from google.appengine.api import users

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.

  """ 

  def wrapped(self):

    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.")

    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_user_account(field_name):

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

  """

  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.

  """ 

  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 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)

      former_accounts = user_entity.former_accounts

      # if it's not the user's current account or one of his former accounts

      if (user_entity.account != user_account  and 

          user_account not in former_accounts):

        # 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 adress.")

    return cleaned_data

  return wrapper