from django.shortcuts import get_object_or_404
from drf_spectacular.utils import extend_schema
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from rest_framework.throttling import ScopedRateThrottle
from rest_framework.views import APIView

from .models import Notification
from .serializers import MarkReadResponseSerializer, NotificationListResponseSerializer

# سقفِ تعدادِ اعلانِ برگشتی؛ جلوی رشدِ نامحدودِ پاسخ برای کاربرِ قدیمی رو
# می‌گیره. صفحه‌بندیِ واقعی (cursor) وقتی فرانت infinite-scroll اضافه کنه.
NOTIFICATIONS_MAX = 100


class GuestAwareReadThrottle(ScopedRateThrottle):
    """همون الگوی GuestAware*Throttle: مهمان با IP کلید می‌خوره."""

    def get_cache_key(self, request, view):
        user = request.user
        if user and user.is_authenticated and getattr(user, 'is_guest', False):
            ident = f'guest-ip:{self.get_ident(request)}'
        elif user and user.is_authenticated:
            ident = user.pk
        else:
            ident = self.get_ident(request)
        return self.cache_format % {'scope': self.scope, 'ident': ident}


class NotificationListView(APIView):
    """GET /api/notifications — فهرست اعلان‌های کاربر (جدیدترین اول)"""

    permission_classes = [IsAuthenticated]
    throttle_scope = 'read'
    throttle_classes = [GuestAwareReadThrottle]

    @extend_schema(responses=NotificationListResponseSerializer, tags=['Notifications (notifications)'])
    def get(self, request):
        qs = Notification.objects.filter(user_id=request.user.id)  # Meta.ordering: جدیدترین اول
        unread_count = qs.filter(is_read=False).count()

        data = {'items': list(qs[:NOTIFICATIONS_MAX]), 'unreadCount': unread_count}
        return Response(NotificationListResponseSerializer(data).data)


class NotificationMarkReadView(APIView):
    """PATCH /api/notifications/{id}/read — علامت‌گذاری یک اعلان به‌عنوان خوانده‌شده"""

    permission_classes = [IsAuthenticated]

    @extend_schema(responses=MarkReadResponseSerializer, tags=['Notifications (notifications)'])
    def patch(self, request, id):
        notification = get_object_or_404(Notification, pk=id, user_id=request.user.id)
        if not notification.is_read:
            notification.is_read = True
            notification.save(update_fields=['is_read'])

        return Response(MarkReadResponseSerializer({'success': True}).data)