namespace Fusion.Addons.KCC
{
	using System;

	/// <summary>
	/// Custom stack implementation for fast push/pop and pre-allocation.
	/// Only for internal KCC purposes.
	/// </summary>
	public sealed class KCCFastStack<T> where T : class, new()
	{
		private T[] _items;
		private int _count;

		public KCCFastStack(int capacity, bool createInstances)
		{
			_items = new T[capacity];
			_count = default;

			if (createInstances == true)
			{
				_count = capacity;

				for (int i = 0; i < capacity; ++i)
				{
					_items[i] = new T();
				}
			}
		}

		public T PopOrCreate()
		{
			if (_count > 0)
			{
				--_count;
				return _items[_count];
			}

			return new T();
		}

		public void Push(T item)
		{
			if (_count == _items.Length)
			{
				Array.Resize(ref _items, _items.Length * 2);
			}

			_items[_count] = item;
			++_count;
		}
	}
}