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use Exception;
use Slim\Middleware;

class CsrfMiddleware extends Middleware
{
	public function call() {
		$this->key = $this->app->config->get('csrf.key');

		$this->app->hook('slim.before', [$this, 'check']);
		
		$this->next->call();
	}

	public function check() {
		if (!isset($_SESSION[$this->key])) {
			$_SESSION[$this->key] = $this->app->hash->hash($this->app->randomlib->generateString(128));
		}

		$token = $_SESSION[$this->key];

		if (in_array($this->app->request()->getMethod(), ['POST', 'PUT', 'DELETE'])) {
			$submittedToken = $this->app->request()->post($this->key) ?: '';

			if (!$this->app->hash->hashCheck($token, $submittedToken)) {
				throw new Exception('CSRF Token Mismatch');
			}
		}

		$this->app->view()->appendData([
			'csrf_key' => $this->key,
			'csrf_token' => $token
		]);
	}
}