Tiered Fixed Price Discount :final_price - Shopify Script

[dmitry_z]

Hi, really need your guys help. 

I'm trying to create a tiered fixed price offer.

Order 3 - for $X

Order 5 for $Y

Order 8 for $Z

However I can't find example in Shopify supplied guide. I was able to create only for 1 offer not tiered like example below. Could anyone help me how can I create similar script as below, BUT tiered?

# ================================ Customizable Settings ================================
# ================================================================
# Buy X of Product Y for $Z
#
# Buy a certain number of matching items for a specific price.
# For example:
#
#   "Buy 2 t-shirts for $20"
#
#   - 'product_selector_match_type' determines whether we look for
#     products that do or don't match the entered selectors. Can
#     be:
#       - ':include' to check if the product does match
#       - ':exclude' to make sure the product doesn't match
#   - 'product_selector_type' determines how eligible products
#     will be identified. Can be either:
#       - ':tag' to find products by tag
#       - ':type' to find products by type
#       - ':vendor' to find products by vendor
#       - ':product_id' to find products by ID
#       - ':variant_id' to find products by variant ID
#       - ':subscription' to find subscription products
#       - ':all' for all products
#   - 'product_selectors' is a list of identifiers (from above)
#     for qualifying products. Product/Variant ID lists should
#     only contain numbers (ie. no quotes). If ':all' is used,
#     this can also be 'nil'.
#   - 'quantity_to_buy' is the number of products needed to
#     qualify
#   - 'final_price` is the amount to charge for all products that
#     are part of the offer
#   - 'discount_message' is the message to show when a discount
#     is applied
# ================================================================
BUY_X_GET_Y_FOR_Z = [
  {
    product_selector_match_type: :include,
    product_selector_type: :tag,
    product_selectors: ["your_tag"],
    quantity_to_buy: 2,
    final_price: 100,
    discount_message: 'Buy 2 for $20',
  },
]

# ================================ Script Code (do not edit) ================================
# ================================================================
# ProductSelector
#
# Finds matching products by the entered criteria.
# ================================================================
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 }
    (@match_type == :include) == @selectors.include?(line_item.variant.product.product_type.downcase.strip)
  end

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

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

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

  def subscription(line_item)
    !line_item.selling_plan_id.nil?
  end

  def all(line_item)
    true
  end
end

# ================================================================
# DollarDiscountApplicator
#
# Applies the entered discount to the supplied line item.
# ================================================================
class DollarDiscountApplicator
  def initialize(discount_message)
    @discount_message = discount_message
  end

  def apply(line_item, discount_amount)
    new_line_price = line_item.line_price - discount_amount
    line_item.change_line_price(new_line_price, message: @discount_message)
  end
end

# ================================================================
# BuyXOfYForZCampaign
#
# Buy a certain number of matching items for a specific price.
# ================================================================
class BuyXOfYForZCampaign
  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],
      )

      eligible_items = cart.line_items.select { |line_item| product_selector.match?(line_item) }

      next if eligible_items.nil?

      eligible_item_count = eligible_items.map(&:quantity).reduce(0, :+)
      quantity_to_buy = campaign[:quantity_to_buy]
      number_of_offers = (eligible_item_count / quantity_to_buy).floor

      next unless number_of_offers > 0

      number_of_discountable_items = number_of_offers * quantity_to_buy
      total_offer_price = Money.new(cents: 100) * (number_of_offers * campaign[:final_price])
      discount_applicator = DollarDiscountApplicator.new(campaign[:discount_message])

      self.loop_items(cart, eligible_items, number_of_discountable_items, total_offer_price, discount_applicator)
    end
  end

  def loop_items(cart, line_items, num_to_discount, total_price, discount_applicator)
    current_price = Money.zero
    avg_price = total_price * (1 / num_to_discount)

    line_items = line_items.sort_by { |line_item| line_item.variant.price }

    line_items.each do |line_item|
      break if num_to_discount <= 0

      if line_item.quantity > num_to_discount
        split_line_item = line_item.split(take: num_to_discount)
        discount_amount = split_line_item.line_price - (total_price - current_price)
        discount_applicator.apply(split_line_item, discount_amount)
        position = cart.line_items.find_index(line_item)
        cart.line_items.insert(position + 1, split_line_item)
        break
      elsif line_item.quantity == num_to_discount
        discount_amount = line_item.line_price - (total_price - current_price)
        discount_applicator.apply(line_item, discount_amount)
        break
      else
        if line_item.variant.price <= avg_price
          current_price += line_item.line_price
        else
          discount_amount = (line_item.variant.price - avg_price) * line_item.quantity
          current_price += (line_item.line_price - discount_amount)
          discount_applicator.apply(line_item, discount_amount)
        end

        num_to_discount -= line_item.quantity
      end
    end
  end
end

CAMPAIGNS = [
  BuyXOfYForZCampaign.new(BUY_X_GET_Y_FOR_Z),
]

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

Output.cart = Input.cart

[PaulNewton]

@dmitry_z Try the following script repo:

https://github.com/Shopify/shopify-scripts 

https://github.com/Shopify/shopify-scripts/tree/master/Line-Item/Tiered%20Pricing%20For%20Bulk%20Pur... 

Plus Merchants that need direct support to either customize business logic , debug , or integrate checkout scripts can contact me at paull.newton+shopifyforums@gmail.com with this topic url, store url, and use case details for pricing.

[dmitry_z]

Thanks for the links, unfortunately I didn't find the correct one.

I need something similar to this but tiered, buy 3, 5, 8: 

BUY_X_GET_Y_FOR_Z = [
  {
    product_selector_match_type: :include,
    product_selector_type: :tag,
    product_selectors: ["your_tag"],
    quantity_to_buy: 3,
    final_price: 100,
    discount_message: 'Buy 3 for $20',

I tried to merging this script + script with tiered data. It was unsuccessful  😞

[PaulNewton]

You'd still have to update the logic in your script to match how it's using that configuration.

Or go the other way and update the tier script to incorporate your scripts logic.

Where PRICE_TIERS becomes BUY_X_GET_Y_FOR_Z  if need be

PRICE_TIERS = [
  # Pricing tiers for Shoes
  {
    product_types: ['Shoes'],
    group_by: :product, # :product or :variant
    tiers: [
      {
        quantity: 10,
        discount_percentage: 10,
        discount_message: '10% off for 10+'
      },
      {
        quantity: 50,
        discount_percentage: 15,
        discount_message: '15% off for 50+'
      }
    ]
  }
]

From https://github.com/Shopify/shopify-scripts/blob/master/Line-Item/Tiered%20Pricing%20For%20Bulk%20Pur...