Send message to a Slack channel (via another internal class) on MailgunEvent events

MailgunWebhookSubscriber.php

<?php
namespace App\Event;

use Azine\MailgunWebhooksBundle\Entity\MailgunEvent;
use Azine\MailgunWebhooksBundle\Entity\MailgunWebhookEvent;
use Ca\ProfileBundle\Services\SlackMessageable;
use Psr\Log\LoggerInterface;
use Symfony\Component\EventDispatcher\Event;
use Symfony\Component\EventDispatcher\EventDispatcherInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\Request;

class MailgunWebhookSubscriber implements EventSubscriberInterface
{
    const DATE_FMT = "Y-m-d\TH:i:s";

    /** @var SlackMessageable `$msg->send('text..')` a message to our slack channel */
    private $msg;
    /** @var LoggerInterface Application log */
    private $log;

    /**
     * @param SlackMessageable $msg
     * @param LoggerInterface  $log ordinary logger, to file
     */
    public function __construct(SlackMessageable $msg, LoggerInterface $log)
    {
        $this->msg = $msg;
        $this->log = $log;
    }

    /**
     * https://github.com/azine/AzineMailgunWebhooksBundle currently only has CREATE_EVENT
     *
     * The potential https://documentation.mailgun.com/api-events.html#event-types are
     * not currently broken down into further Symfony events.
     *
     * @return array MailgunEvent's to handle (currently just ::CREATE_EVENT)
     */
    public static function getSubscribedEvents()
    {
        return array(
            MailgunEvent::CREATE_EVENT => array('genericMailgunEvent'),
        );
    }

    public function sendSlackMsg($text)
    {
        if ($text) {
            return $this->msg->send($text);
        }

        @trigger_error("MailgunWebhookSubscriber::sendSlackMsg with empty message", E_USER_NOTICE);
        return '';
    }

    /**
     * Space to check on system messages,and not log them to Slack.
     *
     * @param MailgunEvent $event [description]
     *
     * @return boolean Should this message be ignored, and not sent to Slack?
     */
    public function isIgnoreable(MailgunEvent $event)
    {
        return false;
    }

    public function genericMailgunEvent(MailgunWebhookEvent $mailGunEvent)
    {
        $event = $mailGunEvent->getMailgunEvent();
        $eventName = $event->getEvent();
        $email = $event->getRecipient();
        $occurredAt = $event->getDateTime()->format(self::DATE_FMT);

        $subject = $event->getEventTitle();

        if ($this->isIgnoreable($event)) {
            $this->log->info("Ignore Mailgun event '{$email}' event:'$eventName' at {$occurredAt}, subject:'{$subject}'");
            return;
        }

        // todo - get msg from a function
        $msg = "Mailgun:{$email} *$eventName* at {$occurredAt}, subject:'$subject'";
        switch ($eventName) {
            case 'accepted':
            case 'clicked':
            case 'delivered':
            case 'opened':
                // swallow, no message displayed to slack. Might log to the file though.
                $this->log->info($msg);
                return;
                break;
            case 'rejected':
                $msg = "{$msg}. Mailgun rejected the request to send/forward the email.";
                break;
            case 'failed':
            case 'dropped':
                $msg = "{$msg}. Mailgun could not deliver the email to the recipient email server.";
                break;
            case 'unsubscribed':
                $msg = "{$msg}. The email recipient clicked on the unsubscribe link.";
                break;
            case 'complained':
                $msg = "{$msg}. The email recipient clicked on the spam complaint button within their email client.";
                break;
            case 'stored':
                $msg = "{$msg}. Mailgun has stored an incoming message";
                break;
            default:
                $this->log->warning(
                    "Mailgun: Unknown event:*{$eventName}* at {$occurredAt}. subject:'{$subject}' to '{$email}'"
                );
                break;
        }

        return $this->sendSlackMsg($msg);
    }
}