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

namespace Competition.Common.Util
{
    public class EncryptionAndDecryption
    {
        #region ========加密======== 

        /// <summary>
        /// md5密码加密
        /// </summary>
        /// <param name="passWord"></param>
        /// <returns></returns>
        public static string GetMD5(string passWord)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] bt = Encoding.Default.GetBytes(passWord);//将待加密字符转为 字节型数组
            byte[] resualt = md5.ComputeHash(bt);//将字节数组转为加密的字节数组
            string pwds = BitConverter.ToString(resualt).Replace("-", "");
            passWord = pwds;
            return passWord;
        }

        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="Text"></param>
        /// <returns></returns>
        public static string Encrypt(string Text)
        {
            return Encrypt(Text, string.Format("NJ-{0}-ZGD", DateTime.Now.ToString("yyyy-MM-dd-HH")));
        }

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

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="Text"></param>
        /// <returns></returns>
        public static string DecryptByLgzn(string Text)
        {
            return Decrypt(Text, "LGZN");
        }
        /// <summary> 
        /// 加密数据 
        /// </summary> 
        /// <param name="Text">明文</param> 
        /// <param name="sKey">密钥</param> 
        /// <returns></returns> 
        public static string Encrypt(string Text, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray;
            inputByteArray = Encoding.Default.GetBytes(Text);
            des.Key = ASCIIEncoding.ASCII.GetBytes(GetMD5(sKey).Substring(0, 8));
            des.IV = ASCIIEncoding.ASCII.GetBytes(GetMD5(sKey).Substring(0, 8));
            using (var ms = new MemoryStream())
            using (var 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 Decrypt(Text, string.Format("NJ-{0}-ZGD", DateTime.Now.ToString("yyyy-MM-dd-HH")));
        }
        /// <summary> 
        /// 解密数据 
        /// </summary> 
        /// <param name="Text">密文</param> 
        /// <param name="sKey">密钥</param> 
        /// <returns></returns> 
        public static string Decrypt(string Text, string sKey)
        {
            try
            {
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                int len;
                len = Text.Length / 2;
                byte[] inputByteArray = new byte[len];
                int x, i;
                for (x = 0; x < len; x++)
                {
                    i = Convert.ToInt32(Text.Substring(x * 2, 2), 16);
                    inputByteArray[x] = (byte)i;
                }
                des.Key = ASCIIEncoding.ASCII.GetBytes(GetMD5(sKey).Substring(0, 8));
                des.IV = ASCIIEncoding.ASCII.GetBytes(GetMD5(sKey).Substring(0, 8));
                using (var ms = new System.IO.MemoryStream())
                using (var cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write))
                {
                    cs.Write(inputByteArray, 0, inputByteArray.Length);
                    cs.FlushFinalBlock();
                    return Encoding.Default.GetString(ms.ToArray());
                }
            }
            catch
            {
                return null;
            }
        }

        #endregion
    }
}