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

public class ClientSocket
{
    private static ClientSocket mInstance;
    public static ClientSocket instance
    {
        get
        {
            if (mInstance == null)
                mInstance = new ClientSocket();
            return mInstance;
        }
    }
    public bool connected = false;
    private byte[] mRecvBuff;
    private Socket mSocket;
    private AsyncCallback mRecvCb;
    private Queue<string> mMSgQueue = new Queue<string>();

    private Socket Init()
    {
        Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        // 接收的消息数据包大小限制为0x4000bytes，即16KB
        mRecvBuff = new byte[0x4000];
        mRecvCb = new AsyncCallback(RecvCallBack);
        return clientSocket;
    }

    /// <summary>
    /// 连接服务器
    /// </summary>
    /// <param name="host">ip地址</param>
    /// <param name="port">端口</param>
    public void Connect(string host, int port)
    {
        if (mSocket == null)
            mSocket = Init();
        try
        {
            GameLogger.Log("connect: " + host + ":" + port);
            mSocket.SendTimeout = 3;
            mSocket.Connect(host, port);
            connected = true;
        }
        catch (Exception e)
        {
            GameLogger.LogError(e);
        }
    }

    /// <summary>
    /// 发送消息
    /// </summary>
    /// <param name="bytes"></param>
    public void SendData(byte[] bytes)
    {
        NetworkStream netstream = new NetworkStream(mSocket);
        netstream.Write(bytes, 0, bytes.Length);
    }

    public void SendData(string jsonStr)
    {
        SendData(System.Text.Encoding.UTF8.GetBytes(jsonStr));
    }

    /// <summary>
    /// 尝试接收消息（每帧调用）
    /// </summary>
    public void BeginReceive()
    {
        mSocket.BeginReceive(mRecvBuff, 0, mRecvBuff.Length, SocketFlags.None, mRecvCb, this);
    }

    /// <summary>
    /// 当收到服务器的消息时会回调这个函数
    /// </summary>
    /// <param name="ar"></param>
    private void RecvCallBack(IAsyncResult ar)
    {
        var len = mSocket.EndReceive(ar);
        byte[] msg = new byte[len];
        Array.Copy(mRecvBuff, msg, len);
        var msgStr = System.Text.Encoding.UTF8.GetString(msg);
        // 将消息塞入队列中
        mMSgQueue.Enqueue(msgStr);
        // 将buffer清零
        for (int i = 0; i < mRecvBuff.Length; i++)
        {
            mRecvBuff[i] = 0;
        }
    }

    /// <summary>
    /// 从消息队列中取出消息（供外部调用）
    /// </summary>
    /// <returns></returns>
    public string GetMsgFromQueue()
    {
        if (mMSgQueue.Count > 0)
            return mMSgQueue.Dequeue();
        return null;
    }

    /// <summary>
    /// 关闭Socket
    /// </summary>
    public void CloseSocket()
    {
        GameLogger.Log("close socket");
        try
        {
            mSocket.Shutdown(SocketShutdown.Both);
            mSocket.Close();
        }
        catch (Exception e)
        {
            // GameLogger.LogError(e);
        }
        finally
        {
            mSocket = null;
            connected = false;
        }
    }
}