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

namespace Bowin.Common.DES
{
    public class DesAccessor: IDesAccessor
    {
        /// <summary>
        /// DES加密
        /// </summary>
        /// <param name="encryptString">待加密的字符串</param>
        /// <param name="key">加密密钥，8倍数</param>
        /// <param name="iv">加密IV，8倍数</param>
        /// <returns></returns>
        public string Encrypt(string encryptString, byte[] key, byte[] iv)
        {
            //byte[] rgbKey = Encoding.UTF8.GetBytes(key.Substring(0, 8));
            byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            des.Mode = CipherMode.ECB;
            des.Padding = PaddingMode.PKCS7;
            MemoryStream mStream = new MemoryStream();
            CryptoStream cStream = new CryptoStream(mStream, des.CreateEncryptor(key, iv), CryptoStreamMode.Write);
            cStream.Write(inputByteArray, 0, inputByteArray.Length);
            cStream.FlushFinalBlock();
            return Convert.ToBase64String(mStream.ToArray());
        }
        /// <summary>
        /// DES解密
        /// </summary>
        /// <param name="decryptString">待解密的字符串</param>
        /// <param name="key">解密密钥,要求为8位,和加密密钥相同</param>
        /// <param name="iv">解密IV,要求为8位,和加密密钥相同</param>
        /// <returns>解密成功返回解密后的字符串,失败返源串</returns>
        public string Decrypt(string decryptString, byte[] key, byte[] iv)
        {
            try
            {
                //byte[] rgbKey = Encoding.UTF8.GetBytes(Key);
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();

                des.Mode = CipherMode.ECB;
                des.Padding = PaddingMode.PKCS7;

                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, des.CreateDecryptor(key, iv), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return "";
            }
        }

        public string DeDesToken(DesModel desModel)
        {
            byte[] vi = new byte[8];
            var dk = "MMmmHHss";
            vi = Encoding.UTF8.GetBytes("00000000");

            byte[] key = Encoding.UTF8.GetBytes(desModel.tm.ToString(dk));

            return Decrypt(desModel.token, key, vi);
        }
    }
}