defmodule Frenzy.Pipeline.Extractor.FinerTech do
  @moduledoc """
  Extractor for https://finertech.com
  """

  alias Frenzy.Pipeline.Extractor
  @behaviour Extractor

  @impl Extractor
  def extract(html_tree) do
    case Floki.find(html_tree, ".entry-content") do
      [content_elem | _] ->
        # remove patreon button
        content_elem = Floki.traverse_and_update(content_elem, &remove_patreon_banner/1)
        {:ok, content_elem}

      _ ->
        {:error, "no matching element"}
    end
  end

  @patreon_class_regex ~r/[a-z0-9_]patreon_button/i

  defp remove_patreon_banner({"div", attrs, _children} = elem) do
    case Enum.find(attrs, fn {attr, _val} -> attr == "class" end) do
      nil ->
        elem

      {"class", class} ->
        if Regex.match?(@patreon_class_regex, class) do
          nil
        else
          elem
        end
    end
  end

  defp remove_patreon_banner(elem), do: elem
end