using System.Security.Cryptography;
using System.Text;

namespace DS.Module.Core.Helpers;

/// <summary>
/// Des加密帮助类
/// </summary>
public static class DesHelper
{
    /// <summary>
    /// 
    /// </summary>
    private static byte[] Keys =
        { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F };

    /// <summary>
    /// DES加密字符串
    /// </summary>
    /// <param name="encryptString">待加密的字符串</param>
    /// <param name="encryptKey">加密密钥,要求为16位</param>
    /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
    public static string EncryptDES(this string encryptString, string encryptKey)
    {
        try
        {
            byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 16));
            byte[] rgbIV = Keys;
            byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);

            using (var DCSP = DES.Create())
            {
                using (MemoryStream mStream = new MemoryStream())
                {
                    using (CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateEncryptor(rgbKey, rgbIV),
                               CryptoStreamMode.Write))
                    {
                        cStream.Write(inputByteArray, 0, inputByteArray.Length);
                        cStream.FlushFinalBlock();
                        return Convert.ToBase64String(mStream.ToArray()).Replace('+', '_').Replace('/', '~');
                    }
                }
            }
        }
        catch (Exception ex)
        {
            throw new Exception("密码加密异常" + ex.Message);
        }
    }

    /// <summary>
    /// DES解密字符串
    /// </summary>
    /// <param name="decryptString">待解密的字符串</param>
    /// <param name="decryptKey">解密密钥,要求为16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 static string DecryptDES(this string decryptString, string decryptKey)
    {
        byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey.Substring(0, 16));
        byte[] rgbIV = Keys;
        byte[] inputByteArray = Convert.FromBase64String(decryptString.Replace('_', '+').Replace('~', '/'));
        using (var DCSP = DES.Create())
        {
            using (MemoryStream mStream = new MemoryStream())
            {
                using (CryptoStream cStream =
                       new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write))
                {
                    byte[] inputByteArrays = new byte[inputByteArray.Length];
                    cStream.Write(inputByteArray, 0, inputByteArray.Length);
                    cStream.FlushFinalBlock();
                    return Encoding.UTF8.GetString(mStream.ToArray());
                }
            }
        }
    }
}