from django.db import models

from django.contrib.contenttypes.models import ContentType

from django.contrib.auth.models import User

from django.utils.translation import ugettext_lazy as _

from django.utils.encoding import smart_unicode

from django.utils.safestring import mark_safe

ADDITION = 1

CHANGE = 2

DELETION = 3

class LogEntryManager(models.Manager):

    def log_action(self, user_id, content_type_id, object_id, object_repr, action_flag, change_message=''):

        e = self.model(None, None, user_id, content_type_id, smart_unicode(object_id), object_repr[:200], action_flag, change_message)

        e.save()

class LogEntry(models.Model):

    action_time = models.DateTimeField(_('action time'), auto_now=True)

    user = models.ForeignKey(User)

    content_type = models.ForeignKey(ContentType, blank=True, null=True)

    object_id = models.TextField(_('object id'), blank=True, null=True)

    object_repr = models.CharField(_('object repr'), max_length=200)

    action_flag = models.PositiveSmallIntegerField(_('action flag'))

    change_message = models.TextField(_('change message'), blank=True)

    objects = LogEntryManager()

    class Meta:

        verbose_name = _('log entry')

        verbose_name_plural = _('log entries')

        db_table = 'django_admin_log'

        ordering = ('-action_time',)

    def __repr__(self):

        return smart_unicode(self.action_time)

    def is_addition(self):

        return self.action_flag == ADDITION

    def is_change(self):

        return self.action_flag == CHANGE

    def is_deletion(self):

        return self.action_flag == DELETION

    def get_edited_object(self):

        "Returns the edited object represented by this log entry"

        return self.content_type.get_object_for_this_type(pk=self.object_id)

    def get_admin_url(self):

        """

        Returns the admin URL to edit the object represented by this log entry.

        This is relative to the Django admin index page.

        """

        return mark_safe(u"%s/%s/%s/" % (self.content_type.app_label, self.content_type.model, self.object_id))