#!/usr/bin/perl -w

use strict;

my $sudo = ''; $sudo = "sudo " if ($> != 0);

my $histf = "$ENV{HOME}/bpdbjobs_history";
my $tempf = "$histf.$$";
my $backf = "$histf.bak";

unlink $backf if (-f $backf);
link $histf, $backf;

open(HISTF, "<$histf") or die "couldn't open $histf for reading";

my $lastrec = 0;
my ($jobid, $state, %active);
while (<HISTF>) {
	($jobid, $state) = (split(',', $_))[0,2];

	$lastrec = $jobid if ($jobid > $lastrec);
	$active{$jobid} = $_ if ($state < 3);
}

close HISTF;

open(TEMPF, ">$tempf") or die "couldn't open $tempf for writing";

my %newer;
foreach (`$sudo bpdbjobs -all_columns`) {
	$jobid = (split(',', $_))[0];
	if ($jobid > $lastrec) {
		print TEMPF $_;
	} elsif (defined($active{$jobid})) {
		$newer{$jobid} = 1;
		print TEMPF $_;
	}
}

open(HISTF, "<$histf") or die "couldn't open $histf for reading";
while (<HISTF>) {
	$jobid = (split(',', $_))[0];
	print TEMPF $_ unless defined($newer{$jobid});
}
close HISTF;

close TEMPF;

unlink $histf or die "couldn't remove old $histf";
link $tempf, $histf or die "couldn't move $tempf to $histf";
unlink $tempf or die "couldn't remove $tempf";

# save on space; it's safe at this point, we're sure the process
# works after using for a month or two, and we're sure by this point
# in the code that we're not losing data doing this
unlink $backf;