using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
using System.Security.Cryptography;
using System.IO;

namespace ClientTest
{
    /*
     *类名称：LoginForm
     *创建人：韩荣伟
     *创建时间：2010-10-30
     *功能描述：用户登录窗口类
     */

    public partial class LoginForm : Form
    {
        private byte[] key = { (byte)'I', (byte)'M', (byte)'m', (byte)'e', (byte)'s', (byte)'n', (byte)'a', (byte)'c' };

        public LoginForm()
        {
            InitializeComponent();
        }
        /*
         *方法名称：btnOK_Click
         *创建人：韩荣伟
         *创建时间：2010-10-30
         *参数描述：object sender 事件发起者, EventArgs e 事件参数
         *返回描述：void
         *功能描述：执行登录
         */

        private void btnOK_Click(object sender, EventArgs e)
        {
            if (Common.frmMain == null)
            {
                Common.frmMain = new FrmMain();
            }

            //check passed
            if (CheckPasswd(tbUserName.Text, tbPassword.Text) == true)
            {
                this.Hide();
                Common.frmMain.ShowDialog();
            }
            else
            {
                MessageBox.Show("用户名或密码错误，登录失败！", "请注意", MessageBoxButtons.OK, MessageBoxIcon.Stop);
            }
            this.Close();
        }

        /// <summary>
        /// 公司通用加解密算法
        /// 孙宜建
        /// </summary>
        /// <param name="src">加解密字符串</param>
        /// <param name="key">密钥</param>
        /// <param name="Encrypt">bool类型，1为加密，否则为解密</param>
        /// <returns></returns>
        public static string EncryptionEngine(string src, string key, Boolean Encrypt)
        {
            int KeyLen;
            int KeyPos;
            int offset;
            string dest;
            int SrcPos;
            int SrcAsc;
            int TmpSrcAsc;
            int Range;

            KeyLen = key.Length;
            if (KeyLen == 0)
            {
                key = "Mesnac";
            }
            KeyPos = 0;
            SrcPos = 0;
            SrcAsc = 0;
            Range = 256;
            if (Encrypt)   //加密
            {
                //System.Random r = new Random(Range);
                //offset = r.Next(Range);
                System.Random r = new Random();
                offset = r.Next() % 256 + 1;
                dest = string.Format("{0:X}", offset);
                if (dest.Length == 1)
                {
                    dest = "0" + dest;
                }
                for (SrcPos = 0; SrcPos < src.Length; SrcPos++)
                {
                    SrcAsc = ((int)src[SrcPos] + offset) % 255;
                    if (KeyPos < KeyLen)
                    {
                        KeyPos = KeyPos + 1;
                    }
                    else { KeyPos = 0; }

                    SrcAsc = SrcAsc ^ (int)key[KeyPos]; //异或

                    string tempSrcAsc = string.Format("{0:X}", SrcAsc);
                    if (tempSrcAsc.Length == 1)
                    {
                        tempSrcAsc = "0" + tempSrcAsc;
                    }
                    dest = dest + tempSrcAsc;
                    offset = SrcAsc;
                }

                return dest;

            }
            else   //解密
            {
                if (src.Length <= 2)
                {
                    return "";
                }
                dest = "";
                //offset = (int)("0x" + src.Substring(1, 2));
                offset = Convert.ToInt32(src.Substring(0, 2), 16);
                SrcPos = 2;
                while (SrcPos < src.Length)
                {
                    SrcAsc = Convert.ToInt32(src.Substring(SrcPos, 2), 16);
                    if (KeyPos < KeyLen)
                    {
                        KeyPos = KeyPos + 1;
                    }
                    else { KeyPos = 0; }

                    TmpSrcAsc = SrcAsc ^ (int)key[KeyPos]; //异或
                    if (TmpSrcAsc <= offset)
                    {
                        TmpSrcAsc = 255 + TmpSrcAsc - offset;
                    }
                    else
                    {
                        TmpSrcAsc = TmpSrcAsc - offset;
                    }
                    dest = dest + (char)TmpSrcAsc;
                    offset = SrcAsc;
                    SrcPos = SrcPos + 2;

