using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.IO;
using Org.BouncyCastle.Security;

namespace DS.Module.Core.Helpers
{
    /// <summary>
    ///  3DES加密 解密
    /// </summary>
    public static class EncrypteHelper
    {
        /// <summary>
        ///  加密
        /// </summary>
        /// <param name="input"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public static string EncryptData(string input, string key)
        {
            var inCipher = CreateCipher(true, key);

            var inputArray = Encoding.UTF8.GetBytes(input);

            byte[] cipherData = inCipher.DoFinal(inputArray);

            return Convert.ToBase64String(cipherData);
        }

        /// <summary>
        ///  解密
        /// </summary>
        /// <param name="input"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public static string DecryptData(string input, string key)
        {
            var inputArrary = Convert.FromBase64String(input);

            var outCipher = CreateCipher(false, key);

            var encryptedDataStream = new MemoryStream(inputArrary, false);

            var dataStream = new MemoryStream();

            var outCipherStream = new CipherStream(dataStream, null, outCipher);

            int ch;
            while ((ch = encryptedDataStream.ReadByte()) >= 0)
            {
                outCipherStream.WriteByte((byte)ch);
            }

            outCipherStream.Close();
            encryptedDataStream.Close();

            var dataBytes = dataStream.ToArray();

            return Encoding.UTF8.GetString(dataBytes);
        }

        static IBufferedCipher CreateCipher(bool forEncryption, string key,
            string cipMode = "DESede/ECB/PKCS5Padding")
        {
            var algorithmName = cipMode;
            if (cipMode.IndexOf('/') >= 0)
            {
                algorithmName = cipMode.Substring(0, cipMode.IndexOf('/'));
            }

            var cipher = CipherUtilities.GetCipher(cipMode);

            var keyBytes = Encoding.UTF8.GetBytes(key);

            var keyParameter = ParameterUtilities.CreateKeyParameter(algorithmName, keyBytes);

            cipher.Init(forEncryption, keyParameter);

            return cipher;
        }
    }
}