using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace NFine.Code
{
    public class DBConnection
    {
        public static bool Encrypt { get; set; }
        public DBConnection(bool encrypt)
        {
            Encrypt = encrypt;
        }
        public static string connectionString
        {
            get
            {
                string connection = FromMd5( System.Configuration.ConfigurationManager.ConnectionStrings["connstr"].ConnectionString);
                if (Encrypt == true)
                {
                    return DESEncrypt.Decrypt(connection);
                }
                else
                {
                    return connection;
                }
            }
        }

        #region 字符串加解密
        /// <summary>
        /// MD5加密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string ToMd5(string str)
        {
            return Encrypts(str, "&%#@?,:*_");
        }
        /// <summary>
        /// MD5解密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string FromMd5(string str)
        {
            return str;
            //return Decrypt(str, "&%#@?,:*_");
        }
        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="strText"></param>
        /// <param name="strEncrKey"></param>
        /// <returns></returns>
        private static String Encrypts(String strText, String strEncrKey)
        {
            Byte[] byKey = { };
            Byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            try
            {
                byKey = System.Text.Encoding.UTF8.GetBytes(strEncrKey.Substring(0, 8));
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                Byte[] inputByteArray = Encoding.UTF8.GetBytes(strText);
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(byKey, IV),
           CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                return Convert.ToBase64String(ms.ToArray());
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
        }

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="strText"></param>
        /// <param name="sDecrKey"></param>
        /// <returns></returns>
        private static String Decrypt(String strText, String sDecrKey)
        {
            Byte[] byKey = { };
            Byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            Byte[] inputByteArray = new byte[strText.Length];
            try
            {
                byKey = System.Text.Encoding.UTF8.GetBytes(sDecrKey.Substring(0, 8));
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                inputByteArray = Convert.FromBase64String(strText);
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(byKey, IV),
           CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                System.Text.Encoding encoding = System.Text.Encoding.UTF8;
                return encoding.GetString(ms.ToArray());
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
        }
        #endregion
    }
}