<?php
$data = "This is my text how do you like it @[John Doe (#6)](client:6) and do you have any thoughts @[Jane Doe (#7)](client:7)";
$regex = "~@\[[^][]+\]\s*\(\K[^()]+~";
?>
PD9waHAKCiRkYXRhID0gIlRoaXMgaXMgbXkgdGV4dCBob3cgZG8geW91IGxpa2UgaXQgQFtKb2huIERvZSAoIzYpXShjbGllbnQ6NikgYW5kIGRvIHlvdSBoYXZlIGFueSB0aG91Z2h0cyBAW0phbmUgRG9lICgjNyldKGNsaWVudDo3KSI7CgokcmVnZXggPSAifkBcW1teXVtdK1xdXHMqXChcS1teKCldK34iOwoKcHJlZ19tYXRjaF9hbGwoJHJlZ2V4LCAkZGF0YSwgJG1hdGNoZXMpOwoKcHJpbnRfcigkbWF0Y2hlcyk7Cgo/Pgo=