                }
            }

            return dest;
        }
        /*
         *方法名称：Encrypt
         *创建人：韩荣伟
         *创建时间：2010-10-30
         *参数描述：String pwd 待加密的口令串
         *返回描述：String 加密后的口令串
         *功能描述：对口令进行加密
         */
        private String Encrypt(String pwd)
        {
            DESCryptoServiceProvider desc = new DESCryptoServiceProvider();//des进行加密
            //PasswordDeriveBytes db = new PasswordDeriveBytes(pwd, null);//产生key
            MemoryStream ms = new MemoryStream();//存储加密后的数据
            CryptoStream cs = new CryptoStream(ms, desc.CreateEncryptor(key, key), CryptoStreamMode.Write);
            byte[] data = Encoding.Unicode.GetBytes(pwd);//取到密码的字节流
            cs.Write(data, 0, data.Length);//进行加密
            cs.FlushFinalBlock();
            byte[] res = ms.ToArray();//取加密后的数据
            return Encoding.Unicode.GetString(res);//转换到字符串返回
        }
        /*
         *方法名称：Decrypt
         *创建人：韩荣伟
         *创建时间：2010-10-30
         *参数描述：String data 被加密的口令串
         *返回描述：String 解密后的口令串
         *功能描述：对口令进行解密
         */
        private String Decrypt(String data)
        {
            DESCryptoServiceProvider desc = new DESCryptoServiceProvider();
            //PasswordDeriveBytes db = new PasswordDeriveBytes(pwd, null);//产生key
            MemoryStream ms = new MemoryStream();//存储解密后的数据
            CryptoStream cs = new CryptoStream(ms, desc.CreateDecryptor(key, key), CryptoStreamMode.Write);
            byte[] databytes = Encoding.Unicode.GetBytes(data);//取到加密后的数据的字节流
            cs.Write(databytes, 0, databytes.Length);//解密数据
            cs.FlushFinalBlock();
            byte[] res = ms.ToArray();
            return Encoding.Unicode.GetString(res);//返回解密后的数据
        }

        /*
         *方法名称：CheckPasswd
         *创建人：韩荣伟
         *创建时间：2010-10-30
         *参数描述：string sUserName 用户名, string sPasswd 加密后的口令串
         *返回描述：bool 密码核对，true 成功，false 失败
         *功能描述：对用户名，口令进行核对
         */
        private bool CheckPasswd(string sUserName, string sPasswd)
        {
            bool res = false;
            //算查询参数
            string sEncryptPasswd = EncryptPassword(sPasswd, "MD5");
            //数据库查询
            string querySQLString = string.Format("select 1 from [dbo].[T_Sys_UserInfo] where [UseName]='{0}' and [UserPwd]='{1}'", sUserName, sEncryptPasswd);//???????????????????sUserName sEncryptPasswd
            string connectMaskString = "database={0};Integrated Security=False;user id=sa;password={1};server={2};Connection Timeout=90";

            int nLen = Common.configReader.sPWD.Length;
            
            if (nLen % 2 != 0)
            {
                return false;
            }

            byte[] btPWD = new byte[nLen / 2];

            for (int i = 0; i < nLen / 2; i++)
            {
                btPWD[i] = Convert.ToByte(Common.configReader.sPWD.Substring(i * 2, 2), 16);
            }

            string sPWDForDB = System.Text.Encoding.Unicode.GetString(btPWD);
            string sPlainPWDForDB = EncryptionEngine(Common.configReader.sPWD, String.Empty, false); //Decrypt(sPWDForDB);

            string connectString = string.Format(connectMaskString, Common.configReader.sDatabase, sPlainPWDForDB, Common.configReader.sServer);
            using (SqlConnection connection = new SqlConnection(connectString))
            {
                SqlCommand command = new SqlCommand(querySQLString, connection);
                try
                {
                    connection.Open();
                    SqlDataReader reader = command.ExecuteReader();
                    if (reader.HasRows)
                    {
                        res = true;
                    }
                }
                catch (Exception e1)
                {
                    //MessageBox.Show(e1.ToString(), "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }

            return res;
        }

        /*
         *方法名称：EncryptPassword
         *创建人：李然
         *创建时间：
         *参数描述：string PasswordString 待加密的字符串, string PasswordFormat 加密格式
         *返回描述：string 加密后的字符串
         *功能描述：加密字符串
         */
        public static string EncryptPassword(string PasswordString, string PasswordFormat)
        {
            string strResult = "";
            if (PasswordFormat == "SHA1")
                strResult = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(PasswordString, "SHA1");
            if (PasswordFormat == "MD5")
                strResult = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(PasswordString, "MD5");
            return strResult;

        }
        /*
         *方法名称：btnCancel_Click
         *创建人：韩荣伟
         *创建时间：2010-10-30
         *参数描述：object sender 事件发起者, EventArgs e 事件参数
         *返回描述：void
         *功能描述：取消登录，关闭窗口
         */

        private void btnCancel_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        /*
         *方法名称：LoginForm_Shown
         *创建人：韩荣伟
         *创建时间：2010-10-30
         *参数描述：object sender 事件发起者, EventArgs e 事件参数
         *返回描述：void
         *功能描述：登录窗口显示处理
         */

        private void LoginForm_Shown(object sender, EventArgs e)
        {
            tbUserName.Focus();
        }
    }
}