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

namespace Sog
{
    /// <summary>
    /// session的轮询管理
    /// </summary>
    public class AcceptedSessionUpdate
    {
        private List<NetSession> m_asyncAddedSessions = new List<NetSession>();
        private object m_asyncAddedSessionsLocker = new object();

        private List<NetSession> m_asyncClosedSessions = new List<NetSession>();
        private object m_asyncClosedSessionsLocker = new object();

        private Dictionary<Socket,NetSession> m_sessionDict = new Dictionary<Socket,NetSession>();

        private List<Socket> m_readList = new List<Socket>();
        private List<Socket> m_writeList = new List<Socket>();
        private List<Socket> m_errorList = new List<Socket>();

        //临时存放所有出错的socket
        private List<Socket> m_needCloseList = new List<Socket>();

        private SessionListener m_listener;

        public AcceptedSessionUpdate(SessionListener listener)
        {
            m_listener = listener;
        }

        public int GetSessionCount()
        {
            return m_sessionDict.Count + m_asyncAddedSessions.Count;
        }


        public void Add(NetSession session)
        {
            if(session.WorkSocket == null)
            {
                return;
            }

            m_sessionDict.Add(session.WorkSocket, session);
        }

        public void AddAsync(NetSession session)
        {
            lock(m_asyncAddedSessionsLocker)
            {
                m_asyncAddedSessions.Add(session);
            }
        }

        public void ForceAsyncCloseSession(NetSession session)
        {
            lock(m_asyncClosedSessionsLocker)
            {
                if(m_asyncClosedSessions.Contains(session))
                {
                    return;
                }

                m_asyncClosedSessions.Add(session);
            }
        }

        public void Close()
        {
            m_readList.Clear();
            m_writeList.Clear();
            m_errorList.Clear();
            m_needCloseList.Clear();
            m_asyncAddedSessions.Clear();
            m_sessionDict.Clear();
        }

        public void Update(long nowMs)
        {
            m_readList.Clear();
            m_writeList.Clear();
            m_errorList.Clear();
            m_needCloseList.Clear();

            foreach (var pair in m_sessionDict)
            {
                NetSession session = pair.Value;
                Socket socket = pair.Key;

                if (session.IsSocketClosed)
                {
                    AddSocketToNeedClose(socket);
                    continue;
                }

                session.CheckSocketAndSendKeepAlive();
                if (session.IsSocketClosed)
                {
                    AddSocketToNeedClose(socket);
                    continue;
                }
                m_readList.Add(socket);

                //是否可写可优化，没数据不判断，提高效率
                if (session.IsHaveDataNeedSend())
                {
                    m_writeList.Add(socket);
                }

                m_errorList.Add(socket);

                //不要太大,windows下最大64,linux下32
                if (m_readList.Count >= 32)
                {
                    Socket.Select(m_readList, m_writeList, m_errorList, 0);
                    process_select_result();
                }
            }

            //最后剩下的
            if (m_readList.Count > 0)
            {
                Socket.Select(m_readList, m_writeList, m_errorList, 0);
                process_select_result();
            }


            //其他线程关闭的session
            if (m_asyncClosedSessions.Count > 0)
            {
                lock (m_asyncClosedSessionsLocker)
                {
                    foreach (var session in m_asyncClosedSessions)
                    {
                        if (session.WorkSocket != null)
                        {
                            AddSocketToNeedClose(session.WorkSocket);
                        }
                    }
                    m_asyncClosedSessions.Clear();
                }
            }

            if (m_needCloseList.Count > 0)
            {
                process_close_result();
            }

            // 异步添加的session在这里放到dict里去
            if (m_asyncAddedSessions.Count > 0)
            {
                lock (m_asyncAddedSessionsLocker)
                {
                    foreach (var session in m_asyncAddedSessions)
                    {
                        Add(session);
                    }

                    m_asyncAddedSessions.Clear();
                }
            }
        }

        private void process_select_result()
        {
            //read
            foreach (Socket socket in m_readList)
            {
                read_socket(socket);
            }
            m_readList.Clear();

            //write
            foreach (Socket socket in m_writeList)
            {
                write_socket(socket);
            }
            m_writeList.Clear();


            //error
            foreach (Socket socket in m_errorList)
            {
                AddSocketToNeedClose(socket);
            }
            m_errorList.Clear();

        }

        private void read_socket(Socket socket)
        {
            NetSession netSession = m_sessionDict[socket];
            if (netSession != null)
            {
                netSession.RecvReadableSocket();

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

                    SessionEventArgs e = new SessionEventArgs();
                    e.Message = message;
                    e.Session = netSession;

                    m_listener.OnDataReceived(null, e);
                }

                //说明接受数据出错了
                if (netSession.IsSocketClosed)
                {
                    AddSocketToNeedClose(socket);
                }
            }

        }

        private void write_socket(Socket socket)
        {
            NetSession netSession = m_sessionDict[socket];
            if (netSession != null)
            {
                netSession.WriteWriteableSocket();

                //说明发送数据出错了
                if (netSession.IsSocketClosed)
                {
                    AddSocketToNeedClose(socket);
                }
            }
        }

        private void AddSocketToNeedClose(Socket socket)
        {
//            if (m_needCloseList.Contains(socket))
//            {
//                return;
//            }

            m_needCloseList.Add(socket);
        }

        private void process_close_result()
        {
            foreach (Socket socket in m_needCloseList)
            {
                if (m_sessionDict.ContainsKey(socket))
                {
                    NetSession session = m_sessionDict[socket];

                    m_sessionDict.Remove(socket);

                    SessionEventArgs e = new SessionEventArgs();
                    e.Session = session;
                    m_listener.OnDisconnected(e);

                    session.Close();
                }
            }
            m_needCloseList.Clear();
        }
    }
}