frontend/controllers/SiteController.php

<?php
namespace frontend\controllers;
use common\components\Mailer;
use Yii;
use common\models\LoginForm;
use frontend\models\PasswordResetRequestForm;
use frontend\models\ResetPasswordForm;
use frontend\models\SignupForm;
use frontend\models\ContactForm;
use yii\base\InvalidParamException;
use yii\web\BadRequestHttpException;
use yii\web\Controller;
use yii\filters\VerbFilter;
use yii\filters\AccessControl;
use yii\web\Response;
use yii\widgets\ActiveForm;
class SiteController extends Controller
{
    public function actionIndex()
    {
        return $this->render('index', [
        ]);
    }
    /**
     * Logs in a user.
     *
     * @return mixed
     */
    public function actionLogin()
    {
        if (!\Yii::$app->user->isGuest) {
            return $this->goHome();
        }
        $model = new LoginForm();
        if ($model->load(Yii::$app->request->post()) && $model->login()) {
            return $this->goBack();
        } else {
            return $this->render('index', [
                'model' => $model,
            ]);
        }
    }
    /**
     * Signs user up.
     *
     * @return mixed
     */
    public function actionSignup()
    {
        if(Yii::$app->request->post()){
            if (Yii::$app->request->isAjax) {
                Yii::$app->response->format = Response::FORMAT_JSON;
                $model = new SignupForm();
                $model->load(Yii::$app->request->post());
                return ActiveForm::validate($model);
            } else {
                $model = new SignupForm();
                $model->load(Yii::$app->request->post());
                if ($user = $model->signup()) {
                    if (Yii::$app->getUser()->login($user)) {
                        return $this->goHome();
                    }
                }
            }
        }
        return $this->render('signup', [
            'model' => $model,
        ]);
    }
}