how to set order status as 'complete' in magento

Question

how do i set order status as 'complete' manually.

I am using the following code, but its giving error saying, The Order State 'complete' must not be set manually.

$order = Mage::getModel('sales/order')->loadByIncrementId($order_id);
        $order->setState(Mage_Sales_Model_Order::STATE_COMPLETE);
        $order->save(); 

Answer 1

i found a solution for my self,

$order = Mage::getModel('sales/order')->loadByIncrementId($order_id);
        $order->setData('state', "complete");
        $order->setStatus("complete");       
        $history = $order->addStatusHistoryComment('Order was set to Complete by our automation tool.', false);
        $history->setIsCustomerNotified(false);
        $order->save();