from __future__ import absolute_import, unicode_literals

from django.shortcuts import get_object_or_404

from rest_framework import generics, status
from rest_framework.response import Response

from documents.models import Document, DocumentPage, DocumentVersion
from rest_api.permissions import MayanPermission

from .models import DocumentPageOCRContent
from .permissions import permission_ocr_content_view, permission_ocr_document
from .serializers import DocumentPageOCRContentSerializer


class APIDocumentOCRView(generics.GenericAPIView):
    mayan_object_permissions = {
        'POST': (permission_ocr_document,)
    }
    permission_classes = (MayanPermission,)
    queryset = Document.objects.all()

    def get_serializer_class(self):
        return None

    def post(self, request, *args, **kwargs):
        """
        Submit a document for OCR.
        ---
        omit_serializer: true
        responseMessages:
            - code: 202
              message: Accepted
        """

        self.get_object().submit_for_ocr()
        return Response(status=status.HTTP_202_ACCEPTED)


class APIDocumentVersionOCRView(generics.GenericAPIView):
    lookup_url_kwarg = 'version_pk'
    mayan_object_permissions = {
        'POST': (permission_ocr_document,)
    }
    permission_classes = (MayanPermission,)
    queryset = DocumentVersion.objects.all()

    def get_document(self):
        return get_object_or_404(Document, pk=self.kwargs['document_pk'])

    def get_queryset(self):
        return self.get_document().versions.all()

    def get_serializer_class(self):
        return None

    def post(self, request, *args, **kwargs):
        """
        Submit a document version for OCR.
        ---
        omit_serializer: true
        responseMessages:
            - code: 202
              message: Accepted
        """

        self.get_object().submit_for_ocr()
        return Response(status=status.HTTP_202_ACCEPTED)


class APIDocumentPageOCRContentView(generics.RetrieveAPIView):
    """
    Returns the OCR content of the selected document page.
    """
    lookup_url_kwarg = 'page_pk'
    mayan_object_permissions = {
        'GET': (permission_ocr_content_view,),
    }
    permission_classes = (MayanPermission,)
    serializer_class = DocumentPageOCRContentSerializer

    def get_document(self):
        return get_object_or_404(Document, pk=self.kwargs['document_pk'])

    def get_document_version(self):
        return get_object_or_404(
            self.get_document().versions.all(), pk=self.kwargs['version_pk']
        )

    def get_queryset(self):
        return self.get_document_version().pages.all()

    def retrieve(self, request, *args, **kwargs):
        instance = self.get_object()

        try:
            ocr_content = instance.ocr_content
        except DocumentPageOCRContent.DoesNotExist:
            ocr_content = DocumentPageOCRContent.objects.none()

        serializer = self.get_serializer(ocr_content)
        return Response(serializer.data)