namespace NBConfigBuilder;

/// <summary>
/// 静态的对象池系统，不支持多线程。
/// </summary>
/// <typeparam name="T"></typeparam>
public static class Pool<T> where T : IPool, new()
{
    private static readonly Queue<T> PoolQueue = new Queue<T>();

    /// <summary>
    /// 池子里可用的数量
    /// </summary>
    public static int Count => PoolQueue.Count;

    /// <summary>
    /// 租借
    /// </summary>
    /// <returns></returns>
    public static T Rent()
    {
        return PoolQueue.Count == 0 ? new T() : PoolQueue.Dequeue();
    }

    /// <summary>
    /// 租借
    /// </summary>
    /// <param name="generator">如果池子里没有，会先执行这个委托。</param>
    /// <returns></returns>
    public static T Rent(Func<T> generator)
    {
        return PoolQueue.Count == 0 ? generator() : PoolQueue.Dequeue();
    }

    /// <summary>
    /// 返还
    /// </summary>
    /// <param name="t"></param>
    public static void Return(T t)
    {
        if (t == null)
        {
            return;
        }

        PoolQueue.Enqueue(t);
    }

    /// <summary>
    /// 返还
    /// </summary>
    /// <param name="t">返还的东西</param>
    /// <param name="reset">返还后执行的委托</param>
    public static void Return(T t, Action<T> reset)
    {
        if (t == null)
        {
            return;
        }

        reset(t);
        PoolQueue.Enqueue(t);
    }

    /// <summary>
    /// 清空池子
    /// </summary>
    public static void Clear()
    {
        PoolQueue.Clear();
    }
}