def search(query, page = 1, search_params = build_search_params(content_type: "video"))
  client = make_client(YT_URL)
  html = client.get("/results?q=#{URI.escape(query)}&page=#{page}&sp=#{search_params}").body
  html = XML.parse_html(html)

  videos = [] of ChannelVideo

  html.xpath_nodes(%q(//ol[@class="item-section"]/li)).each do |item|
    root = item.xpath_node(%q(div[contains(@class,"yt-lockup-video")]/div))
    if !root
      next
    end

    id = root.xpath_node(%q(.//div[contains(@class,"yt-lockup-thumbnail")]/a/@href)).not_nil!.content.lchop("/watch?v=")

    title = root.xpath_node(%q(.//div[@class="yt-lockup-content"]/h3/a)).not_nil!.content

    author = root.xpath_node(%q(.//div[@class="yt-lockup-content"]/div/a)).not_nil!
    ucid = author["href"].rpartition("/")[-1]
    author = author.content

    published = root.xpath_node(%q(.//ul[@class="yt-lockup-meta-info"]/li[1])).not_nil!.content
    published = decode_date(published)

    video = ChannelVideo.new(id, title, published, Time.now, ucid, author)
    videos << video
  end

  return videos
end

def build_search_params(sort_by = "relevance", date : String = "", content_type : String = "", duration : String = "", features : Array(String) = [] of String)
  head = "\x08"
  head += case sort_by
          when "relevance"
            "\x00"
          when "rating"
            "\x01"
          when "upload_date"
            "\x02"
          when "view_count"
            "\x03"
          else
            raise "No sort #{sort_by}"
          end

  body = ""
  body += case date
          when "hour"
            "\x08\x01"
          when "today"
            "\x08\x02"
          when "week"
            "\x08\x03"
          when "month"
            "\x08\x04"
          when "year"
            "\x08\x05"
          else
            ""
          end

  body += case content_type
          when "video"
            "\x10\x01"
          when "channel"
            "\x10\x02"
          when "playlist"
            "\x10\x03"
          when "movie"
            "\x10\x04"
          when "show"
            "\x10\x05"
          else
            ""
          end

  body += case duration
          when "short"
            "\x18\x01"
          when "long"
            "\x18\x02"
          else
            ""
          end

  features.each do |feature|
    body += case feature
            when "hd"
              "\x20\x01"
            when "subtitles"
              "\x28\x01"
            when "creative_commons"
              "\x30\x01"
            when "3d"
              "\x38\x01"
            when "live"
              "\x40\x01"
            when "purchased"
              "\x48\x01"
            when "4k"
              "\x70\x01"
            when "360"
              "\x78\x01"
            when "location"
              "\xb8\x01\x01"
            when "hdr"
              "\xc8\x01\x01"
            else
              raise "Unknown feature #{feature}"
            end
  end

  if body.size > 0
    token = head + "\x12" + body.size.to_u8.unsafe_chr + body
  else
    token = head
  end

  token = Base64.urlsafe_encode(token)
  token = URI.escape(token)

  return token
end