import httplib2
from apiclient.discovery import build
from oauth2client.client import flow_from_clientsecrets
from oauth2client.file import Storage
from oauth2client.tools import run

from pylons import config


def _prepare_credentials( token_filename, credentials_filename ):
    """
    Either returns the user's oauth credentials or uses the credentials
    file to generate a token (by forcing the user to login in the browser)
    """
    storage = Storage( token_filename )
    credentials = storage.get()

    if credentials is None or credentials.invalid:
        flow = flow_from_clientsecrets(credentials_filename,
                scope='https://www.googleapis.com/auth/analytics.readonly',
                message="Can't find the credentials file")
        credentials = run(flow, storage)

    return credentials

def init_service( token_file, credentials_file ):
    """
    Given a file containing the user's oauth token (and another with
    credentials in case we need to generate the token) will return a
    service object representing the analytics API.
    """
    http = httplib2.Http()

    credentials = _prepare_credentials(token_file, credentials_file)
    http = credentials.authorize(http)  # authorize the http object

    return build('analytics', 'v3', http=http)


def get_profile_id(service):
    """
    Get the profile ID for this user and the service specified by the
    'googleanalytics.id' configuration option.
    """
    accounts = service.management().accounts().list().execute()

    if not accounts.get('items'):
        return None

    accountId = accounts.get('items')[0].get('id')
    webPropertyId = config.get('googleanalytics.id')
    profiles = service.management().profiles().list(
        accountId=accountId, webPropertyId=webPropertyId).execute()

    if profiles.get('items'):
        return profiles.get('items')[0].get('id')

    return None