# Pleroma: A lightweight social networking server
# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only

defmodule Pleroma.Web.RichMedia.Parsers.OEmbed do
  def parse(html, _data) do
    with elements = [_ | _] <- get_discovery_data(html),
         {:ok, oembed_url} <- get_oembed_url(elements),
         {:ok, oembed_data} <- get_oembed_data(oembed_url) do
      oembed_data
    else
      _e -> %{}
    end
  end

  defp get_discovery_data(html) do
    html |> Floki.find("link[type='application/json+oembed']")
  end

  defp get_oembed_url(nodes) do
    {"link", attributes, _children} = nodes |> hd()

    {:ok, Enum.into(attributes, %{})["href"]}
  end

  defp get_oembed_data(url) do
    {:ok, %Tesla.Env{body: json}} = Pleroma.HTTP.get(url, [], adapter: [pool: :media])

    {:ok, data} = Jason.decode(json)

    data = data |> Map.new(fn {k, v} -> {String.to_atom(k), v} end)

    {:ok, data}
  end
end