@callback accept_chunk(chunk :: term(), accept_state :: term()) ::
  {:ok, term()} | {:error, term()}

@callback begin_accept(snap_dir :: String.t(), meta :: map()) ::
  {:ok, accept_state :: term()} | {:error, term()}

@callback begin_read(location :: String.t(), context :: map()) ::
  {:ok, meta :: map(), read_state :: term()} | {:error, term()}

@callback complete_accept(chunk :: term(), accept_state :: term()) ::
  :ok | {:ok, non_neg_integer()} | {:error, term()}

@callback context() :: map()

@callback get_size(location :: String.t()) :: {:ok, non_neg_integer()} | {:error, term()}

@callback prepare(index :: non_neg_integer(), state :: term()) :: ref :: term()

@callback read_chunk(
  read_state :: term(),
  chunk_bytes :: non_neg_integer(),
  location :: String.t()
) :: {:ok, chunk :: term(), {:next, term()} | :last} | {:error, term()}

@callback read_meta(location :: String.t()) :: {:ok, map()} | {:error, term()}

@callback recover(location :: String.t()) :: {:ok, map(), term()} | {:error, term()}

@callback sync(location :: String.t()) :: :ok | {:error, term()}

@callback validate(location :: String.t()) :: :ok | {:error, term()}

@callback write(location :: String.t(), meta :: map(), ref :: term(), sync :: boolean()) ::
  :ok | {:ok, bytes :: non_neg_integer()} | {:error, term()}