defmodule Jump.CLI do
  def main(args \\ []) do
    parsed_args = parse_args(args)

    parsed_args
    |> fetch()
    |> calculate(parsed_args)
    |> finish()
  end

  defp parse_args(args) do
    {opts, _, _} = OptionParser.parse(args, switches: [article: :string, days: :integer])
    opts
  end

  defp fetch(args) do
    the_end = Calendar.strftime(DateTime.utc_now(), "%Y%m%d")
    {the_end_int, ""} = Integer.parse(the_end)

    start = the_end_int - args[:days]

    Jump.fetch(args[:article], start, the_end)
  end

  defp calculate(items, args) do
    total_pageviews = Enum.sum_by(items, &Map.get(&1, "views"))
    max_views_item = Enum.max_by(items, &Map.get(&1, "views"))

    %{
      event_name: "campaign_spike_conversion",
      article: args[:article],
      window_days: args[:days],
      total_pageviews: total_pageviews,
      avg_daily_pageviews: total_pageviews / length(items),
      top_day: %{
        date: max_views_item["timestamp"],
        pageviews: max_views_item["views"]
      }
    }
  end

  defp finish(summary) do
    Jump.post(summary)

    IO.inspect(summary)

    IO.puts("done.")
  end

end