from __future__ import absolute_import, unicode_literals

from django.core.exceptions import PermissionDenied
from django.shortcuts import get_object_or_404

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

from acls.models import AccessControlList
from documents.models import Document, DocumentType
from documents.permissions import (
    permission_document_type_view, permission_document_type_edit
)
from permissions import Permission
from rest_api.filters import MayanObjectPermissionsFilter
from rest_api.permissions import MayanPermission

from .models import DocumentMetadata, MetadataType
from .permissions import (
    permission_metadata_document_add, permission_metadata_document_remove,
    permission_metadata_document_edit, permission_metadata_document_view,
    permission_metadata_type_create, permission_metadata_type_delete,
    permission_metadata_type_edit, permission_metadata_type_view
)
from .serializers import (
    DocumentMetadataSerializer, DocumentTypeNewMetadataTypeSerializer,
    MetadataTypeSerializer, DocumentTypeMetadataTypeSerializer
)


class APIMetadataTypeListView(generics.ListCreateAPIView):
    serializer_class = MetadataTypeSerializer
    queryset = MetadataType.objects.all()

    permission_classes = (MayanPermission,)
    filter_backends = (MayanObjectPermissionsFilter,)
    mayan_object_permissions = {'GET': (permission_metadata_type_view,)}
    mayan_view_permissions = {'POST': (permission_metadata_type_create,)}

    def get(self, *args, **kwargs):
        """
        Returns a list of all the metadata types.
        """
        return super(APIMetadataTypeListView, self).get(*args, **kwargs)

    def post(self, *args, **kwargs):
        """
        Create a new metadata type.
        """
        return super(APIMetadataTypeListView, self).post(*args, **kwargs)


class APIMetadataTypeView(generics.RetrieveUpdateDestroyAPIView):
    serializer_class = MetadataTypeSerializer
    queryset = MetadataType.objects.all()

    permission_classes = (MayanPermission,)
    mayan_object_permissions = {
        'GET': (permission_metadata_type_view,),
        'PUT': (permission_metadata_type_edit,),
        'PATCH': (permission_metadata_type_edit,),
        'DELETE': (permission_metadata_type_delete,)
    }

    def delete(self, *args, **kwargs):
        """
        Delete the selected metadata type.
        """
        return super(APIMetadataTypeView, self).delete(*args, **kwargs)

    def get(self, *args, **kwargs):
        """
        Return the details of the selected metadata type.
        """
        return super(APIMetadataTypeView, self).get(*args, **kwargs)

    def patch(self, *args, **kwargs):
        """
        Edit the selected metadata type.
        """
        return super(APIMetadataTypeView, self).patch(*args, **kwargs)

    def put(self, *args, **kwargs):
        """
        Edit the selected metadata type.
        """
        return super(APIMetadataTypeView, self).put(*args, **kwargs)


class APIDocumentMetadataListView(generics.ListCreateAPIView):
    permission_classes = (MayanPermission,)
    serializer_class = DocumentMetadataSerializer

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

    def get_queryset(self):
        document = self.get_document()

        if self.request == 'GET':
            # Make sure the use has the permission to see the metadata for
            # this document
            try:
                Permission.check_permissions(
                    self.request.user, (permission_metadata_document_view,)
                )
            except PermissionDenied:
                AccessControlList.objects.check_access(
                    permission_metadata_document_view, self.request.user,
                    document
                )
            else:
                return document.metadata.all()
        elif self.request == 'POST':
            # Make sure the use has the permission to add metadata to this
            # document
            try:
                Permission.check_permissions(
                    self.request.user, (permission_metadata_document_add,)
                )
            except PermissionDenied:
                AccessControlList.objects.check_access(
                    permission_metadata_document_add, self.request.user,
                    document
                )
            else:
                return document.metadata.all()

    def pre_save(self, serializer):
        serializer.document = self.get_document()

    def get(self, *args, **kwargs):
        """
        Returns a list of selected document's metadata types and values.
        """
        return super(APIDocumentMetadataListView, self).get(*args, **kwargs)

    def post(self, *args, **kwargs):
        """
        Add an existing metadata type and value to the selected document.
        """
        return super(APIDocumentMetadataListView, self).post(*args, **kwargs)


class APIDocumentMetadataView(generics.RetrieveUpdateDestroyAPIView):
    serializer_class = DocumentMetadataSerializer
    queryset = DocumentMetadata.objects.all()

    permission_classes = (MayanPermission,)
    mayan_object_permissions = {
        'GET': (permission_metadata_document_view,),
        'PUT': (permission_metadata_document_edit,),
        'PATCH': (permission_metadata_document_edit,),
        'DELETE': (permission_metadata_document_remove,)
    }

