Generate unique slugs

generateUniqueSlug.php

<?php

protected static function generateUniqueSlug(string $title): string
{
    $slug = str_slug($title);

    if (static::query()->where('slug', $slug)->doesntExist()) {
        return $slug;
    }

    $last = static::query()
        ->selectRaw('CAST(REPLACE(`slug`, ?, "") AS UNSIGNED) `last`', [$slug.'-'])
        ->whereRaw('REPLACE(`slug`, ?, "") REGEXP "\-[0-9]+$"', [$slug])
        ->orderBy('last', 'DESC')
        ->value('last');

    return $slug.'-'.($last + 1);
}