using System.Threading;
using System.Threading.Tasks;
using GB5Shared.DTO.Framework.Login;

namespace FrameworkBLL.Promotion
{
    // ============================================================
    // IPromotionPackageCrypto — hybrid RSA+AES-GCM encryption for Metadata
    // Promotion's Tier 1 package transport (see the plan's Transport section).
    // Asymmetric so no shared secret is ever needed between environments that
    // may not even trust each other's network: the destination's public key
    // encrypts a random per-package AES-256 key, which does the actual bulk
    // encryption (RSA alone can't handle payloads larger than its key size).
    // ============================================================
    public interface IPromotionPackageCrypto
    {
        /// <summary>Encrypts plaintext to the named destination's registered public key
        /// (MPROMOTIONCOUNTERPARTY). Throws if no active counterparty is registered for
        /// destinationEnvironmentCode.</summary>
        Task<byte[]> EncryptPackageAsync(
            byte[] plaintext, string destinationEnvironmentCode, LoginDTO login, CancellationToken ct);

        /// <summary>Decrypts a package using THIS deployment's own private key (Vault-stored,
        /// never accepted from any request). Throws if the package's format version is
        /// unrecognized or decryption fails (wrong key, tampered payload).</summary>
        Task<byte[]> DecryptPackageAsync(byte[] encryptedPackage, CancellationToken ct);
    }
}