phoenix_seo

defprotocol SEO.JSONLD.Build do
  @fallback_to_any true
  @moduledoc """
  Derive or implement this protocol to build JSON-LD structured data for your schema.

  Implement `build/2` which receives your item and conn and returns a map, list of maps,
  or `nil`.

  The map(s) should contain a `"@type"` key, or you can use one of the helper modules
  like `SEO.JSONLD.Article` to build them. `"@context"` is added at render time by
  `SEO.JSONLD.meta/1` on the top-level node(s).

  ## Example

      defimpl SEO.JSONLD.Build, for: MyApp.Article do
        def build(article, _conn) do
          SEO.JSONLD.Article.build(%{
            headline: article.title,
            description: article.description,
            date_published: article.published_at
          })
        end
      end
  """

  @spec build(term, Plug.Conn.t()) :: map() | list(map()) | nil
  def build(thing, conn)
end

defimpl SEO.JSONLD.Build, for: Any do
  def build(_item, _conn), do: nil
end