#!/usr/bin/env python

# Copyright (C) 2013 Google 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.
"""Command-line sample application for listing all objects in a bucket using
the Cloud Storage API.

This sample is used on this page:

    https://cloud.google.com/storage/docs/json_api/v1/json-api-python-samples

For more information, see the README.md under /storage.
"""

import argparse
import json

from googleapiclient import discovery

from oauth2client.client import GoogleCredentials


def create_service():
    """Creates the service object for calling the Cloud Storage API."""
    # Get the application default credentials. When running locally, these are
    # available after running `gcloud init`. When running on compute
    # engine, these are available from the environment.
    credentials = GoogleCredentials.get_application_default()

    # Construct the service object for interacting with the Cloud Storage API -
    # the 'storage' service, at version 'v1'.
    # You can browse other available api services and versions here:
    #     https://developers.google.com/api-client-library/python/apis/
    return discovery.build('storage', 'v1', credentials=credentials)


def get_bucket_metadata(bucket):
    """Retrieves metadata about the given bucket."""
    service = create_service()

    # Make a request to buckets.get to retrieve a list of objects in the
    # specified bucket.
    req = service.buckets().get(bucket=bucket)
    return req.execute()


def list_bucket(bucket):
    """Returns a list of metadata of the objects within the given bucket."""
    service = create_service()

    # Create a request to objects.list to retrieve a list of objects.
    fields_to_return = \
        'nextPageToken,items(name,size,contentType,metadata(my-key))'
    req = service.objects().list(bucket=bucket, fields=fields_to_return)

    all_objects = []
    # If you have too many items to list in one request, list_next() will
    # automatically handle paging with the pageToken.
    while req:
        resp = req.execute()
        all_objects.extend(resp.get('items', []))
        req = service.objects().list_next(req, resp)
    return all_objects


def main(bucket):
    print(json.dumps(get_bucket_metadata(bucket), indent=2))
    print(json.dumps(list_bucket(bucket), indent=2))


if __name__ == '__main__':
    parser = argparse.ArgumentParser(
        description=__doc__,
        formatter_class=argparse.RawDescriptionHelpFormatter)
    parser.add_argument('bucket', help='Your Cloud Storage bucket.')

    args = parser.parse_args()

    main(args.bucket)