#!/usr/bin/perl
# Script Name: pull-debian-source
# Author: Nathan Handler <nhandler@ubuntu.com>
# Usage: pull-debian-source <source package> [release]
# Copyright (C) 2008, 2009 Nathan Handler <nhandler@ubuntu.com>
# License: GNU General Public License
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# On Debian GNU/Linux systems, the complete text of the GNU General
# Public License can be found in the /usr/share/common-licenses/GPL-3 file.

use warnings;
use strict;
use LWP::Simple;
use File::Basename;
use Getopt::Long;

die("Please install 'devscripts'\n") if(! grep -x "$_/dget", split(':',$ENV{'PATH'}));

my($package)=$ARGV[0] || &usage();
my($help)=0;
GetOptions('help' => \$help);
&usage() if($help);
my($release)=$ARGV[1] || 'unstable';
$release=&convertCodeName($release);
&checkRelease($release);
my($dsc)=&getDSC(&getMadison(&getURL($package,$release)));
print "$dsc\n";
exec("dget -xu $dsc");
sub convertCodeName {
	my($release)=shift || die("No Release Passed To convertCodeName!\n");
	chomp $release;
	if($release=~m/^lenny$/i) {
		return "stable";
	}
	elsif($release=~m/^squeeze$/i) {
		return "testing";
	}
	elsif($release=~m/^sid$/i) {
		return "unstable";
	}
	elsif($release=~m/^etch$/i) {
		return "oldstable";
	}
	return $release;
}
sub checkRelease {
	my($release)=shift || die("No Release Passed To checkRelease!\n");
	chomp $release;
	my %releases=(
		'stable' => 1,
		'testing' => 1,
		'unstable' => 1,
		'experimental' => 1,
		'oldstable' => 1
	);
	&invalidRelease(\%releases) unless $releases{$release}
}
sub getURL{
	my($package)=shift || die("No Package Passed To getURL: $!\n");
	my($release)=shift || die("No Release Passed to getURL: $!\n");
	chomp $package;
	chomp $release;
	$package=lc($package);
	$package=~s/\+/%2b/g;
	$release=lc($release);
	my($baseURL)='http://qa.debian.org/madison.php?text=on';
	my($url)=$baseURL . '&package=' . $package . '&s=' . $release;
	return $url;
}
sub getMadison {
	my($url)=shift || die("No URL Passed to getMadison: $!\n");
	chomp $url;
	my($madison)=get($url);
	die("Could Not Get $url") unless (defined $madison && $madison!~m/^\s*$/);
	return $madison;
}
sub getDSC {
	my($madison)=shift || die("No madison Passed to getDSC: $!\n");
	if($madison=~m/^[WE]:/i) {
		die("$madison");
	}
	my($baseURL)='http://ftp.debian.org/debian/pool/main/';
	my(@madison)=split(/\n/,$madison);
	foreach my $line (@madison) {
		my($package,$version,$release,$archs)=split(/\|/,$line,4);
		$package=~s/\s*//g;
		$version=~s/\s*//g;
		$release=~s/\s*//g;
		$archs=~s/\s*//g;
		$version=~s/^.*?\://;
		if($archs=~m/source/) {
			print "Package: $package\nVersion: $version\nRelease: $release\nArchitectures: $archs\n";
			my($firstLetter);
			if($package=~m/^lib/) {
				$firstLetter="lib" . substr($package,3,1);
			}
			else {
				$firstLetter=substr($package,0,1);
			}
			my($url)=$baseURL . $firstLetter . '/' . $package . '/' . $package . '_' . $version . '.dsc';
			return $url;
		}
	}
	die("Unable To Find Source Package On Madison\n");
}
sub usage {
	my($name)=basename($0);
	die("USAGE: $name [-h] <source package> [target release]\n");
}
sub invalidRelease {
	my($releases)=shift || die("Invalid Release!");
	my(%releases)=%$releases;
	my($validReleases);
	while ( my ($key, $value) = each(%releases) ) {
		if($value) {
			$validReleases .= $key . ", ";
		}
	}
	$validReleases=~s/,\s*$//;
	die("Invalid Release!\nValid Releases: $validReleases\n");
}