ash_sitemap

defmodule AshSitemap.Sitemaps.Sitemap do
  @moduledoc """
  A struct module representing a url sitemap.

  See more https://developers.google.com/search/docs/crawling-indexing/sitemaps/build-sitemap#xml
  """

  @enforce_keys [
    :name,
    :path,
    :priority
  ]
  @fields quote(
            do: [
              name: String.t(),
              path: String.t(),
              priority: float(),
              read_action: String.t() | nil,
              news: AshSitemap.Sitemaps.News.t() | nil,
              video: [AshSitemap.Sitemaps.Video.t()],
              image: [AshSitemap.Sitemaps.Image.t()],
              pagemap: AshSitemap.Sitemaps.PageMap.t() | nil
            ]
          )
  @derive []
  defstruct Keyword.keys(@fields)

  @type t() :: %__MODULE__{unquote_splicing(@fields)}

  # defstruct [
  #   :name,
  #   :path,
  #   :priority,
  #   read_action: nil,
  #   news: nil,
  #   video: nil,
  #   image: nil,
  #   pagemap: nil
  # ]

  def build(record, sitemap) do
    callback_fn = fn
      x when is_function(x) -> x.(record)
      x -> x
    end

    news_fn = fn
      x when is_function(x) ->
        x.(record)

      x ->
        to_item_callback(record, x)
    end

    video_fn = fn
      x when is_function(x) ->
        x.(record)

      x when is_list(x) ->
        Enum.map(x, fn v -> to_item_callback(record, v) end)

      x ->
        to_item_callback(record, x)
    end

    image_fn = fn
      x when is_function(x) ->
        x.(record)

      x when is_list(x) ->
        Enum.map(x, fn v -> to_item_callback(record, v) end)

      x ->
        to_item_callback(record, x)
    end

    pagemap_fn = fn
      x when is_function(x) ->
        x.(record)

      x ->
        to_item_callback(record, x)
    end

    path = callback_fn.(sitemap.path)
    priority = callback_fn.(sitemap.priority)
    read_action = callback_fn.(sitemap.read_action)
    news = news_fn.(sitemap.news)
    video = video_fn.(sitemap.video)
    image = image_fn.(sitemap.image)
    pagemap = pagemap_fn.(sitemap.pagemap)

    %__MODULE__{
      name: sitemap.name,
      path: path,
      news: news,
      video: video,
      image: image,
      pagemap: pagemap,
      read_action: read_action,
      priority: priority
    }
  end

  defp to_item_callback(record, value) do
    case value do
      x when is_function(x) ->
        x.(record)

      x when is_atom(x) ->
        record |> Map.get(x)

      x when is_struct(x) ->
        x
        |> Map.from_struct()
        |> Enum.map(fn {k, v} -> {k, to_item_callback(record, v)} end)

      x when is_list(x) ->
        Enum.map(x, fn v -> to_item_callback(record, v) end)

      x ->
        x
    end
  end
end