class MessagePlugin

class MessagePlugin implements PluginInterface, EventSubscriberInterface {
    
    /**
     * Composer object.
     *
     * @var \Composer\Composer
     */
    protected $composer;
    
    /**
     * IO object.
     *
     * @var \Composer\IO\IOInterface
     */
    protected $io;
    
    /**
     * Configuration.
     *
     * @var \Drupal\Composer\Plugin\VendorHardening\Config
     */
    protected $config;
    
    /**
     * {@inheritdoc}
     */
    public function activate(Composer $composer, IOInterface $io) {
        $this->composer = $composer;
        $this->io = $io;
    }
    
    /**
     * {@inheritdoc}
     */
    public function deactivate(Composer $composer, IOInterface $io) {
    }
    
    /**
     * {@inheritdoc}
     */
    public function uninstall(Composer $composer, IOInterface $io) {
    }
    
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() {
        return [
            ScriptEvents::POST_CREATE_PROJECT_CMD => 'displayPostCreateMessage',
            ScriptEvents::POST_INSTALL_CMD => 'displayPostCreateMessage',
        ];
    }
    public function displayPostCreateMessage(Event $event) {
        $message = new Message($this->composer
            ->getPackage(), $event->getName());
        if ($message = $message->getText()) {
            $this->io
                ->write($message);
        }
    }

}