using System;
using System.Collections.Generic;
using System.Text;
using Facebook.MiniJSON;

namespace BF
{
    internal partial class TCPChannel
    {
        private const uint HeartBeat_Req_Group = 3763117270;
        private const uint HeartBeat_Rsp_Group = 3763119103;
        // private const byte HeartBeat_Req_Cmd = 2;
        private const int HeartBeat_Rsp_OK = 0;

        // 上一次发送心跳包的时间
        private double lastSendHeartBeatTime = 0;
        //已发送心跳包的数量；接收到任意返回心跳包就重置
        private int sendHeartBeatCount = 0;
        //不发心跳包的最长时间，超过这个时间，就开始重连（因为某些原因，造成网络线程暂停，此时需要这个逻辑）
        private float maxHeartBeatMissTime = 0;

        /// <summary>
        /// 心跳包同步的服务器当前时间戳 ms
        /// </summary>
        private long serverTimestamp;

        private void InitializeHeartBeat()
        {
            maxHeartBeatMissTime = ownerConnection.configuration.HeartBeatInterval *
                                   ownerConnection.configuration.MaxHeartBeatMissCount;

            ResetHeartBeatStatus();
        }

        private void HeartBeat()
        {
            if (!ownerConnection.configuration.EnableHeartBeat)
            {
                return;
            }

            if (actualStatus != NetConnectStatus.Connected)
            {
                return;
            }

            var nowSecond = NetTime.Now;
            ////距离上一次发送心跳包的时间
            var waitHeartBeatInterval = nowSecond - lastSendHeartBeatTime;
            if (waitHeartBeatInterval < ownerConnection.configuration.HeartBeatInterval)
            {
                return;
            }

            SendHeartBeat(nowSecond, waitHeartBeatInterval);
        }

        /// <summary>
        /// 检测接收的消息是否是心跳包
        /// </summary>
        /// <param name="incomingMessage"></param>
        /// <returns>true: 是心跳包；false: 其他消息</returns>
        private bool FilterHeartBeatIncomingMessage(NetIncomingMessage incomingMessage)
        {
            if (incomingMessage.Group != HeartBeat_Rsp_Group)
            {
                return false;
            }

            //receive heart beat success
            ResetHeartBeatStatus();

            this.serverTimestamp = 0;

            //release heartbeat message
            var heartbeatMessage = ownerConnection.CreateIncomingMessage(NetIncomingMessageType.HeartBeatMessage, null);
            heartbeatMessage.HeartbeatSyncTimestamp = this.serverTimestamp;
            ReleaseMessage(heartbeatMessage);

            LogDebug("Heart beat success !!!");

            return true;
        }

        /// <summary>
        /// receive any message, reset heart beat status
        /// </summary>
        private void ResetHeartBeatStatus()
        {
            sendHeartBeatCount = 0;
            lastSendHeartBeatTime = NetTime.Now;
        }

        /// <summary>
        /// 设置上次心跳时间，立刻发送心跳
        /// </summary>
        private void ForceSendHeartBeatImmediately()
        {
            // lastSendHeartBeatTime = NetTime.Now - ownerConnection.configuration.HeartBeatInterval - 1;
            lastSendHeartBeatTime = NetTime.Now;
        }

        private void SendHeartBeat(double nowSecond, double waitHeartBeatInterval)
        {
            if (actualStatus != NetConnectStatus.Connected)
            {
                return;
            }
            sendHeartBeatCount += 1;
            //miss heart beat message to many, try reconnect.
            if (sendHeartBeatCount > ownerConnection.configuration.MaxHeartBeatMissCount)
            {
                LogDebug("Miss heart beat max count, try reconnect.");
                StartSmartReconnectCountdown();
                ResetHeartBeatStatus();
                return;
            }

            // 如果两次心跳包之间的时间间隔，超过了最大心跳次数的间隔，开始重连；
            // 因为某些原因，造成网络线程暂停，此时需要这个逻辑；
            if (waitHeartBeatInterval > maxHeartBeatMissTime)
            {
                LogDebug("Miss heart beat max time, try reconnect.");
                StartSmartReconnectCountdown();
                ResetHeartBeatStatus();
                return;
            }

            var heartBeat = CreateHeartBeatOutgoingMessage();
            SendInternal(heartBeat);

            lastSendHeartBeatTime = nowSecond;

            LogDebug("Begin send heart beat !!!");
        }

        private NetOutgoingMessage CreateHeartBeatOutgoingMessage()
        {
            var message = ownerConnection.CreateOutgoingMessage(NetOutgoingMessageType.UserData);

            var heartBeatData = SerializeHeartBeatReq();
            message.Encode(HeartBeat_Req_Group, 0, heartBeatData);
            return message;
        }

        /// <summary>
        /// @TODO Temp
        /// </summary>
        /// <returns></returns>
        private byte[] SerializeHeartBeatReq()
        {
            byte[] data = {};

            return data;
        }

        /// <summary>
        /// @TODO Temp
        /// </summary>
        /// <param name="data"></param>
        /// <param name="status"></param>
        /// <returns></returns>
        private bool DeserializeHeartBeatRsp(byte[] data, out long status, out long serverTimestamp)
        {
            serverTimestamp = 0;
            status = 0;

            return true;
        }
    }
}