sfp_api_laravel_ginastica_cerebro/app/Models/Permission.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Database\Eloquent\SoftDeletes;
use Kalnoy\Nestedset\NodeTrait;

class Permission extends Model
{
    use HasFactory, SoftDeletes, NodeTrait;

    /**
     * The attributes that are mass assignable.
     *
     * @var array<int, string>
     */
    protected $fillable = [
        'name',
        'bits',
        'description',
        'parent_id',
    ];

    /**
     * The attributes that should be cast.
     *
     * @return array<string, string>
     */
    protected function casts(): array
    {
        return [
            'parent_id' => 'integer',
        ];
    }

    public function children(): HasMany
    {
        return $this->hasMany(Permission::class, 'parent_id');
    }

    public function parent(): BelongsTo
    {
        return $this->belongsTo(Permission::class, 'parent_id');
    }
}