# Copyright (c) 2013 AnsibleWorks, Inc.
#
# This file is part of Ansible Commander.
# 
# Ansible Commander is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3 of the License. 
#
# Ansible Commander is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with Ansible Commander. If not, see <http://www.gnu.org/licenses/>.


import logging
from django.http import Http404
from rest_framework.exceptions import PermissionDenied
from rest_framework import permissions

logger = logging.getLogger('lib.main.rbac')

# FIXME: this will probably need to be subclassed by object type

class CustomRbac(permissions.BasePermission):

    def _check_permissions(self, request, view, obj=None):
        # Check that obj (if given) is active, otherwise raise a 404.
        active = getattr(obj, 'active', getattr(obj, 'is_active', True))
        if callable(active):
            active = active()
        if not active:
            raise Http404()
        # Don't allow anonymous users. 401, not 403, hence no raised exception.
        if not request.user or request.user.is_anonymous():
            return False
        # Don't allow inactive users (and respond with a 403).
        if not request.user.is_active:
            raise PermissionDenied()
        # Always allow superusers (as long as they are active).
        if request.user.is_superuser:
            return True
        # If no obj is given, check list permissions.
        if obj is None:
            if getattr(view, 'list_permissions_check', None):
                if not view.list_permissions_check(request):
                    raise PermissionDenied()
            elif not getattr(view, 'item_permissions_check', None):
                raise Exception('internal error, list_permissions_check or '
                                'item_permissions_check must be defined')
            return True
        # Otherwise, check the item permissions for the given obj.
        else:
            if not view.item_permissions_check(request, obj):
                raise PermissionDenied()
            return True

    def has_permission(self, request, view, obj=None):
        logger.debug('has_permission(user=%s method=%s data=%r, %s, %r)',
                     request.user, request.method, request.DATA,
                     view.__class__.__name__, obj)
        try:
            response = self._check_permissions(request, view, obj)
        except Exception, e:
            logger.debug('has_permission raised %r', e, exc_info=True)
            raise
        else:
            logger.debug('has_permission returned %r', response)
            return response

    def has_object_permission(self, request, view, obj):
        return self.has_permission(request, view, obj)