text: import datetime
  from django.contrib.auth.models import User
  from django.contrib.comments.managers import CommentManager
  from django.contrib.contenttypes import generic
  from django.contrib.contenttypes.models import ContentType
  from django.contrib.sites.models import Site
  from django.db import models
  from django.core import urlresolvers
  from django.utils.translation import ugettext_lazy as _
  from django.conf import settings
  
  COMMENT_MAX_LENGTH = getattr(settings,'COMMENT_MAX_LENGTH',3000)
  
  class BaseCommentAbstractModel(models.Model):
      """
      An abstract base class that any custom comment models probably should
      subclass.
      """
  
      # Content-object field
      content_type   = models.ForeignKey(ContentType,
              related_name="content_type_set_for_%(class)s")
      object_pk      = models.TextField(_('object ID'))
      content_object = generic.GenericForeignKey(ct_field="content_type", fk_field="object_pk")
  
      # Metadata about the comment
      site        = models.ForeignKey(Site)
  
      class Meta:
          abstract = True
  
      def get_content_object_url(self):
          """
          Get a URL suitable for redirecting to the content object.
          """
          return urlresolvers.reverse(
              "comments-url-redirect",
              args=(self.content_type_id, self.object_pk)
          )
  
  class Comment(BaseCommentAbstractModel):
      """
      A user comment about some object.
      """
  
      # Who posted this comment? If ``user`` is set then it was an authenticated
      # user; otherwise at least user_name should have been set and the comment
      # was posted by a non-authenticated user.
      user        = models.ForeignKey(User, blank=True, null=True, related_name="%(class)s_comments")
      user_name   = models.CharField(_("user's name"), max_length=50, blank=True)
      user_email  = models.EmailField(_("user's email address"), blank=True)
      user_url    = models.URLField(_("user's URL"), blank=True)
  
      comment = models.TextField(_('comment'), max_length=COMMENT_MAX_LENGTH)
  
      # Metadata about the comment
      submit_date = models.DateTimeField(_('date/time submitted'), default=None)
      ip_address  = models.IPAddressField(_('IP address'), blank=True, null=True)
      is_public   = models.BooleanField(_('is public'), default=True,
                      help_text=_('Uncheck this box to make the comment effectively ' \
                                  'disappear from the site.'))
      is_removed  = models.BooleanField(_('is removed'), default=False,
                      help_text=_('Check this box if the comment is inappropriate. ' \
                                  'A "This comment has been removed" message will ' \
                                  'be displayed instead.'))
  
      # Manager
      objects = CommentManager()
  
      class Meta:
          db_table = "django_comments"
          ordering = ('submit_date',)
          permissions = [("can_moderate", "Can moderate comments")]
  
      def __unicode__(self):
          return "%s: %s..." % (self.name, self.comment[:50])
  
      def save(self, force_insert=False, force_update=False):
          if self.submit_date is None:
              self.submit_date = datetime.datetime.now()
          super(Comment, self).save(force_insert, force_update)
  
      def _get_userinfo(self):
          """
          Get a dictionary that pulls together information about the poster
          safely for both authenticated and non-authenticated comments.
  
          This dict will have ``name``, ``email``, and ``url`` fields.
          """
          if not hasattr(self, "_userinfo"):
              self._userinfo = {
                  "name"  : self.user_name,
                  "email" : self.user_email,
                  "url"   : self.user_url
              }
              if self.user_id:
                  u = self.user
                  if u.email:
                      self._userinfo["email"] = u.email
  
                  # If the user has a full name, use that for the user name.
                  # However, a given user_name overrides the raw user.username,
                  # so only use that if this comment has no associated name.
                  if u.get_full_name():
                      self._userinfo["name"] = self.user.get_full_name()
                  elif not self.user_name:
                      self._userinfo["name"] = u.username
          return self._userinfo
      userinfo = property(_get_userinfo, doc=_get_userinfo.__doc__)
  
      def _get_name(self):
          return self.userinfo["name"]
      def _set_name(self, val):
          if self.user_id:
              raise AttributeError(_("This comment was posted by an authenticated "\
                                     "user and thus the name is read-only."))
          self.user_name = val
      name = property(_get_name, _set_name, doc="The name of the user who posted this comment")
  
      def _get_email(self):
          return self.userinfo["email"]
      def _set_email(self, val):
          if self.user_id:
              raise AttributeError(_("This comment was posted by an authenticated "\
                                     "user and thus the email is read-only."))
          self.user_email = val
      email = property(_get_email, _set_email, doc="The email of the user who posted this comment")
  
      def _get_url(self):
          return self.userinfo["url"]
      def _set_url(self, val):
          self.user_url = val
      url = property(_get_url, _set_url, doc="The URL given by the user who posted this comment")
  
      def get_absolute_url(self, anchor_pattern="#c%(id)s"):
          return self.get_content_object_url() + (anchor_pattern % self.__dict__)
  
      def get_as_text(self):
          """
          Return this comment as plain text.  Useful for emails.
          """
          d = {
              'user': self.user or self.name,
              'date': self.submit_date,
              'comment': self.comment,
              'domain': self.site.domain,
              'url': self.get_absolute_url()
          }
          return _('Posted by %(user)s at %(date)s\n\n%(comment)s\n\nhttp://%(domain)s%(url)s') % d
  
  class CommentFlag(models.Model):
      """
      Records a flag on a comment. This is intentionally flexible; right now, a
      flag could be:
  
          * A "removal suggestion" -- where a user suggests a comment for (potential) removal.
  
          * A "moderator deletion" -- used when a moderator deletes a comment.
  
      You can (ab)use this model to add other flags, if needed. However, by
      design users are only allowed to flag a comment with a given flag once;
      if you want rating look elsewhere.
      """
      user      = models.ForeignKey(User, related_name="comment_flags")
      comment   = models.ForeignKey(Comment, related_name="flags")
      flag      = models.CharField(max_length=30, db_index=True)
      flag_date = models.DateTimeField(default=None)
  
      # Constants for flag types
      SUGGEST_REMOVAL = "removal suggestion"
      MODERATOR_DELETION = "moderator deletion"
      MODERATOR_APPROVAL = "moderator approval"
  
      class Meta:
          db_table = 'django_comment_flags'
          unique_together = [('user', 'comment', 'flag')]
  
      def __unicode__(self):
          return "%s flag of comment ID %s by %s" % \
              (self.flag, self.comment_id, self.user.username)
  
      def save(self, force_insert=False, force_update=False):
          if self.flag_date is None:
              self.flag_date = datetime.datetime.now()
          super(CommentFlag, self).save(force_insert, force_update)
  