<?php

namespace App\Modules\Taxonomy\Application;

use App\Modules\Taxonomy\Domain\TaxonomyNode;
use Illuminate\Validation\ValidationException;

final class TaxonomyHierarchy
{
    public function assertValidParent(string $organizationId, string $taxonomyTypeId, ?string $parentId, ?string $movingNodeId = null): void
    {
        if ($parentId === null) {
            return;
        }

        if ($parentId === $movingNodeId) {
            $this->invalidParent();
        }

        $parent = TaxonomyNode::query()
            ->where('organization_id', $organizationId)
            ->where('taxonomy_type_id', $taxonomyTypeId)
            ->find($parentId);

        if (! $parent) {
            $this->invalidParent('The selected parent does not belong to this taxonomy.');
        }

        $visited = [];
        $cursor = $parent;

        while ($cursor !== null) {
            if (isset($visited[$cursor->getKey()]) || $cursor->getKey() === $movingNodeId) {
                $this->invalidParent('The selected parent would create a circular hierarchy.');
            }

            $visited[$cursor->getKey()] = true;
            $cursor = $cursor->parent_id
                ? TaxonomyNode::query()->where('organization_id', $organizationId)->find($cursor->parent_id)
                : null;
        }
    }

    private function invalidParent(string $message = 'A taxonomy node cannot be its own parent.'): never
    {
        throw ValidationException::withMessages(['parentId' => [$message]]);
    }
}