#!/usr/bin/python
#
# pull-lp-source -- pull a source package from Launchpad
# Basic usage: pull-lp-source <source package> [<release>]
#
# Copyright (C) 2008 Iain Lane <iain@orangesquash.org.uk>
#
# BackportFromLP class taken from prevu tool, which is:
# Copyright (C) 2006 John Dong <jdong@ubuntu.com>
# 
# ##################################################################
#
# 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.
# 
# See file /usr/share/common-licenses/GPL for more details.
#
# ##################################################################


import os
import re
import subprocess
import sys
import urllib2
from optparse import OptionParser

# ubuntu-dev-tools modules.
from ubuntutools.lp.lpapicache import Distribution
from ubuntutools.lp.udtexceptions import SeriesNotFoundException, PackageNotFoundException

if not os.path.exists("/usr/bin/dget"):
    print "dget is not installed - please install the 'devscripts' package" \
        " and rerun this script again."
    sys.exit(1)

class BackportFromLP:

    def __getitem__(self, name):
        return getattr(self, name)
    
    def __init__(self, package, target_release):
        self.package = package
        self.target_release = target_release
        self.__prepare_sources()
    
    def __prepare_sources(self):
        # Scrape the source package from Launchpad :)
        contents = urllib2.urlopen('https://launchpad.net/ubuntu/%(target_release)s/+source/%(package)s' % self).read()
        links = re.findall('a href=\"(.*\.dsc)\"', contents)
        
        if len(links) == 1 and \
        subprocess.call(['dget', '-xu', 'https://launchpad.net%s' % links[0]]) == 0:
            print '\nSuccess!'
        else:
            raise ValueError, '\nFailed to fetch and extract the source. ' +\
                'Ensure that the package specified is a valid source ' +\
                'package name and that Launchpad is not down.'

if __name__ == '__main__':
    usage = "Usage: %prog <package> [release]"
    optParser = OptionParser(usage)
    (options, args) = optParser.parse_args()
    
    if not args: optParser.error("Arguments required.")
    
    package = str(args[0]).lower()

    if len(args) == 2: # Custom distribution specified.
        release = str(args[1]).lower()
    else:
        release = os.getenv('DIST') or Distribution('ubuntu').getDevelopmentSeries().name

    # Arguments are correct, proceed.
    # Check that the Ubuntu release and package specified exists.
    try:
        Distribution('ubuntu').getArchive().getSourcePackage(package, release)
    except (SeriesNotFoundException, PackageNotFoundException), e:
        print e
        sys.exit(1)

    # All good - start downloading...
    try:
        print 'Attempting to get %s from release %s...' % \
            (package, release.capitalize())
        BackportFromLP(package, release)
    except ValueError, e:
        print 'Error when downloading package %s from release %s: %s.' % \
            (package, release, e)