使用Eloquent Model在Laravel中基于父级到子级获取子子级

Question

I have products with products category with Multiple Level. I have used elequont model to get the first level of the category. But i am not able to get the sub sub category of the products. Here is how my model looks like:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Services extends Model
{
    //
    protected $fillable = [
        'servicename', 'serviceslug', 'service_id','priceinr', 'priceusd','details', 'footertext','user_id'
    ];

    public function parent()
    {
        return $this->belongsTo('App\Services', 'service_id');
    }

    public function children()
    {
        return $this->hasMany('App\Services', 'service_id');
    }
}

Table structure looks like this:

And this is how my controller looks like:

public function show($id)
    {
        $services = Services::where('service_id', 0)->with('children')->get();
        //return $services;

        return view('services.edit')->with('services', $services);
    }

And in view its normal dropdown.

<select class="form-control" name="service_id">
                                <option value="">Select...</option>
                                @foreach($services as $service)
                                @if($service->service_id == 0)
                                <option value="{{$service->id}}">{{$service->servicename}}</option>
                                @else
                                <option value="{{$service->id}}">&nbsp;&nbsp;&nbsp;{{$service->servicename}}</option>
                                @endif
                            @endforeach
                            </select>

I am able to get this:

Cloths
   Mens
      Shirt    //Not able to get shirt and below level
      trousers    //Not able to get trousers and below level
   Womens
      Tshirt   //Not able to get Tshirt and below level
      Jeans    //Not able to get Jeans and below level

Any solution will be helpful here. I want to get the values in dropdown which can look nested.

Thank you! (In advance)