<?php
/*
 * Experimental version that return chunked http response.
 *
 * Pulling the values is no longer needed as the one request will output
 * the updates every second.
 */
require_once('config.php');

$speed=@(int)$_GET['speed'];
if ($speed <= 0)
	$speed=1;  // seconds


header("Content-Type: text/json");
header("Transfer-Encoding: chunked");
flush();


// Send chunk to browser
function send_chunk($chunk)
{
	// The chunk must fill the output buffer or php won't send it
	$chunk = str_pad($chunk, 4096);

	printf("%x\r\n%s\r\n", strlen($chunk), $chunk);
	flush();
}

while (True) {
	exec("/usr/bin/rrdtool flushcached --daemon ".RRDSOCK." ".RRDFILE);

	$info=rrd_lastupdate(RRDFILE);
	if ($info === FALSE)
		$result=[
			'last_update' => 'unknown',
			'watts' => 'unknown',
			'error' => rrd_error(),
		];
	else
		$result=[
			'last_update' => $info['last_update'],
			'watts' => (float)$info['data'][0],
		];
	send_chunk(json_encode($result));
	sleep($speed);
}
?>