Laravel unique rules on FormRequest

FormRequest.php

<?php

namespace App\Http\Requests;

use Illuminate\Foundation\Http\FormRequest;
use App\Models\Vehicle;

class VehicleRequest extends FormRequest
{

    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()
    {
        return true;
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        $reglas = [];
        switch($this->method())
        {
            case 'GET':
            case 'DELETE':
            {
                return [];
            }
            case 'POST':
            {
                $reglas = [
                    'tag' => 'required|unique:vehicles,tag',
                    'vehicle_status_id' => 'required|exists:vehicle_status,id',
                    'item_id' => 'required|exists:items,id',
                    'location_id' => 'required|exists:locations,id',
                    'cur_location_id' => 'required|exists:locations,id',
                    'chasis' => 'nullable|unique:vehicles,chasis',
                    'plate' => 'nullable|unique:vehicles,plate'
                ];
            }
            case 'PUT':
            case 'PATCH':
            {
                $reglas = [
                    'tag' => 'required|unique:vehicles,tag,' . $this->vehicle,
                    'vehicle_status_id' => 'required|exists:vehicle_status,id',
                    'item_id' => 'required|exists:items,id',
                    'location_id' => 'required|exists:locations,id',
                    'cur_location_id' => 'required|exists:locations,id',
                    'chasis' => 'nullable|unique:vehicles,chasis,' . $this->vehicle,
                    'plate' => 'nullable|unique:vehicles,plate,' . $this->vehicle
                ];
            }
            default:break;
        }

        if (count($reglas)>0 && $this->user()->roll_id==1) {
            $reglas['company_id'] = 'required|exists:companies,id';
        }
        return $reglas;
    }
}