using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Data;
using Common.Exceptions;
using Common.Data;

namespace NSC
{
    /// <summary>
    /// 功能：网络报文解码器
    /// 作者：王昊昇
    /// 时间：2012.11.8
    /// </summary>
    internal static class PacketsDecoder
    {
        /// <summary>
        /// 解析网络数据流
        /// </summary>
        /// <param name="ms">来自网络的数据流</param>
        /// <returns>返回通用服务数据结构体</returns>
        internal static NetServiceStruct ParseNetStream(MemoryStream ms)
        {
            if (ms == null)
            {
                return null;
            }

            byte[] lengthBuffer = null;//长度缓存
            int length = 0;//长度
            byte[] priBuffer = null;//主体部分缓存
            DataSet slvDataSet = null;//附件部分数据表
            byte[] slvTmpBuffer = null;
            Dictionary<int, byte[]> extData = new Dictionary<int, byte[]>();//二进制附件列表

            ms.Position = 0;

            try
            {
                lengthBuffer = new byte[4];
                ms.Read(lengthBuffer, 0, 4);
                length = BitConverter.ToInt32(lengthBuffer, 0);//主体部分长度

                priBuffer = new byte[length];
                ms.Read(priBuffer, 0, length);//读取主体部分

                while (ms.Position < ms.Length)
                {
                    lengthBuffer = new byte[4];
                    ms.Read(lengthBuffer, 0, 4);
                    length = BitConverter.ToInt32(lengthBuffer, 0);//附件部分数据类型

                    switch (length)
                    {
                        case 0://DataTable
                            lengthBuffer = new byte[4];
                            ms.Read(lengthBuffer, 0, 4);
                            length = BitConverter.ToInt32(lengthBuffer, 0);//附件数据表部分长度

                            slvTmpBuffer = new byte[length];
                            ms.Read(slvTmpBuffer, 0, length);//读取附件数据表部分

                            slvDataSet = ByteArrayToDataSet(slvTmpBuffer);
                            break;
                        case 1://Binary
                            lengthBuffer = new byte[4];
                            ms.Read(lengthBuffer, 0, 4);
                            int index = BitConverter.ToInt32(lengthBuffer, 0);//二进制附件编号

                            lengthBuffer = new byte[4];
                            ms.Read(lengthBuffer, 0, 4);
                            length = BitConverter.ToInt32(lengthBuffer, 0);//二进制附件长度

                            byte[] extTmp = new byte[length];
                            ms.Read(extTmp, 0, length);//读取二进制附件

                            extData.Add(index, extTmp);
                            break;
                    }
                }

                //解析主体部分
                NetServiceStruct list = null;
                using (MemoryStream priPart = new MemoryStream(priBuffer.Length))
                {
                    priPart.Write(priBuffer, 0, priBuffer.Length);

                    list = ParseStreamData(priPart, slvDataSet, extData);
                }

                return list;
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                if (slvDataSet != null)
                {
                    slvDataSet.Dispose();
                }
            }
        }

        /// <summary>
        /// 解析流数据
        /// </summary>
        /// <param name="priPart">主体数据流</param>
        /// <returns>返回通用服务数据结构体</returns>
        private static NetServiceStruct ParseStreamData(MemoryStream priPart, DataSet slvDataSet, Dictionary<int, byte[]> extData)
        {
            System.Xml.XmlDocument doc = new System.Xml.XmlDocument();

            try
            {
                doc.LoadXml(Encoding.GetEncoding("gb2312").GetString(priPart.ToArray(), 0, (int)priPart.Length));
                return ParseXML(doc, slvDataSet, extData);
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        /// <summary>
        /// 解码XML内容
        /// </summary>
        /// <param name="doc">XML对象</param>
        /// <param name="slvDataSet">附件</param>
        /// <returns>返回通用服务数据结构体</returns>
        private static NetServiceStruct ParseXML(System.Xml.XmlDocument doc, DataSet slvDataSet, Dictionary<int, byte[]> extData)
        {
            NetServiceStruct nss = new NetServiceStruct();
            System.Xml.XmlNode pNode = doc.SelectSingleNode("NetworkStreamData");
            nss.FirmwareModel = Common.IO.XML.XMLUtil.GetAttribute(pNode, "FirmwareModel");
            nss.FirmwareVersion = Common.IO.XML.XMLUtil.GetAttribute(pNode, "FirmwareVersion");
            nss.UserName = Common.IO.XML.XMLUtil.GetAttribute(pNode, "UserName");

            pNode = pNode.SelectSingleNode("ServiceDefine");

            nss.ServiceName = Common.IO.XML.XMLUtil.GetAttribute(pNode, "ServiceName");
            nss.ExceptionType = (ExceptionType)Enum.Parse(typeof(ExceptionType), Common.IO.XML.XMLUtil.GetAttribute(pNode, "Exception"), true);
            nss.SyncType = (SyncType)Enum.Parse(typeof(SyncType), Common.IO.XML.XMLUtil.GetAttribute(pNode, "SyncType"), true);
            nss.ServiceSN = Common.IO.XML.XMLUtil.GetAttribute(pNode, "ServiceSN");
            nss.Params = new Dictionary<string, ParameterStruct>();

