#!/usr/bin/python2.5

#

# Copyright 2008 the Melange authors.

#

# 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.

"""Basic Google Account and User (Model) query functions.

"""

__authors__ = [

  '"Chen Lunpeng" <forever.clp@gmail.com>',

  '"Todd Larsen" <tlarsen@google.com>',

  ]

from google.appengine.api import users

from soc.logic import models

from soc.views import out_of_band

import soc.models.user

import soc.logic.models.user

def isDeveloper(account=None):

  """Returns True if a Google Account is a Developer with special privileges.

  Since it only works on the current logged-in user, if account matches the

  current logged-in Google Account, the App Engine Users API function

  user.is_current_user_admin() is checked.  If that returns False, or

  account is not the currently logged-in user, the is_developer property of

  the User entity corresponding to the Google Account is checked next.

  This solves the "chicken-and-egg" problem of no User entity having its

  is_developer property set, but no one being able to set it.

  Args:

    account: a Google Account (users.User) object; if not supplied,

      the current logged-in user is checked

  """

  # Get the currently logged in user

  current = users.get_current_user()

  if not (account or current):

    # no Google Account was supplied or is logged in, so an unspecified

    # User is definitely *not* a Developer

    return False

  if (((not account) or (account == current))

      and users.is_current_user_admin()):

    # no account supplied, or current logged-in user, and that user is in the

    # Administration->Developers list in the App Engine console

    return True

  if not account:

    account = current

  user = models.user.logic.getForFields({'account': account}, unique=True)

  if not user:

    # no User entity for this Google Account, and account is not the

    # currently logged-in user, so there is no conclusive way to check the

    # Administration->Developers list in the App Engine console

    return False

  return user.is_developer

def isAccountAvailable(new_account,

                       existing_user=None, existing_key_name=None):

  """Returns True if Google Account is available for use by existing User.

  Args:

    new_account: a Google Account (users.User) object with a (possibly)

      new email

    existing_user: an existing User entity; default is None, in which case

      existing_key_name is used to look up the User entity

    existing_key_name: the key_name of an existing User entity, used

      when existing_user is not supplied; default is None

  """

  if not existing_user:

    existing_user = models.user.logic.getFromKeyName(existing_key_name)

  if existing_user:

    old_email = existing_user.account.email()

  else:

    old_email = None

  if new_account.email().lower() == old_email.lower():

    # "new" email is same as existing User wanting it, so it is "available"

    return True

  # else: "new" email truly is new to the existing User, so keep checking

  if not models.user.logic.getForFields({'account': new_account},

                                        unique=True):

    # new email address also does not belong to any other User,

    # so it is available

    return True

  # email does not already belong to this User, but to some other User

  return False

# TODO(tlarsen): make this generic for any Linkable and move elsewhere

def getUserFromLinkIdOr404(link_id):

  """Like getUserFromLinkId but expects to find a user.

  Raises:

    out_of_band.Error if no User entity is found

  """

  user = models.user.logic.getForFields({'link_id': link_id},

                                        unique=True)

  if user:

    return user

  raise out_of_band.Error(

      'There is no user with a "link ID" of "%s".' % link_id, status=404)