Pseudocode imagining how i might model the problem of creating CSV for creating willcall lists

addon_csv_row.rb

# understands how to display a csv row describing an addon purchase.
class AddonCsvRow
  def initialize(addon, order)
    @addon = addon
    @order = order
  end
  
  def to_csv
    "#{order.box_office_last_name}, #{order.box_office_first_name}, etc, etc"
  end
end
  

box_office_list.rb

# understands how to display a csv describing an item sold for a particular tour date.
class BoxOfficeList
  ADDON_TYPE = :addon
  TICKET_TYPE = :ticket
  def initialize(occurrence, type, object_id)
    @occurrnece = occurrence
    @type = type #TODO raise ArgumentError if unknown type
    @object_id = object_id
  end
  
  def to_csv
    csv = csv_header
    csv << csv_blank_line
    csv << csv_row_header
    csv << if @type == ADDON_TYPE
      addon = AddonItem.find(object_id)
      orders = Core::Order.where(addon_id: object_id).order_by_box_office_name
      orders.map{|order| AddonCsvRow.new(addon, order).to_csv}
    elsif @type == TICKET_TYPE
      ticket = UserCreated::TicketGroup.find(object_id)
      orders = Core::Order.where(ticket_group_id: object_id).order_by_box_office_name
      orders.map{|order| TicketCsvRow.new(addon, order).to_csv}
    end
    csv << csv_footer
  end
  
  def to_s
    if @type == ADDON_TYPE
      AddonItem.find(object_id).name
    elsif @type == TICKET_TYPE
      UserCreated::TicketGroup.find(object_id).name
    end
  end
  
  def csv_header
    #create csv header based on occurrence, type, object
  end
  
  def csv_row_header
    #create row header based on type
  end
  
  def csv_blank_line
    ",,,,,\n"
  end
  
  def csv_footer
    #footer data string
  end
end

box_office_lists.html.erb

<dl class="box_office_lists">
<% @box_office_lists.each_list do |box_office_list| %>
 <dt><%= box_office_list.to_s %></dt><dd><%= link_to box_office_list %></dd>
<%> end <%>
</dl>

box_office_lists.rb

class BoxOfficeLists
  def initialize(occurrence)
    @occurrence = occurrence
  end
  
  def each_list do
    ticket_groups = @occurrence.user_created_ticket_groups_with_sales
    addons = @occurrence.addon_items_with_sales
    (ticket_groups + addons).each do |item|
      type = item.kind_of?(UserCreated::TicketGroup) ? BoxOfficeList::TICKET_TYPE : BoxOfficeList::AddonType
      yield(BoxOfficeList.new(@occurrence, type, item.id))
    end
  end
end

BoxOfficeListController.rb

class BoxOfficeListController < ApplicationController
  def show
    @box_office_lists = BoxOfficeLists.new(params[:occurrence_id])
  end
end

ticket_csv_row.rb

# understands how to display a csv row describing a ticket purchase.
class TicketCsvRow
  def initialize(ticket, order)
    @ticket = ticket
    @order = order
  end
  
  def to_csv
    "#{order.box_office_last_name}, #{order.box_office_first_name}, etc, etc"
  end
end