gistfile1.rb

## On BuyerEmailer

  # Now we don't have to call it in every method...
  sendgrid_category 'buyer'
  
  # This is the hash that connects preference levels to emails
  @@preference_levels = {
    claimed: "important"
  }

  # This is a class method, meaning you call it like: 
  # BuyerEmailer.check_and_send(:claimed, @business)
  def self.check_and_send email, *opts
    # This looks at the class variable and determines the preference level
    level = @@preference_levels[email]
    # This assumes business is the first argument to the method.
    # A lot of these methods will have to be refactored to include business as the first arg
    business = opts.first
    # Then it calls the method on itself 
    # using send http://ruby-doc.org/core-2.0/Object.html#method-i-send
    # ONLY IF the business isn't unsubscribed from that level.
    send(email, *opts).deliver if business.check_prefs level
  end

# On Business

  # You'll have to refactor check_prefs to take in an optional argument of the given level
  
  def check_prefs level=nil
    if email_preferences
      return false if email_preferences["ignore_all"] == true
      return false if level && email_preferences["ignore_#{ level }"] == true  
    end
    setup_unsubscribe_token
    return true
  end
  
  def setup_unsubscribe_token
    unless unsubscribe_token
      self.unsubscribe_token = SecureRandom.hex(16)
      self.save
    end
  end