Shopify Script Discounting example

Shopify Script Discounting

# ================================ Customizable Settings ================================
# ================================================================
# Tiered Discounts by Quantity
#
# A list of discount tier offers where:
#   - '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
#       - ':id' to find products by ID
#       - ':type' to find products by type
#   - 'product_selector' is a list of tags or IDs to identify
#     qualifying products
#   - 'tiers' is a list of tiers where:
#     - 'quantity' is the minimum quantity you need to buy to
#       qualify
#     - 'discount_type' is the type of discount to provide. Can be
#       either:
#         - ':percent'
#         - ':dollar'
#     - 'discount_amount' is the percentage/dollar discount to
#       apply (per item)
#     - 'discount_message' is the message to show when a discount
#       is applied
# ================================================================
PRODUCT_DISCOUNT_TIERS = [
  {
    product_selector_match_type: :include,
    product_selector_type: :type,
    product_selectors: ["Socks"],
    tiers: [
      {
        quantity: 3,
        discount_type: :dollar,
        discount_amount: 8.333,
        discount_message: '3 pairs of Socks for $59!',
      },
    ],
  },
]

# ================================================================
# Bundle Cart Discounts (ie. 'Buy a bib and a jersey, and get 15%
# off all items)
#
# A list of bundle discounts where:
#   - 'bundle_items' is a list of the items that comprise the
#     bundle, where:
#     - 'product_id' is the ID of the product
#     - 'quantity_needed' is the quantity necessary to complete
#       the bundle
#   - 'discount_type' is the type of discount to provide. Can be
#     either:
#       - ':percent'
#       - ':dollar'
#   - 'discount_amount' is the percentage/dollar discount to
#     apply (per item)
#   - 'discount_message' is the message to show when a discount
#     is applied
# ================================================================
BUNDLE_DISCOUNTS = [
  {
    bundle_items: [
      {
        product_selector_match_type: :include,
        product_selector_type: :type,
        product_selectors: ["Men's Bib Shorts", "Women's Bib Shorts"],
        quantity_needed: 1
      },
      {
        product_selector_match_type: :include,
        product_selector_type: :type,
        product_selectors: ["Jersey", "Men's Jersey", "Women's Jersey"],
        quantity_needed: 1
      },
    ],
    discount_type: :percent,
    discount_amount: 15,
    discount_message: "15% off when buying a bib and a jersey!",
  },
]

# ================================ Script Code (do not edit) ================================
# ================================================================
# ProductSelector
#
# Finds matching products - either by product ID or tag
# ================================================================
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 @selector_type == :tag
      product_tags = line_item.variant.product.tags.map { |tag| tag.downcase.strip }
      @selectors = @selectors.map { |selector| selector.downcase.strip }
      (@selectors & product_tags).send(@comparator)
    elsif @selector_type == :id
      if @match_type == :include
        @selectors.include?(line_item.variant.product.id)
      else
        !@selectors.include?(line_item.variant.product.id)
      end
    else
      @selectors = @selectors.map { |selector| selector.downcase.strip }
      
      if @match_type == :include
        @selectors.include?(line_item.variant.product.product_type.downcase.strip)
      else
        !@selectors.include?(line_item.variant.product.product_type.downcase.strip)
      end
    end
  end
end

# ================================================================
# BundleSelector
#
# Finds any items that are part of the entered bundle and saves
# them
# ================================================================
class BundleSelector
  def initialize(bundle_items)
    @bundle_items = bundle_items.reduce([]) do |acc, bundle_item|
      product_selector = ProductSelector.new(
        bundle_item[:product_selector_match_type],
        bundle_item[:product_selector_type],
        bundle_item[:product_selectors],
      )
      
      bundle_item_info = {
        product_selector: product_selector,
        quantity_needed: bundle_item[:quantity_needed],
        total_quantity: 0,
      }
      
      acc.push(bundle_item_info)
      
      acc
    end
  end
  
  def build(cart)
    cart.line_items.each do |line_item|
      @bundle_items.each do |bundle_item|
        next unless bundle_item[:product_selector].match?(line_item)
        
        bundle_item[:total_quantity] += line_item.quantity
      end
    end
    
    @bundle_items
  end
end

# ================================================================
# DiscountApplicator
#
# Applies the entered discount to the supplied line item
# ================================================================
class DiscountApplicator
  def initialize(discount_type, discount_amount, discount_message)
    @discount_type = discount_type
    @discount_message = discount_message

    @discount_amount = if discount_type == :percent
      1 - (discount_amount * 0.01)
    else
      Money.new(cents: 100) * discount_amount
    end
  end

  def apply(line_item)
    new_line_price = if @discount_type == :percent
      line_item.line_price * @discount_amount
    else
      [line_item.line_price - (@discount_amount * line_item.quantity), Money.zero].max
    end

    line_item.change_line_price(new_line_price, message: @discount_message)
  end
end

# ================================================================
# TieredPricingCampaign
#
# Finds any products of the entered type and applies the
# associated tier discount
# ================================================================
class TieredPricingCampaign
  def initialize(discounts)
    @discounts = discounts
  end

  def run(cart)
    @discounts.each do |discount|
      product_selector = ProductSelector.new(
        discount[:product_selector_match_type],
        discount[:product_selector_type],
        discount[:product_selectors],
      )
      
      tiers = discount[:tiers].sort_by { |tier| tier[:quantity] }.reverse
      applicable_items = cart.line_items.select { |line_item| product_selector.match?(line_item) }
      
      next if applicable_items.nil?
      
      total_applicable_quantity = applicable_items.map(&:quantity).reduce(0, :+)
      applicable_tier = tiers.find { |tier| tier[:quantity] <= total_applicable_quantity }
      
      next if applicable_tier.nil?

      discount_applicator = DiscountApplicator.new(
        applicable_tier[:discount_type],
        applicable_tier[:discount_amount],
        applicable_tier[:discount_message]
      )

      applicable_items.each do |line_item|
        next if line_item.discounted?
        discount_applicator.apply(line_item)
      end
    end
  end
end

# ================================================================
# BundleCartDiscountCampaign
#
# If the entered bundle is present, the entered discount is
# applied to each item in the cart
# ================================================================
class BundleCartDiscountCampaign
  def initialize(discounts)
    @discounts = discounts
  end
  
  def run(cart)
    @discounts.each do |discount|
      bundle_selector = BundleSelector.new(discount[:bundle_items])
      bundle_items = bundle_selector.build(cart)
      
      next if bundle_items.any? do |product_info|
        product_info[:total_quantity] < product_info[:quantity_needed]
      end
      
      discount_applicator = DiscountApplicator.new(
        discount[:discount_type],
        discount[:discount_amount],
        discount[:discount_message]
      )

      cart.line_items.each do |line_item|
        next if line_item.discounted?
        discount_applicator.apply(line_item)
      end
    end
  end
end

CAMPAIGNS = [
  TieredPricingCampaign.new(PRODUCT_DISCOUNT_TIERS),
  BundleCartDiscountCampaign.new(BUNDLE_DISCOUNTS),
]

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

Output.cart = Input.cart