ticket.rb

class Ticket < ActiveRecord::Base
  class TicketConfirmer
    attr_reader :ticket, :confirmation_errors
    delegate :user, :grouper :to => :ticket
    def initialize(ticket)
      @ticket = ticket
      @confirmation_errors = []
    end

    def can_confirm?
      confirmation_errors.clear
      run_confirmations
      confirm_errors.any?
    end

    private
      def run_confirmations
        confirmation_errors << [:user, "can't book a Grouper at this time"] if user.blacklisted?
        confirmation_errors << [:user, 'are already going to a Grouper on that day'] if user.has_existing_grouper?(grouper)
        confirmation_errors << [:grouper, 'has already occurred!'] if grouper.full?
        confirmation_errors << [:grouper, 'has already occurred!'] if grouper.past?
        confirmation_errors << [:user, 'have already confirmed this ticket'] if confirmed?
      end
  end
  belongs_to :grouper
  belongs_to :user

  validate :can_confirm , :on => :confirmation 
  
  private
    def can_confirm
      if (ticket_confirmer = TicketConfirmer.new(self)).can_confirm?
        ticket_confirmer.confirmation_errors.each do |object, error|
          errors.add(object, error)
        end
      end
    end
  
end