KISSmetrics plugin for aMember (SaaS style)

hey everyone,
been working on integration for KISSmetrics following the KM SaaS adivces (http://support.kissmetrics.com/best-practices/saas-essentials), code is working fine but still needs development (esp for Upgraded/Downgrade events).

Please keep in mind that I built this for my needs, so might not fit for everyone. It's based on assumption that you use recurring subscription, with trials. It includes registering signups, with email/username as aliases. Recording Billing/Upgrades/Downgrades/Cancels and changing alias if user updates email.

Not a professional dev, so surely some optimisation to be done... Anyhow might be useful for some people so here it is...

PHP:

 
/***********************************************
IMPORTANT REMEMBER TO DO "require km.php"
BEFORE ACTIVATION
https://github.com/kissmetrics/KISSmetrics
*************************************************/
 
 
class Am_Plugin_KISSmetrics extends Am_Plugin
{
 
    const PLUGIN_STATUS = self::STATUS_PRODUCTION;
    const PLUGIN_REVISION = '4.2.11';
 
    protected $id;
    protected $done = false;
    public function __construct(Am_Di $di, array $config)
    {
        $this->id = $di->config->get('KISSmetrics_id');
        parent::__construct($di, $config);
    }
    public function isConfigured()
    {
        return !empty($this->id);
    }
    function onSetupForms(Am_Event_SetupForms $forms)
    {
        $form = new Am_Form_Setup('KISSmetrics');
        $form->setTitle("KISSmetrics");
        $forms->addForm($form);
        $form->addText('KISSmetrics_id', array('size'=>50))
            ->setLabel(array("KISSmetrics API"))
            ->addRule('required', 'This field is required');
        // $form->addText('km_php_dir', array('size'=>50))
        //      ->setLabel(array("Directory of km.php"))
        //      ->addRule('required', 'This field is required');
        //$form->addText('km_log_dir', array('size'=>50))
        //    ->setLabel(array("Kissmetric logs directory"));
        //$form->addCheckbox('km_use_cron')
        //    ->setLabel(array("Use cron ?<br>http://support.kissmetrics.com/apis/cron"));
        //$form->setDefault('km_log_dir', '/tmp');
 
    }
 
 
    function init()
    {
        if($this->isConfigured()) {
            $KM_KEY = $this->getDi()->config->get('KISSmetrics_id');
            //km initialize
            KM::init($KM_KEY, array());
        }
    }
 
    // when user created (before payment) we send Signed Up for Free.
    function onSignupUserAdded(Am_Event $event)
    {
        $user = $event->getUser();
 
        KM::identify($user->login);
        KM::record('Signed Up', array('Plan Name' => 'Free'));
        KM::alias($user->login, $user->email);
 
    }
 
 
    //everytime invoice is created
    function onInvoiceStarted(Am_Event_InvoiceStarted $event)
    {
        $invoice = $event->getInvoice();
        $item = $invoice->getItem(0); // only get first item since site doesn't allow basket checkout
        $user = $event->getUser();
        $has_paid = $user->isPaid();
 
 
        // if invoice status RECURRING_ACTIVE ... may add event for PAID or PENDING
      if ($invoice->status == Invoice::RECURRING_ACTIVE ) {
        /* TO DO :
            should add comparison to see if user has a lower priced sub
            for now if user has paid before it will show as Downgraded
        */
            if($has_paid == 0 ) {
                KM::identify($user->login);
                KM::record('Upgraded', array('Plan Name' => $item->item_title,
                                            'InvoiceId' => $invoice->invoice_id
                                            ));
            }
            else{
                KM::identify($user->login);
                KM::record('Downgraded', array('Plan Name' => $item->item_title,
                                            'InvoiceId' => $invoice->invoice_id
                                            ));
            }
        }
 
    }
 
    //everytime payment is made, we call Billed
    function onPaymentAfterInsert(Am_Event $event)
    {
        $invoice = $event->getInvoice();
        $payment = $event->getPayment();
        $item = $invoice->getItem(0);
        $user = $event->getUser();
 
        // check recurence of payments... using second_payment since I work with trials
        if ($invoice->second_period == '30d' || $invoice->second_period =='1m') $frequency = 'Monthly';
        elseif ($invoice->second_period == '90d' || $invoice->second_period =='3m') $frequency = 'Quarterly';
        elseif ($invoice->second_period == '7d' || $invoice->second_period =='1w') $frequency = 'Weekly';
 
        KM::identify($user->login);
        KM::record('Billed', array(
                            'Billing Amount' => $payment->amount,
                            'Billing Description' => $frequency,
                            'Invoice#' => $payment->invoice_id
                            ));
    }
 
    // change alias if user updates email
    function onUserAfterUpdate(Am_Event_UserAfterUpdate $event) {
        $user = $event->getUser();
        $newEmail = $user->get('email');
        $oldEmail = $event->getOldUser()->get('email');
 
        if ($newEmail != $oldEmail)
            KM::alias($user->login, $newEmail);
    }
 
    // if recurring canceled
    function onInvoiceStatusChange(Am_Event_InvoiceStatusChange $event) {
        /*  [invoice statuses]
            Invoice::PENDING = 0; // pending, not processed yet - initial status
            Invoice::PAID = 1; // paid and not-recurring
            Invoice::RECURRING_ACTIVE=2; // active recurring - there will be rebills, access open
            Invoice::RECURRING_CANCELLED=3; // recurring cancelled, access is open until paid
            Invoice::RECURRING_FAILED=4; // rebilling failed, access is closed
            Invoice::RECURRING_FINISHED=5; // rebilling finished, no access anymore
            Invoice::CHARGEBACK=7; // chargeback processed, no access
            Invoice::NOT_CONFIRMED = 8;
        */
 
        $invoice = $event->getInvoice();
        $username = Am_Di::getInstance()->db->selectCell("SELECT login FROM ?_user WHERE user_id=?d", $invoice->user_id);
 
 
        if ($invoice->status == Invoice::RECURRING_CANCELLED || $invoice->status == Invoice::RECURRING_FAILED || $invoice->status == Invoice::RECURRING_FINISHED) {
            if($invoice->isPaid()) {
                KM::identify($username);
                KM::record('Canceled');
            }
            else {
                KM::identify($username);
                KM::record('Trial Ended');
            }
        }
    }
}