gistfile1.rb

class ShipmentCycle < ActiveRecord::Base
  belongs_to :plan, inverse_of: :shipment_cycles

  has_many :gift_subscriptions, inverse_of: :shipment_cycle

  has_many :plan_allotments, inverse_of: :shipment_cycle

  has_many :subscriptions, inverse_of: :shipment_cycle

  has_one :assortment, through: :plan

  validates :phase,
    presence: true

  validates :plan_id,
    presence: true

  def next_shipment(date = Date.current)
    nearest_shipment(date, days: 1)
  end

  def previous_shipment(date = Date.current)
    nearest_shipment(date, days: -1)
  end

private

  def nearest_shipment(date = Date.current, options = { days: 1 })
    begin
      recurrence = Recurrence.new(plan.days_between_shipments, date)
      date = date.advance(options)
    end until recurrence.phase == phase
    Shipment.new(self, recurrence.date)
  end

end