#!/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 'openstack' write extension'''

import cliapp
import os
import urlparse

import morphlib.writeexts


class OpenStackCheckExtension(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()

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

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

        os_params = self.get_openstack_parameters()

        self.check_openstack_parameters(location, os_params)

    def get_openstack_parameters(self):
        '''Check the environment variables needed and returns all.

        The environment variables are described in the class documentation.
        '''

        keys = ('OPENSTACK_USER', 'OPENSTACK_TENANT',
                'OPENSTACK_IMAGENAME', 'OPENSTACK_PASSWORD')
        for key in keys:
            if key not in os.environ:
                raise cliapp.AppException(key + ' was not given')
        return (os.environ[key] for key in keys)


    def check_location(self, location):
        x = urlparse.urlparse(location)
        if x.scheme not in ['http', 'https']:
            raise cliapp.AppException('URL schema must be http or https in %s' \
                                      % location)
        if (x.path != '/v2.0' and x.path != '/v2.0/'):
            raise cliapp.AppException('API version must be v2.0 in %s'\
                                      % location)

    def check_openstack_parameters(self, auth_url, os_params):
        '''Check OpenStack credentials using glance image-list'''
        self.status(msg='Checking OpenStack credentials...')

        username, tenant_name, image_name, password = os_params
        cmdline = ['glance',
                   '--os-username', username,
                   '--os-tenant-name', tenant_name,
                   '--os-password', password,
                   '--os-auth-url', auth_url,
                   'image-list']
        try:
            cliapp.runcmd(cmdline)
        except cliapp.AppException:
            raise cliapp.AppException('Wrong OpenStack credentals.')

OpenStackCheckExtension().run()