memberships.rb

class User < ActiveRecord::Base
  has_one :subscription, dependent: :destroy
end

class Subscription < ActiveRecord::Base
  acts_as_paranoid

  belongs_to :user

  enum plan: ServicePlans.plan_names

  def data_range_query
    { created_at: data_range }
  end

  def beginning_of_oldest_allowed_date
    (end_of_today - data_window_span).beginning_of_day
  end

  private

  def data_range
    Range.new(beginning_of_oldest_allowed_date, end_of_today)
  end

  def end_of_today
    Time.zone.today.end_of_day
  end

  def data_window_span
    plan_attributes.data_window_span
  end

  def plan_attributes
    ServicePlans.new(user)
  end
end


class ServicePlans
  PLANS = {
    free: {
      index: 0,
      data_window_span: 30.days,
      export_allowed?: false,
    },

    essential: {
      index: 1,
      data_window_span: 90.days,
      export_allowed?: true,
    },

    pro: {
      index: 2,
      data_window_span: 365.days,
      export_allowed?: true,
    },

    enterprise: {
      index: 3,
      data_window_span: (365 * 2).days,
      export_allowed?: true,
    },
  }.freeze

  def self.default_plan
    'pro'
  end

  def self.plan_names
    PLANS.keys
  end

  def initialize(user)
    @user = user
  end

  def data_window_span
    attribute.fetch(:data_window_span)
  end

  def export_allowed?
    attribute.fetch(:export_allowed?)
  end

  private

  attr_reader :user

  def attribute
    PLANS.fetch(plan.to_sym)
  end

  def plan
    subscription.plan
  end

  def subscription
    user.subscription
  end
end

PLANS should be it's own value object, now that I look at it.