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

namespace IStation.DataDockingSocket
{
    //ModBus RTU标准:
    static public class ModBusRtuHelper
    {
        /// <summary>
        /// 得到16位的CRC检验码:低位在前[0],高位在后[1]
        /// </summary>
        /// <param name="message4PT">注意输入的消息长度要求包含CRC的2位，否则计算出来CRC不正确</param>
        /// <param name="CRC"></param>
        public static void GetCRC16(byte[] message, ref byte[] CRC)
        {
            //Function expects a modbus message4PT of any length as well as a 2 byte CRC array in which to 
            //return the CRC values:
            if (CRC == null)
                CRC = new byte[2];

            ushort CRCFull = 0xFFFF;
            byte CRCHigh = 0xFF, CRCLow = 0xFF;
            char CRCLSB;

            for (int i = 0; i < (message.Length) - 2; i++)
            {
                CRCFull = (ushort)(CRCFull ^ message[i]);

                for (int j = 0; j < 8; j++)
                {
                    CRCLSB = (char)(CRCFull & 0x0001);
                    CRCFull = (ushort)((CRCFull >> 1) & 0x7FFF);

                    if (CRCLSB == 1)
                        CRCFull = (ushort)(CRCFull ^ 0xA001);
                }
            }
            CRC[1] = CRCHigh = (byte)((CRCFull >> 8) & 0xFF);
            CRC[0] = CRCLow = (byte)(CRCFull & 0xFF);
        }

        //
        // 摘要:
        //     构建查询消息
        //
        // 参数:
        //    address设备地址,注意是byte格式,最大255
        //    func功能码
        //    startRegister 寄存器开始地址(用十进制的地址)
        //    numRegister   寄存器数量
        //    
        // 返回结果
        //    消息List类型,不成功返回NULL
        public static void BuildSendMessage(byte address, byte func, ushort start, ushort registers, ref byte[] message)
        {
            //构建消息 message数据长度要求包含最后2位的校验码
            message = new byte[8];
            message[0] = address;
            message[1] = func;
            message[2] = (byte)(start >> 8);
            message[3] = (byte)start;
            message[4] = (byte)(registers >> 8);
            message[5] = (byte)registers;

            //计算16位的CRC校验码 
            byte[] CRC = new byte[2];
            GetCRC16(message, ref CRC);

            //赋值校验码
            message[message.Length - 2] = CRC[0];
            message[message.Length - 1] = CRC[1];
        }

        /// <summary>
        /// 写入多个
        /// </summary>
        /// <param name="address"></param>
        /// <param name="start"></param>
        /// <param name="registers"></param>
        /// <param name="v"></param>
        /// <param name="message"></param>
        public static void BuildSendMessage16(byte address, ushort start, ushort registers, float v, ref byte[] message)
        {
            byte[] bytes4Float = BitConverter.GetBytes(v);

            //        09-03-08-40-40-00-00-40-40-00-00-EE-57
            //构建消息 message数据长度要求包含最后2位的校验码
            message = new byte[12];
            message[0] = address;
            message[1] = 0x10;
            message[2] = (byte)(start >> 8);
            message[3] = (byte)start;
            message[4] = (byte)(registers >> 8);
            message[5] = (byte)registers;
            message[6] = (byte)04;//2个就*2
            message[7] = bytes4Float[3];//要倒过来 0x40;
            message[8] = bytes4Float[2];//要倒过来0x80;
            message[9] = bytes4Float[1];//要倒过来0x00;
            message[10] = bytes4Float[0];//要倒过来0x00;
 
            //计算16位的CRC校验码 
            byte[] CRC = new byte[2];
            GetCRC16(message, ref CRC);

            //赋值校验码
            message[message.Length - 2] = CRC[0];
            message[message.Length - 1] = CRC[1];
        }

        /// <summary>
        /// 写入单个
        /// </summary>
        /// <param name="address"></param>
        /// <param name="start"></param>
        /// <param name="registers"></param>
        /// <param name="v"></param>
        /// <param name="message"></param>
        public static void BuildSendMessage06(byte address, ushort start, ushort registers, int v, ref byte[] message)
        {
            byte[] bytes4Value = BitConverter.GetBytes(v);
 