            System.Xml.XmlNodeList args = pNode.SelectNodes("Param");
            foreach (System.Xml.XmlNode a in args)
            {
                ParameterStruct ps = new ParameterStruct();
                ps.DataFormat = Common.IO.XML.XMLUtil.GetAttribute(a, "Type");
                ps.Link = Common.IO.XML.XMLUtil.GetAttribute(a, "Link");
                if (ps.DataFormat == "IList" || ps.DataFormat == "Entity")
                {
                    ps.Data = a;
                }
                else if (ps.DataFormat == "DataTable")
                {
                    ps.Data = slvDataSet.Tables[ps.Link].Copy();
                }
                else if (ps.DataFormat == "Array")
                {
                    ps.Data = ParseArray(a.SelectSingleNode("Items"));
                }
                else if (ps.DataFormat == "Binary")
                {
                    ps.Data = extData[int.Parse(ps.Link)];
                }
                else
                {
                    ps.SetData(Common.IO.XML.XMLUtil.GetAttribute(a, "Value"));
                }
                nss.Params.Add(Common.IO.XML.XMLUtil.GetAttribute(a, "Name"), ps);
            }

            System.Xml.XmlNodeList rets = pNode.SelectNodes("Return");
            if (rets.Count > 0)
            {
                nss.Returns = new Dictionary<string, ParameterStruct>();
            }
            foreach (System.Xml.XmlNode r in rets)
            {
                ParameterStruct ps = new ParameterStruct();
                ps.DataFormat = Common.IO.XML.XMLUtil.GetAttribute(r, "Type");
                ps.Link = Common.IO.XML.XMLUtil.GetAttribute(r, "Link");
                if (ps.DataFormat == "IList" || ps.DataFormat == "Entity")
                {
                    ps.Data = r;
                }
                else if (ps.DataFormat == "DataTable")
                {
                    ps.Data = slvDataSet.Tables[ps.Link].Copy();
                }
                else if (ps.DataFormat == "Array")
                {
                    ps.Data = ParseArray(r.SelectSingleNode("Items"));
                }
                else if (ps.DataFormat == "Binary")
                {
                    ps.Data = extData[int.Parse(ps.Link)];
                }
                else
                {
                    ps.SetData(Common.IO.XML.XMLUtil.GetAttribute(r, "Value"));
                }
                nss.Returns.Add(Common.IO.XML.XMLUtil.GetAttribute(r, "Name"), ps);
            }

            return nss;
        }

        /// <summary>
        /// 解码字符串数组
        /// </summary>
        /// <param name="node">XML节点</param>
        /// <returns>返回字符串数组</returns>
        private static string[] ParseArray(System.Xml.XmlNode node)
        {
            string[] array = new string[node.ChildNodes.Count];

            for (int i = 0; i < node.ChildNodes.Count; i++)
            {
                array[i] = Common.IO.XML.XMLUtil.GetAttribute(node.ChildNodes[i], "Value");
            }
            return array;
        }

        /// <summary>
        /// 解码数据流，可指定读取位置。只支持数据长度和数据链接在一起的数据
        /// </summary>
        /// <param name="ms">数据流</param>
        /// <param name="position">读取位置</param>
        /// <returns>返回流中的数据部分</returns>
        private static byte[] ParseStream(MemoryStream ms, int position)
        {
            byte[] tmp = new byte[4];
            ms.Read(tmp, position, tmp.Length);
            int streamLength = BitConverter.ToInt32(tmp, 0);
            if (streamLength > 0)
            {
                tmp = new byte[streamLength];
                ms.Read(tmp, position + 4, tmp.Length);
                return tmp;
            }
            else
            {
                return null;
            }
        }

        /// <summary>
        /// 解码数据流。只支持数据长度和数据链接在一起的数据
        /// </summary>
        /// <param name="ms">数据流</param>
        /// <returns>返回流中的数据部分</returns>
        private static byte[] ParseStream(MemoryStream ms)
        {
            byte[] tmp = new byte[4];
            ms.Read(tmp, (int)ms.Position, tmp.Length);
            int streamLength = BitConverter.ToInt32(tmp, 0);
            if (streamLength > 0)
            {
                tmp = new byte[streamLength];
                ms.Read(tmp, (int)ms.Position, tmp.Length);
                return tmp;
            }
            else
            {
                return null;
            }
        }

        /// <summary>
        /// 将字节数组转换为数据表集合
        /// </summary>
        /// <param name="data">字节数组</param>
        /// <returns>数据表集合</returns>
        internal static DataSet ByteArrayToDataSet(byte[] data)
        {
            using (MemoryStream ms = new MemoryStream())
            {
                ms.Write(data, 0, data.Length);

                ms.Position = 0;

                System.Xml.XmlTextWriter xtw = new System.Xml.XmlTextWriter(ms, Encoding.GetEncoding("gb2312"));
                xtw.WriteStartDocument();

                //创建xml读取器
                System.Xml.XmlTextReader xtr = new System.Xml.XmlTextReader(ms);

                //创建数据集合
                DataSet ds = new DataSet();

                //将xml数据读入数据集合
                ds.ReadXml(xtr, XmlReadMode.ReadSchema);

                //返回数据集合
                return ds;
            }
        }
    }
}