using System;
using System.Collections.Generic;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace CZFW.Core.Security
{
    public class DesEncrypt
    {
        private const string DesKey = "CZCMS_desencrypt_2016";

        #region ========加密========

        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="text"></param>
        /// <returns></returns>
        public static string Encrypt(string text)
        {
            return Encrypt(text, DesKey);
        }

        /// <summary> 
        /// 加密数据 
        /// </summary> 
        /// <param name="text"></param> 
        /// <param name="sKey"></param> 
        /// <returns></returns> 
        public static string Encrypt(string text, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            var inputByteArray = Encoding.Default.GetBytes(text);
            des.Key = Encoding.ASCII.GetBytes(GetMd5Hash(DesKey).Substring(0, 8));
            des.IV = Encoding.ASCII.GetBytes(GetMd5Hash(DesKey).Substring(0, 8));
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            return ret.ToString();
        }

        #endregion

        #region ========解密========

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="text"></param>
        /// <returns></returns>
        public static string Decrypt(string text)
        {
            return !string.IsNullOrEmpty(text) ? Decrypt(text, DesKey) : "";
        }

        /// <summary> 
        /// 解密数据 
        /// </summary> 
        /// <param name="text"></param> 
        /// <param name="sKey"></param> 
        /// <returns></returns> 
        public static string Decrypt(string text, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            var len = text.Length / 2;
            byte[] inputByteArray = new byte[len];
            int x;
            for (x = 0; x < len; x++)
            {
                var i = Convert.ToInt32(text.Substring(x * 2, 2), 16);
                inputByteArray[x] = (byte)i;
            }
            des.Key = Encoding.ASCII.GetBytes(GetMd5Hash(DesKey).Substring(0, 8));
            des.IV = Encoding.ASCII.GetBytes(GetMd5Hash(DesKey).Substring(0, 8));
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            return Encoding.Default.GetString(ms.ToArray());
        }
        public static string GetMd5Hash(string input)
        {
            MD5 md5Hash = MD5.Create();
            // Convert the input string to a byte array and compute the hash.
            byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));
            // Create a new Stringbuilder to collect the bytes
            // and create a string.
            StringBuilder sBuilder = new StringBuilder();
            // Loop through each byte of the hashed data 
            // and format each one as a hexadecimal string.
            for (int i = 0; i < data.Length; i++)
            {
                sBuilder.Append(data[i].ToString("X2"));
            }
            // Return the hexadecimal string.
            return sBuilder.ToString();
        }
        #endregion
    }
}