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35class Checkout # :nodoc:
attr_reader :basket, :subtotal
def initialize(promotions: [MultibuyPromotion.new, PercentagePromotion.new])
@promotions = promotions
@basket = Hash.new(0)
@subtotal = 0
end
def scan(item)
update_basket(item)
update_subtotal(item)
end
def total
update_total
end
private
def update_basket(item)
@basket[item.code] += 1
end
def update_subtotal(item)
@subtotal += item.price
end
def update_total
total = @subtotal
@promotions.each { |promotion| total -= promotion.apply(basket, total) }
total.round(2).to_f
end
end