null=True)

    name = models.CharField(_("Sponsor Name"), max_length=100)

    external_url = models.URLField(_("external URL"))

    annotation = models.TextField(_("annotation"), blank=True)

    contact_name = models.CharField(_("Contact Name"), max_length=100)

    contact_email = models.EmailField(_(u"Contact Email"))

    level = models.ForeignKey(SponsorLevel, verbose_name=_("level"))

    added = models.DateTimeField(_("added"), default=datetime.datetime.now)

    active = models.BooleanField(_("active"), default=False)

    # Denormalization (this assumes only one logo)

    sponsor_logo = models.ForeignKey("SponsorBenefit", related_name="+", null=True, blank=True,

                                     editable=False)

    # Whether things are complete

    # True = complete, False = incomplate, Null = n/a for this sponsor level

    web_logo_benefit = models.NullBooleanField(_("Web logo benefit"), help_text=_(u"Web logo benefit is complete"))

    print_logo_benefit = models.NullBooleanField(_("Print logo benefit"), help_text=_(u"Print logo benefit is complete"))

    print_description_benefit = models.NullBooleanField(_("Print description benefit"), help_text=_(u"Print description benefit is complete"))

    company_description_benefit = models.NullBooleanField(_("Company description benefit"), help_text=_(u"Company description benefit is complete"))

    objects = SponsorManager()

    def __unicode__(self):

        return self.name

    class Meta:

        verbose_name = _("sponsor")

        verbose_name_plural = _("sponsors")

        ordering = ['name']

    def get_absolute_url(self):

        if self.active:

            return reverse("sponsor_detail", kwargs={"pk": self.pk})

        return reverse("sponsor_list")

    @property

    def website_logo(self):

        if self.sponsor_logo is None:

            benefits = self.sponsor_benefits.filter(

                benefit__type="weblogo", upload__isnull=False)[:1]

            if benefits.count():

                if benefits[0].upload:

                    self.sponsor_logo = benefits[0]

                    self.save()

        return self.sponsor_logo.upload

    @property

    def listing_text(self):

        if not hasattr(self, "_listing_text"):

            self._listing_text = None

            # @@@ better than hard-coding a pk but still not good

            benefits = self.sponsor_benefits.filter(benefit__name="Sponsor Description")

            if benefits.count():

                self._listing_text = benefits[0].text

        return self._listing_text

    def reset_benefits(self):

        """

        Reset all benefits for this sponsor to the defaults for their

        sponsorship level.

        """

        level = None

        allowed_benefits = []

        if level:

            for benefit_level in level.benefit_levels.all():

                # Create all needed benefits if they don't exist already

                sponsor_benefit, created = SponsorBenefit.objects.get_or_create(

                    sponsor=self, benefit=benefit_level.benefit)

                # and set to default limits for this level.

                sponsor_benefit.max_words = benefit_level.max_words

                sponsor_benefit.other_limits = benefit_level.other_limits

                # and set to active

                sponsor_benefit.active = True

                # @@@ We don't call sponsor_benefit.clean here. This means

                # that if the sponsorship level for a sponsor is adjusted

                # downwards, an existing too-long text entry can remain,

                # and won't raise a validation error until it's next

                # edited.

                sponsor_benefit.save()

                allowed_benefits.append(sponsor_benefit.pk)

        # Any remaining sponsor benefits that don't normally belong to

        # this level are set to inactive

        self.sponsor_benefits.exclude(pk__in=allowed_benefits)\

            .update(active=False, max_words=None, other_limits="")

    def send_coordinator_emails(self):

        pass  # @@@ should this just be done centrally?

def _store_initial_level(sender, instance, **kwargs):

    if instance:

        instance._initial_level_id = instance.level_id

post_init.connect(_store_initial_level, sender=Sponsor)

def _check_level_change(sender, instance, created, **kwargs):

    if instance and (created or instance.level_id != instance._initial_level_id):

        instance.reset_benefits()

post_save.connect(_check_level_change, sender=Sponsor)

BENEFIT_TYPE_CHOICES = [

    ("text", "Text"),

    ("file", "File"),

    ("weblogo", "Web Logo"),

    ("simple", "Simple")

]

class Benefit(models.Model):

    name = models.CharField(_("name"), max_length=100)

    description = models.TextField(_("description"), blank=True)

    type = models.CharField(_("type"), choices=BENEFIT_TYPE_CHOICES, max_length=10,

                            default="simple")

    def __unicode__(self):

        return self.name

class BenefitLevel(models.Model):

    benefit = models.ForeignKey(Benefit, related_name="benefit_levels", verbose_name=_("benefit"))

    level = models.ForeignKey(SponsorLevel, related_name="benefit_levels", verbose_name=_("level"))

    # default limits for this benefit at given level

    max_words = models.PositiveIntegerField(_("max words"), blank=True, null=True)

    other_limits = models.CharField(_("other limits"), max_length=200, blank=True)

    class Meta:

        ordering = ["level"]

    def __unicode__(self):

        return u"%s - %s" % (self.level, self.benefit)

class SponsorBenefit(models.Model):

    sponsor = models.ForeignKey(Sponsor, related_name="sponsor_benefits", verbose_name=_("sponsor"))

    benefit = models.ForeignKey(Benefit, related_name="sponsor_benefits", verbose_name=_("benefit"))

    active = models.BooleanField(default=True)

    # Limits: will initially be set to defaults from corresponding BenefitLevel

    max_words = models.PositiveIntegerField(_("max words"), blank=True, null=True)

    other_limits = models.CharField(_("other limits"), max_length=200, blank=True)

    # Data: zero or one of these fields will be used, depending on the

    # type of the Benefit (text, file, or simple)

    text = models.TextField(_("text"), blank=True)

    upload = models.FileField(_("file"), blank=True, upload_to="sponsor_files")

    class Meta:

        ordering = ["-active"]

    def __unicode__(self):

        return u"%s - %s" % (self.sponsor, self.benefit)

    def clean(self):

        num_words = len(self.text.split())

        if self.max_words and num_words > self.max_words:

            raise ValidationError(

                "Sponsorship level only allows for %s words, you provided %d." % (

                    self.max_words, num_words))

    def data_fields(self):

        """

        Return list of data field names which should be editable for

        this ``SponsorBenefit``, depending on its ``Benefit`` type.

        """

        if self.benefit.type == "file" or self.benefit.type == "weblogo":

            return ["upload"]

        elif self.benefit.type == "text":

            return ["text"]

        return []