import logging

from rest_framework import permissions, exceptions

logger = logging.getLogger(__name__)


class DenyAllPermission(permissions.BasePermission):

    def has_permission(self, request, view):
        return False

    def has_object_permission(self, request, view, obj):
        return False


class MethodPermission(permissions.BasePermission):

    def has_permission(self, request, view):
        if not hasattr(view, 'perms_map'):
            raise Exception('{} do not have perms_map attribute'.format(view.__class__))

        try:
            perms = view.perms_map[request.method.upper()]
        except KeyError:
            raise exceptions.MethodNotAllowed(request.method)

        return request.user.has_perms(perms)


class AskTUGModeratorOrStaffWithMethodPermission(permissions.BasePermission):

    def has_permission(self, request, view):
        if not hasattr(view, 'perms_map'):
            raise Exception('{} do not have perms_map attribute'.format(view.__class__))

        request.user.is_asktug_moderator = False
        request.user.is_staff_with_permission = False

        try:
            perms = view.perms_map[request.method.upper()]
        except KeyError:
            raise exceptions.MethodNotAllowed(request.method)

        if not (request.user and request.user.is_authenticated):
            return False

        if request.user.is_staff:
            request.user.is_staff_with_permission = request.user.has_perms(perms)

        asktug_user = request.user.get_asktug_user(log_error_if_not_exists=False)
        if asktug_user and asktug_user.moderator:
            request.user.is_asktug_moderator = True

        return request.user.is_asktug_moderator or request.user.is_staff_with_permission