custom serial based on input by the user

-- HikaShop version -- : 6.0.0
-- HikaSerial version -- : 5.1.0
-- Joomla version -- : 5.3.1
-- PHP version -- : 8.2.28
-- Browser(s) name and version -- : Firefox 139.0.4, Chrome 137.0.7151.104
-- Error-message(debug-mod must be tuned on) -- : can´t see any message that seems relevant to me, screenshot added

Hello,

I have a very specific problem and need help figuring out how to approach it.
We are building a small webshop, initially with only one product category – we call them load codes. To explain: our customers have previously purchased a hardware product (from a retailer, for example) that they can load with additional, freely downloadable software if needed.
However, in order to load this software onto the hardware, they need a load code, which they purchase from our shop.
This load code is checked in the hardware to see if it is valid based on the hardware ID.
Therefore, when purchasing the load code, the customer should be able to enter this hardware ID, and our own algorithm then calculates the load code, which is issued to the customer after payment has been verified - – directly as text (in the form 255.255.255.255) and ideally as a downloadable ‘certificate’ (attach_serial).
I bought HikaSerial in the hope of being able to implement this process. But I'm stuck... I should mention that I'm not a developer, more of a web designer with some experience in remodelling things to suit requirements (also in Joomla).
Just to test it out, I used a random code generator, set up packs and serials – the system works, the code/serial is displayed in the order after payment has been confirmed (once online, this should of course be done via payment methods).
After studying the really extensive documentation, but unfortunately rather overwhelming for me, I tried to write my own generator plugin (with a little help from my friend AI).
To get an input field for the user, I simply created another field in the address for testing purposes. I don't have any other custom fields in Essential (yet). If this is the way to go, I am of course willing to upgrade!
But first, I wanted to read the input from the address field, convert it using MD5hash as the ‘algorithm’ and output it AfterOrderConfitmation.
I wrote the php,xml and index files. It worked to install the Plugin(s) and it showed up in HikaSerial - if it was defined as such. This was allready unclear for me, if I should create a generator plugin for HikaSerial or is this not even a generator and should be a Hikashop Plugin? (As the serial is allways different, depending on the users input). In any case, we would like to see the assigned serial number/code than in the respective order in the admin area.

Anyway - it didn´t work. I tried several variant of the code, nothing showed up. I guess the code is a mess and I had to override also some view files or so? To give you a big laugh, I'll append some code. Maybe it tells you where to lead me.
I would REALLY appreciate instructions that are as detailed as possible. Especially regarding the necessary steps. The exact code will then have to be adapted.

Thank you in advance,
Oliver


This is a first attempt, where I'm obviously missing the output - but should´t it be at least in the order (admin)?

<?php
defined('_JEXEC') or die('Restricted access');

class plgHikaserialLoadcodes extends hikaserialPlugin {
	
    public function onHikaSerialAfterOrder($order, $product)
    {
        // Check if the product belongs to the "Load Codes" category
        if ($product->category_id == '13') {
            // Get the ID number from the order/ $address
            $idnumber = $address->custom_fields['idnumber'];
            
                // Generate the serial code
                $serialCode = $this->generateSerialCode($idNumber);
                
                // Save the serial code to the order
                $this->saveSerialCode($address->id, $serialCode);
            }
        }

    private function generateSerialCode($idNumber) {
        return md5($idNumber); // Example algorithm
    }
//	    private function saveSerialCode($orderId, $serialCode) {
        // Save the serial code to the database or order
//    }

}

<?php
defined('_JEXEC') or die;

class plgHikashopLoadCodes extends hikashopPlugin {
    
    public function onHikashopCartProduct(&$cart, &$product) {
        // Check if the product is in the "Load Codes" category
        if (in_array('Load Codes', $product->categories)) {
            // Add the Decoder ID field
            $product->custom_fields['decoder_id'] = '';
        }
    }

    public function onHikashopBeforeCart(&$cart) {
        foreach ($cart->products as &$product) {
            if (isset($product->custom_fields['decoder_id']) && empty($product->custom_fields['decoder_id'])) {
                // Check if the Decoder ID is filled
                JFactory::getApplication()->enqueueMessage('Please fill in the Decoder ID.', 'error');
                return false;
            }
        }
        return true;
    }

    public function onHikashopAfterOrder(&$order, &$cart) {
        foreach ($cart->products as $product) {
            if (isset($product->custom_fields['decoder_id'])) {
                // Process the Decoder ID
                $processedCode = $this->processDecoderID($product->custom_fields['decoder_id']);
                $order->custom_fields['load_code'] = $processedCode;
            }
        }
    }

    private function processDecoderID($decoderID) {
        // Example processing algorithm (you can replace this with your own logic)
        return str_replace('.', '-', $decoderID);
    }

    public function onHikashopAfterOrderConfirmation(&$order) {
        // Add the processed Load Code to the confirmation email
        if (isset($order->custom_fields['load_code'])) {
            $order->email_content .= '<p>Your Load Code: ' . $order->custom_fields['load_code'] . '</p>';
        }
    }
}

Thanks a lot for the quick answer and your advices,
I will follow them and go step by step...
regards, Oliver