#!/usr/bin/python
# Copyright (C) 2015  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, see <http://www.gnu.org/licenses/>.

'''Preparatory checks for Baserock 'ostree' write extension.'''

from gi.repository import GLib
from gi.repository import Gio
from gi.repository import OSTree

import logging
import os
import urlparse

import writeexts


class OSTreeCheckExtension(writeexts.WriteExtension):

    def process_args(self, args):
        if len(args) != 1:
            raise writeexts.ExtensionError(
                'Wrong number of command line args')

        upgrade = self.get_environment_boolean('UPGRADE')
        if upgrade:
            raise writeexts.ExtensionError(
                'Use the `ssh-rsync` write extension to deploy upgrades to an '
                'existing remote system.')

        location = args[0]
        self.check_location(location)

        self.check_ostree_parameters()

    def check_location(self, location):
        repo = OSTree.Repo.new(Gio.File.new_for_path(location))
        try:
            repo.open()
        except GLib.GError as e:
            logging.debug("Error from OSTree: %s", e)
            if 'No such file or directory' in e.message:
                raise writeexts.ExtensionError(
                    "OSTree repo %s was not found." % location)
            else:
                raise writeexts.ExtensionError(
                    "Error opening OSTree repo %s: %s" % (location, e))

    def check_ostree_parameters(self):
        required = ['OSTREE_BRANCH', 'OSTREE_COMMIT_SUBJECT']
        for var in required:
            if os.environ.get(var, '') == '':
                raise writeexts.ExtensionError('%s was not given' % var)


OSTreeCheckExtension().run()