@spec available?() :: boolean()

Returns true if the NIF is loaded and available.

@spec can_passthrough?(reference(), non_neg_integer()) ::
  {:ok, boolean()} | {:error, atom()} | boolean()

Returns true if the user's decryptor has an active passthrough (epoch transition grace period).

@spec create_key_package(reference()) ::
  {:ok, {:ok, binary()}} | {:ok, binary()} | {:error, atom()}

Creates and returns the client's MLS key package as {:ok, binary}.

@spec decrypt_audio(reference(), non_neg_integer(), binary()) ::
  {:ok, {:ok, binary()}} | {:ok, binary()} | {:error, atom()}

Decrypts a DAVE-encrypted audio packet. Returns {:ok, decrypted_binary}.

@spec encrypt_opus(reference(), binary()) ::
  {:ok, {:ok, binary()}}
  | {:ok, binary()}
  | {:error, :not_ready | :encryption_failed | :error}

Encrypts an Opus audio packet using DAVE E2EE.

Returns {:ok, encrypted_binary} or {:error, :not_ready | :encryption_failed | :error}.

@spec get_epoch(reference()) ::
  {:ok, non_neg_integer()} | {:error, atom()} | non_neg_integer()

Returns the current MLS epoch number.

@spec max_protocol_version() :: pos_integer()

Returns the maximum DAVE protocol version supported by the davey crate.

@spec new_session(pos_integer(), non_neg_integer(), non_neg_integer()) ::
  {:ok, reference()} | {:error, atom()} | reference() | no_return()

Creates a new MLS session for the given protocol version, user ID, and channel ID.

@spec process_commit(reference(), binary()) :: :ok | :error

Processes an MLS commit from the gateway.

@spec process_proposals(reference(), :append | :revoke, binary(), [non_neg_integer()]) ::
  {:ok, {:ok, binary(), binary() | nil}}
  | {:ok, binary(), binary() | nil}
  | {:error, atom()}

Processes MLS proposals from the gateway.

operation_type is :append or :revoke. user_ids is a list of connected client user IDs (integers). Returns {:ok, commit_binary, welcome_binary_or_nil}.

@spec process_welcome(reference(), binary()) :: :ok | :error

Processes an MLS welcome message from the gateway.

@spec protocol_version(reference()) ::
  {:ok, pos_integer()} | {:error, atom()} | pos_integer()

Returns the DAVE protocol version of this session.

@spec ready?(reference()) :: {:ok, boolean()} | {:error, atom()} | boolean()

Returns true if the MLS session is ready (group established).

@spec reinit(reference(), pos_integer(), non_neg_integer(), non_neg_integer()) ::
  :ok | :error

Re-initializes the session with new parameters without creating a new resource.

@spec reset(reference()) :: :ok | :error

Resets the MLS group state without losing key material or external sender.

@spec set_external_sender(reference(), binary()) :: :ok | :error

Sets the external sender credential (from the voice gateway).

@spec set_passthrough_mode(reference(), boolean()) :: :ok | :error

Sets passthrough mode (disable/enable E2EE without destroying the session).

@spec status(reference()) ::
  {:ok, :inactive | :pending | :awaiting_response | :active}
  | {:error, atom()}
  | :inactive
  | :pending
  | :awaiting_response
  | :active

Returns the session status: :inactive, :pending, :awaiting_response, or :active.