defmodule Nola.Plugins.Link.PDF do
  require Logger
  @behaviour Nola.Plugins.Link

  @impl true
  def match(_, _), do: false

  @impl true
  def post_match(_url, "application/pdf" <> _, _header, _opts) do
    {:file, nil}
  end

  def post_match(_, _, _, _), do: false

  @impl true
  def post_expand(url, file, _, _) do
    case System.cmd("pdftitle", ["-p", file]) do
      {text, 0} ->
        text =
          text
          |> String.trim()

        if text == "" do
          :error
        else
          basename = Path.basename(url, ".pdf")

          text =
            ("[#{basename}] " <> text)
            |> String.split("\n")

          {:ok, text}
        end

      {_, 127} ->
        Logger.error(
          "dependency `pdftitle` is missing, please install it: `pip3 install pdftitle`."
        )

        :error

      {error, code} ->
        Logger.warn("command `pdftitle` exited with status code #{code}:\n#{inspect(error)}")
        :error
    end
  end
end