#!/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.

"""Generic cleaning methods.

"""

__authors__ = [

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

    '"Sverre Rabbelier" <sverre@rabbelier.nl>',

    '"Lennard de Rijk" <ljvderijk@gmail.com>',

    ]

from google.appengine.api import users

from django import forms

from django.forms.util import ErrorList

from django.utils.translation import ugettext

from soc.logic import rights as rights_logic

from soc.logic import validate

from soc.logic.models import site as site_logic

from soc.logic.models import user as user_logic

from soc.models import document as document_model

DEF_LINK_ID_IN_USE_MSG = ugettext(

    'This link ID is already in use, please specify another one')

DEF_NO_RIGHTS_FOR_ACL_MSG = ugettext(

     'You do not have the required rights for that ACL.')

def check_field_is_empty(field_name):

  """Returns decorator that bypasses cleaning for empty fields.

  """

  def decorator(fun):

    """Decorator that checks if a field is empty if so doesn't do the cleaning.

    Note Django will capture errors concerning required fields that are empty.

    """

    from functools import wraps

    @wraps(fun)

    def wrapper(self):

      field_content = self.cleaned_data.get(field_name)

      if not field_content:

        # field has no content so bail out

        return None

      else:

        # field has contents

        return fun(self)

    return wrapper

  return decorator

def clean_link_id(field_name):

  """Checks if the field_name value is in a valid link ID format.

  """

  @check_field_is_empty(field_name)

  def wrapper(self):

    # convert to lowercase for user comfort

    link_id = self.cleaned_data.get(field_name).lower()

    if not validate.isLinkIdFormatValid(link_id):

      raise forms.ValidationError("This link ID is in wrong format.")

    return link_id

  return wrapper

def clean_scope_path(field_name):

  """Checks if the field_name value is in a valid scope path format.

  """

  @check_field_is_empty(field_name)

  def wrapper(self):

    # convert to lowercase for user comfort

    scope_path = self.cleaned_data.get(field_name).lower()

    if not validate.isScopePathFormatValid(scope_path):

      raise forms.ValidationError("This scope path is in wrong format.")

    return scope_path

  return wrapper

def clean_agrees_to_tos(field_name):

  """Checks if there is a ToS to see if it is allowed to leave 

     the field_name field false.

  """

  @check_field_is_empty(field_name)

  def wrapper(self):

    agrees_to_tos = self.cleaned_data.get(field_name)

    if not site_logic.logic.getToS(site_logic.logic.getSingleton()):

      return agrees_to_tos

    # Site settings specify a site-wide ToS, so agreement is *required*

    if agrees_to_tos:

      return True

    # there was no agreement made so raise an error

    raise forms.ValidationError(

        'The site-wide Terms of Service must be accepted to participate'

        ' on this site.')

  return wrapper

def clean_existing_user(field_name):

  """Check if the field_name field is a valid user.

  """

  @check_field_is_empty(field_name)

  def wrapped(self):

    link_id = clean_link_id(field_name)(self)

    user_entity = user_logic.logic.getForFields({'link_id': link_id}, 

        unique=True)

    if not user_entity:

      # user does not exist

      raise forms.ValidationError("This user does not exist.")

    return user_entity

  return wrapped

def clean_user_is_current(field_name):

  """Check if the field_name value is a valid link_id and resembles the 

     current user.

  """

  @check_field_is_empty(field_name)

  def wrapped(self):

    link_id = clean_link_id(field_name)(self)

    user_entity = user_logic.logic.getForCurrentAccount()

    if not user_entity or user_entity.link_id != link_id:

      # this user is not the current user

      raise forms.ValidationError("This user is not you.")

    return user_entity

  return wrapped

def clean_user_not_exist(field_name):

  """Check if the field_name value is a valid link_id and a user with the

     link id does not exist.

  """ 

  @check_field_is_empty(field_name)

  def wrapped(self):

    link_id = clean_link_id(field_name)(self)

    user_entity = user_logic.logic.getForFields({'link_id': link_id}, 

        unique=True)

    if user_entity:

      # user exists already

      raise forms.ValidationError("There is already a user with this link id.")

    return link_id

  return wrapped

def clean_users_not_same(field_name):

  """Check if the field_name field is a valid user and is not 

     equal to the current user.

  """

  @check_field_is_empty(field_name)

  def wrapped(self):

    clean_user_field = clean_existing_user(field_name)

    user_entity = clean_user_field(self)

    current_user_entity = user_logic.logic.getForCurrentAccount()

    if user_entity.key() == current_user_entity.key():

      # users are equal

      raise forms.ValidationError("You cannot enter yourself here.")

    return user_entity

  return wrapped

def clean_user_account(field_name):

  """Returns the User with the given field_name value.

  """

  @check_field_is_empty(field_name)

  def wrapped(self):

    email_adress = self.cleaned_data.get(field_name).lower()

    # get the user account for this email

    user_account = users.User(email_adress)

    return user_account

  return wrapped

def clean_user_account_not_in_use(field_name):

  """Check if the field_name value contains an email 

     address that hasn't been used for an existing account.

