<?php
 
$correctNumbers = [ 
  '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'
];
$incorrectNumbers = [
  '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 + */
];
 
$regexp = "/^(\+\s?7|\s?8)([\s\(\)\-]*\d){10}$/";
foreach (array_merge($correctNumbers, $incorrectNumbers) as $numbers ) {
if (preg_match($regexp, $numbers)) {
		echo "Номер {$numbers} - верный\n";
		$regexp2 = ["/^\+\s?7/" , "([/\s()-/]*)"];
		$numberReplace = preg_replace($regexp2, ['8', ''], $numbers);
		echo "{$numberReplace}\n";
	}
	else {
		echo "Номер {$numbers} - неверный, исправте его.\n";
	}
}

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