autocde2.0/app/Models/RequirementGroup.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;
use Illuminate\Database\Eloquent\SoftDeletes;

class RequirementGroup extends Model
{
    use HasFactory,Filterable,SoftDeletes;

    protected $fillable = [
        'name', 'abbr_name', 'asset_id','parent_id','company_id'
    ];

    protected static function booted(): void
    {
        static::addGlobalScope(new CompanyScope);

        static::creating(function (RequirementGroup $requirementGroup){
            $type =DisplayIndexObjectType::REQUIREMENTGROUP;
            $displayIndex = IndexHelper::getObjectMaxIndex($type);
            $requirementGroup->display_id =$displayIndex;
        });
    }


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

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

    public function requirement(){
        return $this->hasMany(Requirement::class,'requirement_group_id');
    }

    public function asset()
    {
        return $this->belongsTo(Asset::class, 'asset_id');
    }
}