using System.Security.Cryptography;

namespace ComplianceBLL.Adapter;

// Shared AES-256/ECB helper used by GSP adapters (GSTCafe, and any future adapter needing the same
// payload/credential encryption scheme) — not tied to any single adapter implementation.
public static class AesCryptoHelper
{
    public static byte[] AES256Encrypt(byte[] bytesToBeEncrypted, byte[] passwordBytes)
    {
        try
        {
            using var ms = new MemoryStream();
            using (var aes = Aes.Create())
            {
                aes.Key = passwordBytes;
                aes.Mode = CipherMode.ECB;

                // "zero" IV
                aes.IV = new byte[16];

                using var cs = new CryptoStream(ms, aes.CreateEncryptor(), CryptoStreamMode.Write);
                cs.Write(bytesToBeEncrypted, 0, bytesToBeEncrypted.Length);
                cs.Close();
            }

            return ms.ToArray();
        }
        catch
        {
            throw;
        }
    }

    public static byte[] AES256Decrypt(byte[] bytesToBeDecrypted, byte[] passwordBytes)
    {
        try
        {
            using var ms = new MemoryStream();
            using (var aes = Aes.Create())
            {
                aes.Key = passwordBytes;
                aes.Mode = CipherMode.ECB;

                // "zero" IV
                aes.IV = new byte[16];

                using var cs = new CryptoStream(ms, aes.CreateDecryptor(), CryptoStreamMode.Write);
                cs.Write(bytesToBeDecrypted, 0, bytesToBeDecrypted.Length);
                cs.Close();
            }

            return ms.ToArray();
        }
        catch
        {
            throw;
        }
    }
}