Starting point

gistfile1.txt

require 'digest/sha1'

class EmoteList < Array
  attr_accessor :type, :sort, :tags, :user
  attr_reader :randomized

  def assign_properties(properties = {})
    @type = properties[:type]
    @sort = properties[:sort]
    @tags = properties[:tags]
    @user = properties[:user]
  end

  def most_recently_updated
    self.sort {| a, b | a.updated_at <=> b.updated_at }
  end

  def randomize!
    self.sort_by! { rand }
    @randomized = true
  end

  def cache_key
    raise NoEmoteListTypeSpecifiedError if @type.nil?
    raise NoEmoteListSortSpecifiedError if @sort.nil?

    key = "emote_list/#{@type}/#{sort}/"
    key += cachify_key_tags
    key += cachify_key_user
    key += self.most_recently_updated.updated_at
  end

  private

  def cachify_key_tags
    return '' if @tags.nil?
    return (Digest::SHA1.hexdigest @tags) + "/"
  end

  def cachify_key_user
    return '' if @user.nil?
    return @user.id.to_s + "/"
  end
end

class NoEmoteListTypeSpecifiedError < StandardError
end

class NoEmoteListSortSpecifiedError < StandardError
end

class CantCacheRandomizedEmoteList < StandardError
end