using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;

namespace SuperPolarity
{
    static class ActorManager
    {

        static Game Game;
        static int OutlierBounds;
        static List<Actor> Actors;

        static ActorManager()
        {
            OutlierBounds = 100;
            Actors = new List<Actor>();
        }

        static public void CheckIn(Actor actor)
        {
            Actors.Add(actor);
        }

        static public void CheckOut(Actor actor)
        {
            Actors.Remove(actor);
        }

        static public void Update(GameTime gameTime) 
        {
            CheckActors();
            CheckOutliers();
            foreach (Actor actor in Actors)
            {
                actor.Update(gameTime);
            }
        }

        static public void Draw(SpriteBatch spriteBatch)
        {
            foreach (Actor actor in Actors)
            {
                actor.Draw(spriteBatch);
            }
        }

        static void CheckActors()
        {
            var i = 0;
            foreach (Actor actor in Actors)
            {
                i++;
                foreach (Actor other in Actors.Skip(i))
                {
                    CheckCollision(actor, other);

                    if (actor.GetType().IsSubclassOf(typeof(Ship)) && other.GetType().IsSubclassOf(typeof(Ship)))
                    {
                        CheckMagnetism((Ship)actor, (Ship)other);
                    }
                }
            }
        }

        static void CheckCollision(Actor actor, Actor other)
        {

        }

        static void CheckMagnetism(Ship actor, Ship other)
        {
            if (actor.CurrentPolarity != Ship.Polarity.Neutral && other.CurrentPolarity != Ship.Polarity.Neutral)
            {
                var dy = other.Position.Y - actor.Position.Y;
                var dx = other.Position.X - actor.Position.X;
                var linearDistance = Math.Sqrt(Math.Pow(dx, 2) + Math.Pow(dy, 2));
                var angle = (float) Math.Atan2(dy, dx);
                var otherAngle = (float)Math.Atan2(-dy, -dx);

                if (linearDistance < actor.MagneticRadius || linearDistance < other.MagneticRadius)
                {
                    actor.Magnetize(other, (float)linearDistance, angle);
                    other.Magnetize(actor, (float)linearDistance, otherAngle);
                }
            }
        }

        static void CheckOutliers()
        {
            for (var i = Actors.Count; i > 0; i--)
            {
                var actor = Actors[i-1];
                if (actor.Position.X < -OutlierBounds || actor.Position.Y < -OutlierBounds ||
                    actor.Position.X > Game.GraphicsDevice.Viewport.Width + OutlierBounds ||
                    actor.Position.Y > Game.GraphicsDevice.Viewport.Height + OutlierBounds)
                {
                    CheckOut(actor);
                }
            }
        }

        internal static void SetGame(Game game)
        {
            Game = game;
        }
    }
}