#!/usr/bin/perl

# Usage: all-packages

# Run this script from a build area after running gen-packages and
# dasource.  The script will output a list of normal Debian packages
# (not equivs or debathenify packages) in dependency order.
#
# This script is imperfect in a couple of ways:
#
# (1) It knows nothing about Provides declarations, because those are
#     computed when a package is built and this script is intended to
#     operate before binary packages are built.
#
# (2) It will always pick the first package of a disjunction.

use strict;

# Process a Build-Depends specification into a list of package names.
sub list {
	my ($l) = @_;
	my @a = split(/, /, $l);
	foreach (@a) {
	    s/ \(.*\)$//;
	    s/ \|.*$//;
	    s/ \[.*$//;
	}
	return @a;
}

# Read in the package-to-directory map.
my %dirmap;
open(PACKAGES, "<", "packages")
  || die "Can't read packages file; create with gen-packages";
while (<PACKAGES>) {
    chomp;
    /^(\S+)\s+(\S+)$/ || die "Malformed packages line";
    $dirmap{$1} = $2;
}
close(PACKAGES);

# Read the dsc file for each package to get build dependencies.
my %deps;
foreach my $name (keys(%dirmap)) {
    # Look for dsc files under $name and pick the one that sorts highest.
    my @dscfiles = sort glob("$name/*.dsc");
    if (scalar @dscfiles == 0) {
	die "No source package for $name; create with dasource"
    }
    my $dscfile = $dscfiles[$#dscfiles];

    open(DSC, "<", $dscfile) || die "Can't read $dscfile";
    $deps{$name} = [];
    while (<DSC>) {
	chomp;
	(my ($depline) = /^Build-Depends: (.*)$/) || next;
	push @{$deps{$name}}, list($depline);
    }
    close(DSC);
}

# Recursively output a package's dependency names and then the package
# name itself, without outputting any name twice.
my %done;
sub process {
    my ($name) = @_;
    return if ($done{$name});
    foreach my $dep (@{${deps{$name}}}) {
	process($dep) if ($dirmap{$dep});
    }
    print $name, "\n";
    $done{$name} = 1;
}

foreach my $name (keys(%dirmap)) {
    process($name);
}