#!/usr/bin/python
# Copyright (C) 2014  Codethink Limited
#
# 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 of the License.
#
# 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.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

'''Preparatory checks for Morph 'rawdisk' write extension'''

import cliapp

import morphlib.writeexts

import os


class RawdiskCheckExtension(morphlib.writeexts.WriteExtension):
    def process_args(self, args):
        if len(args) != 1:
            raise cliapp.AppException('Wrong number of command line args')

        self.require_btrfs_in_deployment_host_kernel()

        location = args[0]
        upgrade = self.get_environment_boolean('UPGRADE')
        if upgrade:
            if not os.path.isfile(location):
                raise cliapp.AppException(
                    'Cannot upgrade %s: it is not an existing disk image' %
                    location)

            version_label = os.environ.get('VERSION_LABEL')
            if version_label is None:
                raise cliapp.AppException(
                    'VERSION_LABEL was not given. It is required when '
                    'upgrading an existing system.')
        else:
            if os.path.exists(location):
                raise cliapp.AppException(
                    'Target %s already exists. Pass --upgrade if you want to '
                    'update an existing image.' % location)

RawdiskCheckExtension().run()