defmodule Hercules do
  @moduledoc """
  Hercules is a Prometheus client for Elixir focused on ease of use.
  """

  alias Hercules.{
    Histogram
  }

  @type metric :: Histogram.t()

  @doc """
  Registers given Prometheus metric. You need to do this first
  before you can record events for this metric name.

  You want to call this as early as possible, before your application starts.
  """
  @spec new!(metric) :: :ok
  def new!(metric) do
    erl_module =
      case metric do
        %Histogram{} ->
          :prometheus_histogram

        _ ->
          raise "Not implemented"
      end

    args =
      metric
      |> Map.drop([:__struct__])
      |> Map.to_list()

    Kernel.apply(erl_module, :new, [args])
  end
end