from collections import Counter
from itertools import chain

from django.shortcuts import get_object_or_404
from django_filters.rest_framework import DjangoFilterBackend
from rest_framework import viewsets, generics, filters
from rest_framework.decorators import action
from rest_framework.permissions import IsAuthenticated, IsAdminUser
from rest_framework.response import Response
from rest_framework.views import APIView

from .models import Project, Label, Document, Seq2seqAnnotation
from .permissions import IsAdminUserAndWriteOnly, IsProjectUser, IsOwnAnnotation
from .serializers import ProjectSerializer, LabelSerializer, DocumentSerializer


class ProjectViewSet(viewsets.ModelViewSet):
    queryset = Project.objects.all()
    serializer_class = ProjectSerializer
    pagination_class = None
    permission_classes = (IsAuthenticated, IsAdminUserAndWriteOnly)

    def get_queryset(self):
        return self.request.user.projects

    @action(methods=['get'], detail=True)
    def progress(self, request, pk=None):
        project = self.get_object()
        return Response(project.get_progress())


class LabelList(generics.ListCreateAPIView):
    queryset = Label.objects.all()
    serializer_class = LabelSerializer
    pagination_class = None
    permission_classes = (IsAuthenticated, IsProjectUser, IsAdminUserAndWriteOnly)

    def get_queryset(self):
        queryset = self.queryset.filter(project=self.kwargs['project_id'])

        return queryset

    def perform_create(self, serializer):
        project = get_object_or_404(Project, pk=self.kwargs['project_id'])
        serializer.save(project=project)


class ProjectStatsAPI(APIView):
    pagination_class = None
    permission_classes = (IsAuthenticated, IsProjectUser, IsAdminUserAndWriteOnly)

    def get(self, request, *args, **kwargs):
        p = get_object_or_404(Project, pk=self.kwargs['project_id'])
        labels = [label.text for label in p.labels.all()]
        users = [user.username for user in p.users.all()]
        docs = [doc for doc in p.documents.all()]
        nested_labels = [[a.label.text for a in doc.get_annotations()] for doc in docs]
        nested_users = [[a.user.username for a in doc.get_annotations()] for doc in docs]

        label_count = Counter(chain(*nested_labels))
        label_data = [label_count[name] for name in labels]

        user_count = Counter(chain(*nested_users))
        user_data = [user_count[name] for name in users]

        response = {'label': {'labels': labels, 'data': label_data},
                    'user': {'users': users, 'data': user_data}}

        return Response(response)


class LabelDetail(generics.RetrieveUpdateDestroyAPIView):
    queryset = Label.objects.all()
    serializer_class = LabelSerializer
    permission_classes = (IsAuthenticated, IsProjectUser, IsAdminUser)

    def get_queryset(self):
        queryset = self.queryset.filter(project=self.kwargs['project_id'])

        return queryset

    def get_object(self):
        queryset = self.filter_queryset(self.get_queryset())
        obj = get_object_or_404(queryset, pk=self.kwargs['label_id'])
        self.check_object_permissions(self.request, obj)

        return obj


class DocumentList(generics.ListCreateAPIView):
    queryset = Document.objects.all()
    serializer_class = DocumentSerializer
    filter_backends = (DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter)
    search_fields = ('text', )
    permission_classes = (IsAuthenticated, IsProjectUser, IsAdminUserAndWriteOnly)

    def get_queryset(self):
        queryset = self.queryset.filter(project=self.kwargs['project_id'])
        if not self.request.query_params.get('is_checked'):
            return queryset

        project = get_object_or_404(Project, pk=self.kwargs['project_id'])
        is_null = self.request.query_params.get('is_checked') == 'true'
        queryset = project.get_documents(is_null).distinct()

        return queryset


class AnnotationList(generics.ListCreateAPIView):
    pagination_class = None
    permission_classes = (IsAuthenticated, IsProjectUser)

    def get_serializer_class(self):
        project = get_object_or_404(Project, pk=self.kwargs['project_id'])
        self.serializer_class = project.get_annotation_serializer()

        return self.serializer_class

    def get_queryset(self):
        project = get_object_or_404(Project, pk=self.kwargs['project_id'])
        document = project.documents.get(id=self.kwargs['doc_id'])
        self.queryset = document.get_annotations()
        self.queryset = self.queryset.filter(user=self.request.user)

        return self.queryset

    def perform_create(self, serializer):
        doc = get_object_or_404(Document, pk=self.kwargs['doc_id'])
        serializer.save(document=doc, user=self.request.user)


class AnnotationDetail(generics.RetrieveUpdateDestroyAPIView):
    permission_classes = (IsAuthenticated, IsProjectUser, IsOwnAnnotation)

    def get_serializer_class(self):
        project = get_object_or_404(Project, pk=self.kwargs['project_id'])
        self.serializer_class = project.get_annotation_serializer()

        return self.serializer_class

    def get_queryset(self):
        document = get_object_or_404(Document, pk=self.kwargs['doc_id'])
        self.queryset = document.get_annotations()

        return self.queryset

    def get_object(self):
        queryset = self.filter_queryset(self.get_queryset())
        obj = get_object_or_404(queryset, pk=self.kwargs['annotation_id'])
        self.check_object_permissions(self.request, obj)

        return obj