Custom Dynamic Sources

<?php
namespace modules\sitemodule\dynamic;

use Craft;
use craft\base\ElementInterface;
use craft\elements\Entry;
use craft\helpers\Cp;
use verbb\navigation\base\DynamicSource;
use verbb\navigation\elements\Node;
use verbb\navigation\models\ProjectedNode;
use verbb\navigation\Navigation;

class EntryTypeDynamicSource extends DynamicSource
{
    public static function handle(): string
    {
        return 'entryType';
    }

    public static function displayName(): string
    {
        return 'Entry Type';
    }

    public static function elementType(): string
    {
        return Entry::class;
    }

    public static function getAddNodeSchema(array $context): array
    {
        return [
            [
                '$field' => 'select',
                'name' => 'data.entryTypeId',
                'label' => 'Entry type',
                'validation' => 'required',
                'options' => self::_entryTypeOptions(),
            ],
        ];
    }

    public static function getAddNodeDefaultData(): array
    {
        return ['entryTypeId' => ''];
    }

    public static function renderSlideoutHtml(Node $node): string
    {
        return Craft::$app->getView()->namespaceInputs(
            fn() => Cp::selectFieldHtml([
                'label' => 'Entry type',
                'id' => 'entryTypeId',
                'name' => 'entryTypeId',
                'value' => $node->data['entryTypeId'] ?? '',
                'options' => self::_entryTypeOptions(),
                'required' => true,
            ]),
            'data',
        );
    }

    public static function applyPostData(Node $node): void
    {
        // The slide-out field is already saved to `data`, so there's nothing to normalise.
    }

    public static function validateNode(Node $node): bool
    {
        if (!self::_getEntryType($node)) {
            $node->addError('data', 'Choose an entry type.');

            return false;
        }

        return true;
    }

    public static function getDefaultTitle(Node $node): ?string
    {
        return self::_getEntryType($node)?->name;
    }

    public static function getTypeLabel(Node $node): ?string
    {
        return self::_getEntryType($node)?->name;
    }

    public static function getProjectedChildren(Node $parent, int $siteId): array
    {
        $entryType = self::_getEntryType($parent);

        if (!$entryType) {
            return [];
        }

        $query = Entry::find()
            ->typeId($entryType->id)
            ->siteId($siteId)
            ->orderBy(['title' => SORT_ASC]);

        Navigation::$plugin->getDynamicSources()->applyProjectionStatus($query);

        return array_map(
            fn(Entry $entry) => ProjectedNode::fromElement($entry, $parent),
            $query->all(),
        );
    }

    public static function getCacheTags(Node $node): array
    {
        $entryType = self::_getEntryType($node);

        if (!$entryType) {
            return [];
        }

        $cache = Navigation::$plugin->getNavigationCache();
        $tags = [];

        foreach (Craft::$app->getEntries()->getAllSections() as $section) {
            foreach ($section->getEntryTypes() as $sectionEntryType) {
                if ($sectionEntryType->id === $entryType->id) {
                    $tags[] = $cache->sectionTag($section->uid);
                }
            }
        }

        return $tags;
    }

    public static function getCacheTagsForProjectedElement(ElementInterface $element): array
    {
        if (!$element instanceof Entry || !$element->getSection()) {
            return [];
        }

        return [Navigation::$plugin->getNavigationCache()->sectionTag($element->getSection()->uid)];
    }

    public static function shouldDeleteNodeOnSourceDelete(Node $node, string $sourceType, int $sourceId): bool
    {
        return false;
    }

    private static function _getEntryType(Node $node): ?\craft\models\EntryType
    {
        $id = (int)($node->data['entryTypeId'] ?? 0);

        return $id ? Craft::$app->getEntries()->getEntryTypeById($id) : null;
    }

    private static function _entryTypeOptions(): array
    {
        $options = [['label' => 'Select an entry type', 'value' => '']];

        foreach (Craft::$app->getEntries()->getAllEntryTypes() as $entryType) {
            $options[] = ['label' => $entryType->name, 'value' => (string)$entryType->id];
        }

        return $options;
    }
}

use modules\sitemodule\dynamic\EntryTypeDynamicSource;
use verbb\navigation\events\RegisterDynamicSourceEvent;
use verbb\navigation\services\DynamicSources;
use yii\base\Event;

Event::on(DynamicSources::class, DynamicSources::EVENT_REGISTER_DYNAMIC_SOURCES, function(RegisterDynamicSourceEvent $event) {
    $event->providers[] = EntryTypeDynamicSource::class;
});