using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Sockets;

namespace Mesnac.Communication
{
    public sealed class SocketAsyncEventArgsPool : IDisposable
    {
        private Stack<SocketAsyncEventArgsWithId> pool;
        private IDictionary<string, SocketAsyncEventArgsWithId> busypool;
        //private string[] keys;

        public Int32 Count
        {
            get
            {
                lock (this.pool)
                {
                    return this.pool.Count;
                }
            }
        }

        public string[] OnlineUID
        {
            get
            {
                string[] keys = null;
                lock (this.busypool)
                {
                    //busypool.Keys.CopyTo(keys, 0);
                    keys = busypool.Keys.ToArray<string>();
                }
                return keys;
            }
        }

        public Stack<SocketAsyncEventArgsWithId> Pool { get { return this.pool; } }

        public IDictionary<string, SocketAsyncEventArgsWithId> BusyPool { get { return this.busypool; } }

        public SocketAsyncEventArgsPool(Int32 capacity)
        {
            //keys = new string[capacity];
            this.pool = new Stack<SocketAsyncEventArgsWithId>(capacity);
            this.busypool = new Dictionary<string, SocketAsyncEventArgsWithId>(capacity);
        }

        public SocketAsyncEventArgsWithId Pop(string uid)
        {
            if (uid == string.Empty || uid == "")
                return null;
            SocketAsyncEventArgsWithId si = null;
            lock (this.pool)
            {
                si = this.pool.Pop();
            }
            si.UID = uid;
            si.State = true;    //mark the state of pool is not the initial step 
            busypool.Add(uid, si);
            return si;
        }

        public void Push(SocketAsyncEventArgsWithId item)
        {
            if (item == null)
                throw new ArgumentNullException("SocketAsyncEventArgsWithId对象为空");
            if (item.State == true)
            {
                if (busypool.Keys.Count != 0)
                {
                    if (busypool.Keys.Contains(item.UID))
                        busypool.Remove(item.UID);
                    //else
                    //    throw new ArgumentException("SocketAsyncEventWithId不在忙碌队列中");
                }
                else
                    throw new ArgumentException("忙碌队列为空");
            }
            item.UID = "-1";
            item.State = false;
            lock (this.pool)
            {
                this.pool.Push(item);
            }
        }

        public SocketAsyncEventArgsWithId FindByUID(string uid)
        {
            if (uid == string.Empty || uid == "")
                return null;
            SocketAsyncEventArgsWithId si = null;
            foreach (string key in this.OnlineUID)
            {
                if (key == uid)
                {
                    si = busypool[uid];
                    break;
                }
            }
            return si;
        }

        public bool BusyPoolContains(string uid)
        {
            lock (this.busypool)
            {
                return busypool.Keys.Contains(uid);
            }
        }

        public void Dispose()
        {
            this.pool.Clear();
            this.busypool.Clear();
            this.pool = null;
            this.busypool = null;
        }
    }
}