DISCOUNTS_BY_QUANTITY = {
  8 => 275.00,
  4 => 150.00,
}
if Input.cart.line_items.length  == 4 || Input.cart.line_items.length == 8
  discount = Input.cart.subtotal_price - (Money.new(cents: 100) * DISCOUNTS_BY_QUANTITY[Input.cart.line_items.length])
  Input.cart.line_items.each do |line_item|
    next line_item.properties.has_key?("_bundle")
    new_line_price = 0
    discount_after_item_disc = discount - line_item.variant.price
    if discount_after_item_disc >= 0 * Money.new(cents: 100)
      new_line_price = line_item.variant.price - line_item.variant.price
    else
      new_line_price = line_item.variant.price - discount
    end
    if discount >= 0 * Money.new(cents: 100)
      discount = discount_after_item_disc
      line_item.change_line_price(new_line_price, message: { message: "Bundle" })
    end
  end
end

Output.cart = Input.cart