aMember (site.php): sequential invoice numbers

site.php

<?php

function _get_my_number($record)
{
    $prefix = $record instanceof InvoicePayment ? 'INV' : 'RFD';
    $year = date('Y', amstrtotime($record->dattm));
    $table = $record instanceof InvoicePayment ? '?_invoice_payment' : '?_invoice_refund';

    $num = Am_Di::getInstance()->db->selectCell(<<<CUT
        SELECT COUNT(*) + 1 FROM {$table}
            WHERE dattm < ?
            AND YEAR(dattm) = ?
CUT
        , $record->dattm, $year);
    
    return sprintf("%s-%s-%03d", $prefix, $year, $num);
}

Am_Di::getInstance()->hook->add([
    Am_Event::SET_DISPLAY_INVOICE_PAYMENT_ID,
    Am_Event::SET_DISPLAY_INVOICE_REFUND_ID], function(Am_Event $e) {

    $e->setReturn(_get_my_number($e->getRecord()));
});

//add column with Invoice Number to payments grid in Admin UI
Am_Di::getInstance()->hook->add([
    'gridPaymentInitGrid',
    'gridRefundInitGrid'], function(Am_Event_Grid $e) {

    $e->getGrid()->prependField('display_invoice_id', ___('Invoice Number')); 
});