/*
 * crypto/crypto.h — TLS 1.3 (mbedTLS) and the media AEAD (libsodium).
 *
 * Design: docs/security.md. Control channel = TLS 1.3. Media = keys exported from the TLS
 * session (RFC 5705 / 8446) + per-frame ChaCha20-Poly1305 with a counter nonce and a
 * sliding-window replay filter. Encryption is MANDATORY — never add a plaintext path.
 *
 * STATUS: M0 stub.
 */
#ifndef VOICECAT_CRYPTO_CRYPTO_H
#define VOICECAT_CRYPTO_CRYPTO_H

#include <cstddef>
#include <cstdint>

namespace voicecat::crypto {

// TLS 1.3 endpoint wrapper (mbedTLS). Provides the keying-material exporter that seeds
// MediaCrypto, so the UDP path inherits the authenticated control session's trust.
class TlsContext {
   public:
    // TODO(M1): client/server handshake; read/write; export_keying_material(label,...).
};

// Per-frame media encryption. Abstracted so the backend (exported-key AEAD now; a DTLS 1.3
// backend later, if a permissive impl matures) is swappable without touching voice code.
class MediaCrypto {
   public:
    virtual ~MediaCrypto() = default;
    // seal/open one voice frame; `aad` carries the routable header fields (e.g. ssrc).
    // Returns bytes written, or -1 on failure (replay/auth). TODO(M2).
    virtual long seal(const uint8_t* plain, size_t len, const uint8_t* aad, size_t aad_len,
                      uint8_t* out, size_t out_cap) = 0;
    virtual long open(const uint8_t* sealed, size_t len, const uint8_t* aad, size_t aad_len,
                      uint8_t* out, size_t out_cap) = 0;
};

}  // namespace voicecat::crypto

#endif  // VOICECAT_CRYPTO_CRYPTO_H