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

namespace WX.CRM.Common
{
    public class AESHelper
    {
        public static string Decrypt(string text, string key)
        {
            try
            {
                byte[] encryptedData = strToHexByte(text);
                RijndaelManaged rijndaelCipher = new RijndaelManaged();
                rijndaelCipher.Key = Encoding.UTF8.GetBytes(key);
                rijndaelCipher.Mode = CipherMode.ECB;
                rijndaelCipher.Padding = PaddingMode.None;
                ICryptoTransform transform = rijndaelCipher.CreateDecryptor();
                byte[] plainText = transform.TransformFinalBlock(encryptedData, 0, encryptedData.Length);
                string result = Encoding.Default.GetString(plainText);
                return result;

            }
            catch (Exception ex)
            {
                return null;
            }
        }

        public static string Encrypt(string text, string key)
        {
            try
            {
                byte[] encryptedData = Encoding.UTF8.GetBytes(text);
                encryptedData = padding(encryptedData);
                RijndaelManaged rijndaelCipher = new RijndaelManaged();
                rijndaelCipher.Key = Encoding.UTF8.GetBytes(key);
                rijndaelCipher.Mode = CipherMode.ECB;
                rijndaelCipher.Padding = PaddingMode.None;
                ICryptoTransform transform = rijndaelCipher.CreateEncryptor();
                byte[] plainText = transform.TransformFinalBlock(encryptedData, 0, encryptedData.Length);
                return byteToHexStr(plainText);
            }
            catch (Exception ex)
            {
                return null;
            }
        }

        private static byte[] strToHexByte(string hexString)
        {
            hexString = hexString.Replace(" ", "");
            if ((hexString.Length % 2) != 0)
                hexString += " ";
            byte[] returnBytes = new byte[hexString.Length / 2];
            for (int i = 0; i < returnBytes.Length; i++)
                returnBytes[i] = Convert.ToByte(hexString.Substring(i * 2, 2), 16);
            return returnBytes;
        }


        private static byte[] padding(byte[] src)
        {
            if (src.Length % 16 == 0)
            {
                return src;
            }
            byte[] buffer = new byte[src.Length / 16 * 16 + 16];
            System.Array.Copy(src, 0, buffer, 0, src.Length);
            return buffer;
        }

        private static string byteToHexStr(byte[] bytes)
        {
            string hexString = string.Empty;
            if (bytes != null)
            {
                StringBuilder strB = new StringBuilder();
                for (int i = 0; i < bytes.Length; i++)
                {
                    strB.Append(bytes[i].ToString("X2"));
                }
                hexString = strB.ToString();
            }
            return hexString.ToLower();
        }
    }
}