import logging

import uuid

from django.db.models.signals import pre_delete, post_save

from django.utils.functional import curry

from renkanmanager.models import Renkan, Revision

from . import send_delete_renkan, send_create_renkan, send_update_renkan

logger = logging.getLogger(__name__)

class TrackingMiddleware(object):

    def process_request(self, request):

        if not request.method in ('GET', 'HEAD', 'OPTIONS', 'TRACE'):

            if hasattr(request, 'user') and request.user.is_authenticated():

                user = request.user.external_id

            else:

                user = None

            request.renkan_request_id = uuid.uuid4()

            pre_delete.connect(curry(self.renkan_delete, user), sender=Renkan, dispatch_uid = (self.__class__,  request.renkan_request_id,), weak=False)

            post_save.connect(curry(self.revision_save, user), sender=Revision, dispatch_uid = (self.__class__,  request.renkan_request_id,), weak=False)

    def process_response(self, request, response):

        if hasattr(request, 'renkan_request_id'):

            pre_delete.disconnect(dispatch_uid =  (self.__class__,  request.renkan_request_id,))

            post_save.disconnect(dispatch_uid =  (self.__class__,  request.renkan_request_id,))

        return response

    def process_exception(self, request, exception):

        if hasattr(request, 'renkan_request_id'):

            pre_delete.disconnect(dispatch_uid =  (self.__class__,  request.renkan_request_id,))

            post_save.disconnect(dispatch_uid =  (self.__class__,  request.renkan_request_id,))

        return None

    def process_view(self, request, view_func, view_args, view_kwargs):

        if view_func.__name__ == 'RenkanDetail' and view_func.__module__ == 'renkanmanager.api.views' and request.method == 'PUT' and 'renkan_guid' in view_kwargs:

            if hasattr(request, 'user') and request.user.is_authenticated():

                user = request.user.external_id

            else:

                user = None

            send_update_renkan(None, user, request.body.decode('utf-8'))

        return None

    def renkan_delete(self, user, sender, **kwargs):

        renkan = kwargs.get('instance', None)

        if not renkan:

            return

        send_delete_renkan(renkan, user)

    def revision_save(self, user, sender, **kwargs):

        revision = kwargs.get('instance', None)

        if not revision:

            return

        if kwargs.get('created', False) and revision.parent_renkan.revision_count <= 1:

            send_create_renkan(revision.parent_renkan, user)