#!/usr/bin/perl -w
#
# which_deb
#
# Simple helper tool to find the appropriate version of a package in
# the archive to meet a requirement in the debian-cd build

use strict;
use List::Util qw{first};
# Give prefernce to i386 and amd64, if specified, or if building a
# source-only CD.
my @ARCHES;
if ( $ENV{ARCHES} ) {
    push @ARCHES, 'i386' if $ENV{ARCHES} =~ /i386/;
    push @ARCHES, 'amd64' if $ENV{ARCHES} =~ /amd64/;
    push @ARCHES, grep { !/source|i386|amd64/ } split /\s+/, $ENV{ARCHES};
}
@ARCHES = qw{i386 amd64} unless @ARCHES;

my ($mirror, $codename, $pkg, $pth, $output);

$mirror = shift;
$codename = shift;
$pkg = shift;
$output = shift;
$pth = "$mirror/dists/$codename";

my @components = qw(main);
push @components, 'contrib' if $ENV{CONTRIB};
push @components, 'non-free' if $ENV{NONFREE};
push @components, 'local' if $ENV{LOCAL};

if (!defined ($output)) {
    $output = "binary";
}

sub grab_bin_info {
    my $pth = shift;
    my $arch = shift;
    my $pkgname = shift;
    my $old_split = $/;
    my $match;
    my $result = "";
    
    $/ = ''; # Browse by paragraph    

    for my $component ( @components ) {
        my $pgz = "$pth/$component/binary-$arch/Packages.gz";
        if ( $component eq 'local' and $ENV{LOCALDEBS} ) {
            $pgz = "$ENV{LOCALDEBS}/dists/$codename/local/binary-$arch/Packages.gz";
        }
        if (-e $pgz) {
            open(PFILE, "zcat $pgz |") or
                die "Failed to read Packages file $pgz";

            while (defined($match = <PFILE>)) {
                if (($match =~ /^Package: \Q$pkgname\E$/m)) {
                    $result = $match;
                    close PFILE;
                    return $result;
                }
            }
            # Fell through
            close PFILE;
        }
    }
    return "";
}

sub grab_src_info {
    my $pth = shift;
    my $pkgname = shift;
    my $old_split = $/;
    my $match;
    my $result = "";
    
    $/ = ''; # Browse by paragraph    

    for my $component ( @components ) {
        my $pgz = "$pth/$component/source/Sources.gz";

        if (-e $pgz) {
            open(PFILE, "zcat $pgz |") or
                die "Failed to read Sources file $pgz";

            while (defined($match = <PFILE>)) {
                if (($match =~ /^Package: \Q$pkgname\E$/m)) {
                    $result = $match;
                    close PFILE;
                    return $result;
                }
            }
            # Fell through
            close PFILE;
        }
    }
    return "";
}

my $bin_deb = "";
my $pkgdata = "";
my $srcname = "";

if ($pkg eq "silo") {
    $pkgdata = grab_bin_info($pth, "sparc", $pkg);

} elsif ($pkg eq "syslinux") {
    first { $pkgdata = grab_bin_info($pth, $_, "syslinux-common") } @ARCHES;
    if (length($pkgdata) < 3) {
        first { $pkgdata = grab_bin_info($pth, $_, "syslinux") } @ARCHES;
    }
} elsif ($pkg eq "yaboot") {
    $pkgdata = grab_bin_info($pth, "powerpc", $pkg);
} else { # Fallthrough for all other packages
    first { $pkgdata = grab_bin_info($pth, $_, $pkg) } @ARCHES;
}

if (length($pkgdata) > 2) {
    if ($output eq "binary") {
        $pkgdata =~ m/^Filename: (\S+)/m and $bin_deb = $1;
        print "$bin_deb\n";
    }
    elsif ($output eq "source") {
        $srcname = $pkg;
        $pkgdata =~ m/^Source: (\S+)/m and $srcname = $1;
        $pkgdata = grab_src_info($pth, $srcname);
        if (length($pkgdata) > 2) {
            my $dir;
            $pkgdata =~ m/^Directory: (\S+)/m and $dir = $1;
            $pkgdata =~ m/^ (\S+) (\S+) ((\S+).*dsc)/m and print "$dir/$3\n";
            $pkgdata =~ m/^ (\S+) (\S+) ((\S+).*diff.gz)/m and print "$dir/$3\n";
            $pkgdata =~ m/^ (\S+) (\S+) ((\S+).*tar.gz)/m and print "$dir/$3\n";
        }
    }
}