Migrating a skip already discounted items script

# GENERATED BY THE SHOPIFY SCRIPT CREATOR APP
# Version 0.12.0

class Campaign
  def initialize(condition, *qualifiers)
    @condition = (condition.to_s + '?').to_sym
    @qualifiers = PostCartAmountQualifier ? [] : [] rescue qualifiers.compact
    @post_amount_qualifiers = []
    @line_item_selector = qualifiers.last unless @line_item_selector
    qualifiers.compact.each do |qualifier|
      is_multi_select = qualifier.instance_variable_get(:@conditions).is_a?(Array)
      if is_multi_select
        qualifier.instance_variable_get(:@conditions).each do |nested_q|
          @post_amount_qualifiers << nested_q if nested_q.is_a?(PostCartAmountQualifier)
          @qualifiers << qualifier
        end
      else
        @post_amount_qualifiers << qualifier if qualifier.is_a?(PostCartAmountQualifier)
        @qualifiers << qualifier
      end
    end if @qualifiers.empty?
  end
end

class Selector
end

class ReducedItemSelector < Selector
  def initialize(match_type)
    @invert = match_type == :not
  end

  def match?(line_item)
    @invert ^ line_item.discounted?
  end
end

class PercentageDiscount
  def initialize(percent, message)
    @discount = (100 - percent) / 100.0
    @message = message
  end

  def apply(line_item)
    line_item.change_line_price(line_item.line_price * @discount, message: @message)
  end
end

class ConditionalDiscount < Campaign
  def initialize(condition, customer_qualifier, cart_qualifier, line_item_selector, discount, max_discounts)
    super(condition, customer_qualifier, cart_qualifier)
    @line_item_selector = line_item_selector
    @discount = discount
    @items_to_discount = max_discounts == 0 ? nil : max_discounts
  end

  def run(cart)
    raise "Campaign requires a discount" unless @discount
    return unless qualifies?(cart)
    applicable_items = cart.line_items.select { |item| @line_item_selector.nil? || @line_item_selector.match?(item) }
    applicable_items.each do |item|
      @discount.apply(item)
    end
  end
end

CAMPAIGNS = [
  ConditionalDiscount.new(
    :all,
    nil,
    nil,
    ReducedItemSelector.new(:not),
    PercentageDiscount.new(10, "10% off full price items"),
    0
  ),
].freeze

CAMPAIGNS.each do |campaign|
  campaign.run(Input.cart)
end

Output.cart = Input.cart