#!/usr/bin/perl -w



my $pid;
$pid = fork;

if($pid == 0)
{
	my $pid1 = open(CHILD, "|-", "gnuplot -persist ") or die "Couldn't fork: $!\n";
	local $/=undef;
	my $plot=<DATA>;
	print CHILD "$plot\n";	
	close(CHILD);
	print"forking\n";	
	exit;
}

use LWP::Simple;
use Fcntl qw(:DEFAULT :flock);
$|++;
$SIG{TERM}=sub{print "ok1\n";alarm(0);exit;};
my $url='https://www.cryptonator.com/api/ticker/btc-gbp';
print"ok2\n";
my $interval = 30; # seconds between calls
fetch();
sub fetch{
	
	print"ok3\n";
	my $replie = get($url);
	print"$replie \n";
	my($a,$b,$c,$d)= $replie  =~ /^.+?(\d+\.\d+).+?(\d+\.\d+)?.+?(\d+\.\d+).+?(\d+).*$/;
$a="not defined" unless defined($a);
$b="not defined" unless defined($b);
$c="not defined" unless defined($c);
$d="not defined" unless defined($d);
		open(OUT,">>","/home/philip/Desktop/PERLBITCOIN/TICKER/bitgbp1.dat") or die "BIT File open error $!\n";
		unless (flock(OUT, LOCK_EX|LOCK_NB)) 
		{
			warn "can't immediately write-lock the file ($!), blocking ...";
			unless (flock(OUT, LOCK_EX))
			{
				die "can't get write-lock on numfile: $!";
			}
		}
		print OUT "$c,$a,$d\n";
		flock(OUT, LOCK_UN) or die  "cant unlock file\n";
		close(OUT);		
		#print  "$c,$a,$d\n";
	
	alarm($interval);
};
$SIG{ALRM}=\&fetch;

1 while 1;
__DATA__
reset
delta_v(x) = ( vD = x - old_v, old_v = x, vD)
old_v = NaN
unset key
set xtics border in scale 0,0 nomirror rotate by -90  offset character 0,0  autojustify
set datafile separator ','
set bmargin at screen 0.15
#set palette defined (100 "red", 200 "green", 300 "blue")
set palette defined (-1 "red", 1 "#1B6821")
#set palette model RGB defined ( -1 'red', 1 '#006400', 0 'black' )
set cbrange [-1:1]
set grid
set yrange [*:*]
unset colorbox
set style fill solid noborder
#set xrange [1446061653-946684800:1446064653-946684800]
set xdata time
set timefmt "%s"
set format x "%H:%M"     # or anything else
set xlabel "time"  
set xtics autofreq
data=system("tail -n 1 '/home/philip/Desktop/PERLBITCOIN/TICKER/bitgbp1.dat' | awk '{print $0}'")
print delta_v(2)
plot '< tail -n 40 /home/philip/Desktop/PERLBITCOIN/TICKER/bitgbp1.dat'  using 3:2:((delta_v($2) > 0.0) ? 1 : -1 )with impulses lw 2 palette   
pause 10
reread
replot;