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

namespace Infrastructure.Extensions
{
    public static class SecurityEncDecryptExtensions
    {
        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());
                    }
                }
            }
        }

        public static bool TryDecryptDES(this string decryptString, string decryptKey, out string result)
        {
            result = "";
            try
            {
                result = DecryptDES(decryptString, decryptKey);
                return true;
            }
            catch
            {
                return false;
            }
        }
    }
}