require "nokogiri"
require "open-uri"
require "open_uri_redirections"
require "house/episode"

module House
  class Podcast
    def initialize(url)
      @url = url
      @podcast = Nokogiri::XML(open(url, allow_redirections: :all))
      @items = []
      raise "The supplied url is not a valid podcast rss" if @podcast.at_xpath("/rss").nil?
    end

    def title;            attr("/rss/channel/title");           end
    def description;      attr("/rss/channel/description");     end
    def language;         attr("/rss/channel/language");        end
    def last_build_date;  attr("/rss/channel/lastBuildDate");   end
    def site_link;        attr("/rss/channel/link");            end

    def image_url;        attr("/rss/channel/image/url");       end
    def image_title;      attr("/rss/channel/image/title");     end
    def image_link;       attr("/rss/channel/image/link");      end

    def author;           attr("/rss/channel/itunes:author");   end
    def subtitle;         attr("/rss/channel/itunes:subtitle"); end
    def summary;          attr("/rss/channel/itunes:summary");  end

    def keywords
      attr("/rss/channel/itunes:keywords").to_s.split(",")
    end

    def explicit?
      explicit = attr("/rss/channel/itunes:explicit")
      case explicit
      when "yes" then true
      when "no"  then false
      else
        nil
      end
    end

    def publish_date
      pub_date = attr("/rss/channel/pubDate") || attr("/rss/channel/item[1]/pubDate")
      Time.parse(pub_date)
    end

    def items
      if @items.empty? && @podcast.xpath("/rss/channel/item")
        @podcast.xpath("/rss/channel/item").each do |node|
          @items << House::Episode.new(node)
        end
      end
      @items
    end

    def download_image_to(file_path)
      dir_path = File.dirname(file_path)
      FileUtils.mkdir_p(dir_path) unless File.exist?(dir_path)
      File.open(file_path, "w") do |f|
        f.write open(self.image_url).read
      end
    end

    def updated_since?(time)
      publish_date > time
    end

    private

    def attr(xpath)
      node = @podcast.xpath(xpath)
      if node.nil? || node.empty?
        nil
      else
        node.text
      end
    end
  end
end