guild/frontend/modules/card/models/UserCard.php

<?php

namespace frontend\modules\card\models;

use common\models\CardSkill;
use frontend\modules\api\models\UserCardPortfolioProjects;
use Yii;
use yii\db\ActiveQuery;
use yii\helpers\ArrayHelper;

/**
 * @property UserCardPortfolioProjects[] $userCardPortfolioProjects
 */
class UserCard extends \common\models\UserCard
{
    public $fields;
    public $skill;

    public function init()
    {
        parent::init();

        $skill = ArrayHelper::getColumn(
            CardSkill::find()->where(['card_id' => Yii::$app->request->get('id')])->all(),
            'skill_id'
        );

        if (!empty($skill)) {
            $this->skill = $skill;
        }
    }

    public function afterSave($insert, $changedAttributes)
    {
        if (Yii::$app->request->post('UserCard')) {
            $post = Yii::$app->request->post('UserCard');

            if ($post['skill']) {
                CardSkill::deleteAll(['card_id' => $this->id]);

                foreach ($post['skill'] as $item) {
                    $skill = new CardSkill();
                    $skill->skill_id = $item;
                    $skill->card_id = $this->id;

                    $skill->save();
                }
            }
        }

        parent::afterSave($insert, $changedAttributes); // TODO: Change the autogenerated stub
    }

    public static function findByUserId($userId): ?UserCard
    {
        return self::findOne(['id_user' => $userId]);
    }

    public function getUserCardPortfolioProjects(): ActiveQuery
    {
        return $this->hasMany(UserCardPortfolioProjects::class, ['card_id' => 'id']);
    }
}