# Copyright 2013 Rackspace, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import base64

import json
import os

from ironic_python_agent import utils


class ConfigDriveWriter(object):
    def __init__(self):
        self.metadata = {}
        self.files = utils.get_ordereddict()

    def add_metadata(self, key, value):
        self.metadata[key] = value

    def add_file(self, filepath, contents):
        self.files[filepath] = contents

    def write(self, location, prefix='openstack', version='latest'):
        os.makedirs(os.path.join(location, prefix, version))
        os.makedirs(os.path.join(location, prefix, 'content'))

        metadata = {}
        for k, v in self.metadata.items():
            metadata[k] = v

        if self.files:
            metadata['files'] = []
        filenumber = 0
        for filepath, contents in self.files.items():
            content_path = '/content/{0:04}'.format(filenumber)
            file_info = {
                'content_path': content_path,
                'path': filepath
            }
            metadata['files'].append(file_info)

            content_path = os.path.join(location, prefix, content_path[1:])
            with open(content_path, 'wb') as f:
                f.write(contents)

            filenumber += 1

        json_metadata = json.dumps(metadata)
        metadata_path = '{0}/{1}/meta_data.json'.format(prefix, version)
        metadata_path = os.path.join(location, metadata_path)
        with open(metadata_path, 'wb') as f:
            f.write(json_metadata)


def write_configdrive(location, metadata, files, prefix='openstack',
                      version='latest'):
    """Generates and writes a valid configdrive to `location`.
    `files` are passed in as a dict {path: base64_contents}.
    """
    writer = ConfigDriveWriter()

    for k, v in metadata.items():
        writer.add_metadata(k, v)

    for path, b64_contents in files.items():
        contents = base64.b64decode(b64_contents)
        writer.add_file(path, contents)

    writer.write(location, prefix=prefix, version=version)