MainAero/yii2-gtm-widget

<?php
namespace mainaero\yii\gtm\widget;

use yii\base\Widget;
use Yii;

class GTM extends Widget
{
    const PARAM_ENV = 'gtm_env';
    const PARAM_ID = 'gtm_id';

    const TYPE_SCRIPT = 'script';
    const TYPE_NOSCRIPT = 'noscript';
    const TYPE_PUSH = 'dataLayerPush';

    const SESSION_KEY = 'gtm-data-layer-push';

    public $type = '';

    public function init()
    {
        parent::init();
        if ($this->type != self::TYPE_SCRIPT
            && $this->type != self::TYPE_NOSCRIPT
            && $this->type != self::TYPE_PUSH) {
            $this->type = self::TYPE_SCRIPT;
        }
    }

    public function run()
    {
        if ($this->type == self::TYPE_PUSH)
          return $this->runPush();

        $params = $this->getParams();
        if ($this->paramMissing($params))
            return '';

        return $this->render($this->type, $params);
    }

    private function runPush() : String {
      $session = Yii::$app->getSession();
      $dataLayerPushItems = $session->get(self::SESSION_KEY) ?? [];

      if (empty($dataLayerPushItems))
        return '';

      $session->remove(self::SESSION_KEY);
      return $this->render($this->type, ['dataLayerPushItems' => $dataLayerPushItems]);
    }

    private function paramMissing(array $params) : bool
    {
        return empty($params[self::PARAM_ID]);
    }

    private function getParams() : array
    {
        return [
          self::PARAM_ENV => Yii::$app->params[self::PARAM_ENV] ?? '',
          self::PARAM_ID => Yii::$app->params[self::PARAM_ID] ?? ''
        ];
    }
}