
                    ball.accelerate(
                        vector2d5.get_x() * d3,
                        vector2d5.get_y() * d3);
                    ball1.accelerate(
                        vector2d6.get_x() * d3,
                        vector2d6.get_y() * d3);
                    double d4 = vector2d.length() * 0.5D;
                    double d5 = d4 - ball.radius();
                    double d6 = d4 - ball1.radius();
                    d4 = d5 + d6;
                    double d7 = d4 / 2D;
                    double d8 = vector2d.length();
                    Vector2D vector2d7 = vector2d.scale(d7 / d8);
                    ball.setPos(
                        ball.pos_x() - vector2d7.get_x(),
                        ball.pos_y() - vector2d7.get_y());
                    ball1.setPos(
                        ball1.pos_x() + vector2d7.get_x(),
                        ball1.pos_y() + vector2d7.get_y());
                }
            }

            if (ball.pos_y() > m_height - ball.radius())
                ball.setPos(ball.pos_x(), m_height - ball.radius());

            if (ball.pos_y() < ball.radius())
                ball.setPos(ball.pos_x(), ball.radius());

            if (ball.pos_x() > m_width - ball.radius())
                ball.setPos(m_width - ball.radius(), ball.pos_y());

            if (ball.pos_x() < ball.radius())
                ball.setPos(ball.radius(), ball.pos_y());
        }
    }
}