using IOTContainer.Common;
using System;
using System.Security.Cryptography;
using System.Text;

namespace IOTContainer.Common
{
    public class SecurityHelper
    {
        #region AES加密解密 
        
        /// <summary>
        /// 128位处理key 
        /// </summary>
        /// <param name="keyArray">原字节</param>
        /// <param name="key">处理key</param>
        /// <returns></returns>
        private static byte[] GetAesKey(byte[] keyArray, string key)
        {
            byte[] newArray = new byte[16];
            if (keyArray.Length < 16)
            {
                for (int i = 0; i < newArray.Length; i++)
                {
                    if (i >= keyArray.Length)
                    {
                        newArray[i] = 0;
                    }
                    else
                    {
                        newArray[i] = keyArray[i];
                    }
                }
            }
            else
                newArray = keyArray;

            return newArray;
        }
        /// <summary>
        /// 使用AES加密字符串,按128位处理key
        /// </summary>
        /// <param name="content">加密内容</param>
        /// <param name="key">秘钥，需要128位、256位.....</param>
        /// <returns>Base64字符串结果</returns>
        public static string AesEncrypt(string content, bool autoHandle = true)
        {
            byte[] keyArray = Encoding.UTF8.GetBytes(StringDecode(ComParameters.Parameters.SecurityKey));
            if (autoHandle)
            {
                keyArray = GetAesKey(keyArray, StringDecode(ComParameters.Parameters.SecurityKey));
            }
            byte[] toEncryptArray = Encoding.UTF8.GetBytes(content);

            SymmetricAlgorithm des = Aes.Create();
            des.Key = keyArray;
            des.Mode = CipherMode.ECB;
            des.Padding = PaddingMode.PKCS7;
            ICryptoTransform cTransform = des.CreateEncryptor();
            byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
            return Convert.ToBase64String(resultArray);
        }
        /// <summary>
        /// 使用AES解密字符串,按128位处理key
        /// </summary>
        /// <param name="content">内容</param>
        /// <param name="key">秘钥，需要128位、256位.....</param>
        /// <returns>UTF8解密结果</returns>
        public static string AesDecrypt(string content, bool autoHandle = true)
        {
            byte[] keyArray = Encoding.UTF8.GetBytes(StringDecode(ComParameters.Parameters.SecurityKey));
            if (autoHandle)
            {
                keyArray = GetAesKey(keyArray, StringDecode(ComParameters.Parameters.SecurityKey));
            }
            byte[] toEncryptArray = Convert.FromBase64String(content);

            SymmetricAlgorithm des = Aes.Create();
            des.Key = keyArray;
            des.Mode = CipherMode.ECB;
            des.Padding = PaddingMode.PKCS7;

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

            return Encoding.UTF8.GetString(resultArray);
        }
        #endregion

        /// <summary>
        /// 解密(反转再base64解码)，常规配置，例如密码
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string StringDecode(string str)
        {
            string result = string.Empty;
            try
            {
                if (!string.IsNullOrEmpty(str))
                {
                    char[] arr = str.ToCharArray();
                    Array.Reverse(arr);
                    result = Encoding.UTF8.GetString(Convert.FromBase64String(new string(arr)));
                }
            }
            catch (Exception ex)
            {
                Log.MyLog.WriteLogFile(ex.ToString());
            }
            return result;
        }
    }
}