using System;
using System.Data;
using System.Data.SqlClient;
using System.Xml;
using System.Security;
using System.Security.Cryptography;
using System.Text;
using System.IO;
using System.Web;
using System.Web.UI.WebControls;

namespace Example_8_8
{
	/// <summary>
	/// Summary description for XMLComponent.
	/// </summary>
	public class XMLComponent
	{
		public static String DataFile = "bin/XMLDataFile.xml";
		public DataSet GetDataFromXml(int nUserID,String xmlDataFile)
		{
			DataSet ds = new DataSet();		

			DataTable dataTable = new DataTable("Account");
			dataTable.Columns.Add("消費主題",typeof(string));
			dataTable.Columns.Add("消費現金（單位：元）",typeof(Decimal));
			dataTable.Columns.Add("消費時間",typeof(DateTime));
			dataTable.Columns.Add("消費信息詳細說明",typeof(string));
			dataTable.Columns.Add("消費類型",typeof(string));
			
			try
			{
				SymmetricMethodData symmetric = new SymmetricMethodData();
				XmlDocument accountDoc = new XmlDocument();
				accountDoc.Load(xmlDataFile);

				XmlNodeList nodeList = accountDoc.SelectNodes("/Accounts/Account[@UserID=" + nUserID.ToString() + "]");
				int index = 0;
				foreach(XmlNode node in nodeList)
				{
					if(index < 15)
					{
						DataRow row = dataTable.NewRow();
						row["消費主題"] = symmetric.DecryptoData(node.Attributes["Title"].Value);
						row["消費現金（單位：元）"] = Convert.ToDecimal(symmetric.DecryptoData(node.Attributes["Money"].Value));					
						row["消費時間"] = Convert.ToDateTime(node.Attributes["Pubdate"].Value);
						row["消費信息詳細說明"] = symmetric.DecryptoData(node.Attributes["OtherInfo"].Value);
						row["消費類型"] = symmetric.DecryptoData(node.Attributes["AccountType"].Value);
						dataTable.Rows.Add(row);
					}
					index++;
				}
			}
			catch(Exception ex)
			{
				String exMessage = ex.Message;
			}

			ds.Tables.Add(dataTable);
			return(ds);
		}
	}

	/// <summary>
	/// 對稱加密類的構造函數
	/// </summary>
	public class SymmetricMethodData
	{ 
		private SymmetricAlgorithm mobjCryptoService;
		private string Key;
		
		public SymmetricMethodData()
		{
			mobjCryptoService = new RijndaelManaged();
			Key = "Guz(%&hj7x89H$yuBI0456FtmaT5&fvHUFCy76*h%(HilJ$lhj!y6&(*jkP87jH7";
		}

		/// <summary>
		/// 獲得密鑰
		/// </summary>
		/// <returns>密鑰</returns>
		private byte[] GetLegalKey()
		{
			string sTemp = Key;
			mobjCryptoService.GenerateKey();
			byte[] bytTemp = mobjCryptoService.Key;
			int KeyLength = bytTemp.Length;
			if (sTemp.Length > KeyLength)
				sTemp = sTemp.Substring(0, KeyLength);
			else if (sTemp.Length < KeyLength)
				sTemp = sTemp.PadRight(KeyLength, ' ');
			return ASCIIEncoding.ASCII.GetBytes(sTemp);
		}

		/// <summary>
		/// 獲得初始向量IV
		/// </summary>
		/// <returns>初試向量IV</returns>
		private byte[] GetLegalIV()
		{
			string sTemp = "E4ghj*Ghg7!rNIfb&95GUY86GfghUb#er57HBh(u%g6HJ($jhWk7&!hg4ui%$hjk";
			mobjCryptoService.GenerateIV();
			byte[] bytTemp = mobjCryptoService.IV;
			int IVLength = bytTemp.Length;
			if (sTemp.Length > IVLength)
				sTemp = sTemp.Substring(0, IVLength);
			else if (sTemp.Length < IVLength)
				sTemp = sTemp.PadRight(IVLength, ' ');
			return ASCIIEncoding.ASCII.GetBytes(sTemp);
		}

		/// <summary>
		/// 加密方法
		/// </summary>
		/// <param name="Source">待加密的串</param>
		/// <returns>經過加密的串</returns>
		public string EncryptoData(string Source)
		{
			byte[] bytIn = UTF8Encoding.UTF8.GetBytes(Source);
			MemoryStream ms = new MemoryStream();
			mobjCryptoService.Key = GetLegalKey();
			mobjCryptoService.IV = GetLegalIV();
			ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor();
			CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
			cs.Write(bytIn, 0, bytIn.Length);
			cs.FlushFinalBlock();
			ms.Close();
			byte[] bytOut = ms.ToArray();
			return Convert.ToBase64String(bytOut);
		}

		/// <summary>
		/// 解密方法
		/// </summary>
		/// <param name="Source">待解密的串</param>
		/// <returns>經過解密的串</returns>
		public string DecryptoData(string Source)
		{
			byte[] bytIn = Convert.FromBase64String(Source);
			MemoryStream ms = new MemoryStream(bytIn, 0, bytIn.Length);
			mobjCryptoService.Key = GetLegalKey();
			mobjCryptoService.IV = GetLegalIV();
			ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor();
			CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
			StreamReader sr = new StreamReader(cs);
			return sr.ReadToEnd();
		}
	}
}