<?php
function ckratelimit($headers,$echofun,$onlyret=false,$verbose=false) {//$echofun has to be the name of a defined function to pass messages to
	$ret=null;
	if (is_array($headers)) {
		//echo "ckratelimit: {$headers}: ".print_r($headers,true));
		$buff=[];
		array_shift($headers);
		foreach ($headers as $header)
			if (preg_match('/^([^:]+):(.*)$/Uu',$header,$matches)===1)
				$buff[$matches[1]]=trim($matches[2]);
		$headers=$buff;
		//print_r($headers);
		if (isset($headers['Date']) && isset($headers['X-RateLimit-Reset']) && isset($headers['X-RateLimit-Remaining'])) {
			//Wed, 30 Mar 2022 21:27:22 GMT
			$srvnow=strtotime($headers['Date']);
			//2022-03-31T04:05:00.058705Z
			$srvrlreset=strtotime($headers['X-RateLimit-Reset']);
			$srvrlremain=$headers['X-RateLimit-Remaining'];
			$secstoreset=$srvrlreset-$srvnow;
			$ret=['remaining'=>$srvrlremain,'secstoreset'=>$secstoreset];
			if ($onlyret)
				return $ret;
			if ($verbose) $echofun("ckratelimit: X-RateLimit-Remaining: {$srvrlremain}; server time: {$srvnow}: ".gmdate('c',$srvnow).'; X-RateLimit-Reset: '.gmdate('c',$srvrlreset).'; current seconds before reset: '.$secstoreset.".\n");
			if ($srvrlremain==0) {
				$echofun("Reached rate limit, waiting {$secstoreset} seconds for rate limit reset ...\n");
				sleep($secstoreset);
			}
		} else {
			if ($verbose) $echofun("ckratelimit: no «Date» / «X-RateLimit-Reset» / «X-RateLimit-Remaining» header(s)!\n");
		}
	} else {
		if ($verbose) $echofun("ckratelimit: headers is not an array!\n");
	}
	return $ret;
}
?>