blah.rb

class Price
  def pricer(quantity, item)
  end

  case
  when setpoint
    SetPrice
  when bulkpoint
    BulkPrice
  end

end
class SetPrice
end
class BulkPrice
end


class Pricing
  def initialize(
    lookup
  end
  def to_a
    ..
  end

end
class Item
  #price & quantity & set points/bulk points..
  # base_price : 1.50
  # 3 for 2 : 3
   
#  pricing 
#   Item   | types |  amount  |  bulk_price
#   apples | set   |   3     | 1
#   apples | set   |   1     | 1.5 
#   beef   | bulk  |  1      | 2
#   beef   | bulk  |  5      | 9

end


class CheckoutItem < Item
  def initialize(item, quantity)
    @item = item
    @quantiy = quantity
  end

  def price
    pricing = Pricing.new(@item) #=> [ SetPrice.new(1, 1.5), SetPrice.new(3, 1) ]


    result = 0

    pricing.sort.each do |pricing|
      if quantity > pricing.quantity
        result = quantity * pricing.price
        quantity -= pricing.quantity
      else
        next
      end
    end

    result
  end

end

class Checkout
   # takes item & quantity, returns price?
  def initialize()
    @items = {}
  end

  def add_item(item, quantity)
    @items[item] += quantity
  end

  def final_price
    @items.map do |item, quantity|

      CheckoutItem.new(item,quantity).price

    end.inject(&:+)
  end

end


@checkout = Checkout.new
@checkout.add_item(apple: 1)
@checkout.final_price


def test_final_price_is_zero
  @checkout = Checkout.new
  assert 0, @checkout.final_price
end