from pathlib import Path

from django.conf import settings
from django.db.models import Min
from rest_framework import mixins, status, viewsets
from rest_framework.decorators import action
from rest_framework.parsers import FormParser, MultiPartParser
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from rest_framework.views import APIView

from . import services
from .models import MediaItem
from .serializers import MediaItemSerializer


class MediaItemViewSet(
    mixins.ListModelMixin,
    mixins.RetrieveModelMixin,
    mixins.UpdateModelMixin,
    viewsets.GenericViewSet,
):
    serializer_class = MediaItemSerializer
    lookup_field = "md5"
    http_method_names = ["get", "patch", "head", "options"]

    def get_queryset(self):
        queryset = MediaItem.objects.prefetch_related("locations").annotate(
            name=Min("locations__rel_path")
        )
        search = self.request.query_params.get("search", "").strip()
        if search:
            queryset = queryset.filter(locations__rel_path__icontains=search)
        ratings = [
            value
            for value in self.request.query_params.get("rating", "").split(",")
            if value in {"s", "q", "e"}
        ]
        if ratings:
            queryset = queryset.filter(rating__in=ratings)
        ordering = self.request.query_params.get("ordering", "").strip()
        allowed = {"name", "-name", "size", "-size", "created_at", "-created_at"}
        queryset = queryset.order_by(ordering if ordering in allowed else "-created_at")
        return queryset.distinct()

    @action(detail=True, methods=["get"])
    def raw(self, request, md5=None):
        item = self.get_object()
        location = item.locations.first()
        if location is None:
            return Response(
                {"detail": "No file for this item."},
                status=status.HTTP_404_NOT_FOUND,
            )
        return services.serve_file(
            request, location.path, download=request.query_params.get("download") == "1"
        )

    @action(detail=True, methods=["get"])
    def thumbnail(self, request, md5=None):
        item = self.get_object()
        location = item.locations.first()
        if location is None:
            return Response(
                {"detail": "No file for this item."},
                status=status.HTTP_404_NOT_FOUND,
            )
        path = Path(location.path)
        if path.suffix.lower() in services.VIDEO_EXTENSIONS:
            thumbnail = services.generate_video_thumbnail(item.md5, path)
            if thumbnail is None:
                return Response(
                    {"detail": "Thumbnail unavailable."},
                    status=status.HTTP_404_NOT_FOUND,
                )
            return services.serve_file(request, thumbnail)
        return services.serve_file(request, path)


class UploadView(APIView):
    permission_classes = [IsAuthenticated]
    parser_classes = [MultiPartParser, FormParser]

    def post(self, request):
        upload = request.FILES.get("file")
        if upload is None:
            return Response(
                {"detail": "A file is required."}, status=status.HTTP_400_BAD_REQUEST
            )
        folder = Path(settings.WATCHED_FOLDER)
        destination = services.unique_destination(folder, upload.name)
        with open(destination, "wb") as output:
            for chunk in upload.chunks():
                output.write(chunk)
        try:
            item, _, _ = services.index_file(destination, folder)
        except Exception as exc:  # noqa: BLE001 - report indexing failures
            destination.unlink(missing_ok=True)
            return Response(
                {"detail": f"Could not index upload: {exc}"},
                status=status.HTTP_400_BAD_REQUEST,
            )

        update_fields = []
        rating = request.data.get("rating") or ""
        if rating in {"s", "q", "e"} and item.rating != rating:
            item.rating = rating
            update_fields.append("rating")
        tags = services.parse_tags(request.data.get("tags"))
        if tags is not None:
            item.tags = tags
            update_fields.append("tags")
        notes = request.data.get("notes")
        if notes is not None:
            item.notes = str(notes)
            update_fields.append("notes")
        if update_fields:
            item.save(update_fields=update_fields + ["updated_at"])

        return Response(
            MediaItemSerializer(item, context={"request": request}).data,
            status=status.HTTP_201_CREATED,
        )