import uuid
from pathlib import Path

from django.conf import settings
from django.db.models import Q
from django_filters.rest_framework import DjangoFilterBackend
from rest_framework import permissions, status, viewsets
from rest_framework.decorators import action
from rest_framework.parsers import FormParser, MultiPartParser
from rest_framework.response import Response

from content.models import Article, Organize, Professor
from content.serializers import (
    ArticleListSerializer,
    OrganizeListSerializer,
    ProfessorSerializer,
)
from content.views import IsAdminOrReadOnly, PublicMixin

ALLOWED_IMAGE_EXT = {".jpg", ".jpeg", ".png", ".gif", ".webp", ".svg"}
MAX_UPLOAD_BYTES = 8 * 1024 * 1024

from .models import (
    AboutInfo,
    ContactUs,
    CopyrightInfo,
    ExtendLink,
    HomeBanner,
    Keyword,
    News,
    Publication,
    Report,
)
from .serializers import (
    AboutInfoSerializer,
    ContactUsSerializer,
    CopyrightInfoSerializer,
    ExtendLinkSerializer,
    HomeBannerSerializer,
    KeywordSerializer,
    NewsListSerializer,
    NewsSerializer,
    PublicationListSerializer,
    PublicationSerializer,
    ReportSerializer,
)


class NewsViewSet(PublicMixin, viewsets.ModelViewSet):
    queryset = News.objects.all()
    permission_classes = [IsAdminOrReadOnly]
    filter_backends = [DjangoFilterBackend]
    filterset_fields = ["is_disabled"]

    def get_serializer_class(self):
        if self.action == "list":
            return NewsListSerializer
        return NewsSerializer

    def retrieve(self, request, *args, **kwargs):
        instance = self.get_object()
        News.objects.filter(pk=instance.pk).update(read_num=instance.read_num + 1)
        instance.refresh_from_db()
        return Response(self.get_serializer(instance).data)


class PublicationViewSet(PublicMixin, viewsets.ModelViewSet):
    queryset = Publication.objects.all()
    permission_classes = [IsAdminOrReadOnly]
    filter_backends = [DjangoFilterBackend]
    filterset_fields = ["is_disabled"]

    def get_serializer_class(self):
        if self.action == "list":
            return PublicationListSerializer
        return PublicationSerializer


class ReportViewSet(PublicMixin, viewsets.ModelViewSet):
    queryset = Report.objects.all()
    serializer_class = ReportSerializer
    permission_classes = [IsAdminOrReadOnly]
    filter_backends = [DjangoFilterBackend]
    filterset_fields = ["year", "is_disabled"]


class AboutInfoViewSet(viewsets.ModelViewSet):
    queryset = AboutInfo.objects.all()
    serializer_class = AboutInfoSerializer
    permission_classes = [IsAdminOrReadOnly]

    @action(detail=False, methods=["get"])
    def current(self, request):
        obj = self.get_queryset().first()
        if not obj:
            return Response({})
        return Response(self.get_serializer(obj).data)


class CopyrightInfoViewSet(viewsets.ModelViewSet):
    queryset = CopyrightInfo.objects.all()
    serializer_class = CopyrightInfoSerializer
    permission_classes = [IsAdminOrReadOnly]

    @action(detail=False, methods=["get"])
    def current(self, request):
        obj = self.get_queryset().first()
        if not obj:
            return Response({})
        return Response(self.get_serializer(obj).data)


class ContactUsViewSet(viewsets.ModelViewSet):
    queryset = ContactUs.objects.all()
    serializer_class = ContactUsSerializer
    permission_classes = [IsAdminOrReadOnly]

    @action(detail=False, methods=["get"])
    def current(self, request):
        obj = self.get_queryset().first()
        if not obj:
            return Response({})
        return Response(self.get_serializer(obj).data)


class ExtendLinkViewSet(PublicMixin, viewsets.ModelViewSet):
    queryset = ExtendLink.objects.all()
    serializer_class = ExtendLinkSerializer
    permission_classes = [IsAdminOrReadOnly]


class HomeBannerViewSet(PublicMixin, viewsets.ModelViewSet):
    queryset = HomeBanner.objects.all()
    serializer_class = HomeBannerSerializer
    permission_classes = [IsAdminOrReadOnly]

    @action(
        detail=False,
        methods=["post"],
        url_path="upload",
        parser_classes=[MultiPartParser, FormParser],
        permission_classes=[permissions.IsAdminUser],
    )
    def upload(self, request):
        """上传轮播图片，返回可直接写入 image_url 的路径。"""
        file = request.FILES.get("file")
        if not file:
            return Response({"detail": "请选择图片文件"}, status=status.HTTP_400_BAD_REQUEST)
        if file.size > MAX_UPLOAD_BYTES:
            return Response({"detail": "图片不能超过 8MB"}, status=status.HTTP_400_BAD_REQUEST)
        ext = Path(file.name).suffix.lower()
        if ext not in ALLOWED_IMAGE_EXT:
            return Response(
                {"detail": f"不支持的格式，请上传 {', '.join(sorted(ALLOWED_IMAGE_EXT))}"},
                status=status.HTTP_400_BAD_REQUEST,
            )
        filename = f"{uuid.uuid4().hex}{ext}"
        rel_dir = Path("banners")
        abs_dir = Path(settings.MEDIA_ROOT) / rel_dir
        abs_dir.mkdir(parents=True, exist_ok=True)
        abs_path = abs_dir / filename
        with open(abs_path, "wb") as out:
            for chunk in file.chunks():
                out.write(chunk)
        url = f"/{settings.MEDIA_URL.strip('/')}/{rel_dir.as_posix()}/{filename}"
        return Response({"url": url, "name": file.name})


class KeywordViewSet(viewsets.ModelViewSet):
    queryset = Keyword.objects.all()
    serializer_class = KeywordSerializer
    permission_classes = [IsAdminOrReadOnly]

    def get_queryset(self):
        qs = super().get_queryset()
        if self.action in ("list", "retrieve"):
            user = self.request.user
            if not (user and user.is_staff):
                qs = qs.filter(is_show=True)
        return qs


class SearchViewSet(viewsets.ViewSet):
    """全站搜索（文献 / 机构 / 专家 / 新闻）。"""

    permission_classes = [permissions.AllowAny]

    def list(self, request):
        q = (request.query_params.get("q") or "").strip()
        if not q:
            return Response({"articles": [], "organizes": [], "professors": [], "news": []})

        articles = Article.objects.filter(
            is_disabled=False, is_deleted=False
        ).filter(Q(title__icontains=q) | Q(introduction__icontains=q))[:20]
        organizes = Organize.objects.filter(
            is_disabled=False, name__icontains=q
        )[:10]
        professors = Professor.objects.filter(
            is_disabled=False, name__icontains=q
        )[:10]
        news = News.objects.filter(is_disabled=False, title__icontains=q)[:10]

        return Response(
            {
                "articles": ArticleListSerializer(articles, many=True).data,
                "organizes": OrganizeListSerializer(organizes, many=True).data,
                "professors": ProfessorSerializer(professors, many=True).data,
                "news": NewsListSerializer(news, many=True).data,
            }
        )