bp_dd_get_random_date( int $days_from = 30, int $days_to )

function bp_dd_get_random_date( $days_from = 30, $days_to = 0 ) {
	// $days_from should always be less than $days_to
	if ( $days_to > $days_from ) {
		$days_to = $days_from - 1;
	}

	$date_from = new DateTime( 'now - ' . $days_from . ' days' );
	$date_to   = new DateTime( 'now - ' . $days_to . ' days' );

	return date( 'Y-m-d H:i:s', mt_rand( $date_from->getTimestamp(), $date_to->getTimestamp() ) );
}