Sindbad~EG File Manager

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

namespace mod_data\form;

use context;
use moodle_exception;
use moodle_url;
use core_form\dynamic_form;

/**
 * Save database as preset form.
 *
 * @package    mod_data
 * @copyright  2021 Mihail Geshoski <paulh@moodle.com>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class save_as_preset extends dynamic_form {

    /**
     * Form definition
     */
    protected function definition() {

        $this->_form->addElement('hidden', 'd');
        $this->_form->setType('d', PARAM_INT);
        $this->_form->addElement('hidden', 'action', 'save2');
        $this->_form->setType('action', PARAM_ALPHANUM);
        $this->_form->addElement('text', 'name', get_string('name'), ['size' => 60]);
        $this->_form->setType('name', PARAM_FILE);
        $this->_form->addRule('name', null, 'required');
        $this->_form->addElement('checkbox', 'overwrite', '', get_string('overrwritedesc', 'data'));
    }

    /**
     * Return form context
     *
     * @return context
     */
    protected function get_context_for_dynamic_submission(): context {
        global $DB;

        $d = $this->optional_param('d', null, PARAM_INT);
        $data = $DB->get_record('data', array('id' => $d), '*', MUST_EXIST);
        $course = $DB->get_record('course', array('id' => $data->course), '*', MUST_EXIST);
        $cm = get_coursemodule_from_instance('data', $data->id, $course->id, null, MUST_EXIST);

        return \context_module::instance($cm->id, MUST_EXIST);
    }

    /**
     * Perform some validation.
     *
     * @param array $formdata
     * @param array $files
     * @return array
     */
    public function validation($formdata, $files): array {

        $errors = parent::validation($formdata, $files);
        $context = $this->get_context_for_dynamic_submission();

        if (!empty($formdata['overwrite'])) {
            $presets = data_get_available_presets($context);
            $selectedpreset = new \stdClass();
            foreach ($presets as $preset) {
                if ($preset->name == $formdata['name']) {
                    $selectedpreset = $preset;
                    break;
                }
            }
            if (isset($selectedpreset->name) && !data_user_can_delete_preset($context, $selectedpreset)) {
                $errors['name'] = get_string('cannotoverwritepreset', 'data');
            }
        } else {
            // If the preset exists now then we need to throw an error.
            $sitepresets = data_get_available_site_presets($context);
            foreach ($sitepresets as $preset) {
                if ($formdata['name'] == $preset->name) {
                    $errors['name'] = get_string('errorpresetexists', 'data');
                }
            }
        }

        return $errors;
    }

    /**
     * Check if current user has access to this form, otherwise throw exception.
     *
     * @return void
     * @throws moodle_exception
     */
    protected function check_access_for_dynamic_submission(): void {
        global $DB;

        if (!has_capability('mod/data:managetemplates', $this->get_context_for_dynamic_submission())) {
            throw new moodle_exception('saveaspresetmissingcapability', 'data');
        }

        $d = $this->optional_param('d', null, PARAM_INT);
        $hasfields = $DB->record_exists('data_fields', ['dataid' => $d]);

        if (!$hasfields) {
            throw new moodle_exception('nofieldindatabase', 'data');
        }
    }

    /**
     * Process the form submission, used if form was submitted via AJAX.
     *
     * @return array
     */
    public function process_dynamic_submission(): array {
        global $DB, $CFG;
        require_once($CFG->dirroot . '/mod/data/lib.php');

        $result = false;
        $errors = [];
        $data = $DB->get_record('data', array('id' => $this->get_data()->d), '*', MUST_EXIST);
        $course = $DB->get_record('course', array('id' => $data->course), '*', MUST_EXIST);
        $cm = get_coursemodule_from_instance('data', $data->id, $course->id, null, MUST_EXIST);
        $context = \context_module::instance($cm->id, MUST_EXIST);

        try {
            if (!empty($this->get_data()->overwrite)) {
                $presets = data_get_available_presets($context);
                $selectedpreset = new \stdClass();
                foreach ($presets as $preset) {
                    if ($preset->name == $this->get_data()->name) {
                        $selectedpreset = $preset;
                        break;
                    }
                }
                if (isset($selectedpreset->name) && data_user_can_delete_preset($context, $selectedpreset)) {
                    data_delete_site_preset($this->get_data()->name);
                }
            }
            data_presets_save($course, $cm, $data, $this->get_data()->name);
            $result = true;
        } catch (\Exception $e) {
            $errors[] = $e->getMessage();
        }

        return [
            'result' => $result,
            'errors' => $errors,
        ];
    }

    /**
     * Load in existing data as form defaults.
     *
     * @return void
     */
    public function set_data_for_dynamic_submission(): void {
        $data = (object)[
            'd' => $this->optional_param('d', 0, PARAM_INT),
        ];
        $this->set_data($data);
    }

    /**
     * Returns url to set in $PAGE->set_url() when form is being rendered or submitted via AJAX
     *
     * @return moodle_url
     */
    protected function get_page_url_for_dynamic_submission(): moodle_url {
        $d = $this->optional_param('d', null, PARAM_INT);

        return new moodle_url('/user/field.php', ['d' => $d]);
    }
}