defmodule OpenTelemetry.Observer do
  @moduledoc """

      require OpenTelemetry.Observer

      OpenTelemetry.Observer.set_callback("some.counter", fn o -> OpenTelemetry.Observer.observe(o, 33, []))
  """

  defmacro set_callback(observer, callback) do
    quote do
      :ot_meter.set_observer_callback(
        :opentelemetry.get_meter(__MODULE__),
        unquote(observer),
        unquote(callback)
      )
    end
  end

  defdelegate observe(observer_result, number, label_set), to: :ot_observer
end