Форматирование номера телефона

phone.php

<?php
function format_phone($phone = '', $convert = false, $trim = true) {
    if (empty($phone)) return '';
    $phone = preg_replace("/[^0-9A-Za-z]/", "", $phone);
    if ($convert == true) {
        $replace = array('2'=>array('a','b','c'),'3'=>array('d','e','f'),'4'=>array('g','h','i'),'5'=>array('j','k','l'),'6'=>array('m','n','o'),'7'=>array('p','q','r','s'),'8'=>array('t','u','v'), '9'=>array('w','x','y','z'));
        foreach($replace as $digit=>$letters) {
            $phone = str_ireplace($letters, $digit, $phone);
        }
    }
    if ($trim == true && strlen($phone)>11) {
        $phone = substr($phone,  0, 11);
    } 
 
    // Perform phone number formatting here
    if (strlen($phone) == 7) {
        return preg_replace("/([0-9a-zA-Z]{3})([0-9a-zA-Z]{4})/", "$1-$2", $phone);
    } elseif (strlen($phone) == 10) {
        return preg_replace("/([0-9a-zA-Z]{3})([0-9a-zA-Z]{3})([0-9a-zA-Z]{4})/", "($1) $2-$3", $phone);
    } elseif (strlen($phone) == 11) {
        return preg_replace("/([0-9a-zA-Z]{4})([0-9a-zA-Z]{3})([0-9a-zA-Z]{4})/", "($1) $2-$3", $phone);
    }
    return $phone;
}