using System;
using System.Net.Sockets;
using System.Threading;

namespace Curtain.Net.Sockets.PLC
{
    /// <summary>
    /// 扩展Socket，接收数据超时功能
    /// </summary>
    internal static class TimeoutSocket //: Socket
    {
        //public TimeoutSocket(SocketInformation socketInformation)
        //    :base(socketInformation)
        //{
        //}
        //public TimeoutSocket(AddressFamily addressFamily, SocketType socketType, ProtocolType protocolType)
        //    : base(addressFamily, socketType, protocolType)
        //{
        //}

        /// <summary>
        /// 开始从连接的 System.Net.Sockets.Socket 中异步接收数据（超时后关闭连接的Socket）。
        /// </summary>
        /// <param name="socket"></param>
        /// <param name="buffer"></param>
        /// <param name="offset"></param>
        /// <param name="size"></param>
        /// <param name="socketFlags"></param>
        /// <param name="callback"></param>
        /// <param name="timeoutCallback"></param>
        /// <param name="timeout"></param>
        /// <param name="state"></param>
        /// <returns></returns>
        public static IAsyncResult BeginReceiveByTimeout(this Socket socket, byte[] buffer, int offset, int size, SocketFlags socketFlags,
            AsyncCallback callback, AsyncCallback timeoutCallback, int timeout, object state)
        {
            StateInfo stateInfo = new StateInfo(socket, callback, timeoutCallback, state);

            //IAsyncResult result = socket.BeginReceive(buffer, offset, size, socketFlags, ReceiveCallback, stateInfo);
            IAsyncResult result = socket.BeginReceive(buffer, offset, size, socketFlags, callback, state);
            stateInfo.Result = result;

            var registeredWaitHandle =
                ThreadPool.RegisterWaitForSingleObject(
                    result.AsyncWaitHandle,
                    WatchTimeOut,
                    stateInfo,
                    timeout,
                    true);

            // stateInfo中保存RegisteredWaitHandle，以方便在WatchTimeOut
            // 中unregister.
            stateInfo.RegisteredWaitHandle = registeredWaitHandle;

            return result;
        }

        private static void WatchTimeOut(object state, bool timeout)
        {
            //Framework.Log.Logger.Debug("WatchTimeOut:timeout="+ timeout, "timeout");
            if (state is StateInfo stateInfo)
            {
                // 设置的timeout前，操作未完成，则设置为操作Timeout
                if (timeout)
                {
                    stateInfo.SetTimeout();
                }

                // 取消之前注册的WaitOrTimerCallback
                stateInfo.RegisteredWaitHandle.Unregister(
                    stateInfo.Result.AsyncWaitHandle);
            }
        }

        //private static void ReceiveCallback(IAsyncResult result)
        //{
        //    //if (result.AsyncState is StateInfo stateInfo)
        //    //{
        //    //    var count = stateInfo.Socket.EndReceive(stateInfo.Result);
        //    //    //stateInfo.SetResult(count);
        //    //}
        //}
    }

    /// <summary>
    /// 异步接收数据，超时时回调事件状态
    /// </summary>
    internal class StateInfo
    {
        /// <summary>
        /// 异步接收数据，超时时回调事件状态
        /// </summary>
        public StateInfo(Socket socket, AsyncCallback cb, AsyncCallback tcb, object state)
        {
            Callback = cb;
            TimeoutCallback = tcb;
            this.Socket = socket;
            this.State = state;
            //this.AsycResult = result;
        }
        public Socket Socket
        {
            get; set;
        }
        public object State
        {
            get; set;
        }
        public AsyncCallback Callback
        {
            get; set;
        }
        public AsyncCallback TimeoutCallback
        {
            get; set;
        }
        public IAsyncResult Result
        {
            get; set;
        }
        public RegisteredWaitHandle RegisteredWaitHandle
        {
            get; set;
        }

        //public void SetResult(int count)
        //{
        //    this.IsCompleted = true;
        //    this.ReceivedCount = count;
        //    //this.m_waitHandle.Set();

        //    Callback?.Invoke(this);
        //}

        /// <summary>
        /// 超时后执行回调
        /// </summary>
        public void SetTimeout()
        {
            TimeoutCallback?.Invoke(this.Result);
        }
    }

    /*
    public class AsyncResultTimeout : IAsyncResult
    {
        private ManualResetEvent m_waitHandle = new ManualResetEvent(false);
        public AsyncResultTimeout(Socket socket, object state)
        {
            this.Socket = socket;
            this.AsyncState = state;
        }

        #region IAsyncResult

        public object AsyncState
        {
            get; private set;
        }
        public WaitHandle AsyncWaitHandle
        {
            get; internal set;
        }
        public bool CompletedSynchronously
        {
            get
            {
                return false;
            }
        }
        public bool IsCompleted
        {
            get; private set;
        }

        #endregion

        public Socket Socket
        {
            get; private set;
        }
    }
    */
}