namespace CounsellorBL.Helper
{
    using OT.COM.Encryption;
    using OT.COM.LogisticsUtil;
    using System;

    public static class EncryptHelper
    {
        private static readonly byte[] _Key = System.Text.Encoding.Unicode.GetBytes(Util.GetSettingString("KEY"));
        private static readonly byte[] _IV = System.Text.Encoding.Unicode.GetBytes(Util.GetSettingString("IV"));
        private static readonly AES _aes = new AES();
        /// <summary>
        /// 函式名稱:Encrypt
        /// 函式說明:加密API
        /// 起始作者:Hercules
        /// 起始日期:2016/06/17
        ///	最新修改人: Hercules
        ///	最新修日期: 2016/06/17
        /// </summary>
        /// <param name="i_sPlaintext">明碼</param>
        /// <param name="o_sCiphertext">暗碼</param>
        /// <returns>錯誤訊息，若成功則為Null</returns>
        public static string Encrypt(string i_sPlaintext, out string o_sCiphertext)
        {
            string sMsg = null;
            string sRes = null;


            try
            {
                do
                {
                    byte[] baRes = _aes.EncryptStringToByte(
                       i_sPlaintext,
                       _Key,
                       _IV);
                    sRes = Convert.ToBase64String(baRes);
                }
                while (false);

            }            
            finally
            {
                o_sCiphertext = sRes;
            }

            return sMsg;
        }

        /// <summary>
        /// 函式名稱:Decrypt
        /// 函式說明:解密API
        /// 起始作者:Hercules
        /// 起始日期:2016/06/17
        ///	最新修改人: Hercules
        ///	最新修日期: 2016/06/17
        /// </summary>
        /// <param name="i_sCiphertext">暗碼</param>
        /// <param name="o_sPlaintext">明碼</param>
        /// <returns>錯誤訊息，若成功則為Null</returns>
        public static string Decrypt(string i_sCiphertext, out string o_sPlaintext)
        {
            string sMsg = null;
            string sRes = null;

            try
            {
                do
                {
                    byte[] baCiphertext = Convert.FromBase64String(i_sCiphertext);
                    sRes = _aes.DecryptByteToString(
                       baCiphertext,
                       _Key,
                       _IV);
                }
                while (false);

            }           
            finally
            {
                o_sPlaintext = sRes;
            }

            return sMsg;
        }
   
    }

}