abstract class Buff
{
   public abstract void Apply(IBuffTargetable<Buff> target);
   public abstract void Unapply();
}
class PlayerBuff : Buff
{
	public Player AffectedPlayer { get; private set; }
 
	public override void Apply(IBuffTargetable<Buff> target)
	{
		AffectedPlayer = (Player)target;
	}
	public override void Unapply()
	{
		AffectedPlayer = null;
	}
}
 
interface IBuffTargetable<T> where T : Buff
{
   T[] AppliedBuffs { get; }
   void ApplyBuff(T buff);
   void UnapplyBuff(T buff);
}
 
class Player : IBuffTargetable<PlayerBuff>
{
	private List<PlayerBuff> appliedBuffs;
	public PlayerBuff[] AppliedBuffs
	{
		get { return appliedBuffs.ToArray(); }
	}
 
	public void ApplyBuff(PlayerBuff buff)
	{
		buff.Apply((IBuffTargetable<Buff>)this);
		appliedBuffs.Add(buff);
	}
	public void UnapplyBuff(PlayerBuff buff)
	{
		if (appliedBuffs.Remove(buff))
			buff.Unapply();
	}
 
	private void Awake()
	{
		appliedBuffs = new List<PlayerBuff>(10);
	}
}
 

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