using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Net;
using System.Text;
using UnityEngine;

namespace BF
{
    /// <summary>
    ///  Current version only support one connection
    /// </summary>
    internal class RpcService : MonoBehaviour
    {
        internal class ResponseMessage
        {
            /// <summary>
            /// 是否请求成功
            /// </summary>
            public bool isSuccess { get; set; }

            /// <summary>
            /// 请求失败后的错误消息；成功时，没有此消息
            /// </summary>
            public string errorMsg { get; set; }

            public string payload { get; set; }
        }


        private class RequestMessage
        {
            public byte group;
            public byte cmd;
            public byte[] data;
            public Action<ResponseMessage> callback;
        }

        public enum RpcState
        {
            None,
            Connecting,
            PrepareSend,
            WaitingRsp,
        }

        private const string ConnectId = nameof(RpcService);

        private RpcState rpcState;
        private RequestMessage currentMessage = new RequestMessage();
        private ResponseMessage replyMessage = new ResponseMessage();
        private bool netClientInitialized = false;
        private NetConfiguration configuration;
        private int remainRetryCount;
        private float requestTimeout = 6;
        private string ipAddress;
        private int port;


        #region Instance

        private static RpcService instance;
        public static RpcService Instance
        {
            get
            {
                if (!instance)
                {
                    var gameObj = new GameObject(nameof(RpcService));
                    instance = gameObj.AddComponent<RpcService>();
                }

                return instance;
            }
        }

        private void Awake()
        {
            DontDestroyOnLoad(gameObject);
        }

        private void OnDestroy()
        {
            instance = null;
        }

        #endregion

        internal void SendRequest(string address, int port, byte group, byte cmd, string args, Action<ResponseMessage> response,
            int retryCount,float timeout)
        {
            // service is busy directly response error
            if (rpcState != RpcState.None)
            {
                replyMessage.isSuccess = false;
                replyMessage.errorMsg = "Current rpc service is busy";
                replyMessage.payload = string.Empty;
                response?.Invoke(replyMessage);
                return;
            }

            currentMessage.cmd = cmd;
            currentMessage.@group = group;
            currentMessage.data = Encoding.UTF8.GetBytes(args);
            currentMessage.callback = response;

            // set state to connecting
            rpcState = RpcState.Connecting;

            // setup retry
            remainRetryCount = retryCount;
            requestTimeout = timeout;
            ipAddress = address;
            this.port = port;

            StartRpcService(address, port);

            // start timeout
            Invoke(nameof(OnRequestTimeout),requestTimeout);
        }

        private void StartRpcService(string address, int port)
        {
            // lazy initialize
            if (configuration == null)
            {
                configuration = new NetConfiguration
                {
                    ServiceType = NetServiceType.TCPService,
                    ThreadName = "TcpService"
                };
            }

            var netClient = NetClient.Instance;
            netClient.Init();
            netClient.SetupService(configuration);
            netClient.Start();

            Connect(ConnectId, address, port);
        }

        private void Connect(string connectId, string ip, int port)
        {
            var netClient = NetClient.Instance;
            NetConnectConfiguration configuration =
                new NetConnectConfiguration(NetServiceType.TCPService, connectId);

            configuration.EnableMessageType(NetIncomingMessageType.DebugMessage);
            configuration.EnableMessageType(NetIncomingMessageType.WarningMessage);
            configuration.EnableMessageType(NetIncomingMessageType.ErrorMessage);

            // disable reconnect
            // if connection disconnected when sending data
            // we will directly response error and close connection
            configuration.EnableSilenceReconnect = false;
            configuration.HeartBeatInterval = 20;
            configuration.MaxHeartBeatMissCount = 3;

