Shopify Gift With Purchase

gwp.rb

Variant_ids = [18334016901,   17782905285 ]
Product_ids = [5782681861,    5620148101  ]
Prices      = [2450,          500        ]
Triggers    = [15000,         2500        ]


def gwp(product_id, variant_id, product_price, activation_total)

  should_trigger_gift = false

  #first, add up all the line items' prices
  total = Money.new(cents:0)
  Input.cart.line_items.each do |line_item|
    found = false;
    for var_id in Variant_ids
      if line_item.variant.id == var_id
        found = true;
      end
    end
    next if found
    
    total = total + line_item.line_price
  end



  #should we should trigger the gift?
  if total > Money.new(cents:activation_total)
    should_trigger_gift = true
  else
    should_trigger_gift = false
  end


  if should_trigger_gift
    Input.cart.line_items.each do |line_item|

      product = line_item.variant.product
      next if product.gift_card?
      next unless product.id == product_id
      
      line_price = line_item.line_price
      line_discount = Money.new(cents:product_price)
      
      new_line_price = line_price - line_discount
      
      line_item.change_line_price( new_line_price , message: "1x Free Gift!")
      break
    end

  else
    Input.cart.line_items.each do |line_item|
      product = line_item.variant.product
      next if product.gift_card?
      next unless product.id == product_id
      
      line_price = line_item.line_price
      regular_price = Money.new(cents:product_price)

      new_line_price = regular_price * line_item.quantity
      
      line_item.change_line_price( new_line_price , message: "1x Free Gift!")
      break
    end
  end
  
  Output.cart = Input.cart
end


#apply product one
gwp(Product_ids[0],Variant_ids[0],Prices[0],Triggers[0])

#apply product two
gwp(Product_ids[1],Variant_ids[1],Prices[1],Triggers[1])