using System;
using System.Security.Cryptography;
using System.Text;
 
namespace HackForums.gigajew
{
    /// <summary>
    /// Created by gigajew@hf
    /// </summary>
    public sealed class MultiCrypt
    {
        public string Key
        {
            get { return Convert.ToBase64String(_key); }
            set { _key = Convert.FromBase64String(value); }
        }
 
        public string IV
        {
            get { return Convert.ToBase64String(_iv); }
            set { _iv = Convert.FromBase64String(value); }
        }
 
        public void GenerateKey(MultiCryptType type)
        {
            SymmetricAlgorithm symmetricAlgorithm;
            using (symmetricAlgorithm = FromMultiCryptType(type))
            {
                symmetricAlgorithm.GenerateKey();
                _key = symmetricAlgorithm.Key;
            }
        }
 
        public void GenerateIV(MultiCryptType type)
        {
            SymmetricAlgorithm symmetricAlgorithm;
            using (symmetricAlgorithm = FromMultiCryptType(type))
            {
                symmetricAlgorithm.GenerateIV();
                _iv = symmetricAlgorithm.IV;
            }
        }
 
        public byte[] Encrypt(MultiCryptType type, byte[] data)
        {
            if (_key == null)
                GenerateKey(type);
 
            if (_iv == null)
                GenerateIV(type);
 
            SymmetricAlgorithm symmetricAlgorithm;
            using (symmetricAlgorithm = FromMultiCryptType(type))
            {
                symmetricAlgorithm.Key = _key;
                symmetricAlgorithm.IV = _iv;
                using (ICryptoTransform transformer = symmetricAlgorithm.CreateEncryptor())
                {
                    return transformer.TransformFinalBlock(data, 0, data.Length);
                }
            }
        }
 
        public string Encrypt(MultiCryptType type, string data)
        {
            return Convert.ToBase64String(Encrypt(type, Encoding.UTF8.GetBytes(data)));
        }
 
        public byte[] Decrypt(MultiCryptType type, byte[] data)
        {
            if (_key == null)
                GenerateKey(type);
 
            if (_iv == null)
                GenerateIV(type);
 
            SymmetricAlgorithm symmetricAlgorithm;
            using (symmetricAlgorithm = FromMultiCryptType(type))
            {
                symmetricAlgorithm.Key = _key;
                symmetricAlgorithm.IV = _iv;
                using (ICryptoTransform transformer = symmetricAlgorithm.CreateDecryptor())
                {
                    return transformer.TransformFinalBlock(data, 0, data.Length);
                }
            }
        }
 
        public string Decrypt(MultiCryptType type, string data)
        {
            return Encoding.UTF8.GetString(Decrypt(type, Convert.FromBase64String(data)));
        }
 
        private SymmetricAlgorithm FromMultiCryptType(MultiCryptType type)
        {
            switch (type)
            {
                case MultiCryptType.Rijndael:
                    return RijndaelManaged.Create();
                case MultiCryptType.TripleDES:
                    return TripleDES.Create();
                case MultiCryptType.DES:
                    return DES.Create();
                case MultiCryptType.RC2:
                    return RC2.Create();
                default:
                    return RijndaelManaged.Create();
            }
        }
 
        private byte[] _key;
        private byte[] _iv;
    }
 
    public enum MultiCryptType
    {
        Rijndael, TripleDES, DES, RC2
    }
}