Where is order ID generated?

Question

I have been overriding the function saveOrderAction in the OnepageController.php (/app/code/core/Mage/Checkout/controllers) with my custom code.

I have implemented the logic for this successfully. I believe at this point at the start of the function as the order hasn't been completed there is no order ID. Instead I have access to the 'quote ID'.

What I need to do now is find out where the Order ID is generated for the order. My first question is which file/function is best to override for when the Order ID is created?

My second question is, is there a way to link the quote ID to the Order ID which is generated?

Essentially my aim is to get the order ID of the currently ordered items so I can do further custom processing.

---

My observer code is through this path: /local/James/Aftercheckout

config.xml - /local/James/Aftercheckout/etc

Observer.php - /local/James/Aftercheckout/Model

Contents of config.xml:

<?xml version="1.0"?>
<config>
<modules>

    <James_Aftercheckout>

        <version>0.1.0</version>

    </James_Aftercheckout>

    </modules>        
<global>        
    <events>
        <sales_model_service_quote_submit_before>
            <observers>
                <james_aftercheckout_observer>
                    <type>singleton</type>
                    <class>James_Aftercheckout_Model_Observer</class>
                    <method>test</method>
                </james_aftercheckout_observer>
            </observers>
        </sales_model_service_quote_submit_before>
    </events>
</global>

Code for Observer.php :

class James_Aftercheckout_Model_Observer
{   

public function test($observer)
{
    $quote = $observer->getEvent()->getQuote();
    $incrementId = $quote->getReservedOrderId();


    $to = "myemail@gmail.com";
    $subject = "Test mail";
    $message = "Hello! This is a simple email message! .".$incrementId;
    $from = "randomemail@example.com";
    $headers = "From:" . $from;
    mail($to,$subject,$message,$headers);
}
}

Answer 1

The increment id of the order is created when the order is submitted, in this method Mage_Sales_Model_Service_Quote::submitOrder(). The line responsible for the creation is $quote->reserveOrderId();.
If you want to access it you can hook onto the event sales_model_service_quote_submit_before.
You will be able to get the increment id in you observer like this:

public function doSomething($observer){//observer for the event
    $quote = $observer->getEvent()->getQuote();
    $incrementId = $quote->getReservedOrderId();
    //do stuff
}