/*
 Sog 游戏基础库
 2016 by zouwei
 */


using System;
using System.Net;
using System.Net.Sockets;
using System.Collections.Generic;
using System.Text;
using System.Threading;
using System.Threading.Tasks;


namespace Sog
{
    public class TcpClientSession : ClientSession
    {
        private SocketAsyncEventArgs connArgs;

        private object m_asyncLocker = new object();
        private long checkKeepAliveAsyncTime;

        public TcpClientSession(ClientSessionSettings clientSettings, SessionNetSelectMode netMode)
            :base(clientSettings, netMode)
        {
            AllockSocket();

            NetSessionObj = new TcpSession(m_socketClient);

            if(netMode == SessionNetSelectMode.Asynchronous)
            {
                connArgs = new SocketAsyncEventArgs();
                connArgs.RemoteEndPoint = settings.RemoteEndPoint;
                connArgs.Completed += OnConnectCallback;

                NetSessionObj.AsyncModeDataReceived += OnDataReceived;
            }
        }

        private void AllockSocket()
        {
            m_socketClient = new Socket(settings.RemoteEndPoint.AddressFamily, 
                SocketType.Stream, ProtocolType.Tcp);

            if (netSelectMode == SessionNetSelectMode.Synchronous)
            {
                m_socketClient.Blocking = false;
            }

            m_socketClient.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, (int)1);
        }

        public override void Connect()
        {
            TraceLog.Trace("TcpClientSession.Connect remote {0}", settings.RemoteEndPoint);

            m_isConnected = false;
            m_isConnecting = true;

            bool connFail = false;
            try
            {
                if (netSelectMode == SessionNetSelectMode.Asynchronous)
                {
                    if (!m_socketClient.ConnectAsync(connArgs))
                    {
                        TraceLog.Debug("TcpClientSession.Connect ConnectAsync return immediately, remote {0} result {1}"
                            , settings.RemoteEndPoint, connArgs.SocketError);
                        OnConnectCallback(this, connArgs);
                    }
                    else
                    {
                        TraceLog.Trace("TcpClientSession.Connect ConnectAsync return true, remote {0} wait OnConnectCallback callback"
                            , settings.RemoteEndPoint);
                    }
                }
                else
                {
                    m_socketClient.Connect(settings.RemoteEndPoint);
                }
            }
            catch (ObjectDisposedException ex)
            {
                TraceLog.Error("TcpClientSession.Connect {0} ObjectDisposedException message {1}",
                    settings.RemoteEndPoint, ex.Message);
                connFail = true;
            }
            catch (InvalidOperationException ex)
            {
                TraceLog.Error("TcpClientSession.Connect {0} InvalidOperationException message {1}",
                    settings.RemoteEndPoint, ex.Message);
                connFail = true;
            }
            catch (SocketException ex)
            {
                if (netSelectMode == SessionNetSelectMode.Synchronous)
                {
                    //这个是正常的
                    TraceLog.Trace("TcpClientSession.Connect {0}, wait connected finish SocketErrorCode {1},",
                        settings.RemoteEndPoint, ex.SocketErrorCode);
                }
                else
                {
                    TraceLog.Debug("TcpClientSession.Connect {0} async, SocketException err code {1}",
                        settings.RemoteEndPoint, ex.SocketErrorCode);
                    connFail = true;
                }
            }
            catch (Exception ex)
            {
                TraceLog.Error("TcpClientSession.Connect {0} fail, exception {1}", settings.RemoteEndPoint, ex);
                connFail = true;
            }

            if (connFail)
            {
                TcpConnectFail();
            }
        }

        public override void Reconnect()
        {
            TraceLog.Trace("TcpClientSession.Reconnect remote {0}", settings.RemoteEndPoint);

            // 重连时m_socketClient如果不是null，要丢掉session中未发送和未解析的信息
            if (m_socketClient != null)
            {
                TraceLog.Error("TcpClientSession.Reconnect close old socket");
                CloseSession();
            }

            //重连的时候重新allock socket，linux下必须如此
            AllockSocket();

            Connect();
        }

        private void OnConnectCallback(object sender, SocketAsyncEventArgs e)
        {
            TraceLog.Trace("TcpClientSession.OnConnectCallback remote {0} ret {1}"
                , settings.RemoteEndPoint, e.SocketError);

