package ch.nuth.zhaw.exbox;

/**
 * Provides the functionality to draw hilbert curves.
 */
public class HilbertServer implements CommandExecutor {
    @Override
    public String execute(String command) {
        int depth = Integer.parseInt(command);
        Turtle turtle = Turtle.instance();
        double dist = 0.8 / (Math.pow(2, depth + 1) - 1);
        turtle.reset(0.1, 0.1);
        hilbert(turtle, depth, dist, -90);
        return turtle.getTrace();
    }

    private void hilbert(Turtle turtle, int depth, double dist, double angle) {
        if (depth > 0) {
            turtle.turn(-angle);
            hilbert(turtle, depth - 1, dist, -angle);
            turtle.move(dist);
            turtle.turn(angle);
            hilbert(turtle, depth - 1, dist, angle);
            turtle.move(dist);
            hilbert(turtle, depth - 1, dist, angle);
            turtle.turn(angle);
            turtle.move(dist);
            hilbert(turtle, depth - 1, dist, -angle);
            turtle.turn(-angle);
        } else {
            turtle.turn(-angle);
            turtle.move(dist);
            turtle.turn(angle);
            turtle.move(dist);
            turtle.turn(angle);
            turtle.move(dist);
            turtle.turn(-angle);
        }
    }
}