#!/usr/bin/python
# -*- coding: utf-8 -*-
# ##################################################################
#
# 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; version 2.
#
# 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-2 for more details.
#
# ##################################################################

import logging
import optparse
import os
import shutil
import subprocess
import sys
import tempfile

from debian.deb822 import Dsc

devnull = open('/dev/null', 'r+')

def error(msg, *args, **kwargs):
    logging.error(msg, *args, **kwargs)
    sys.exit(1)

def parse(args):
    usage = 'Usage: %prog [options]'
    p = optparse.OptionParser(usage)
    p.add_option('-t', '--to',
                 dest='dest_releases',
                 default=[],
                 action='append',
                 help='Backport to DEST release (required)',
                 metavar='DEST')
    p.add_option('-f', '--from',
                 dest='source_release',
                 default=None,
                 help='Backport from SOURCE release (required)',
                 metavar='SOURCE')
    p.add_option('-s', '--source',
                 dest='package',
                 help='Backport SOURCE package (required)',
                 metavar='SOURCE')
    p.add_option('-u', '--upload',
                 dest='upload',
                 help='Specify an upload destination (required)',
                 metavar='UPLOAD')

    opts, args = p.parse_args(args)
    if len(args):
        p.error('Invalid arguments')
    if not opts.package:
        p.error('You must specify a package to backport')
    if not opts.dest_releases:
        p.error('You must specify at least one destination release')
    if not opts.source_release:
        p.error('You must specify the source release')
    if not opts.upload:
        p.error('You must specify an upload destination')

    return opts, args

def main(args):
    logging.basicConfig(level=logging.INFO)
    os.environ['DEB_VENDOR'] = 'Ubuntu'

    opts, _ = parse(args[1:])
    package = opts.package
    source_release = opts.source_release
    dest_releases = opts.dest_releases
    upload = opts.upload

    tmpdir = tempfile.mkdtemp(prefix='backportpackage-')
    try:
        for pocket in ('-updates', '-security', ''):
            if 0 == subprocess.call(['pull-lp-source', package, source_release + pocket],
                                    cwd=tmpdir,
                                    stdout=devnull, stderr=devnull):
                logging.info('Found package %s in pocket %s' % (package, source_release + pocket))
                break
        else:
            error('Unable to find source package %s in release %s' % (package, source_release))

        for dscfile in os.listdir(tmpdir):
            if dscfile.endswith('.dsc'):
                break
        else:
            error('Unable to find a .dsc file for package %s' % package)

        dsc = Dsc(open(os.path.join(tmpdir, dscfile)))
        v = dsc['Version']

        for dest_release in dest_releases:
            srcdir = os.path.join(tmpdir, package)
            if 0 != subprocess.call(['dpkg-source',
                                     '-x',
                                     dscfile,
                                     package],
                                    cwd=tmpdir):
                error('Something went wrong unpacking package %s' % package)

            bp_version = v + ('~%s1' % dest_release)
            bp_dist = dest_release
            if upload.startswith('ppa:'):
                bp_version += '~ppa1'
            elif upload == 'ubuntu':
                bp_dist += '-backports'
            if 0 != subprocess.call(['dch',
                                     '--force-bad-version',
                                     '--preserve',
                                     '--newversion', bp_version,
                                     '--distribution', dest_release,
                                     'No-change backport to %s' % dest_release],
                                    cwd=srcdir):
                error('Something went wrong updating the package changelog')
            if 0 != subprocess.call(['debuild', '-S', '-sa'],
                                    cwd=srcdir):
                error('Something went wrong while building the source package')

            if ':' in bp_version:
                bp_version = bp_version[bp_version.find(':')+1:]

            print 'Please check the package in file://%s carefully' % tmpdir
            while True:
                answer = raw_input('Do you still want to upload this to %s? [Y/n] ' % upload).strip().lower()
                if answer in ('', 'y', 'yes'):
                    if 0 != subprocess.call(['dput',
                                             upload,
                                             '%s_%s_source.changes' % (package, bp_version)],
                                            cwd=tmpdir):
                        error('Something went wrong uploading the package %s to %s' % package, upload)

                    break
                elif answer in ('n', 'no'):
                    break
            shutil.rmtree(srcdir)
    finally:
        shutil.rmtree(tmpdir)

if __name__ == '__main__':
    sys.exit(main(sys.argv))