import os
from collections import OrderedDict

from django.contrib.auth.models import Group
from django.contrib.auth.models import User
from django.db.models.functions import Lower
from django.http import HttpResponse
from django.views.generic import View
from django_filters.rest_framework import DjangoFilterBackend
from rest_framework.filters import OrderingFilter
from rest_framework.pagination import PageNumberPagination
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from rest_framework.viewsets import ModelViewSet

from documents.permissions import PaperlessObjectPermissions
from paperless.filters import GroupFilterSet
from paperless.filters import UserFilterSet
from paperless.serialisers import GroupSerializer
from paperless.serialisers import UserSerializer


class StandardPagination(PageNumberPagination):
    page_size = 25
    page_size_query_param = "page_size"
    max_page_size = 100000

    def get_paginated_response(self, data):
        return Response(
            OrderedDict(
                [
                    ("count", self.page.paginator.count),
                    ("next", self.get_next_link()),
                    ("previous", self.get_previous_link()),
                    ("all", self.get_all_result_ids()),
                    ("results", data),
                ],
            ),
        )

    def get_all_result_ids(self):
        ids = []
        if hasattr(self.page.paginator.object_list, "saved_results"):
            results_page = self.page.paginator.object_list.saved_results[0]
            if results_page is not None:
                for i in range(0, len(results_page.results.docs())):
                    try:
                        fields = results_page.results.fields(i)
                        if "id" in fields:
                            ids.append(fields["id"])
                    except Exception:
                        pass
        else:
            for obj in self.page.paginator.object_list:
                if hasattr(obj, "id"):
                    ids.append(obj.id)
                elif hasattr(obj, "fields"):
                    ids.append(obj.fields()["id"])
        return ids

    def get_paginated_response_schema(self, schema):
        response_schema = super().get_paginated_response_schema(schema)
        response_schema["properties"]["all"] = {
            "type": "array",
            "example": "[1, 2, 3]",
        }
        return response_schema


class FaviconView(View):
    def get(self, request, *args, **kwargs):  # pragma: nocover
        favicon = os.path.join(
            os.path.dirname(__file__),
            "static",
            "paperless",
            "img",
            "favicon.ico",
        )
        with open(favicon, "rb") as f:
            return HttpResponse(f, content_type="image/x-icon")


class UserViewSet(ModelViewSet):
    model = User

    queryset = User.objects.exclude(
        username__in=["consumer", "AnonymousUser"],
    ).order_by(Lower("username"))

    serializer_class = UserSerializer
    pagination_class = StandardPagination
    permission_classes = (IsAuthenticated, PaperlessObjectPermissions)
    filter_backends = (DjangoFilterBackend, OrderingFilter)
    filterset_class = UserFilterSet
    ordering_fields = ("username",)


class GroupViewSet(ModelViewSet):
    model = Group

    queryset = Group.objects.order_by(Lower("name"))

    serializer_class = GroupSerializer
    pagination_class = StandardPagination
    permission_classes = (IsAuthenticated, PaperlessObjectPermissions)
    filter_backends = (DjangoFilterBackend, OrderingFilter)
    filterset_class = GroupFilterSet
    ordering_fields = ("name",)