    def delete(self, *args, **kwargs):
        """
        Delete the selected document metadata type and value.
        """
        try:
            return super(
                APIDocumentMetadataView, self
            ).delete(*args, **kwargs)
        except Exception as exception:
            return Response(
                status=status.HTTP_400_BAD_REQUEST, data={
                    'non_fields_errors': unicode(exception)
                }
            )

    def get(self, *args, **kwargs):
        """
        Return the details of the selected document metadata type and value.
        """
        return super(APIDocumentMetadataView, self).get(*args, **kwargs)

    def patch(self, *args, **kwargs):
        """
        Edit the selected document metadata type and value.
        """
        try:
            return super(
                APIDocumentMetadataView, self
            ).patch(*args, **kwargs)
        except Exception as exception:
            return Response(
                status=status.HTTP_400_BAD_REQUEST, data={
                    'non_fields_errors': unicode(exception)
                }
            )

    def put(self, *args, **kwargs):
        """
        Edit the selected document metadata type and value.
        """
        try:
            return super(APIDocumentMetadataView, self).put(*args, **kwargs)
        except Exception as exception:
            return Response(
                status=status.HTTP_400_BAD_REQUEST, data={
                    'non_fields_errors': unicode(exception)
                }
            )


class APIDocumentTypeMetadataTypeOptionalListView(generics.ListCreateAPIView):
    permission_classes = (MayanPermission,)

    mayan_view_permissions = {'POST': (permission_document_type_edit,)}

    required_metadata = False

    def get_queryset(self):
        document_type = get_object_or_404(
            DocumentType, pk=self.kwargs['document_type_pk']
        )
        try:
            Permission.check_permissions(
                self.request.user, (permission_document_type_view,)
            )
        except PermissionDenied:
            AccessControlList.objects.check_access(
                permission_document_type_view, self.request.user,
                document_type
            )

        return document_type.metadata.filter(required=self.required_metadata)

    def get(self, *args, **kwargs):
        """
        Returns a list of selected document type's optional metadata types.
        """
        return super(
            APIDocumentTypeMetadataTypeOptionalListView, self
        ).get(*args, **kwargs)

    def get_serializer_class(self):
        if self.request.method == 'GET':
            return DocumentTypeMetadataTypeSerializer
        elif self.request.method == 'POST':
            return DocumentTypeNewMetadataTypeSerializer

    def post(self, request, *args, **kwargs):
        """
        Add an optional metadata type to a document type.
        """
        document_type = get_object_or_404(
            DocumentType, pk=self.kwargs['document_type_pk']
        )

        try:
            Permission.check_permissions(
                self.request.user, (permission_document_type_edit,)
            )
        except PermissionDenied:
            AccessControlList.objects.check_access(
                permission_document_type_edit, self.request.user,
                document_type
            )

        serializer = self.get_serializer(data=self.request.POST)

        if serializer.is_valid():
            metadata_type = get_object_or_404(
                MetadataType, pk=serializer.data['metadata_type_pk']
            )
            document_type.metadata_type.add(
                metadata_type, required=self.required_metadata
            )
            return Response(status=status.HTTP_201_CREATED)
        else:
            return Response(status=status.HTTP_400_BAD_REQUEST)


class APIDocumentTypeMetadataTypeRequiredListView(APIDocumentTypeMetadataTypeOptionalListView):
    required_metadata = True

    def get(self, *args, **kwargs):
        """
        Returns a list of the selected document type's required metadata
        types.
        """
        return super(
            APIDocumentTypeMetadataTypeRequiredListView, self
        ).get(*args, **kwargs)

    def post(self, request, *args, **kwargs):
        """
        Add a required metadata type to a document type.
        """
        return super(
            APIDocumentTypeMetadataTypeRequiredListView, self
        ).get(*args, **kwargs)


class APIDocumentTypeMetadataTypeRequiredView(views.APIView):
    def delete(self, request, *args, **kwargs):
        """
        Remove a metadata type from a document type.
        """

        document_type = get_object_or_404(
            DocumentType, pk=self.kwargs['document_type_pk']
        )
        try:
            Permission.check_permissions(
                self.request.user, (permission_document_type_edit,)
            )
        except PermissionDenied:
            AccessControlList.objects.check_access(
                permission_document_type_edit, self.request.user,
                document_type
            )

        metadata_type = get_object_or_404(
            MetadataType, pk=self.kwargs['metadata_type_pk']
        )
        document_type.metadata_type.remove(metadata_type)
        return Response(status=status.HTTP_204_NO_CONTENT)