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, DocumentAnnotation, SequenceAnnotation, Seq2seqAnnotation
from .permissions import IsAdminUserAndWriteOnly, IsProjectUser, IsOwnAnnotation
from .serializers import ProjectSerializer, LabelSerializer


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

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

        return queryset

    def perform_create(self, serializer):
        project_id = self.kwargs['project_id']
        project = get_object_or_404(Project, pk=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 ProjectLabelAPI(generics.RetrieveUpdateDestroyAPIView):
    queryset = Label.objects.all()
    serializer_class = LabelSerializer
    permission_classes = (IsAuthenticated, IsProjectUser, IsAdminUser)

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

        return queryset

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

        return obj


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

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

        return self.serializer_class

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

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

        return queryset


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

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

        return self.serializer_class

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

        return self.queryset

    def post(self, request, *args, **kwargs):
        doc = get_object_or_404(Document, pk=self.kwargs['doc_id'])
        project = get_object_or_404(Project, pk=self.kwargs['project_id'])
        self.serializer_class = project.get_annotation_serializer()
        if project.is_type_of(Project.DOCUMENT_CLASSIFICATION):
            label = get_object_or_404(Label, pk=request.data['label_id'])
            annotation = DocumentAnnotation(document=doc, label=label, manual=True,
                                            user=self.request.user)
        elif project.is_type_of(Project.SEQUENCE_LABELING):
            label = get_object_or_404(Label, pk=request.data['label_id'])
            annotation = SequenceAnnotation(document=doc, label=label, manual=True,
                                            user=self.request.user,
                                            start_offset=request.data['start_offset'],
                                            end_offset=request.data['end_offset'])
        elif project.is_type_of(Project.Seq2seq):
            text = request.data['text']
            annotation = Seq2seqAnnotation(document=doc,
                                           text=text,
                                           manual=True,
                                           user=self.request.user)
        annotation.save()
        serializer = self.serializer_class(annotation)

        return Response(serializer.data)


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

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

        return self.queryset

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

        return obj

    def put(self, request, *args, **kwargs):
        doc = get_object_or_404(Document, pk=self.kwargs['doc_id'])
        project = get_object_or_404(Project, pk=self.kwargs['project_id'])
        self.serializer_class = project.get_annotation_serializer()
        if project.is_type_of(Project.Seq2seq):
            text = request.data['text']
            annotation = get_object_or_404(Seq2seqAnnotation, pk=request.data['id'])
            annotation.text = text

        annotation.save()
        serializer = self.serializer_class(annotation)

        return Response(serializer.data)