  """ 

  @check_field_is_empty(field_name)

  def wrapped(self):

    email_adress = self.cleaned_data.get(field_name).lower()

    # get the user account for this email and check if it's in use

    user_account = users.User(email_adress)

    fields = {'account': user_account}

    user_entity = user_logic.logic.getForFields(fields, unique=True)

    if user_entity or user_logic.logic.isFormerAccount(user_account):

      raise forms.ValidationError("There is already a user with this email adress.")

    return user_account

  return wrapped

def clean_feed_url(self):

  feed_url = self.cleaned_data.get('feed_url')

  if feed_url == '':

    # feed url not supplied (which is OK), so do not try to validate it

    return None

  if not validate.isFeedURLValid(feed_url):

    raise forms.ValidationError('This URL is not a valid ATOM or RSS feed.')

  return feed_url

def clean_url(field_name):

  """Clean method for cleaning a field belonging to a LinkProperty.

  """

  @check_field_is_empty(field_name)

  def wrapped(self):

    value = self.cleaned_data.get(field_name)

    # call the Django URLField cleaning method to properly clean/validate this field

    return forms.URLField.clean(self.fields[field_name], value)

  return wrapped

def validate_user_edit(link_id_field, account_field):

  """Clean method for cleaning user edit form.

  Raises ValidationError if:

    -Another User has the given email address as account

    -Another User has the given email address in it's FormerAccounts list

  """

  def wrapper(self):

    cleaned_data = self.cleaned_data

    link_id = cleaned_data.get(link_id_field)

    user_account = cleaned_data.get(account_field)

    # if both fields were valid do this check

    if link_id and user_account:

      # get the user from the link_id in the form

      fields = {'link_id': link_id}

      user_entity = user_logic.logic.getForFields(fields, unique=True)

      # if it's not the user's current account

      if user_entity.account != user_account:

        # get the user having the given account

        fields = {'account': user_account}

        user_from_account_entity = user_logic.logic.getForFields(fields, 

            unique=True)

        # if there is a user with the given account or it's a former account

        if user_from_account_entity or user_logic.logic.isFormerAccount(user_account):

          # raise an error because this email address can't be used

          raise forms.ValidationError("There is already a user with this email address.")

    return cleaned_data

  return wrapper

def validate_new_group(link_id_field, scope_path_field, 

                       group_logic, group_app_logic):

  """Clean method used to clean the group application or new group form.

    Raises ValidationError if:

    -A application with this link id and scope path already exists

    -A group with this link id and scope path already exists

  """

  def wrapper(self):

      cleaned_data = self.cleaned_data

      fields = {}

      link_id = cleaned_data.get(link_id_field)

      if link_id:

        fields['link_id'] = link_id

        scope_path = cleaned_data.get(scope_path_field)

        if scope_path:

          fields['scope_path'] = scope_path

        # get the application

        group_app_entity = group_app_logic.logic.getForFields(fields, unique=True)

        # get the current user

        user_entity = user_logic.logic.getForCurrentAccount()

        # make sure it's not the applicant creating the new group

        if group_app_entity and (

            group_app_entity.applicant.key() != user_entity.key()):

          # add the error message to the link id field

          self._errors[link_id_field] = ErrorList([DEF_LINK_ID_IN_USE_MSG])

          del cleaned_data[link_id_field]

          # return the new cleaned_data

          return cleaned_data

        # check if there is already a group for the given fields

        group_entity = group_logic.logic.getForFields(fields, unique=True)

        if group_entity:

          # add the error message to the link id field

          self._errors[link_id_field] = ErrorList([DEF_LINK_ID_IN_USE_MSG])

          del cleaned_data[link_id_field]

          # return the new cleaned_data

          return cleaned_data

      return cleaned_data

  return wrapper

def validate_document_acl(view):

  """Validates that the document ACL settings are correct.

  """

  def wrapper(self):

    cleaned_data = self.cleaned_data

    read_access = cleaned_data.get('read_access')

    write_access = cleaned_data.get('write_access')

    if not (read_access and write_access and ('prefix' in cleaned_data)):

      return cleaned_data

    if read_access != 'public':

      ordening = document_model.Document.DOCUMENT_ACCESS

      if ordening.index(read_access) < ordening.index(write_access):

        raise forms.ValidationError(

            "Read access should be less strict than write access.")

    validate_access(self, view, 'read_access')

    validate_access(self, view, 'write_access')

    return cleaned_data

  return wrapper

def validate_access(self, view, field):

  """Validates that the user has access to the ACL for the specified fields.

  """

  access_level = self.cleaned_data[field]

  prefix = self.cleaned_data['prefix']

  scope_path = self.cleaned_data['scope_path']

  params = view.getParams()

  rights = params['rights']

  user = user_logic.logic.getForCurrentAccount()

  rights.setCurrentUser(user.account, user)

  checker = rights_logic.Checker(prefix)

  roles = checker.getMembership(access_level)

  if not rights.hasMembership(roles, {'scope_path': scope_path}):

    self._errors[field] = ErrorList([DEF_NO_RIGHTS_FOR_ACL_MSG])

    del self.cleaned_data[field]