#!/usr/bin/perl -w
# $Id: debup2date,v 1.2 2003/08/16 14:51:51 cb Exp $

# (c) Christoph Berg <cb@df7cb.de>
# This program is free software covered by the GNU GPL.
# 030816 cb v1.0 (The Debian 10th anniversary release)

use Getopt::Std;
getopts('ant:v');
$opt_a ||= 0;
$opt_n ||= 0;
$opt_t ||= "stable";
$opt_v ||= 0;

$ENV{'LC_ALL'} = "C";

sub vercmp {
	my $a = shift;
	my $b = shift;
	system "dpkg --compare-versions $a ge $b";
	return ($? >> 8) == 0;
}

sub check_package{
	my $package = shift;
	my ($inst_version, $cand_version, $want_version, $version);

	open APT, "apt-cache policy $package 2>&1 |" or die "apt-cache: $!";
	while(<APT>) {
		if(/^(\S+):$/) {
			die if $1 ne $package;
		} elsif(/^  Installed: \(none\)/) {
		} elsif(/^  Installed: (.*)/) {
			$inst_version = $1;
		} elsif(/^  Candidate: \(none\)/) {
		} elsif(/^  Candidate: (.*)/) {
			$cand_version = $1;
		} elsif(/^  Version Table:/) {
		} elsif(/^ (\*\*\*|   ) (.*) 0$/) {
			$version = $2;
		} elsif(/^  *(\d+) (.*)/) {
			if($2 =~ /$opt_t/) {
				if(defined $want_version and $want_version ne $version) {
					print "more than one version ($want_version, $version) for $package in release $opt_t found, check output of 'apt-cache policy $package' to see if something is wrong\n";
				}
				$want_version ||= $version;
			}
		} elsif(/W: Unable to locate package/) {
			print "$_";
			return;
		} else {
			die "unknown line: $_";
		}
	}
	close APT;

	if(! defined $cand_version) {
		print "$package exists, but has no candidate, ";
		# we assume more output is to come, hence no \n
	}

	if(! defined $inst_version) {
		print "$package is not installed\n";
		return;
	}

	if($inst_version ne $cand_version) {
		$a = vercmp($inst_version, $cand_version) > 0 ? "older" : "newer";
		print "$package $inst_version has a $a candidate $cand_version\n";
	}

	if(! defined $want_version) {
		print "no version for $package found in release $opt_t\n";
		return;
	}

	if($inst_version ne $want_version) {
		$v = vercmp($inst_version, $want_version) > 0;
		$a = $v ? "newer" : "older";
		print "$package $inst_version is $a than $want_version in release $opt_t\n" unless $opt_n and !$v;
	} elsif($opt_v) {
		print "$package is up-to-date\n";
	}

	return;
}

if($opt_a) {
	open DPKG, "dpkg --get-selections |" or die "dpkg: $!";
	while(<DPKG>) {
		/(\S+)\s+(\S+)/ or die "bad match";
		check_package($1);
	}
	close DPKG;
} else {
	if(@ARGV == 0) {

		print <<EOT;
debup2date v1.0 (c) Christoph Berg <cb\@df7cb.de>
This program is free software covered by the GNU GPL.

debup2date looks at the output of 'apt-cache policy' to determine which
packages do not match the version in a specific Debian release. This can
be used to find packages that are ahead of a release, e.g. those installed
from testing or unstable on a stable system, or packages installed from
non-Debian repositories. Similarly, it notifies of packages where a newer
version is available.

Usage: $0 [-t release] [-n] [-v] {-a | package ...}
-t release  release to check against (regexp, matches apt-cache policy
            output, default is "stable")
-n          only show notification of newer versions
-v          verbose (per default, prints nothing about up-to-date packages)
-a          operate on all packages from 'dpkg --get-selections'
EOT
	}
	foreach(@ARGV) {
		check_package($_);
	}
}