Laravel QueryBuilder and augmented orderBy - order through relations

OrderThroughRelationTrait.php

<?php

use Illuminate\Database\Eloquent\Relations\HasOneOrMany;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

trait OrderThroughRelationTrait {

    /**
     * Add an "order by" clause to the query and handles relations if specified.
     *
     * Supported relations: hasOne, hasMany, belongsTo
     *
     * Examples:
     * Store::orderThroughRelation('name')->get() //same as Store::orderBy('name')->get()
     * Store::orderThroughRelation('categories.name')->get()
     * Store::orderThroughRelation('categories.subcategories.name')->get()
     * Store::orderThroughRelation('categories.subcategories.products.name')->get()
     *
     * @param  Illuminate\Database\Eloquent\Builder $query
     * @param  string  $column
     * @param  string  $direction
     * @return $query
     */
    public function scopeOrderThroughRelation( $query, $column, $direction = 'asc' ) {
        if ( $column ) {
            if ( strpos( $column,'.') !== false ) {
                $relation_names = explode( '.', $column );
                $column = array_pop( $relation_names );

                array_reduce( $relation_names, function( $model, $relation_name ) use ($query, &$relation) {
                $relation = $model->{ $relation_name }();

                if ( $relation instanceof HasOneOrMany ) {
                    $query->join(
                            $relation->getModel()->getTable(),
                            $relation->getQualifiedParentKeyName(),
                            '=',
                            $relation->getExistenceCompareKey() );
                } else if ( $relation instanceof BelongsTo) {
                    $query->join(
                            $relation->getModel()->getTable(),
                            $relation->getQualifiedOwnerKeyName(),
                            '=',
                            $relation->getQualifiedForeignKey() );
                } else {
                        throw new \Error(get_class($relation));
                }

                return $relation->getModel();
                }, $query->getModel() );

                $query->orderBy( $relation->getModel()->getTable() . '.' . $column, $direction);

            } else {
                $query->orderBy( $column, $direction );
            }
        }
        return $query;
    }
}