EXCUSE_STATUS_CHOICES = (
    ('Y', 'Yes'),
    ('N', 'No'),
    ('M', 'Maybe')
)

class Excuse(models.Model):
    title = models.CharField(maxlength=255)
    event = models.ForeignKey(Event)
    author = models.ForeignKey(User)
    reason = models.TextField()
    status = models.CharField(maxlength=1, choices=EXCUSE_STATUS_CHOICES)

    def save(self):
        userID = currentUser().id
        if gettattr(self, 'author_id', None) is None:
            self.author_id = userID
        if gettattr(self, 'status', None) is None:
            self.status = 'M'

    class Admin:
        fields = ()
        list_display = ('author', 'event', 'status')

    def __str__(self): return self.title

class ExcuseAdminOptions(AdminOptions):
    def _fields(self):
        user = currentUser()
        if user is None or user.is_anonymous():
            return ()
        elif user.has_perm('status.change_excuse'):
            return ((None, {'fields' : ('title', 'event', 'reason', 'status')}))
        else:
            return ((None, {'fields' : ('title', 'event', 'reason')}))
    fields = property(_fields)

del Excuse._meta.admin.fields
Excuse._meta.admin.__class__ = ExcuseAdminOptions