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

namespace General_Ledger_Service.Helpers
{
    public static class EncryptionHelper
    {
        private static readonly byte[] Key = Convert.FromBase64String("6pY8vR2Nf+Xz9WkLm4TqQzB7vA9uS1nE5jR3hG6fM8o=");

        public static string Encrypt(string plainText)
        {
            using Aes aes = Aes.Create();
            aes.Key = Key;
            aes.GenerateIV();

            using var encryptor = aes.CreateEncryptor();
            byte[] plainBytes = Encoding.UTF8.GetBytes(plainText);
            byte[] cipherBytes = encryptor.TransformFinalBlock(plainBytes, 0, plainBytes.Length);

            return Convert.ToBase64String(aes.IV.Concat(cipherBytes).ToArray());
        }

        public static string Decrypt(string combinedText)
        {
            byte[] combinedBytes = Convert.FromBase64String(combinedText);
            using Aes aes = Aes.Create();
            aes.Key = Key;

            byte[] iv = [.. combinedBytes.Take(16)];
            byte[] cipherBytes = [.. combinedBytes.Skip(16)];

            using var decryptor = aes.CreateDecryptor(aes.Key, iv);
            byte[] plainBytes = decryptor.TransformFinalBlock(cipherBytes, 0, cipherBytes.Length);

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