using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FINSTCPIP
{
    //用来解析FINS包的数据和将数据打包
   public class FINSParse
   {
        public FINSParse ()
        {
            _socketConnected = false;
            _finsConnected = false;
            _ifIniting = true;
        }

        readonly byte[] HEADER_FINS = new byte[4] { FINS_F, FINS_I, FINS_N, FINS_S };   //FINS 的 ASCII

        public byte[] _clientaddr = new byte[4];    //客户端IP第四节（程序）
        public byte[] _serveraddr = new byte[4];    //服务端IP第四节（PLC）
        public bool _socketConnected;   //socket连接
        public bool _finsConnected;     //FINS连接
        public bool _ifIniting;         //正在初始化      
        public int connectTimes;


        string _errname = string.Empty;
        public string CommLayerError
        {
            get { return _errname; }
            set { _errname = value; }
        }
        public const byte SID = 255;

        #region 『FINS/TCP Header 』 
        // Header
        public const byte FINS_F = 0x46;
        public const byte FINS_I = 0x49;
        public const byte FINS_N = 0x4e;
        public const byte FINS_S = 0x53;

        // Length 报文中的字段长度，从 Command 开始，到报文结束（不包括Header的长度和Length的长度）
        public const byte SHAKEHAND_SEND_LENGTH = 12;   //FINS 握手请求报文中 Length 的值
        public const byte SHAKEHAND_RECV_LENGTH = 16;   //FINS 握手回复报文中 Length 的值
        public const byte FRAM_NODATA_SEND_LENGTH = 26; //FINS 发送读报文中无数据的 Length 的值
        public const byte FRAM_NODATA_RECV_LENGTH = 22; //FINS 收到读报文中无数据的 Length 的值

        // Command
        public const byte CLIENT_SERVER = 0;
        public const byte SERVER_CLIENT = 1;
        public const byte FINS_FRAME = 2;
        public const byte ERROR_FRAME = 3;
        public const byte CONNECT_RIGHT = 6;

        // ErrorCode
        // 0 正常
        // 01 Header不正确
        // 02 数据过长
        // 03 命令Command错误
        // 20 连接/通道被占用
        #endregion

        
        /// <summary>
        /// 返回 FINS 握手需要的数据
        /// </summary>
        public byte[] GetConnectInfo(byte clientAddr = 0)
        {
            byte[] SendByte = new byte[8 + SHAKEHAND_SEND_LENGTH];
           
            SendByte[0] = HEADER_FINS[0];  //header
            SendByte[1] = HEADER_FINS[1];
            SendByte[2] = HEADER_FINS[2];
            SendByte[3] = HEADER_FINS[3];

            SendByte[4] = 0; //cmd length
            SendByte[5] = 0;
            SendByte[6] = 0;
            SendByte[7] = SHAKEHAND_SEND_LENGTH;

            SendByte[8] = 0; //frame command
            SendByte[9] = 0;
            SendByte[10] = 0;
            SendByte[11] = CLIENT_SERVER;

            SendByte[12] = 0;//err
            SendByte[13] = 0;
            SendByte[14] = 0;
            SendByte[15] = 0;

            SendByte[16] = 0;//FINS Frame (本机节点)(0为自动，PLC返回)
            SendByte[17] = 0;
            SendByte[18] = 0;
            SendByte[19] = clientAddr;
        
            return SendByte; 
        }
        

        /// <summary>
        /// 读取 DM 内存时所需的信息。由上层定时调用
        /// </summary>
        /// <param name="startAdress">要读取的起始地址</param>
        /// <param name="lenth">要读的长度</param>
        /// <param name="isbit">是否按位读取</param>
        public byte[] GetInfo_DMRead(ushort startAdress, ushort lenth, bool isbit = false)
        {
            try
            {
                byte[] SendByte = new byte[FRAM_NODATA_SEND_LENGTH + 8];

                SendByte[0] = HEADER_FINS[0]; //header
                SendByte[1] = HEADER_FINS[1];
                SendByte[2] = HEADER_FINS[2];
                SendByte[3] = HEADER_FINS[3];

                SendByte[4] = 0; //cmd length
                SendByte[5] = 0;
                SendByte[6] = 0;
                SendByte[7] = FRAM_NODATA_SEND_LENGTH;

                SendByte[8] = 0;//frame command
                SendByte[9] = 0;
                SendByte[10] = 0;
                SendByte[11] = FINS_FRAME;

                SendByte[12] = 0;//err
                SendByte[13] = 0;
                SendByte[14] = 0;
                SendByte[15] = 0;

                //command frame header
                SendByte[16] = 0x80;//ICF
                SendByte[17] = 0x00;//RSV
                SendByte[18] = 0x02;//GCT, less than 8 network layers
                SendByte[19] = 0x00;//DNA, local network
                SendByte[20] = _serveraddr[3];//DA1
                SendByte[21] = 0x00;//DA2, CPU unit
                SendByte[22] = 0x00;//SNA, local network
                SendByte[23] = _clientaddr[3];//SA1
                SendByte[24] = 0x00;//SA2, CPU unit
                SendByte[25] = Convert.ToByte(SID);//SID

