//-----------------------------------------------------------------------
// <copyright file="DES.cs" company="Origtek">
//     DES belongs to Copyright (c) Origtek. All rights reserved.
// </copyright>
//-----------------------------------------------------------------------

namespace OT.COM.Encryption
{
    using System;
    using System.IO;
    using System.Security.Cryptography;

    /// <summary>
    /// DES Encrypt Decrypt  
    /// </summary>
    public partial class DES : AEncryption
    {
        /// <summary>
        /// Main encrypt function
        /// </summary>
        /// <param name="plainText">
        /// Plain text to be encrypt
        /// </param>
        /// <param name="byaKey">
        /// Encrypt key
        /// </param>
        /// <param name="byaIV">
        /// Encrypt initial vector
        /// </param>
        /// <returns>
        /// Encrypt result byte
        /// </returns>
        public override byte[] EncryptStringToByte(string plainText, byte[] byaKey, byte[] byaIV)
        {
            //// Check arguments.
            if (plainText == null || plainText.Length <= 0)
            {
                throw new ArgumentNullException("plainText");
            }

            if (byaKey == null || byaKey.Length != 8)
            {
                throw new ArgumentException("Key == null || Key.Length != 8");
            }

            if (byaIV == null || byaIV.Length != 8)
            {
                throw new ArgumentException("IV == null || IV.Length != 8");
            }

            byte[] encrypted;
            //// Create an Aes object
            //// with the specified key and IV.

            using (DESCryptoServiceProvider desAlg = new())
            {
                desAlg.Key = byaKey;
                desAlg.IV = byaIV;

                //// Create a decrytor to perform the stream transform.
                ICryptoTransform encryptor = desAlg.CreateEncryptor(desAlg.Key, desAlg.IV);

                //// Create the streams used for encryption.
                using (MemoryStream msEncrypt = new())
                {
                    using (CryptoStream csEncrypt = new(msEncrypt, encryptor, CryptoStreamMode.Write))
                    {
                        using (StreamWriter swEncrypt = new(csEncrypt))
                        {
                            //// Write all data to the stream.
                            swEncrypt.Write(plainText);
                        }

                        encrypted = msEncrypt.ToArray();
                    }
                }
            }

            //// Return the encrypted bytes from the memory stream.
            return encrypted;
        }

        /// <summary>
        /// Main decrypt function
        /// </summary>
        /// <param name="cipherText">
        /// Plain text to be decrypt
        /// </param>
        /// <param name="byaKey">
        /// decrypt key
        /// </param>
        /// <param name="byaIV">
        /// decrypt initial vector
        /// </param>
        /// <returns>
        /// decrypt result
        /// </returns>
        public override string DecryptByteToString(byte[] cipherText, byte[] byaKey, byte[] byaIV)
        {
            //// Check arguments.
            if (cipherText == null || cipherText.Length <= 0)
            {
                throw new ArgumentNullException("cipherText");
            }

            if (byaKey == null || byaKey.Length != 8)
            {
                throw new ArgumentException("Key == null || Key.Length != 8");
            }

            if (byaIV == null || byaIV.Length != 8)
            {
                throw new ArgumentException("IV == null || IV.Length != 8");
            }

            //// Declare the string used to hold
            //// the decrypted text.
            string plaintext = null;

            //// Create an Aes object
            //// with the specified key and IV.
            using (DESCryptoServiceProvider desAlg = new())
            {
                desAlg.Key = byaKey;
                desAlg.IV = byaIV;
                //// Create a decrytor to perform the stream transform.
                ICryptoTransform decryptor = desAlg.CreateDecryptor(desAlg.Key, desAlg.IV);

                //// Create the streams used for decryption.
                using (MemoryStream msDecrypt = new(cipherText))
                {
                    using (CryptoStream csDecrypt = new(msDecrypt, decryptor, CryptoStreamMode.Read))
                    {
                        using (StreamReader srDecrypt = new(csDecrypt))
                        {
                            //// Read the decrypted bytes from the decrypting stream
                            //// and place them in a string.
                            plaintext = srDecrypt.ReadToEnd();
                        }
                    }
                }
            }

            return plaintext;
        }
    }
}