import math

from django.shortcuts import render
from django.db.models import F, ExpressionWrapper, FloatField
from django.db.models.functions import Sqrt, Power, Sin, Cos, Radians, ATan2
from rest_framework import generics, filters, permissions
from django_filters.rest_framework import DjangoFilterBackend
import logging

from location import models, serializers

logger = logging.getLogger(__name__)

# PROVINCES
class ProvinceList(generics.ListCreateAPIView):
    queryset = models.Province.objects.all()
    serializer_class = serializers.ProvinceSerializer
    filter_backends = [filters.SearchFilter, filters.OrderingFilter, DjangoFilterBackend]
    search_fields = ['name', 'code']
    filterset_fields = ['name', 'code']
    ordering_fields = '__all__'

    def get_permissions(self):
        if self.request.method == 'POST':
            return [permissions.IsAdminUser()]
        return [permissions.IsAuthenticated()]

class ProvinceDetail(generics.RetrieveUpdateDestroyAPIView):
    queryset = models.Province.objects.all()
    serializer_class = serializers.ProvinceSerializer

    def get_permissions(self):
        if self.request.method == 'PUT' or self.request.method == 'DELETE':
            return [permissions.IsAdminUser()]
        return [permissions.IsAuthenticated()]

# REGENCY/CITY

class RegencyCityList(generics.ListCreateAPIView):
    queryset = models.RegencyCity.objects.all()
    serializer_class = serializers.RegencyCitySerializer
    filter_backends = [filters.SearchFilter, filters.OrderingFilter, DjangoFilterBackend]
    search_fields = ['name', 'code']
    filterset_fields = ['name', 'code', 'province']
    ordering_fields = '__all__'

    def get_serializer_class(self):
        serializer_class = self.serializer_class

        if self.request.method == 'GET':
            serializer_class = serializers.RegencyCityDetailSerializer

        return serializer_class

    def get_permissions(self):
        if self.request.method == 'POST':
            return [permissions.IsAdminUser()]
        return [permissions.IsAuthenticated()]

class RegencyCityDetail(generics.RetrieveUpdateDestroyAPIView):
    queryset = models.RegencyCity.objects.all()
    serializer_class = serializers.RegencyCitySerializer

    def get_serializer_class(self):
        serializer_class = self.serializer_class

        if self.request.method == 'GET':
            serializer_class = serializers.RegencyCityDetailSerializer

        return serializer_class
    
    def get_permissions(self):
        if self.request.method == 'PUT' or self.request.method == 'DELETE':
            return [permissions.IsAdminUser()]
        return [permissions.IsAuthenticated()]

# LOCATION
class LocationList(generics.ListCreateAPIView):
    queryset = models.Location.objects.all()
    serializer_class = serializers.LocationSerializer
    filter_backends = [filters.SearchFilter, filters.OrderingFilter, DjangoFilterBackend]
    search_fields = ['name']
    filterset_fields = ['name', 'totem_code', 'province', 'regency_city', 'active']
    ordering_fields = '__all__'

    def get_queryset(self):
        queryset = models.Location.objects.all()

        lat = self.request.query_params.get('lat')
        lng = self.request.query_params.get('lng')
        radius = self.request.query_params.get('radius')

        if lat and lng:
            lat = float(lat)
            lng = float(lng)
            radius = float(radius) if radius else 50  # default 50m

            min_lat, max_lat, min_lng, max_lng = get_bounding_box(lat, lng, radius)

            logger.info(f"Filtering locations within radius {radius}m of point ({lat}, {lng})")

            # Step 1: bounding box filter
            queryset = queryset.filter(
                totem_latitude__range=(min_lat, max_lat),
                totem_longitude__range=(min_lng, max_lng)
            )

            # Step 2: haversine formula
            distance_expr = ExpressionWrapper(
                6371000 * 2 * ATan2(
                    Sqrt(
                        Power(Sin((Radians(F('totem_latitude')) - Radians(lat)) / 2), 2) +
                        Cos(Radians(lat)) *
                        Cos(Radians(F('totem_latitude'))) *
                        Power(Sin((Radians(F('totem_longitude')) - Radians(lng)) / 2), 2)
                    ),
                    Sqrt(1 - (
                        Power(Sin((Radians(F('totem_latitude')) - Radians(lat)) / 2), 2) +
                        Cos(Radians(lat)) *
                        Cos(Radians(F('totem_latitude'))) *
                        Power(Sin((Radians(F('totem_longitude')) - Radians(lng)) / 2), 2)
                    ))
                ),
                output_field=FloatField()
            )

            queryset = queryset.annotate(
                distance=distance_expr
            ).filter(
                distance__lte=radius
            ).order_by('distance')

            logger.info(f"Queryset after applying bounding box and distance filter: {queryset.query}")
            logger.info(f"Applied bounding box filter: lat between {min_lat} and {max_lat}, lng between {min_lng} and {max_lng}")
            logger.info(f"Found {queryset.count()} locations within radius {radius}m of point ({lat}, {lng})")

        return queryset

    def get_serializer_class(self):
        serializer_class = self.serializer_class

        if self.request.method == 'GET':
            serializer_class = serializers.LocationDetailSerializer

        return serializer_class
    
    def get_permissions(self):
        if self.request.method == 'POST':
            return [permissions.IsAdminUser()]
        return [permissions.IsAuthenticated()]
    
class LocationDetail(generics.RetrieveUpdateDestroyAPIView):
    queryset = models.Location.objects.all()
    serializer_class = serializers.LocationSerializer

    def get_serializer_class(self):
        serializer_class = self.serializer_class

        if self.request.method == 'GET':
            serializer_class = serializers.LocationDetailSerializer

        return serializer_class
    
    def get_permissions(self):
        if self.request.method == 'PUT' or self.request.method == 'DELETE':
            return [permissions.IsAdminUser()]
        return [permissions.IsAuthenticated()]

def get_bounding_box(lat, lng, radius_in_meters):
    earth_radius = 6371000  # meter

    lat_delta = (radius_in_meters / earth_radius) * (180 / math.pi)
    lng_delta = (radius_in_meters / earth_radius) * (180 / math.pi) / math.cos(lat * math.pi/180)

    return (
        lat - lat_delta,
        lat + lat_delta,
        lng - lng_delta,
        lng + lng_delta
    )