from django import template

from django.contrib.admin.models import LogEntry

register = template.Library()

class AdminLogNode(template.Node):

    def __init__(self, limit, varname, user):

        self.limit, self.varname, self.user = limit, varname, user

    def __repr__(self):

        return "<GetAdminLog Node>"

    def render(self, context):

        if self.user is None:

            context[self.varname] = LogEntry.objects.all().select_related('content_type', 'user')[:self.limit]

        else:

            if not self.user.isdigit():

                self.user = context[self.user].id

            context[self.varname] = LogEntry.objects.filter(user__id__exact=self.user).select_related('content_type', 'user')[:self.limit]

        return ''

class DoGetAdminLog:

    """

    Populates a template variable with the admin log for the given criteria.

    Usage::

        {% get_admin_log [limit] as [varname] for_user [context_var_containing_user_obj] %}

    Examples::

        {% get_admin_log 10 as admin_log for_user 23 %}

        {% get_admin_log 10 as admin_log for_user user %}

        {% get_admin_log 10 as admin_log %}

    Note that ``context_var_containing_user_obj`` can be a hard-coded integer

    (user ID) or the name of a template context variable containing the user

    object whose ID you want.

    """

    def __init__(self, tag_name):

        self.tag_name = tag_name

    def __call__(self, parser, token):

        tokens = token.contents.split()

        if len(tokens) < 4:

            raise template.TemplateSyntaxError, "'%s' statements require two arguments" % self.tag_name

        if not tokens[1].isdigit():

            raise template.TemplateSyntaxError, "First argument in '%s' must be an integer" % self.tag_name

        if tokens[2] != 'as':

            raise template.TemplateSyntaxError, "Second argument in '%s' must be 'as'" % self.tag_name

        if len(tokens) > 4:

            if tokens[4] != 'for_user':

                raise template.TemplateSyntaxError, "Fourth argument in '%s' must be 'for_user'" % self.tag_name

        return AdminLogNode(limit=tokens[1], varname=tokens[3], user=(len(tokens) > 5 and tokens[5] or None))

register.tag('get_admin_log', DoGetAdminLog('get_admin_log'))