                SendByte[26] = 0x01;    //0101 Read
                SendByte[27] = 0x01;
                

                byte[] head = AddrToByte("DM", startAdress, lenth, isbit);
                SendByte[28] = head[0];
                SendByte[29] = head[1];
                SendByte[30] = head[2];
                SendByte[31] = head[3];
                SendByte[32] = head[4];
                SendByte[33] = head[5];

                return SendByte;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }


        /// <summary>
        /// 写入 DM 内存时所需的信息。由上层定时调用.(lenth好像不太对，目前只保证写16位的变量时没问题)
        /// </summary>
        /// <param name="startAdress">要写入的起始地址</param>
        /// <param name="lenth">要写的长度</param>
        /// <param name="data">要写数据</param>
        /// <param name="isbit">是否按位写入</param>
        public byte[] GetInfo_DMWrite(ushort startAdress, ushort lenth, byte[] data, bool isbit = false)
        {
            try
            {
                byte[] SendByte = new byte[8 + data.Length + FRAM_NODATA_SEND_LENGTH];
                SendByte[0] = HEADER_FINS[0];
                SendByte[1] = HEADER_FINS[1];
                SendByte[2] = HEADER_FINS[2];
                SendByte[3] = HEADER_FINS[3];


                SendByte[4] = 0;//cmd length
                SendByte[5] = 0;
                SendByte[6] = 0;
                SendByte[7] = Convert.ToByte(FRAM_NODATA_SEND_LENGTH + data.Length);

                SendByte[8] = 0;//frame command
                SendByte[9] = 0;
                SendByte[10] = 0;
                SendByte[11] = FINS_FRAME;

                SendByte[12] = 0;//err
                SendByte[13] = 0;
                SendByte[14] = 0;
                SendByte[15] = 0;

                //command frame header
                SendByte[16] = 0x80;//ICF
                SendByte[17] = 0x00;//RSV
                SendByte[18] = 0x02;//GCT, less than 8 network layers
                SendByte[19] = 0x00;//DNA, local network
                SendByte[20] = _serveraddr[3];//DA1
                SendByte[21] = 0x00;//DA2, CPU unit
                SendByte[22] = 0x00;//SNA, local network
                SendByte[23] = _clientaddr[3];//SA1
                SendByte[24] = 0x00;//SA2, CPU unit
                SendByte[25] = Convert.ToByte(SID);//SID

                SendByte[26] = 0x01;    //0102 Write
                SendByte[27] = 0x02;


                byte[] head = AddrToByte("DM", startAdress, lenth, isbit);
                SendByte[28] = head[0];
                SendByte[29] = head[1];
                SendByte[30] = head[2];
                SendByte[31] = head[3];
                SendByte[32] = head[4];
                SendByte[33] = head[5];

                Array.Copy(data, 0, SendByte, 34, data.Length);

                return SendByte;
            }
            catch (Exception ex)
            {
                throw ex;   //理论上不会报错
            }
        }

        /// <summary>
        /// 地址格式转换.PLC的内存地址(区域.地址.字长度 如：WR.10.4)
        /// </summary>
        /// <param name="memory">内存区域</param>
        /// <param name="startaddr">起始地址</param> 
        /// <param name="len">读写长度</param>  
        /// <param name="isBit">数据类型为位</param>
        private byte[] AddrToByte(string memory, int startaddr, int  len, bool isBit)
        {
          
            byte[] CH = BitConverter.GetBytes(startaddr);
            byte[] Count = BitConverter.GetBytes(len);
            byte[] Addrs = new byte[6];
            
            if (!isBit)   //字处理            
            {
                switch (memory)
                {
                    case "CIO":
                        Addrs[0] = 0xB0;
                        break;
                    case "WR":
                        Addrs[0] = 0xB1;
                        break;
                    case "DM":
                        Addrs[0] = 0x82;
                        break;
                    case "HR":
                        Addrs[0] = 0xB2;
                        break;
                    case "TIM":
                        Addrs[0] = 0x89;
                        break;
                    case "AR":
                        Addrs[0] = 0xB3;
                        break;
                    case "CNT":
                        Addrs[0] = 0x89;
                        break;
                    default:
                        Addrs[0] = 0x00;
                        break;
                }

                Addrs[1] = CH[1];
                Addrs[2] = CH[0];
                Addrs[3] = 0x00;
                Addrs[4] = Count[1];
                Addrs[5] = Count[0];//读写字的长度
            }
            else //位处理            
            {
                switch (memory)
                {
                    case "CIO":
                        Addrs[0] = 0x30;
                        break;
                    case "WR":
                        Addrs[0] = 0x31;
                        break;
                    case "DM":
                        Addrs[0] = 0x02;
                        break;
                    case "HR":
                        Addrs[0] = 0x32;
                        break;
                    case "TIM":
                        Addrs[0] = 0x09;
                        break;
                    case "AR":
                        Addrs[0] = 0x33;
                        break;
                    case "CNT":
                        Addrs[0] = 0x09;
                        break;
                    default:
                        Addrs[0] = 0x00;
                        break;
                }

