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

namespace Common.Helpers
{
    /// <summary>
    /// AES加解密工具类
    /// </summary>
    public class AESEncrypt
    {
        static string KeysString = "^%*7&%1)1~1`(UNIC):&*d|`></?s&/2";

        /// <summary>
        /// AES加密
        /// </summary>
        /// <param name="toEncrypt">要加密的内容</param>
        /// <param name="strKey">密钥
        /// <para>16个字节长(128位)</para>
        /// <para>32个字节长(256位)</para> 
        /// <para>注：一个汉字，2个字节</para> 
        /// <para>为空时，系统默认256位进行加/解密</para>
        /// </param>
        /// <returns>Base64转码后的密文</returns>
        public static string Encrypt(string toEncrypt, string strKey)
        {
            if (strKey.Length != 16 && strKey.Length != 32)
                strKey = KeysString;

            byte[] keyArray = UTF8Encoding.UTF8.GetBytes(strKey);
            byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);
            string tmp = string.Empty;
            RijndaelManaged rDel = new RijndaelManaged();//using System.Security.Cryptography;    
            try
            {
                rDel.Key = keyArray;
                rDel.Mode = CipherMode.ECB;//using System.Security.Cryptography;    
                rDel.Padding = PaddingMode.PKCS7;//using System.Security.Cryptography;    

                ICryptoTransform cTransform = rDel.CreateEncryptor();//using System.Security.Cryptography;    
                byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

                tmp = Convert.ToBase64String(resultArray, 0, resultArray.Length);
            }
            catch (Exception ex)
            {
                tmp = ex.Message;
            }
            return tmp;
        }

        /// <summary>
        /// AES解密
        /// </summary>
        /// <param name="toDecrypt">要解密的内容</param>
        /// <param name="strKey">密钥
        /// <para>16个字节长(128位)</para>
        /// <para>32个字节长(256位)</para> 
        /// <para>注：一个汉字，2个字节</para> 
        /// <para>为空时，系统默认256位进行加/解密</para>
        /// </param>
        /// <returns>解密后的明文</returns>
        public static string Decrypt(string toDecrypt, string strKey)
        {
            if (strKey.Length != 16 && strKey.Length != 32)
                strKey = KeysString;
            byte[] keyArray = UTF8Encoding.UTF8.GetBytes(strKey);
            byte[] toEncryptArray = Convert.FromBase64String(toDecrypt);

            RijndaelManaged rDel = new RijndaelManaged();
            rDel.Key = keyArray;
            rDel.Mode = CipherMode.ECB;
            rDel.Padding = PaddingMode.PKCS7;

            ICryptoTransform cTransform = rDel.CreateDecryptor();
            byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

            return UTF8Encoding.UTF8.GetString(resultArray);
        }

        static 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 (RijndaelManaged rijAlg = new RijndaelManaged())
            {
                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 (MemoryStream msEncrypt = new MemoryStream())
                {
                    using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                    {
                        using (StreamWriter 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;

        }

        static 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 = null;

            // Create an RijndaelManaged object
            // with the specified key and IV.
            using (RijndaelManaged rijAlg = new RijndaelManaged())
            {
                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 (MemoryStream msDecrypt = new MemoryStream(cipherText))
                {
                    using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                    {
                        using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                        {

                            // Read the decrypted bytes from the decrypting stream
                            // and place them in a string.
                            plaintext = srDecrypt.ReadToEnd();
                        }
                    }
                }

            }

            return plaintext;

        }
    }

}