using System;
using System.Collections.Generic;
using System.IO.Compression;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace YuanXuan.IM.Common.Helpers
{
    public static class AesEncryptHelper
    {
        static string key = "ThisIsAVerySecre";
        static string iv = "16ByteIV12345678";

        // 使用CBC模式加密并返回Base64字符串
        public static string EncryptToShortString(string plainText)
        {
            using (Aes aesAlg = Aes.Create())
            {
                aesAlg.Key = Encoding.UTF8.GetBytes(key);
                aesAlg.IV = Encoding.UTF8.GetBytes(iv);
                aesAlg.Mode = CipherMode.CBC;
                aesAlg.Padding = PaddingMode.PKCS7;

                ICryptoTransform encryptor = aesAlg.CreateEncryptor();
                byte[] encryptedBytes = encryptor.TransformFinalBlock(
                    Encoding.UTF8.GetBytes(plainText), 0, plainText.Length);

                return Convert.ToBase64String(encryptedBytes);
            }
        }

        // 解密Base64加密字符串
        public static string DecryptFromShortString(string cipherText)
        {
            using (Aes aesAlg = Aes.Create())
            {
                aesAlg.Key = Encoding.UTF8.GetBytes(key);
                aesAlg.IV = Encoding.UTF8.GetBytes(iv);
                aesAlg.Mode = CipherMode.CBC;
                aesAlg.Padding = PaddingMode.PKCS7;

                ICryptoTransform decryptor = aesAlg.CreateDecryptor();
                byte[] cipherBytes = Convert.FromBase64String(cipherText);
                byte[] decryptedBytes = decryptor.TransformFinalBlock(
                    cipherBytes, 0, cipherBytes.Length);

                return Encoding.UTF8.GetString(decryptedBytes);
            }
        }
    }
}