autocde2.0/app/Models/Department.php

<?php

namespace App\Models;

use App\Http\Requests\IndexHelper;
use App\Models\Enums\DisplayIndexObjectType;
use App\Models\Scopes\CompanyScope;
use EloquentFilter\Filterable;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Department extends Model
{
    use HasFactory,Filterable;

    protected $table = 'department';
    protected $fillable = [
        'name',
        'parent_id',
        'company_id',
        'manager_id',
    ];



    protected static function booted()
    {
        parent::booted(); // TODO: Change the autogenerated stub

        static::addGlobalScope(new CompanyScope);

        static::creating(function (Department $department){
            $type =DisplayIndexObjectType::DEPARTMENT;
            $displayIndex = IndexHelper::getObjectMaxIndex($type);
            $department->display_id =$displayIndex;
        });
    }

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

    public function users(){
        return $this->hasMany(User::class, 'department_id');
    }
}