Migrating a script scoped to a tag, vendor or product type

Danger pair D13. This file and its partner look almost identical and behave differently, so read both before you decide which one you have.

# ================================ Customizable Settings ================================
PRODUCT_DISCOUNTS = [
  {
    product_selector_match_type: :include,
    product_selector_type: :tag,
    product_selectors: ["sale"],
    discount_type: :percent,
    discount_amount: 20,
    discount_message: "20% off sale items",
  },
]

# ================================ Script Code (do not edit) ================================
class ProductSelector
  def initialize(match_type, selector_type, selectors)
    @match_type = match_type
    @comparator = match_type == :include ? 'any?' : 'none?'
    @selector_type = selector_type
    @selectors = selectors
  end

  def match?(line_item)
    if self.respond_to?(@selector_type)
      self.send(@selector_type, line_item)
    else
      raise RuntimeError.new('Invalid product selector type')
    end
  end

  def tag(line_item)
    product_tags = line_item.variant.product.tags.map { |tag| tag.downcase.strip }
    @selectors = @selectors.map { |selector| selector.downcase.strip }
    (@selectors & product_tags).send(@comparator)
  end

  def type(line_item)
    @selectors = @selectors.map { |selector| selector.downcase.strip }
    (@selectors.include?(line_item.variant.product.product_type.downcase.strip)) == (@match_type == :include)
  end

  def vendor(line_item)
    @selectors = @selectors.map { |selector| selector.downcase.strip }
    (@selectors.include?(line_item.variant.product.vendor.downcase.strip)) == (@match_type == :include)
  end

  def product_id(line_item)
    (@selectors.include?(line_item.variant.product.id)) == (@match_type == :include)
  end

  def variant_id(line_item)
    (@selectors.include?(line_item.variant.id)) == (@match_type == :include)
  end

  def all(line_item)
    true
  end
end

class ProductDiscountCampaign
  def initialize(campaigns)
    @campaigns = campaigns
  end

  def run(cart)
    @campaigns.each do |campaign|
      product_selector = ProductSelector.new(
        campaign[:product_selector_match_type],
        campaign[:product_selector_type],
        campaign[:product_selectors],
      )

      cart.line_items.each do |line_item|
        next unless product_selector.match?(line_item)
        line_item.change_line_price(
          line_item.line_price * (1 - (campaign[:discount_amount] * 0.01)),
          message: campaign[:discount_message],
        )
      end
    end
  end
end

CAMPAIGNS = [
  ProductDiscountCampaign.new(PRODUCT_DISCOUNTS),
]

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

Output.cart = Input.cart

Recognised as Percentage off and rebuilt as a volume offer. These are the real configuration keys the offer is saved with, so you can check your own rebuild against them field by field.

Built on our public demo store, Meridian Goods, so every price here can be reproduced rather than taken on trust. The discount below is what the same engine that runs at checkout computes for this exact cart.

Danger pair D9. This file and its partner look almost identical and behave differently, so read both before you decide which one you have.

Input.cart.line_items.each do |li|
  next unless li.variant.product.tags.include?('sale')
  li.change_line_price(li.original_line_price * (1.0 - (20 / 100.0)), message: "20% off sale")
end

Output.cart = Input.cart

Recognised as Percentage off and rebuilt as a volume offer. These are the real configuration keys the offer is saved with, so you can check your own rebuild against them field by field.

Built on our public demo store, Meridian Goods, so every price here can be reproduced rather than taken on trust. The discount below is what the same engine that runs at checkout computes for this exact cart.