Levels

using System;
using System.Collections.Generic;
using System.Drawing;

namespace func_rocket
{
    public class LevelsTask
    {
        static readonly Physics StandardPhysics = new Physics();
        static double distance;
        static Rocket rocket = new Rocket(new Vector(200, 500), Vector.Zero, -0.5*Math.PI);
        static Vector target = new Vector(600, 200);

        public static Vector GravityWhiteHole(double x, double y)
        {
            var vector = new Vector(x - 600, y - 200);
            distance = Math.Sqrt(Math.Pow(600 - x, 2.0) + Math.Pow(200 - y, 2.0));
            return vector.Normalize() * (140 * distance) / (distance * distance + 1);
        }

        public static Vector GravityBlackHole(double x, double y)
        {
            var coorXOfAnomalies = (200 + 600) / 2.0;
            var coorYOfAnomalies = (500 + 200) / 2.0;
            var vector = new Vector(x - coorXOfAnomalies, y - coorYOfAnomalies);
            distance =
                Math.Sqrt(Math.Pow(coorXOfAnomalies - x, 2.0) + Math.Pow(coorYOfAnomalies - y, 2.0));
            return -1 * vector.Normalize() * (300 * distance) / (distance * distance + 1);
        }

        public static Level CreateLevel(string name, Gravity gravity)
        {
            return new Level(name, rocket, target, gravity, StandardPhysics);
        }
        public static IEnumerable<Level> CreateLevels()
        {
            yield return CreateLevel("Zero", (size, location) => Vector.Zero);

            yield return CreateLevel("Heavy", (size, location) => new Vector(0.0, 0.9));

            yield return new Level("Up", rocket, new Vector(700, 500),
                (size, location) => new Vector(0, -(300 / (size.Height - location.Y + 300.0))), StandardPhysics);

            yield return CreateLevel("WhiteHole",
                (size, location) => GravityWhiteHole(location.X, location.Y));

            yield return CreateLevel("BlackHole",
                (size, location) => GravityBlackHole(location.X, location.Y));

            yield return CreateLevel("BlackAndWhite",
                    (size, location) => (GravityBlackHole(location.X, location.Y) + GravityWhiteHole(location.X, location.Y))/2);
        }
    }
}