<?php

function ckratelimit($headers,$showrem=false) {
	$aaheaders=[];
	array_shift($headers);
	foreach ($headers as $header)
		if (preg_match('#^([^:]+): (.*)$#',$header,$matches)===1)
			$aaheaders[strtolower($matches[1])]=$matches[2];
	//$aaheaders['x-ratelimit-remaining']=0;
	//print_r($aaheaders);
	if (!isset($aaheaders['date'])) return ['ok'=>false,'error'=>'no «date» header'];
	if (!isset($aaheaders['x-ratelimit-reset'])) return ['ok'=>false,'error'=>'no «x-ratelimit-reset» header'];
	if (!isset($aaheaders['x-ratelimit-remaining'])) return ['ok'=>false,'error'=>'no «x-ratelimit-remaining» header'];
	if (preg_match('#^\d+$#',$aaheaders['x-ratelimit-remaining'])!==1) return ['ok'=>false,'error'=>'«x-ratelimit-remaining» header is not an integer'];
	$remaining=$aaheaders['x-ratelimit-remaining']+0;
	if ($showrem) echo "ckratelimit: remaining: {$remaining}\n";
	$date=@strtotime($aaheaders['date']);
	if (!is_int($date)) return ['ok'=>false,'error'=>'«date» header could not be converted to a unix timestamp'];
	$reset=@strtotime($aaheaders['x-ratelimit-reset']);
	if (!is_int($reset)) return ['ok'=>false,'error'=>'«x-ratelimit-reset» header could not be converted to a unix timestamp'];
	// don't do the one on the line below, since it happens lots of times
	//if ($reset<$date) return ['ok'=>false,'error'=>'the unix timestamp parsed from «x-ratelimit-reset» header is less than the unix timestamp parsed from «date» header'];
	return ['ok'=>true,'sleep'=>$reset-$date+1,'remaining'=>$remaining];
}

/*
// test
$context=[
	'http'=>[
		'header'=>"Accept: application/json\r\n";
	]
];
$context=stream_context_create($context);
while (true) {
	$res=@file_get_contents('https://livellosegreto.it/api/v2/instance',false,$context);
	echo "{$res}\n";
	print_r($http_response_header);
	$rl=ckratelimit($http_response_header);
	print_r($rl);
	if ($rl['sleep']>0) {
		echo 'Reached rate limit, sleeping for '.ght($rl['sleep']).' (until '.date('c',time()+$rl['sleep']).') ...';
		sleep($rl['sleep']);
		echo "\n";
	}
}
exit(0);*/

?>