#!/usr/bin/php
<?php
// Quick alpha-quality code
// Uses command line tools to decode an HD Radio stream via RTL-SDR, then encode it for Icecast Streaming
//
// Tools used: PHP (duh), RTLSDR, nrsc5, ffmpeg, ezstream, Icecast

$debug = 0;
$ppm = 19;
$bitrate = 256;
$metafile = "/home/zefie/.config/.hdradio_meta";

$signal = 0;
$oldtitle = "";
$oldartist = "";
$buffdat = "";
$totalrcv = 0;
$totalsnd = 0;
$rate = 1024;

// Program direction (aka if program is gonna send data to a pipe (write), use "w")
$desc = array(
   0 => array("pipe", "r"),
   1 => array("pipe", "w"),
   2 => array("pipe", "w")
);

$cwd = '/home/zefie';
if (@$argv[1] && @$argv[2] !== null) {
	if (@$argv[3] !== null) {
		$gain = intval($argv[3] * 10);
	} else {
		$gain = 480;
	}
	$freq = intval($argv[1] * 1000000);
	$prog = intval($argv[2]);
} else {
        echo "Usage: ".$_SERVER['PHP_SELF']." <freq> <program> [gain]\n";
        echo "Example: ".$_SERVER['PHP_SELF']." 99.5 0 48.0\n";
        exit(1);
}

$hdradio = proc_open('nrsc5 -l 1 -g '.$gain.' -p '.$ppm.' -o - -f adts '.$freq.' '.$prog, $desc, $radio_pipes, $cwd);
echo "Searching for HD Radio Signal on ".floatval($freq / 1000000)."MHz...\n";

if (is_resource($hdradio)) {
	$hdradio_status = proc_get_status($hdradio);
	if ($debug) echo "Decoder PID: ".$hdradio_status['pid']."\n";
	stream_set_blocking($radio_pipes[1], 0);
	stream_set_blocking($radio_pipes[2], 0);
	while(true) {
		if ($signal) {
			if (is_resource(@$encoder) && is_resource(@$streamer)) {
				$decdata = fread($radio_pipes[1],$rate);
				if (strlen($decdata) > 0) {
					fwrite($encoder_pipes[0],$decdata);
				}
				$strdata = fread($encoder_pipes[1],(($bitrate / 8) * 1024) + 128); // try to keep up, eh?
				if (strlen($strdata) > 0) {
					fwrite($streamer_pipes[0],$strdata);
				}
				
				$totalrcv = $totalrcv + strlen($decdata);
				$totalsnd = $totalsnd + strlen($strdata);
			} else {					
				$encoder = proc_open('ffmpeg -loglevel panic -i /dev/stdin -c:a vorbis -b:a '.$bitrate.'k -ar 44100 -f ogg -strict -2 -', $desc, $encoder_pipes, $cwd);
				if (is_resource($encoder)) {
					$encoder_status = proc_get_status($encoder);
					if ($debug) echo "Encoder PID: ".$encoder_status['pid']."\n";
					stream_set_blocking($encoder_pipes[0], 0);
					stream_set_blocking($encoder_pipes[1], 0);
				}
				$streamer = proc_open('ezstream -n -c /home/zefie/.config/ezstream_hdradio.cfg', $desc, $streamer_pipes, $cwd);	
				if (is_resource($streamer)) {
					$streamer_status = proc_get_status($streamer);
					if ($debug) echo "Streamer PID: ".$streamer_status['pid']."\n";		
					stream_set_blocking($streamer_pipes[0], 0);
				}
			}
		}
		
		$radiodata = fread($radio_pipes[2],1024);
		while (substr($radiodata,strlen($radiodata)-1,1) != PHP_EOL) {
			$radiodata .= fread($radio_pipes[2],1);
		}
		if ($debug) echo $radiodata;		
		$radiodata = preg_split("/\n/",$radiodata);
		foreach ($radiodata as $r) {
			if (strpos($r,"rtlsdr_open error") > 0) {
				clearLine();
				echo $r."\n";
				exit(1);
			}
			
			if (strpos($r,"Synchronized") > 0) {
				$signal = 1;
				clearLine();
				echo "Found HDRadio Signal\n";
			}
			
			if (strpos($r,"lost sync") > 0) {
				$signal = 0;
				clearLine();
				echo "Lost HDRadio Signal\n";
			}

			if (strpos($r,": MER:") > 0) {
				$a = (strpos($r,": MER:") + 7);
				$b = strlen($r) - $a;
				$siglvl = substr($r,$a,$b);
			}
			
			if (strpos($r,": Title:") > 0) {
				$a = (strpos($r,": Title:") + 9);
				$b = strlen($r) - $a;
				$title = substr($r,$a,$b);
			}
			
			if (strpos($r,": Artist:") > 0) {
				$a = (strpos($r,": Artist:") + 10);
				$b = strlen($r) - $a;
				$artist = substr($r,$a,$b);
			}
		}
		if ((@$artist != $oldartist) && (@$title != $oldtitle)) {
			$oldartist = $artist;
			$oldtitle = $title;
			clearLine();
			echo "Song: ".$artist." - ".$title."\n";
			$fp = fopen($metafile,"w");
			fwrite($fp,$artist."\n".$title);
			fclose($fp);
			posix_kill($streamer_status['pid'],12); // SIGUSR2
		}
		
		if ($signal) {
			if (@$siglvl) {
				echo "Signal: ".$siglvl." | ";
			}
			echo "FM Recv'd: ".friendlyBytes($totalrcv)." | INet Sent: ".friendlyBytes($totalsnd);
			echo "   \r";
		} else {
			sleep(1);
		}
	}
}

function getScreenWidth() { 
	preg_match_all("/rows.([0-9]+);.columns.([0-9]+);/", strtolower(exec('stty -a |grep columns')), $output);
	if(sizeof($output) == 3) {
		return $output[2][0];
	}
}

function clearLine() {
	for ($i=0; $i<(getScreenWidth()-1); $i++) {
		echo " ";
	}
	echo "\r";
}

function friendlyBytes($size) {
        if ($size > 1073741824) {
                return round(($size / 1073741824),2)."GB";
        }
        if ($size > 1048576) {
                return round(($size / 1048576),2)."MB";
        }
        if ($size > 1024) {
                return round(($size / 1024),2)."KB";
        }
        return $size."B";
}