defmodule ElixirFeedParser.Parsers.ITunesRSS2 do
  import ElixirFeedParser.Parsers.Helper
  alias ElixirFeedParser.XmlNode
  alias ElixirFeedParser.Parsers.RSS2

  # http://www.apple.com/itunes/whatson/podcasts/specs.html
  def can_parse?(xml) do
    RSS2.can_parse?(xml) && itunes_namespace?(xml)
  end

  def parse(xml) do
    feed = XmlNode.find(xml, "/rss/channel")

    xml |> RSS2.parse |> Map.merge(%{
      itunes_author:         feed |> element("itunes:author"),
      itunes_block:          feed |> element("itunes:block"),
      itunes_image:          feed |> element("itunes:image", [attr: "href"]),
      itunes_explicit:       feed |> element("itunes:explicit"),
      itunes_keywords:       feed |> element("itunes:keywords"),
      itunes_new_feed_url:   feed |> element("itunes:new_feed_url"),
      itunes_subtitle:       feed |> element("itunes:subtitle"),
      itunes_summary:        feed |> element("itunes:summary"),
      categories:            feed |> elements("itunes:category", [attr: "text"]),
      itunes_category:       feed |> elements("itunes:category", [attr: "text"]),

      itunes_owners:         parse_itunes_owners(feed),
      entries:               parse_entries(feed)
    })
  end

  def parse_entry(feed, entry) do
    feed |> RSS2.parse_entry(entry) |> Map.merge(%{
      itunes_author:    entry |> element("itunes:author"),
      itunes_block:     entry |> element("itunes:block"),
      itunes_duration:  entry |> element("itunes:duration"),
      itunes_explicit:  entry |> element("itunes:explicit"),
      itunes_keywords:  entry |> element("itunes:keywords"),
      itunes_subtitle:  entry |> element("itunes:subtitle"),
      itunes_image:     entry |> element("itunes:image", [attr: "href"]),
      itunes_order:     entry |> element("itunes:order"),
      itunes_summary:   entry |> element("itunes:summary"),
      itunes_is_closed_captioned:   entry |> element("itunes:isClosedCaptioned")
    })
  end

  defp parse_itunes_owners(feed) do
    XmlNode.map_children(feed, "itunes:owner", fn(owner) ->
      %{
        itunes_name: owner |> element("itunes:name"),
        itunes_email: owner |> element("itunes:email")
      }
    end)
  end

  defp parse_entries(feed) do
    XmlNode.map_children(feed, "item", fn(e) -> parse_entry(feed, e) end)
  end

  defp itunes_namespace?(xml) do
    namespaces = xml |> XmlNode.find("/rss") |> XmlNode.namespaces
    namespaces["itunes"] == "http://www.itunes.com/dtds/podcast-1.0.dtd"
  end

end