from __future__ import absolute_import, unicode_literals

import logging

from django.http import HttpResponse
from django.shortcuts import get_object_or_404

from django_downloadview import DownloadMixin, VirtualFile
from rest_framework import generics, status
from rest_framework.response import Response

from acls.models import AccessControlList
from rest_api.filters import MayanObjectPermissionsFilter
from rest_api.permissions import MayanPermission

from .literals import DOCUMENT_IMAGE_TASK_TIMEOUT
from .models import (
    Document, DocumentType, RecentDocument
)
from .permissions import (
    permission_document_create, permission_document_delete,
    permission_document_download, permission_document_edit,
    permission_document_new_version, permission_document_properties_edit,
    permission_document_restore, permission_document_trash,
    permission_document_view, permission_document_type_create,
    permission_document_type_delete, permission_document_type_edit,
    permission_document_type_view, permission_document_version_revert,
    permission_document_version_view
)
from .runtime import cache_storage_backend
from .serializers import (
    DeletedDocumentSerializer, DocumentPageSerializer, DocumentSerializer,
    DocumentTypeSerializer, DocumentVersionSerializer,
    NewDocumentSerializer, NewDocumentVersionSerializer,
    RecentDocumentSerializer, WritableDocumentSerializer,
    WritableDocumentTypeSerializer, WritableDocumentVersionSerializer
)
from .tasks import task_generate_document_page_image

logger = logging.getLogger(__name__)


class APIDeletedDocumentListView(generics.ListAPIView):
    """
    Returns a list of all the trashed documents.
    """

    filter_backends = (MayanObjectPermissionsFilter,)
    mayan_object_permissions = {'GET': (permission_document_view,)}
    permission_classes = (MayanPermission,)
    queryset = Document.trash.all()
    serializer_class = DeletedDocumentSerializer


class APIDeletedDocumentView(generics.RetrieveDestroyAPIView):
    """
    Returns the selected trashed document details.
    """

    mayan_object_permissions = {
        'DELETE': (permission_document_delete,),
        'GET': (permission_document_view,)
    }
    permission_classes = (MayanPermission,)
    queryset = Document.trash.all()
    serializer_class = DeletedDocumentSerializer

    def delete(self, *args, **kwargs):
        """
        Delete the trashed document.
        """

        return super(APIDeletedDocumentView, self).delete(*args, **kwargs)

    def get(self, *args, **kwargs):
        """
        Retreive the details of the trashed document.
        """

        return super(APIDeletedDocumentView, self).get(*args, **kwargs)


class APIDeletedDocumentRestoreView(generics.GenericAPIView):
    """
    Restore a trashed document.
    ---
    POST:
        omit_serializer: true
    """

    mayan_object_permissions = {
        'POST': (permission_document_restore,)
    }
    permission_classes = (MayanPermission,)
    queryset = Document.trash.all()

    def get_serializer(self, *args, **kwargs):
        return None

    def get_serializer_class(self):
        return None

    def post(self, *args, **kwargs):
        self.get_object().restore()
        return Response(status=status.HTTP_200_OK)


class APIDocumentDownloadView(DownloadMixin, generics.RetrieveAPIView):
    """
    Download the latest version of a document.
    ---
    GET:
        omit_serializer: true
        parameters:
            - name: pk
              paramType: path
              type: number
    """

    mayan_object_permissions = {
        'GET': (permission_document_download,)
    }
    permission_classes = (MayanPermission,)
    queryset = Document.objects.all()

    def get_encoding(self):
        return self.get_object().latest_version.encoding

    def get_file(self):
        instance = self.get_object()
        return VirtualFile(instance.latest_version.file, name=instance.label)

    def get_mimetype(self):
        return self.get_object().latest_version.mimetype

    def get_serializer(self, *args, **kwargs):
        return None

    def get_serializer_class(self):
        return None

    def retrieve(self, request, *args, **kwargs):
        return self.render_to_response()


class APIDocumentListView(generics.ListCreateAPIView):
    filter_backends = (MayanObjectPermissionsFilter,)
    mayan_object_permissions = {'GET': (permission_document_view,)}
    permission_classes = (MayanPermission,)
    queryset = Document.objects.all()

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

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

    def perform_create(self, serializer):
        AccessControlList.objects.check_access(
            permissions=(permission_document_create,), user=self.request.user,
            obj=serializer.validated_data['document_type']
        )
        serializer.save(_user=self.request.user)

    def post(self, *args, **kwargs):
        """
        Create a new document.
        Endpoint returns a 202 status code to indicate that a document is not
        immediately created at request. From the request data, the creation of
        a document is instead queued as a background task. An ID that
        represents the eventual document is returned.
        ---
        omit_serializer: false
        parameters:
            - name: description
              paramType: form
              type: file string
            - name: document_type
              paramType: form
              required: true
              type: file string
            - name: file
              paramType: form
              required: true
              type: file object
            - name: label
              paramType: form
              type: file string
            - name: language
              paramType: form
              type: file string
        responseMessages:
            - code: 202
              message: Accepted
        """
        return super(APIDocumentListView, self).post(*args, **kwargs)


class APIDocumentVersionDownloadView(DownloadMixin, generics.RetrieveAPIView):
    """
    Download a document version.
    ---
    GET:
        omit_serializer: true
        parameters:
            - name: pk
              paramType: path
              type: number
            - name: preserve_extension
              paramType: query
              type: boolean
    """
    lookup_url_kwarg = 'version_pk'

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

        AccessControlList.objects.check_access(
            permissions=(permission_document_download,), user=self.request.user,
            obj=document
        )
        return document

    def get_encoding(self):
        return self.get_object().encoding

    def get_file(self):
        preserve_extension = self.request.GET.get(
            'preserve_extension', self.request.POST.get(
                'preserve_extension', False
            )
        )

        preserve_extension = preserve_extension == 'true' or preserve_extension == 'True'

        instance = self.get_object()
        return VirtualFile(
            instance.file, name=instance.get_rendered_string(
                preserve_extension=preserve_extension
            )
        )

    def get_mimetype(self):
        return self.get_object().mimetype

    def get_serializer(self, *args, **kwargs):
        return None

    def get_serializer_class(self):
        return None

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

    def retrieve(self, request, *args, **kwargs):
        return self.render_to_response()


class APIDocumentView(generics.RetrieveUpdateDestroyAPIView):
    """
    Returns the selected document details.
    """

    mayan_object_permissions = {
        'GET': (permission_document_view,),
        'PUT': (permission_document_properties_edit,),
        'PATCH': (permission_document_properties_edit,),
        'DELETE': (permission_document_trash,)
    }
    permission_classes = (MayanPermission,)
    queryset = Document.objects.all()

    def delete(self, *args, **kwargs):
        """
        Move the selected document to the thrash.
        """

        return super(APIDocumentView, self).delete(*args, **kwargs)

    def get(self, *args, **kwargs):
        """
        Return the details of the selected document.
        """

        return super(APIDocumentView, self).get(*args, **kwargs)

    def get_serializer_context(self):
        return {
            'format': self.format_kwarg,
            'request': self.request,
            'view': self
        }

    def get_serializer_class(self):
        if self.request.method == 'GET':
            return DocumentSerializer
        else:
            return WritableDocumentSerializer

    def patch(self, *args, **kwargs):
        """
        Edit the properties of the selected document.
        """

        return super(APIDocumentView, self).patch(*args, **kwargs)

    def put(self, *args, **kwargs):
        """
        Edit the properties of the selected document.
        """

        return super(APIDocumentView, self).put(*args, **kwargs)


class APIDocumentPageImageView(generics.RetrieveAPIView):
    """
    Returns an image representation of the selected document.
    ---
    GET:
        omit_serializer: true
        parameters:
            - name: size
              description: 'x' seprated width and height of the desired image representation.
              paramType: query
              type: number
            - name: zoom
              description: Zoom level of the image to be generated, numeric value only.
              paramType: query
              type: number
    """

    lookup_url_kwarg = 'page_pk'

    def get_document(self):
        if self.request.method == 'GET':
            permission_required = permission_document_view
        else:
            permission_required = permission_document_edit

        document = get_object_or_404(Document, pk=self.kwargs['pk'])

        AccessControlList.objects.check_access(
            permission_required, self.request.user, document
        )
        return document

    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 get_serializer(self, *args, **kwargs):
        return None

    def get_serializer_class(self):
        return None

    def retrieve(self, request, *args, **kwargs):
        size = request.GET.get('size')
        zoom = request.GET.get('zoom')

        if zoom:
            zoom = int(zoom)

        rotation = request.GET.get('rotation')

        if rotation:
            rotation = int(rotation)

        task = task_generate_document_page_image.apply_async(
            kwargs=dict(
                document_page_id=self.kwargs['page_pk'], size=size, zoom=zoom,
                rotation=rotation
            )
        )

        cache_filename = task.get(timeout=DOCUMENT_IMAGE_TASK_TIMEOUT)
        with cache_storage_backend.open(cache_filename) as file_object:
            return HttpResponse(file_object.read(), content_type='image')


class APIDocumentPageView(generics.RetrieveUpdateAPIView):
    """
    Returns the selected document page details.
    """

    lookup_url_kwarg = 'page_pk'
    serializer_class = DocumentPageSerializer

    def get(self, *args, **kwargs):
        """
        Returns the selected document page details.
        """

        return super(APIDocumentPageView, self).get(*args, **kwargs)

    def get_document(self):
        if self.request.method == 'GET':
            permission_required = permission_document_view
        else:
            permission_required = permission_document_edit

        document = get_object_or_404(Document, pk=self.kwargs['pk'])

        AccessControlList.objects.check_access(
            permission_required, self.request.user, document
        )
        return document

    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 patch(self, *args, **kwargs):
        """
        Edit the selected document page.
        """

        return super(APIDocumentPageView, self).patch(*args, **kwargs)

    def put(self, *args, **kwargs):
        """
        Edit the selected document page.
        """

        return super(APIDocumentPageView, self).put(*args, **kwargs)


class APIDocumentTypeListView(generics.ListCreateAPIView):
    filter_backends = (MayanObjectPermissionsFilter,)
    mayan_object_permissions = {'GET': (permission_document_type_view,)}
    mayan_view_permissions = {'POST': (permission_document_type_create,)}
    permission_classes = (MayanPermission,)
    queryset = DocumentType.objects.all()
    serializer_class = DocumentTypeSerializer

    def get(self, *args, **kwargs):
        """
        Returns a list of all the document types.
        """

        return super(APIDocumentTypeListView, self).get(*args, **kwargs)

    def get_serializer_class(self):
        if self.request.method == 'GET':
            return DocumentTypeSerializer
        else:
            return WritableDocumentTypeSerializer

    def post(self, *args, **kwargs):
        """
        Create a new document type.
        """

        return super(APIDocumentTypeListView, self).post(*args, **kwargs)


class APIDocumentTypeView(generics.RetrieveUpdateDestroyAPIView):
    """
    Returns the selected document type details.
    """

    mayan_object_permissions = {
        'GET': (permission_document_type_view,),
        'PUT': (permission_document_type_edit,),
        'PATCH': (permission_document_type_edit,),
        'DELETE': (permission_document_type_delete,)
    }
    permission_classes = (MayanPermission,)
    queryset = DocumentType.objects.all()

    def delete(self, *args, **kwargs):
        """
        Delete the selected document type.
        """

        return super(APIDocumentTypeView, self).delete(*args, **kwargs)

    def get(self, *args, **kwargs):
        """
        Return the details of the selected document type.
        """

        return super(APIDocumentTypeView, self).get(*args, **kwargs)

    def get_serializer_class(self):
        if self.request.method == 'GET':
            return DocumentTypeSerializer
        else:
            return WritableDocumentTypeSerializer

    def patch(self, *args, **kwargs):
        """
        Edit the properties of the selected document type.
        """

        return super(APIDocumentTypeView, self).patch(*args, **kwargs)

    def put(self, *args, **kwargs):
        """
        Edit the properties of the selected document type.
        """

        return super(APIDocumentTypeView, self).put(*args, **kwargs)


class APIDocumentTypeDocumentListView(generics.ListAPIView):
    """
    Returns a list of all the documents of a particular document type.
    """

    filter_backends = (MayanObjectPermissionsFilter,)
    mayan_object_permissions = {'GET': (permission_document_view,)}
    serializer_class = DocumentSerializer

    def get_queryset(self):
        document_type = get_object_or_404(DocumentType, pk=self.kwargs['pk'])
        AccessControlList.objects.check_access(
            permissions=permission_document_type_view, user=self.request.user,
            obj=document_type
        )

        return document_type.documents.all()


class APIRecentDocumentListView(generics.ListAPIView):
    serializer_class = RecentDocumentSerializer

    def get_queryset(self):
        return RecentDocument.objects.filter(user=self.request.user)

    def get(self, *args, **kwargs):
        """
        Return a list of the recent documents for the current user.
        """

        return super(APIRecentDocumentListView, self).get(*args, **kwargs)


class APIDocumentVersionPageListView(generics.ListAPIView):
    serializer_class = DocumentPageSerializer

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

        AccessControlList.objects.check_access(
            permission_document_view, self.request.user, document
        )
        return document

    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 get_serializer_context(self):
        return {
            'format': self.format_kwarg,
            'request': self.request,
            'view': self
        }


class APIDocumentVersionsListView(generics.ListCreateAPIView):
    """
    Return a list of the selected document's versions.
    """

    filter_backends = (MayanObjectPermissionsFilter,)
    mayan_object_permissions = {
        'GET': (permission_document_version_view,),
    }
    mayan_permission_attribute_check = 'document'
    permission_classes = (MayanPermission,)

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        self.perform_create(serializer)
        headers = self.get_success_headers(serializer.data)
        return Response(status=status.HTTP_202_ACCEPTED, headers=headers)

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

    def get_queryset(self):
        return get_object_or_404(Document, pk=self.kwargs['pk']).versions.all()

    def perform_create(self, serializer):
        document = get_object_or_404(Document, pk=self.kwargs['pk'])

        AccessControlList.objects.check_access(
            permissions=(permission_document_new_version,),
            user=self.request.user, obj=document
        )
        serializer.save(document=document, _user=self.request.user)

    def post(self, request, *args, **kwargs):
        """
        Create a new document version.
        """

        return super(
            APIDocumentVersionsListView, self
        ).post(request, *args, **kwargs)


class APIDocumentVersionView(generics.RetrieveUpdateDestroyAPIView):
    """
    Returns the selected document version details.
    """

    lookup_url_kwarg = 'version_pk'

    def delete(self, *args, **kwargs):
        """
        Delete the selected document version.
        """

        return super(APIDocumentVersionView, self).delete(*args, **kwargs)

    def get_document(self):
        if self.request.method == 'GET':
            permission_required = permission_document_view
        elif self.request.method == 'DELETE':
            permission_required = permission_document_version_revert
        else:
            permission_required = permission_document_edit

        document = get_object_or_404(Document, pk=self.kwargs['pk'])

        AccessControlList.objects.check_access(
            permission_required, self.request.user, document
        )
        return document

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

    def get_serializer_class(self):
        if self.request.method == 'GET':
            return DocumentVersionSerializer
        else:
            return WritableDocumentVersionSerializer

    def get_serializer_context(self):
        return {
            'format': self.format_kwarg,
            'request': self.request,
            'view': self
        }

    def patch(self, *args, **kwargs):
        """
        Edit the selected document version.
        """

        return super(APIDocumentVersionView, self).patch(*args, **kwargs)

    def put(self, *args, **kwargs):
        """
        Edit the selected document version.
        """

        return super(APIDocumentVersionView, self).put(*args, **kwargs)