class TwitterService
  def client
    raise "Twitter API keys not set" if Danbooru.config.twitter_api_key.nil?

    @client ||= begin
      rest_client = Twitter::REST::Client.new do |config|
        config.consumer_key = Danbooru.config.twitter_api_key
        config.consumer_secret = Danbooru.config.twitter_api_secret
        if bearer_token = Cache.get("twitter-api-token")
          config.bearer_token = bearer_token
        end
      end

      Cache.put("twitter-api-token", rest_client.bearer_token)

      rest_client
    end
  end

  def extract_urls_for_status(tweet)
    tweet.media.map do |obj|
      if obj.is_a?(Twitter::Media::Photo)
        obj.media_url.to_s + ":orig"
      elsif obj.is_a?(Twitter::Media::Video)
        video = obj.video_info.variants.select do |x|
          x.content_type == "video/mp4"
        end.max_by {|y| y.bitrate}
        if video
          video.url.to_s
        end
      end
    end.compact
  end

  def extract_og_image_from_page(url, n = 5)
    raise "too many redirects" if n == 0

    Net::HTTP.start(url.host, url.port, :use_ssl => (url.normalized_scheme == "https")) do |http|
      resp = http.request_get(url.request_uri)
      if resp.is_a?(Net::HTTPMovedPermanently) && resp["Location"]
        redirect_url = Addressable::URI.parse(resp["Location"])
        redirect_url.host = url.host if redirect_url.host.nil?
        redirect_url.scheme = url.scheme if redirect_url.scheme.nil?
        redirect_url.port = url.port if redirect_url.port.nil?
        return extract_og_image_from_page(redirect_url, n - 1)
      elsif resp.is_a?(Net::HTTPSuccess)
        doc = Nokogiri::HTML(resp.body)
        images = doc.css("meta[property='og:image']")
        return images.first.attr("content")
      end
    end
  end

  def extract_urls_for_card(attrs)
    urls = attrs.urls.map {|x| x.expanded_url}
    url = urls.reject {|x| x.host == "twitter.com"}.first
    if url.nil?
      url = urls.first
    end
    [extract_og_image_from_page(url)].compact
  end

  def image_urls(tweet_url)
    tweet_url =~ %r{/status/(\d+)}
    twitter_id = $1
    tweet = client.status(twitter_id)
    urls = []

    if tweet.media.any?
      urls = extract_urls_for_status(tweet)
    elsif tweet.urls.any?
      urls = extract_urls_for_card(tweet)
    end

    urls.uniq
  rescue => e
    []
  end
end