defmodule Snowhite.Modules.Rss.RssItem do
  @moduledoc """
  Represents a RSS item that is displayable in the view
  """
  alias __MODULE__
  defstruct id: nil, title: nil, original_link: nil, link: nil, qr_code: nil, updated: nil

  @type t :: %__MODULE__{}
  alias Snowhite.Modules.Rss.UrlShortener

  @type raw_entry :: %{
          :id => String.t(),
          :title => String.t(),
          :"rss2:link" => String.t(),
          :updated => Timex.Types.datetime()
        }
  @type option :: {:qr_codes, boolean()} | {:short_link, boolean()}
  @doc """
  Casts a Rss entry to a RssItem and puts short url and qr_code.
  """
  @spec new(raw_entry(), [option()]) :: t()
  def new(entry, options \\ []) do
    link = Map.get(entry, :"rss2:link")

    %RssItem{
      id: entry.id,
      title: String.trim(entry.title),
      original_link: link,
      updated: entry.updated
    }
    |> shorten_link(options)
    |> put_qr_code(options)
  end

  defp put_qr_code(%RssItem{link: link} = item, options) do
    if Keyword.get(options, :qr_codes, true) do
      %RssItem{item | qr_code: EQRCode.encode(link)}
    else
      item
    end
  end

  defp shorten_link(%RssItem{original_link: link} = item, options) do
    short = if Keyword.get(options, :short_link, true), do: shorten_link(link), else: link

    %RssItem{item | link: short}
  end

  defp shorten_link(link) when is_bitstring(link) do
    case UrlShortener.shorten(link) do
      nil -> link
      short -> short
    end
  end
end