10% off 3 items / 15% off 7 items via product type

bundle script

item = 0

Input.cart.line_items.each do |line_item|
  product = line_item.variant.product
  if product.product_type == "Underwear"
    item+=line_item.quantity
  elsif product.product_type == "Socks"
    item+=line_item.quantity
  end
end

Input.cart.line_items.each do |line_item|
  product = line_item.variant.product
  if product.product_type == "Underwear" || product.product_type == "Socks"
    if item > 2 && item < 7
      line_item.change_line_price(line_item.line_price * 0.90, message: "Customers with 3+ pairs of shoes or socks receive 10% off each pair")
    elsif item > 6
      line_item.change_line_price(line_item.line_price * 0.85, message: "Customers with 7+ pairs of shoes or socks receive 15% off each pair.")
    end
  end
end

Output.cart = Input.cart