update stock

gistfile1.txt

 old_stock = Inventory::StockByWarehouse.where(master_data_item: master_data_item)
                                           .where(' warehouse_id in (?)', warehouses_ids)
                                           .select('sum(physical_quantity) as physical_quantity,
                                           sum(reserved_quantity) as reserved_quantity')
                                           
    old_total = old_stock[0].physical_quantity.nil? ? 0 : (old_stock[0].physical_quantity * master_data_item.unit_cost)
    
    buy = (transaction_cost * quantity)
    
    new_cost = 0
    
    if old_stock[0].physical_quantity != 0
      new_cost = (buy + old_total) / (
        (old_stock[0].physical_quantity.nil? ? 0 : old_stock[0].physical_quantity) + quantity)
    else
      new_cost = transaction_cost
    end