import datetime

import logging

from auditlog.models import LogEntry

from django.utils import timezone

from notes.models import Note, Session

from rest_framework import permissions

from rest_framework.response import Response

from rest_framework.views import APIView

logger = logging.getLogger(__name__)

class ListLogsView(APIView):

    """

    View to list tle log of changes on Note and Sessions.

    * Only registered users are able to access this view.

    * the results are filtered by connected user

    """

    permission_classes = (permissions.IsAuthenticated,)

    def __filter_object(self, model, user, modified_since, client_id):

        """

        Log entries are filtered by model, actor and timestamp.

        If a client id is given, log entries from this client are ignored.

        """

        log_entries = LogEntry.objects.get_for_model(model).filter(actor=user)

        if modified_since:

            log_entries = log_entries.filter(timestamp__gte=modified_since)

        if client_id:

            log_entries = log_entries.exclude(client=client_id)

        return log_entries.order_by('timestamp')

    def __process_log_entries(self, model, user, modified_since, client_id):

        '''

        Process log entries

        '''

        log_entries = self.__filter_object(model, user, modified_since, client_id)

        res = {}

        for log_entry in log_entries:

            ext_id = log_entry.additional_data.get('ext_id')

            if not ext_id:

                continue

            sync_entry = res.get(ext_id, {})

            new_action = {

                (None                  , LogEntry.Action.CREATE): LogEntry.Action.CREATE,

                (LogEntry.Action.CREATE, LogEntry.Action.CREATE): LogEntry.Action.CREATE,

                (LogEntry.Action.UPDATE, LogEntry.Action.CREATE): LogEntry.Action.UPDATE,

                (LogEntry.Action.DELETE, LogEntry.Action.CREATE): LogEntry.Action.UPDATE,

                (None                  , LogEntry.Action.UPDATE): LogEntry.Action.UPDATE,

                (LogEntry.Action.CREATE, LogEntry.Action.UPDATE): LogEntry.Action.CREATE,

                (LogEntry.Action.UPDATE, LogEntry.Action.UPDATE): LogEntry.Action.UPDATE,

                (LogEntry.Action.DELETE, LogEntry.Action.UPDATE): LogEntry.Action.DELETE,

                (None                  , LogEntry.Action.DELETE): LogEntry.Action.DELETE,

                (LogEntry.Action.CREATE, LogEntry.Action.DELETE): None,

                (LogEntry.Action.UPDATE, LogEntry.Action.DELETE): LogEntry.Action.DELETE,

                (LogEntry.Action.DELETE, LogEntry.Action.DELETE): LogEntry.Action.DELETE,

            } [(sync_entry.get('action'), log_entry.action)]

            if new_action is None:

                del res[ext_id]

            else:

                res[ext_id] = {

                    'type': log_entry.content_type.model,

                    'ext_id': ext_id,

                    'action': new_action,

                    'timestamp': log_entry.timestamp

                }

        return res

    def get(self, request, format=None):

        """

        Return an aggregations of all changes.

        """

        modified_since_str = request.query_params.get('modified_since', None)

        modified_since = None

        if modified_since_str is not None:

            modified_since = datetime.datetime.fromtimestamp(

                float(modified_since_str),

                timezone.utc

            )

        user = request.user

        client_id = request.META.get('HTTP_AUDITLOG_CLIENT', None)

        res_sessions = self.__process_log_entries(Session, user, modified_since, client_id)

        res_notes = self.__process_log_entries(Note, user, modified_since, client_id)

        return Response({

            'sessions': res_sessions.values(),

            'notes': res_notes.values()

        })