﻿/*
 * Copyright 2001-2008 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
using System;
using System.Collections.Generic;
using System.IO;

using System.Security.Cryptography;
using System.Text;

namespace org.apache.juddi.v3.client.cryptor
{
    /// <summary>
    /// An abstract class for AES functions
    /// </summary>
    /// <see cref="org.apache.juddi.v3.client.cryptor.AES128Cryptor"/>
    /// <see cref="org.apache.juddi.v3.client.cryptor.AES256Cryptor"/>
    /// <author><a href="mailto:alexoree@apache.org">Alex O'Ree</a></author> 
    public  abstract class AESCryptor : Cryptor
    {

        protected internal abstract int GetKeySize();
        protected internal abstract byte[] GetKey();
        protected internal abstract byte[] GetIV();
        protected internal abstract int GetBlockSize();
        public string encrypt(string str)
        {
          
            // Encrypt the string to an array of bytes.
            byte[] encryptedPassword = EncryptStringToBytes(str, GetKey(), GetKey());
           
            return Convert.ToBase64String(encryptedPassword);

        }

        public string decrypt(string str)
        {
            byte[] encryptedPassword = Convert.FromBase64String(str);
            string clear = DecryptStringFromBytes(encryptedPassword, GetKey(), GetKey());
           
            return clear;
        }

        
        internal byte[] EncryptStringToBytes(string plainText, byte[] key, byte[] iv)
        {
            // Check arguments.
            if (plainText == null || plainText.Length <= 0)
            {
                throw new ArgumentNullException("plainText");
            }
            if (key == null || key.Length <= 0)
            {
                throw new ArgumentNullException("key");
            }
            if (iv == null || iv.Length <= 0)
            {
                throw new ArgumentNullException("key");
            }


            byte[] encrypted;
            // Create an RijndaelManaged object
            // with the specified key and IV.
            using (var rijAlg = new RijndaelManaged())
            {
                rijAlg.BlockSize = this.GetBlockSize();
                rijAlg.KeySize = this.GetKeySize();
                rijAlg.Key = key;
                rijAlg.IV = iv;

                // Create a decrytor to perform the stream transform.
                ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);

                // Create the streams used for encryption.
                using (var msEncrypt = new MemoryStream())
                {
                    using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                    {
                        using (var swEncrypt = new StreamWriter(csEncrypt))
                        {
                            //Write all data to the stream.
                            swEncrypt.Write(plainText);
                        }
                        encrypted = msEncrypt.ToArray();
                    }
                }
            }


            // Return the encrypted bytes from the memory stream.
            return encrypted;

        }

        internal  string DecryptStringFromBytes(byte[] cipherText, byte[] key, byte[] iv)
        {
            // Check arguments.
            if (cipherText == null || cipherText.Length <= 0)
                throw new ArgumentNullException("cipherText");
            if (key == null || key.Length <= 0)
                throw new ArgumentNullException("key");
            if (iv == null || iv.Length <= 0)
                throw new ArgumentNullException("key");

            // Declare the string used to hold
            // the decrypted text.
            string plaintext;

            // Create an RijndaelManaged object
            // with the specified key and IV.
            using (var rijAlg = new RijndaelManaged())
            {
                rijAlg.BlockSize = this.GetBlockSize();
                rijAlg.KeySize = this.GetKeySize();
                rijAlg.Key = key;
                rijAlg.IV = iv;

                // Create a decrytor to perform the stream transform.
                ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);

                // Create the streams used for decryption.
                using (var msDecrypt = new MemoryStream(cipherText))
                {
                    using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                    {
                        using (var srDecrypt = new StreamReader(csDecrypt))
                        {
                            // Read the decrypted bytes from the decrypting stream
                            // and place them in a string.
                            plaintext = srDecrypt.ReadToEnd();
                        }
                    }
                }

            }
            return plaintext;
        }
    }
}