MobileNumberClassifier return the carrier of the phone number. e.g. NTC, NCELL etc. (For Nepal)

MobileNumberClassifier.php

<?php
/**
 * @Author Bhaktaraz Bhatta <bhattabhakta@gmail.com>
 */

namespace SMS\Bundle\MainBundle\Services;

/**
 * MobileNumberClassifier return the carrier of the phone number. e.g. NTC, NCELL etc.
 */
class MobileNumberClassifier
{

    /**
     * @param $mobileNumber
     * @return string
     */
    public function getMobileNumberCarrier($mobileNumber)
    {
        $firstThreeNumbers = substr($mobileNumber, 0, 3);

        $ncellFirstThreeNumbers = ['980', '981', '982'];
        $ntcFirstThreeNumbers = ['984', '985', '985'];

        if (in_array($firstThreeNumbers, $ntcFirstThreeNumbers)) {
            return 'NTC';
        }

        if (in_array($firstThreeNumbers, $ncellFirstThreeNumbers)) {
            return 'NCELL';
        }

        return 'UNKNOWN';
    }
}