            //构建消息 message数据长度要求包含最后2位的校验码
            message = new byte[8];
            message[0] = address;
            message[1] = 0x06;
            message[2] = (byte)(start >> 8);
            message[3] = (byte)start;
 
            message[4] = bytes4Value[1];//要倒过来0x00;
            message[5] = bytes4Value[0];//要倒过来0x00;

            //计算16位的CRC校验码 
            byte[] CRC = new byte[2];
            GetCRC16(message, ref CRC);

            //赋值校验码
            message[message.Length - 2] = CRC[0];
            message[message.Length - 1] = CRC[1];
        }

        /**
    * 将int数值转换为占四个字节的byte数组，本方法适用于(低位在前，高位在后)的顺序。 和bytesToInt（）配套使用
    * @param value
    *            要转换的int值
    * @return byte数组
    */
        public static byte[] intToBytes(int value)
        {
            byte[] src = new byte[2];

            src[1] = (byte)((value >> 8) & 0xFF);
            src[0] = (byte)(value & 0xFF);
            return src;
        }
        /**
        * 将int数值转换为占四个字节的byte数组，本方法适用于(高位在前，低位在后)的顺序。  和bytesToInt2（）配套使用
        */
        public static byte[] intToBytes2(int value)
        {
            byte[] src = new byte[2];

            src[2] = (byte)((value >> 8) & 0xFF);
            src[3] = (byte)(value & 0xFF);
            return src;
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="address"></param>
        /// <param name="func"></param>
        /// <param name="start"></param>
        /// <param name="registers"></param>
        /// <returns></returns>
        public static byte[] BuildSendMessage(byte address, byte func, ushort start, ushort registers)
        {
            byte[] message = null;
            BuildSendMessage(address, func, start, registers,ref message);
            return message;
        }

        /// <summary>
        /// 得到收到的信息中的数据
        /// </summary>
        /// <param name="byteMessage"></param>
        /// <param name="rValueArray"></param>
        /// <returns></returns>
        public static int GetReceivedDatas(byte[] byteMessage, out double[] rValueArray)
        {
            rValueArray = null;

            string strMessage = BitConverter.ToString(byteMessage, 0, byteMessage.Length); // byte[] -> 16进制字符串
            string[] strValueList = strMessage.Split('-');

            int iReadAddress = -1;
            if (strValueList.Length <= 6)
            {
                //!数据没有收完，直接返回
                return -1;
            }
            try
            {
                iReadAddress = int.Parse(strValueList[0]); //!获得设备ID

                //int iFunID = int.Parse(strValueList[1]);//!读取功能吗

                int dataNum = int.Parse(strValueList[2]) / 2;//!获得数据长度(除以2就是数据个数)
                if (dataNum < 1)
                    return -1;

                List<double> rValueList = new List<double>();
                for (int i = 0; i < dataNum; i++)
                {
                    string strHigh = strValueList[3 + 2 * i];
                    string strLow = strValueList[3 + 2 * i + 1];

                    byte byteHigh = Convert.ToByte(strHigh);
                    byte byteLow = Convert.ToByte(strLow);

                    double rValue = byteHigh * 256.0 + byteLow;

                   // rValue = rValue * 10000 / Math.Pow(10, GetDecimalPlaces(1));
                    rValueList.Add(rValue);
                }

                rValueArray = rValueList.ToArray();
            }
            catch
            {
                return -1;
            }

            return iReadAddress;
        }

        //
        // 摘要:
        //     检查收到的信息的校验码是否正确
        //
        // 参数:
        //      得到的二进制数据
        //
        // 返回结果:
        //    是否成功
        public static bool CheckReceivedMessage(byte[] byteMessage)
        {
            //计算校验码
            byte[] CRC = new byte[2];
            GetCRC16(byteMessage, ref CRC);

            //比较是否和消息中的校验码一致
            if (CRC[0] == byteMessage[byteMessage.Length - 2] && CRC[1] == byteMessage[byteMessage.Length - 1])
                return true;
            else
                return false;
        }

    }

}