using System;
using System.Collections.Generic;

namespace Thousandto.Core.Base
{
    //Set集的堆栈
    public class SetStack<T>
    {
        //id关联的索引
        private Dictionary<int, int> _indexes = new Dictionary<int, int>();
        //数据列表
        private List<T> _items = new List<T>();

        public int Count
        {
            get
            {
                return _items.Count;
            }
        }

        public List<T> Items
        {
            get
            {
                return _items;
            }
        }

        public T this[int index]
        {
            get
            {
                return _items[index];
            }
        }
            

        public bool Push(T obj)
        {
            if (obj != null)
            {
                var id = obj.GetHashCode();
                if (!_indexes.ContainsKey(id))
                {
                    _items.Add(obj);
                    _indexes[id] = _items.Count - 1;
                    return true;
                }
            }
            return false;
        }

        public void PushFast(T obj)
        {
            _items.Add(obj);
            _indexes[obj.GetHashCode()] = _items.Count - 1;
        }

        public T Pop()
        {
            var cnt = _items.Count;
            if (cnt > 0)
            {
                var obj = _items[cnt - 1];
                _items.RemoveAt(cnt - 1);
                _indexes.Remove(obj.GetHashCode());
                return obj;
            }
            return default(T);
        }

        public void Foreach(Action<T> func)
        {
            for (int i = 0; i < _items.Count; i++)
            {
                func(_items[i]);
            }
        }

        public bool Contains(T obj)
        {
            return _indexes.ContainsKey(obj.GetHashCode());
        }

        public void TrimExcess()
        {
            _items.TrimExcess();
        }

        public void Clear()
        {
            _items.Clear();
            _indexes.Clear();
        }
    }

}