            // check address is domain or ip address
            if (IPAddress.TryParse(ip, out IPAddress ipAddress))
            {
                netClient.Connect(configuration, ipAddress, port);
            }
            else
            {
                netClient.Connect(configuration, ip, port);
            }
        }

        private void Update()
        {
            // when connected , message send next frame
            if (rpcState == RpcState.PrepareSend)
            {
                // send data
                NetClient.Instance.Send(ConnectId, currentMessage.group, currentMessage.cmd,
                    currentMessage.data);
                rpcState = RpcState.WaitingRsp;
            }

            var netClient = NetClient.Instance;
            INetIncomingMessage incomingMessage = null;
            while ((incomingMessage = netClient.ReadMessage(ConnectId)) != null)
            {
                HandleIncomingMessage(incomingMessage);
                netClient.RecycleMessage(ConnectId, incomingMessage);
            }
        }

        private void HandleIncomingMessage(INetIncomingMessage message)
        {
            switch (message.MessageType)
            {
                case NetIncomingMessageType.DebugMessage:
                case NetIncomingMessageType.WarningMessage:
                    Debug($"Debug Info : {message.ErrorCode} : {message.ErrorMsg}");
                    break;

                case NetIncomingMessageType.ErrorMessage:
                    HandleErrorMessage(message);
                    break;

                case NetIncomingMessageType.Data:
                    HandleDataMessage(message);
                    break;

                case NetIncomingMessageType.StatusChange:
                    HandleStatusMessage(message);
                    break;

                case NetIncomingMessageType.HeartBeatMessage:
                    // don't care
                    break;

                default:
                    throw new NotImplementedException();
            }
        }

        private void HandleErrorMessage(INetIncomingMessage message)
        {
            UnityEngine.Debug.LogError($"Debug Info : {message.ErrorCode} : {message.ErrorMsg}");
            replyMessage.isSuccess = false;
            replyMessage.errorMsg = message.ErrorMsg;
            replyMessage.payload = string.Empty;
            currentMessage.callback?.Invoke(replyMessage);
            ResetState();
        }

        private void HandleDataMessage(INetIncomingMessage message)
        {
            if (currentMessage.cmd != message.CMD || currentMessage.@group != message.Group)
            {
                // ignore not matched data
                replyMessage.isSuccess = false;
                replyMessage.errorMsg = "Message type dis-matched";
            }
            else
            {
                replyMessage.isSuccess = true;
                replyMessage.errorMsg = string.Empty;
                replyMessage.payload = Encoding.UTF8.GetString(message.Data);
            }

            currentMessage.callback?.Invoke(replyMessage);
            ResetState();
        }

        private void HandleStatusMessage(INetIncomingMessage message)
        {
            NetConnectStatus status = message.ConnectStatus;
            // connect success
            // will send data in next frame
            if (status == NetConnectStatus.Connected && rpcState == RpcState.Connecting)
            {
                rpcState = RpcState.PrepareSend;
            }
            // waiting server reply but the connection disconnected
            // reply error
            else if (status == NetConnectStatus.Disconnected && rpcState == RpcState.WaitingRsp)
            {
                replyMessage.isSuccess = false;
                replyMessage.errorMsg = "Connection disconnected when waiting for reply;Maybe server not support the request";
                replyMessage.payload = string.Empty;
                currentMessage.callback?.Invoke(replyMessage);
                ResetState();
            }

        }

        private void ResetState()
        {
            CancelInvoke(nameof(OnRequestTimeout));
            currentMessage.callback = null;
            rpcState = RpcState.None;
            NetClient.Instance.Close(ConnectId);
            NetClient.Instance.Shutdown();
        }

        private void OnRequestTimeout()
        {
            replyMessage.isSuccess = false;
            replyMessage.errorMsg = "Waiting reply timeout";
            replyMessage.payload = string.Empty;
            remainRetryCount--;
            if (remainRetryCount < 0)
            {
                currentMessage?.callback.Invoke(replyMessage);
                ResetState();
            }
            else
            {
                CancelInvoke(nameof(OnRequestTimeout));
                // start timeout
                Invoke(nameof(OnRequestTimeout),requestTimeout);
                rpcState = RpcState.None;
                NetClient.Instance.Close(ConnectId);
                // try reconnect
                Connect(ConnectId, ipAddress, port);
            }
        }

        [Conditional("BF_DEBUG")]
        private static void Debug(string message)
        {
            UnityEngine.Debug.Log(message);
        }
    }
}