# app/models/user.rb
class User
  include YodleeRegistrable
end

# app/models/concers/yodlee_registrable.rb
module YodleeRegistrable
  extend ActiveSupport::Concern

  included do
    has_one :yodlee_user

    scope :already_registered_on_yodlee?, ->(user_id) do
      #TODO
    end
  end

  def default_yodlee_username
    "saveup_user_#{id}_#{name[0..7]}"
  end

  def create_or_get_default_yoddlee_user
    return yodlee_user if yodlee_user.present?

    yodlee_user = self.build_yodlee_user

    yodlee_user.tap do |y_u|
      y_u.email = user.email
      y_u.username = user.default_yodlee_username
      y_u.password = YodleePassGenerator.create
    end

    yodlee_user.save!
  end
end

# app/models/yodlee_user.rb
class YodleeUser
  belongs_to :user
  #columns: email, username, password, user_id
end

# app/services/register_new_yodlee_user.rb
class RegisterNewYodleeUser
  def call(user_id)
    raise Error if User.registered_on_yodlee?(user_id)
    user = User.find(user_id)

    result = Yodlee::Api::V1::User.new.register(user.create_or_get_default_yoddlee_user)
    if result.success?
      yodlee_registrable.update_attributes!(yodlee_id: result.userId)
    else
      # Manage the error
    end
  end
end