                Addrs[1] = CH[1];
                Addrs[2] = CH[0];
                Addrs[3] = Count[0];
                Addrs[4] = 0x00;
                Addrs[5] = 0x01;//每次读写一位
            }

            return Addrs;
        }

        //前四位是 'FINS'
        public bool IsHeader(byte[] recv)
        {
            if (recv.Length < HEADER_FINS.Length)
            {
                CommLayerError = "Header is too short, not enough four!";
                return false;
            }
            if (recv[0] != HEADER_FINS[0] || recv[1] != HEADER_FINS[1] || recv[2] != HEADER_FINS[2] || recv[3] != HEADER_FINS[3])
            {
                CommLayerError = "Header is not 'FINS'!";
                return false;
            }
            return true;
        }
        //根据接收到的包，来判断FINS连接是否成功，并更新_clientaddr和_serveraddr
        public bool IsConnectRight(List<byte> recv)
        {
            if (recv.Count < SHAKEHAND_RECV_LENGTH + 8)
            {
                CommLayerError = "建立连接时，收到的数据长度不够。";
                return false;
            }
            int err = 0;
            if (recv[11] == ERROR_FRAME || recv[14] != 0 || recv[15] != 0)
            {
                switch (recv[15])
                {
                    case 0x01:
                        err = 2;
                        CommLayerError = "ERROR CODE:2——header is not 'FINS'";
                        break;//the head is not 'FINS'
                    case 0x02: 
                        err = 3;
                        CommLayerError = "ERROR CODE:4——the data length is too long";
                        break;//the data length is too long 
                    case 0x03:
                        err = 4;
                        CommLayerError = "ERROR CODE:8——the command is not supported";
                        break;//the command is not supported
                    case 0x20:
                        err = 32;
                        CommLayerError = "ERROR CODE:32——PLC 拒绝访问，请重启 PLC!";
                        break;//the command is not supported
                    default:
                        err = 1;
                        break;
                }

            }

            if (recv[7] == SHAKEHAND_RECV_LENGTH && recv[11] == SERVER_CLIENT && recv[15] == 0)
            {
                _clientaddr[0] = recv[16];
                _clientaddr[1] = recv[17];
                _clientaddr[2] = recv[18];
                _clientaddr[3] = recv[19];

                _serveraddr[0] = recv[20];
                _serveraddr[1] = recv[21];
                _serveraddr[2] = recv[22];
                _serveraddr[3] = recv[23];
            }


            if (err == 0)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        //需要返回错误类型（未完成）
        private bool IsFrameHeaderRight(byte[] recv)
        {
            int err = 0;
            if (recv[0] != 128 && recv[0] != 192)
            {
                err = 1;// ICF错误
            }
            if (recv[1] != 0)
            {
                err = 1;
            }
            if (recv[2] != 2)
            {
                err = 1;
            }
            if (recv[4] != _clientaddr[3])
            {
                err = 1;
            }
            if (recv[7] != _serveraddr[3])
            {
                err = 1;
            }
            if (recv[9] != SID)
            {
                //err = 1;
            }
            if (err == 0)
                return true;
            else
                return false;

        }
        //
        private bool IsFrameCommandRight(byte[] recv)
        {
            int err = -1;
            if (recv[0] == 1 && recv[1] == 1 && recv[2] == 0 && recv[3] == 0)
            {//读内存
                err = 0;
            }
            if (recv[0] == 1 && recv[1] == 2 && recv[2] == 0 && recv[3] == 0)
            {//写内存
                err = 0;
            }

            if (err == 0)
                return true;
            else
                return false;

        }

        //
        public bool IsRecvRight(List<byte> recv)
        {
            if (recv.Count < FRAM_NODATA_RECV_LENGTH + 8)
            {
                CommLayerError = "数据长度不够。";
                return false;
            }
            int err = 0;
            if (recv[11] == ERROR_FRAME)
            {
                switch (recv[15])
                {
                    case 0x01: err = 2; CommLayerError = "ERROR CODE:2——the head is not 'FINS'。"; break;//the head is not 'FINS'
                    case 0x02: err = 3; CommLayerError = "ERROR CODE:4——the data length is too long。"; break;//the data length is too long 
                    case 0x03: err = 4; CommLayerError = "ERROR CODE:8——the command is not supported。"; break;//the command is not supported
                }

            }

            if (recv[7] >= FRAM_NODATA_RECV_LENGTH && recv[11] == FINS_FRAME && recv[15] == 0)
            {

                byte[] header = new byte[10];
                recv.CopyTo(SHAKEHAND_RECV_LENGTH, header, 0, 10);
                if (IsFrameHeaderRight(header) == false)
                {
                    err = 1;
                    CommLayerError = "FrameHeader不正确。";
                }
                byte[] commad = new byte[4];
                recv.CopyTo(FRAM_NODATA_SEND_LENGTH, commad, 0, 4);
                if (IsFrameCommandRight(commad) == false)
                {
                    err = 1;
                    CommLayerError = "FrameCommand不正确。";
                }
            }

            if (err == 0)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}