LocalStore.rb

class LocalStore
  def self.increase_popularity(model_class_name, model_id)
    key = key(model_class_name)

    REDIS.pipelined do
      ensure_ttl(key)
      REDIS.zincrby(key, 1, model_id)
    end
  end

  def self.popular_products
    key = key('product')
    REDIS.zrevrange(key, 0, 3)
  end

  def self.popular_store
    key = key('store')
    REDIS.zrevrange(key, 0, 0).first
  end

private
  def self.key(model_class_name)
    "popular_#{model_class_name.pluralize}"
  end

  def self.ensure_ttl(key)
    REDIS.expire(key, 86400) if REDIS.ttl(key) == -1
  end
end