            //异步模式下加个锁，防止主线程UpdateAsynchronousMode和socket回调互相影响, 同步模式下也lock下算了，性能影响不大，调用connect频率不高
            lock (m_asyncLocker)
            {
                if (e.SocketError == SocketError.Success)
                {
                    ConnectSucc();
                    return;
                }

                TcpConnectFail();
            }
        }


        private void TcpConnectFail()
        {
            TraceLog.Trace("TcpClientSession.TcpConnectFail remote {0}", settings.RemoteEndPoint);

            CloseSession();
           
            SessionEventArgs arg = new SessionEventArgs();
            arg.Session = NetSessionObj;
            OnConnectFail(arg);
        }

        public override void Update(long nowMs)
        {
            UpdateConnect();
            UpdateReadWrite(nowMs);
        }

        public void UpdateConnect()
        {
            if (! m_isConnecting || m_socketClient == null
                || netSelectMode != SessionNetSelectMode.Synchronous)
            {
                return;
            }

            if (m_socketClient.Poll(0, SelectMode.SelectError))
            {
                TcpConnectFail();
            }
            else
            {
                if (m_socketClient.Poll(0, SelectMode.SelectWrite))
                {
                    ConnectSucc();
                }
            }
        }

        protected void UpdateReadWrite(long nowMs)
        {
            if (m_socketClient == null)
            {
                return;
            }

            if (m_isConnected)
            {
                if (netSelectMode == SessionNetSelectMode.Synchronous)
                {
                    UpdateSynchronousMode();
                }
                else if (netSelectMode == SessionNetSelectMode.Asynchronous)
                {
                    UpdateAsynchronousMode(nowMs);
                }
            }
        }

        protected virtual void UpdateSynchronousMode()
        {
            if (NetSessionObj.IsSocketClosed)
            {
                SocketErrorOnUpdate();
                return;
            }

            bool bError = m_socketClient.Poll(0, SelectMode.SelectError);
            if (bError)
            {
                SocketErrorOnUpdate();
                return;
            }

            bool bReadable = m_socketClient.Poll(0, SelectMode.SelectRead);
            if (bReadable)
            {
                NetSessionObj.RecvReadableSocket();

                Queue<MessageData> dataQueue = NetSessionObj.GetReceivedDataQueue();
                while (dataQueue.Count > 0)
                {
                    MessageData message = dataQueue.Dequeue();

                    SessionEventArgs e = new SessionEventArgs();
                    e.Message = message;
                    e.Session = NetSessionObj;
                    OnDataReceived(this, e);
                }
            }

            //read出错的情况下，read调用之后有可能socket会被关闭
            if (NetSessionObj.IsSocketClosed)
            {
                SocketErrorOnUpdate();
                return;
            }

            NetSessionObj.CheckSocketAndSendKeepAlive();

            //write出错的情况下，write调用之后有可能socket会被关闭
            if (NetSessionObj.IsSocketClosed)
            {
                SocketErrorOnUpdate();
                return;
            }

            if (NetSessionObj.IsHaveDataNeedSend())
            {
                bool bWriteable = m_socketClient.Poll(0, SelectMode.SelectWrite);
                if (bWriteable)
                {
                    NetSessionObj.WriteWriteableSocket();
                }
            }

            //write出错的情况下，write调用之后有可能socket会被关闭
            if (NetSessionObj.IsSocketClosed)
            {
                SocketErrorOnUpdate();
                return;
            }
        }

        // 异步模式update只负责发送心跳包
        protected virtual void UpdateAsynchronousMode(long nowMs)
        {
            if(NetSessionObj == null)
            {
                return;
            }

            if(checkKeepAliveAsyncTime == 0)
            {
                checkKeepAliveAsyncTime = nowMs;
                return;
            }

            if(nowMs - checkKeepAliveAsyncTime > 5000)
            {
                checkKeepAliveAsyncTime = nowMs;
                lock (m_asyncLocker)
                {
                    if (m_isConnected && NetSessionObj.IsSocketClosed)
                    {
                        SocketErrorOnUpdate();
                        return;
                    }

                    NetSessionObj.StartSendAsync();
                }
            }
        }


        protected override void CloseSession()
        {
            TraceLog.Trace("TcpClientSession.CloseSession session {0}", NetSessionObj.SessionID);

            m_isConnected = false;
            m_isConnecting = false;

            //丢弃正在发送和接收的数据，关闭socket
            NetSessionObj.Close();
            m_socketClient = null;
        }
    }
}