#!/usr/bin/python

import urllib, sys, optparse, re, subprocess

kernel_pkg_re = re.compile('linux-(generic|firmware|headers|image|backports|ec2|source|virtual|preempt)')

def parse_argv():
    '''Parse CLI options.

    Return (options, manifest) tuple.
    '''

    optparser = optparse.OptionParser('''%prog [options] <manifest>

Install/remove packages according to a CD build manifest.
<manifest> can be a local file or URL.''')
    optparser.add_option('-k', '--keep-kernel',
            help='Do not change kernel packages', action='store_true',
            dest='keep_kernel', default=False)
    options, args = optparser.parse_args()

    if len(args) != 1:
        optparser.error('You need to specify exactly one manifest argument, see --help')
        sys.exit(1)

    return (options, args[0])

#
# main
#

(options, manifest) = parse_argv()

selection = ''
for l in urllib.urlopen(manifest):
    pkg = l.split()[0]
    if options.keep_kernel and kernel_pkg_re.match(pkg):
        continue
    selection += '%s\tinstall\n' % pkg

# add local kernel packages on --keep-kernel
if options.keep_kernel:
    dpkg = subprocess.Popen(['dpkg', '--get-selections'],
            stdout=subprocess.PIPE)
    for l in dpkg.stdout:
        pkg, status = l.split()
        if status != 'install':
            continue
        if kernel_pkg_re.match(pkg):
            selection += '%s\tinstall\n' % pkg

if subprocess.call(['which', 'dselect'], stdout=subprocess.PIPE) != 0:
    print >> sys.stderr, 'INFO: installing dselect (needed by this script)'
    assert subprocess.call(['apt-get', 'install', 'dselect']) == 0

# now apply the new selections
assert subprocess.call(['dpkg', '--clear-selections']) == 0
dpkg = subprocess.Popen(['dpkg', '--set-selections'], stdin=subprocess.PIPE)
dpkg.communicate(selection)
assert dpkg.returncode == 0

# commit!
subprocess.call(['dselect', 'install'])