MicroFrameWork/app/services/UserService.php

<?php

namespace app\services;

use app\helpers\Debug;
use app\models\User;
use kernel\FormModel;

class UserService
{

    public function create(FormModel $form_model): false|User
    {
        $model = new User();
        $model->username = $form_model->getItem('username');
        $model->email = $form_model->getItem('email');
        $model->password_hash = password_hash($form_model->getItem('password'), PASSWORD_DEFAULT);
        if ($model->save()){
            return $model;
        }

        return false;
    }

    public function update(FormModel $form_model, User $user): false|User
    {
        $user->username = $form_model->getItem('username');
        $user->email = $form_model->getItem('email');
        $user->password_hash = password_hash($form_model->getItem('password'), PASSWORD_DEFAULT);
        if ($user->save()){
            return $user;
        }

        return false;
    }

    public static function createUsernameArr(): array
    {
        foreach (User::all()->toArray() as $user) {

            $userArr[$user['id']] = $user['username'];
        }
        if (!empty($userArr)) {
            return $userArr;
        }
        return [];
    }

}