#!/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>',

    '"Pawel Solyga" <pawel.solyga@gmail.com>',

    ]

from htmlsanitizer import HtmlSanitizer

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 document as document_logic

from soc.logic.models.site import logic as site_logic

from soc.logic.models.user import logic 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_ORGANZIATION_NOT_ACTIVE_MSG = ugettext(

    "This organization is not active or doesn't exist.")

DEF_NO_SUCH_DOCUMENT_MSG = ugettext(

    "There is no such document with that link ID under this entity.")

DEF_MUST_BE_ABOVE_LIMIT_FMT = ugettext(

    "Must be at least %d characters, it has %d characters.")

DEF_MUST_BE_UNDER_LIMIT_FMT = ugettext(

    "Must be under %d characters, it has %d characters.")

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):

      """Decorator wrapper method.

      """

      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_empty_field(field_name):

  """Incorporates the check_field_is_empty as regular cleaner.

  """

  @check_field_is_empty(field_name)

  def wrapper(self):

    """Decorator wrapper method.

    """

    return self.cleaned_data.get(field_name)

  return wrapper

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):

    """Decorator wrapper method.

    """

    # 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):

    """Decorator wrapper method.

    """

    # 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):

    """Decorator wrapper method.

    """

    agrees_to_tos = self.cleaned_data.get(field_name)

    if not site_logic.getToS(site_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):

    """Decorator wrapper method.

    """

    link_id = clean_link_id(field_name)(self)

    user_entity = user_logic.getFromKeyFields({'link_id': link_id})

    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, as_user=True):

  """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):

    """Decorator wrapper method.

    """

    link_id = clean_link_id(field_name)(self)

    user_entity = user_logic.getForCurrentAccount()

    # pylint: disable-msg=E1103

    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 if as_user else link_id

  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):

    """Decorator wrapper method.

    """

    link_id = clean_link_id(field_name)(self)

    user_entity = user_logic.getFromKeyFields({'link_id': link_id})

    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):

    """Decorator wrapper method.

    """

    clean_user_field = clean_existing_user(field_name)

    user_entity = clean_user_field(self)

    current_user_entity = user_logic.getForCurrentAccount()

    # pylint: disable-msg=E1103

    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):

    """Decorator wrapper method.

    """

    email_adress = self.cleaned_data[field_name]

    return users.User(email_adress)

  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):

    """Decorator wrapper method.

    """

    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.getForFields(fields, unique=True)

    if user_entity or user_logic.isFormerAccount(user_account):

      raise forms.ValidationError("There is already a user "

          "with this email adress.")

    return user_account

  return wrapped

def clean_ascii_only(field_name):

  """Clean method for cleaning a field that may only contain ASCII-characters.

  """

  @check_field_is_empty(field_name)

  def wrapper(self):

    """Decorator wrapper method.

    """

    value = self.cleaned_data.get(field_name)

    try:

      # encode to ASCII

      value = value.encode("ascii")

    except UnicodeEncodeError:

      # can not encode as ASCII

      raise forms.ValidationError("Only ASCII characters are allowed")

    return value

  return wrapper

def clean_content_length(field_name, min_length=0, max_length=500):

  """Clean method for cleaning a field which must contain at least min and

     not more then max length characters.

  Args:

    field_name: the name of the field needed cleaning

    min_length: the minimum amount of allowed characters

    max_length: the maximum amount of allowed characters

  """

  @check_field_is_empty(field_name)

  def wrapper(self):

    """Decorator wrapper method.

    """

    value = self.cleaned_data[field_name]

    value_length = len(value)

    if value_length < min_length:

      raise forms.ValidationError(DEF_MUST_BE_ABOVE_LIMIT_FMT %(

          min_length, value_length))

    if value_length > max_length:

      raise forms.ValidationError(DEF_MUST_BE_UNDER_LIMIT_FMT %(

          max_length, value_length))

    return value

  return wrapper

def clean_phone_number(field_name):

  """Clean method for cleaning a field that may only contain numerical values.

  """

  @check_field_is_empty(field_name)

  def wrapper(self):

    """Decorator wrapped method.

    """

    value = self.cleaned_data.get(field_name)

    # allow for a '+' prefix which means '00'

    if value[0] == '+':

      value = '00' + value[1:]

    if not value.isdigit():

      raise forms.ValidationError("Only numerical characters are allowed")

    return value

  return wrapper

def clean_feed_url(self):

  """Clean method for cleaning feed url.

  """

  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_html_content(field_name):

  """Clean method for cleaning HTML content.

  """

  @check_field_is_empty(field_name)

  def wrapped(self):

    """Decorator wrapper method.

    """

    from HTMLParser import HTMLParseError

    content = self.cleaned_data.get(field_name)

    # clean_html_content is called when writing data into GAE rather than 

    # when reading data from GAE. This short-circuiting of the sanitizer 

    # only affects html authored by developers. The isDeveloper test for 

    # example allows developers to add javascript.

    if user_logic.isDeveloper():

      return content

    try:

      cleaner = HtmlSanitizer.Cleaner()

      cleaner.string = content

      cleaner.clean()

    except HTMLParseError, msg:

      raise forms.ValidationError(msg)

    content = cleaner.string

    content = content.strip().replace('\r\n', '\n')

    return content

  return wrapped

def clean_url(field_name):

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

  """

  @check_field_is_empty(field_name)

  def wrapped(self):

    """Decorator wrapper method.

    """

    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 clean_refs(params, fields):

  """Cleans all references to make sure they are valid.

  """

  logic = params['logic']

  def wrapped(self):

    """Decorator wrapper method.

    """

    scope_path = logic.getKeyNameFromFields(self.cleaned_data)

    key_fields = {

        'scope_path': scope_path,

        'prefix': params['document_prefix'],

        }

    for field in fields:

      link_id = self.cleaned_data.get(field)

      if not link_id:

        continue

      key_fields['link_id'] = link_id

      ref = document_logic.logic.getFromKeyFields(key_fields)

      if not ref:

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

        del self.cleaned_data[field]

      else:

        self.cleaned_data['resolved_%s' % field] = ref

    return self.cleaned_data

  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):

    """Decorator wrapper method.

    """

    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

      user_entity = user_logic.getFromKeyFields({'link_id': link_id})

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

      if user_entity.account != user_account: