from django.http import HttpResponseForbidden, HttpResponseNotFound
from django.http.request import QueryDict
from django.views.static import serve

from openslides.core.models import Projector

from ..utils.auth import has_perm, in_some_groups
from ..utils.autoupdate import inform_changed_data
from ..utils.rest_api import ModelViewSet, Response, ValidationError, list_route
from .access_permissions import MediafileAccessPermissions
from .config import watch_and_update_configs
from .models import Mediafile


# Viewsets for the REST API


class MediafileViewSet(ModelViewSet):
    """
    API endpoint for mediafile objects.

    There are the following views: metadata, list, retrieve, create,
    partial_update, update and destroy.
    """

    access_permissions = MediafileAccessPermissions()
    queryset = Mediafile.objects.all()

    def check_view_permissions(self):
        """
        Returns True if the user has required permissions.
        """
        if self.action in ("list", "retrieve", "metadata"):
            result = self.get_access_permissions().check_permissions(self.request.user)
        elif self.action in ("create", "partial_update", "update", "move", "destroy"):
            result = has_perm(self.request.user, "mediafiles.can_see") and has_perm(
                self.request.user, "mediafiles.can_manage"
            )
        else:
            result = False
        return result

    def create(self, request, *args, **kwargs):
        """
        Customized view endpoint to upload a new file.
        """
        # The form data may send the groups_id
        if isinstance(request.data, QueryDict):
            request.data._mutable = True

        # convert formdata string "<id, <id>, id>" to a list of numbers.
        if "access_groups_id" in request.data and isinstance(request.data, QueryDict):
            access_groups_id = request.data.get("access_groups_id")
            if access_groups_id:
                request.data.setlist(
                    "access_groups_id", [int(x) for x in access_groups_id.split(", ")]
                )
            else:
                del request.data["access_groups_id"]

        is_directory = bool(request.data.get("is_directory", False))
        if is_directory and request.data.get("mediafile"):
            raise ValidationError(
                {"detail": "Either create a path or a file, but not both"}
            )
        if not request.data.get("mediafile") and not is_directory:
            raise ValidationError({"detail": "You forgot to provide a file."})

        return super().create(request, *args, **kwargs)

    def destroy(self, *args, **kwargs):
        with watch_and_update_configs():
            response = super().destroy(*args, **kwargs)
        return response

    def update(self, *args, **kwargs):
        with watch_and_update_configs():
            response = super().update(*args, **kwargs)
        inform_changed_data(self.get_object().get_children_deep())
        return response

    @list_route(methods=["post"])
    def move(self, request):
        """
        {
            ids: [<id>, <id>, ...],
            directory_id: <id>
        }
        Move <ids> to the given directory_id. This will raise an error, if
        the move would be recursive.
        """

        # Validate data:
        if not isinstance(request.data, dict):
            raise ValidationError({"detail": "The data must be a dict"})
        ids = request.data.get("ids")
        if not isinstance(ids, list):
            raise ValidationError({"detail": "The ids must be a list"})
        for id in ids:
            if not isinstance(id, int):
                raise ValidationError({"detail": "All ids must be an int"})
        directory_id = request.data.get("directory_id")
        if directory_id is not None and not isinstance(directory_id, int):
            raise ValidationError({"detail": "The directory_id must be an int"})
        if directory_id is None:
            directory = None
        else:
            try:
                directory = Mediafile.objects.get(pk=directory_id, is_directory=True)
            except Mediafile.DoesNotExist:
                raise ValidationError({"detail": "The directory does not exist"})

        ids_set = set(ids)  # keep them in a set for fast lookup
        ids = list(ids_set)  # make ids unique

        mediafiles = []
        for id in ids:
            try:
                mediafiles.append(Mediafile.objects.get(pk=id))
            except Mediafile.DoesNotExist:
                raise ValidationError(
                    {"detail": f"The mediafile with id {id} does not exist"}
                )

        # Search for valid parents (None is not included, but also safe!)
        if directory is not None:
            valid_parent_ids = set()

            queue = list(Mediafile.objects.filter(parent=None, is_directory=True))
            for mediafile in queue:
                if mediafile.pk in ids_set:
                    continue  # not valid, because this is in the input data
                valid_parent_ids.add(mediafile.pk)
                queue.extend(
                    list(Mediafile.objects.filter(parent=mediafile, is_directory=True))
                )

            if directory_id not in valid_parent_ids:
                raise ValidationError({"detail": "The directory is not valid"})

        # Ok, update all mediafiles
        with watch_and_update_configs():
            for mediafile in mediafiles:
                mediafile.parent = directory
                mediafile.save(skip_autoupdate=True)
        if directory is None:
            inform_changed_data(Mediafile.objects.all())
        else:
            inform_changed_data(directory.get_children_deep())

        return Response()


def get_mediafile(request, path):
    """
    returnes the mediafile for the requested path and checks, if the user is
    valid to retrieve the mediafile. If not, None will be returned.
    A user must have all access permissions for all folders the the file itself,
    or the file is a special file (logo or font), then it is always returned.

    If the mediafile cannot be found,  a Mediafile.DoesNotExist will be raised.
    """
    if not path:
        raise Mediafile.DoesNotExist()
    parts = path.split("/")
    parent = None
    can_see = has_perm(request.user, "mediafiles.can_see")
    for i, part in enumerate(parts):
        is_directory = i < len(parts) - 1
        if is_directory:
            mediafile = Mediafile.objects.get(
                parent=parent, is_directory=is_directory, title=part
            )
        else:
            mediafile = Mediafile.objects.get(
                parent=parent, is_directory=is_directory, original_filename=part
            )
        if mediafile.access_groups.exists() and not in_some_groups(
            request.user.id, [group.id for group in mediafile.access_groups.all()]
        ):
            can_see = False
        parent = mediafile

    # Check, if this file is projected
    is_projected = False
    for projector in Projector.objects.all():
        for element in projector.elements:
            name = element.get("name")
            id = element.get("id")
            if name == "mediafiles/mediafile" and id == mediafile.id:
                is_projected = True
                break

    if not can_see and not mediafile.is_special_file and not is_projected:
        mediafile = None

    return mediafile


def protected_serve(request, path, document_root=None, show_indexes=False):
    try:
        mediafile = get_mediafile(request, path)
    except Mediafile.DoesNotExist:
        return HttpResponseNotFound(content="Not found.")

    if mediafile:
        return serve(request, mediafile.mediafile.name, document_root, show_indexes)
    else:
        return HttpResponseForbidden(content="Forbidden.")