ActiveRecord で Enumerize と StateMachine 使うやつ

yokkyu.rb

class Yokkyu < ActiveRecord::Base
  extend Enumerize

  enumerize :status, scope: true, default: :awaiting in: {
    awaiting: 1,
    approved: 2,
    rejected: 3,
  }

  state_machine :status do
    state :awaiting
    state :approved
    state :rejected

    before_transition any => :approve,  do: :set_approved_at
    before_transition any => :rejected, do: :set_rejected_at

    event :approve do
      transition to: :approved, from: [:awaiting]
    end

    event :reject do
      transition to: :rejected, from: [:awaiting, :approved]
    end
  end

  def change_status(event)
    event = event.to_sym
    if event.in?(status_events)
      send(event)
    else
      errors.add(:status, :invalid_transition)
      false
    end
  end

  private

  def set_approved_at
    self.approved_at = Time.now
  end

  def set_rejected_at
    self.rejected_at = Time.now
  end
end