-type api() ::
          #{name := binary(),
            version := binary(),
            endpoints := [endpoint()],
            schemas := #{ref() => schema()}}.

-type body() :: #{ref := ref(), required := boolean()}.

-type endpoint() :: #{path := path(), parameters := [parameter()], operations := [operation()]}.

-type method() :: erf:method().

-type operation() ::
          #{id := binary(),
            method := method(),
            parameters := [parameter()],
            request := request(),
            responses := #{'*' | status_code() := response()}}.

-type parameter() ::
          #{ref := ref(), name := parameter_name(), type := parameter_type(), required := boolean()}.

-type parameter_name() :: binary().

-type parameter_type() :: header | cookie | path | query.

-type path() :: binary().

-type ref() :: binary().

-type request() :: #{body := body()}.

-type response() :: #{body := body()}.

-type schema() :: ndto:schema().

-type status_code() :: 100..599.