<?php
 
error_reporting(-1);
 
$regexp = '/^([- \\)\\(]*)(\\+[- \\)\\(]*7|8)(([- \\)\\(]*)([0-9])([- \\)\\(]*)){10}$/ui';
 
 
$correctNumbers = array( 
  '84951234567',  '+74951234567', '8-495-1-234-567', 
  ' 8 (8122) 56-56-56', '8-911-1234567', '8 (911) 12 345 67', 
  '8-911 12 345 67', '8 (911) - 123 - 45 - 67', '+ 7 999 123 4567', 
  '8 ( 999 ) 1234567', '8 999 123 4567', '8 4951234567'
);
 
$incorrectNumbers = array(
  '02', '84951234567 позвать люсю', '849512345', '849512345678', 
  '8 (409) 123-123-123', '7900123467', '5005005001', '8888-8888-88',
  '84951a234567', '8495123456a', 
  '+1 234 5678901', /* неверный код страны */
  '+8 234 5678901', /* либо 8 либо +7 */
  '7 234 5678901' /* нет + */
);
 
validate($correctNumbers, $regexp);
validate($incorrectNumbers, $regexp);
 
function validate($numbers, $regexp){
    foreach ($numbers as $number) {
        if (preg_match($regexp, $number)) {
            echo "Номер {$number} корректен\n";
            $regexp2 = '/[\\(\\) -]/ui';
            $result = preg_replace($regexp2, '', $number);
            $regexp3 = '/\\+7/ui';
            $result = preg_replace($regexp3, '8', $result);
            echo "{$result}\n";
        } else {
            //echo "Номер {$number} некорректен\n";
        }
    }
}

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