sub main()
{
	my $uri = $ENV{REQUEST_URI} || '';
	$uri =~ s/\/[^\/]+$//;
	$uri =~ s/\//,/g;
	$uri =~ s/(\~|\%7E)/tilde,/g;
	mkdir $tmp_dir, 0777 unless -d $tmp_dir;
	mkdir "$tmp_dir/$uri", 0777 unless -d "$tmp_dir/$uri";

	my $img = $ENV{QUERY_STRING};
	if(defined $img and $img =~ /\S/) {
		if($img =~ /^(\d+)-n$/) {
			my $file = "$tmp_dir/$uri/mailgraph_$1.png";
			graph($graphs[$1]{seconds}, $file);
			send_image($file);
		}
		elsif($img =~ /^(\d+)-e$/) {
			my $file = "$tmp_dir/$uri/mailgraph_$1_err.png";
			graph_err($graphs[$1]{seconds}, $file);
			send_image($file);
		}
		else {
			die "ERROR: invalid argument\n";
		}
	}
	else {
		print_html;
	}
}