voyage/backend/server/adventures/views/location_view.py

from django.utils import timezone
from django.db import transaction
from django.core.exceptions import PermissionDenied
from django.db.models import Q, Max, Prefetch
from django.db.models.functions import Lower
from rest_framework import viewsets, status
from rest_framework.decorators import action
from rest_framework.response import Response
import requests
from adventures.models import Location, Category, CollectionItineraryItem, Visit
from django.contrib.contenttypes.models import ContentType
from adventures.permissions import IsOwnerOrSharedWithFullAccess
from adventures.serializers import LocationSerializer, MapPinSerializer, CalendarLocationSerializer
from adventures.utils import pagination

class LocationViewSet(viewsets.ModelViewSet):
    """
    ViewSet for managing Adventure objects with support for filtering, sorting,
    and sharing functionality.
    """
    serializer_class = LocationSerializer
    permission_classes = [IsOwnerOrSharedWithFullAccess]
    pagination_class = pagination.StandardResultsSetPagination

    # ==================== QUERYSET & PERMISSIONS ====================

    def get_queryset(self):
        """
        Returns queryset based on user authentication and action type.
        Public actions allow unauthenticated access to public locations.
        """
        user = self.request.user
        public_allowed_actions = {'retrieve', 'additional_info'}

        if not user.is_authenticated:
            if self.action in public_allowed_actions:
                return Location.objects.retrieve_locations(
                    user, include_public=True
                ).order_by('-updated_at')
            return Location.objects.none()

        include_public = self.action in public_allowed_actions
        return Location.objects.retrieve_locations(
            user,
            include_public=include_public,
            include_owned=True,
            include_shared=True
        ).order_by('-updated_at')

    # ==================== SORTING & FILTERING ====================

    def apply_sorting(self, queryset):
        """Apply sorting and collection filtering to queryset."""
        order_by = self.request.query_params.get('order_by', 'updated_at')
        order_direction = self.request.query_params.get('order_direction', 'asc')
        include_collections = self.request.query_params.get('include_collections', 'true')

        # Validate parameters
        valid_order_by = ['name', 'type', 'date', 'rating', 'updated_at']
        if order_by not in valid_order_by:
            order_by = 'name'

        if order_direction not in ['asc', 'desc']:
            order_direction = 'asc'

        # Apply sorting logic
        queryset = self._apply_ordering(queryset, order_by, order_direction)

        # Filter locations without collections if requested
        if include_collections == 'false':
            queryset = queryset.filter(collections__isnull=True)

        return queryset

    def _apply_ordering(self, queryset, order_by, order_direction):
        """Apply ordering to queryset based on field type."""
        if order_by == 'date':
            queryset = queryset.annotate(
                latest_visit=Max('visits__start_date')
            ).filter(latest_visit__isnull=False)
            ordering = 'latest_visit'
        elif order_by == 'name':
            queryset = queryset.annotate(lower_name=Lower('name'))
            ordering = 'lower_name'
        elif order_by == 'rating':
            queryset = queryset.filter(rating__isnull=False)
            ordering = 'rating'
        elif order_by == 'updated_at':
            # Special handling for updated_at (reverse default order)
            ordering = '-updated_at' if order_direction == 'asc' else 'updated_at'
            return queryset.order_by(ordering)
        else:
            ordering = order_by

        # Apply direction
        if order_direction == 'desc':
            ordering = f'-{ordering}'

        return queryset.order_by(ordering)

    # ==================== CRUD OPERATIONS ====================

    @transaction.atomic
    def perform_create(self, serializer):
        """Create adventure with collection validation and ownership logic."""
        collections = serializer.validated_data.get('collections', [])

        # Validate permissions for all collections
        self._validate_collection_permissions(collections)

        # Determine what user to assign as owner
        user_to_assign = self.request.user
        
        if collections:
            # Use the current user as owner since ManyToMany allows multiple collection owners
            user_to_assign = self.request.user

        serializer.save(user=user_to_assign)

    def perform_update(self, serializer):
        """Update adventure."""
        # Just save the adventure - the signal will handle publicity updates
        serializer.save()

    def update(self, request, *args, **kwargs):
        """Handle adventure updates with collection permission validation."""
        instance = self.get_object()
        partial = kwargs.pop('partial', False)

        serializer = self.get_serializer(instance, data=request.data, partial=partial)
        serializer.is_valid(raise_exception=True)

        # Validate collection permissions if collections are being updated
        if 'collections' in serializer.validated_data:
            self._validate_collection_update_permissions(
                instance, serializer.validated_data['collections']
            )
        else:
            # Remove collections from validated_data if not provided
            serializer.validated_data.pop('collections', None)

        self.perform_update(serializer)
        return Response(serializer.data)
    
    def destroy(self, request, *args, **kwargs):
        """Only allow the owner to delete a location."""
        instance = self.get_object()
        
        # Check if the user is the owner
        if instance.user != request.user:
            raise PermissionDenied("Only the owner can delete this location.")
        
        return super().destroy(request, *args, **kwargs)

    # ==================== CUSTOM ACTIONS ====================

    @action(detail=False, methods=['get'])
    def filtered(self, request):
        """Filter locations by category types and visit status."""
        types = request.query_params.get('types', '').split(',')
        
        # Handle 'all' types
        if 'all' in types:
            types = Category.objects.filter(
                user=request.user
            ).values_list('name', flat=True)
        else:
            # Validate provided types
            if not types or not all(
                Category.objects.filter(user=request.user, name=type_name).exists() 
                for type_name in types
            ):
                return Response(
                    {"error": "Invalid category or no types provided"}, 
                    status=400
                )

        # Build base queryset
        queryset = Location.objects.filter(
            category__in=Category.objects.filter(name__in=types, user=request.user),
            user=request.user.id
        )

        # Apply visit status filtering
        queryset = self._apply_visit_filtering(queryset, request)
        queryset = self.apply_sorting(queryset)
        
        return self.paginate_and_respond(queryset, request)

    @action(detail=False, methods=['get'])
    def all(self, request):
        """Get all locations (public and owned) with optional collection filtering."""
        if not request.user.is_authenticated:
            return Response({"error": "User is not authenticated"}, status=400)

        include_collections = request.query_params.get('include_collections', 'false') == 'true'
        nested = request.query_params.get('nested', 'false') == 'true'
        allowedNestedFields = request.query_params.get('allowed_nested_fields', '').split(',')
        
        # Build queryset with collection filtering
        base_filter = Q(user=request.user.id)
        
        if include_collections:
            queryset = Location.objects.filter(base_filter)
        else:
            queryset = Location.objects.filter(base_filter, collections__isnull=True)

        queryset = self.apply_sorting(queryset)
        serializer = self.get_serializer(queryset, many=True, context={'nested': nested, 'allowed_nested_fields': allowedNestedFields})
        return Response(serializer.data)

    @action(detail=False, methods=['get'])
    def calendar(self, request):
        """Return a lightweight payload for calendar rendering."""
        if not request.user.is_authenticated:
            return Response({"error": "User is not authenticated"}, status=400)

        queryset = (
            self.get_queryset()
            .filter(visits__isnull=False)
            .select_related('category')
            .prefetch_related(
                Prefetch(
                    'visits',
                    queryset=Visit.objects.only('id', 'start_date', 'end_date', 'timezone')
                )
            )
            .only('id', 'name', 'location', 'category__name', 'category__icon')
            .distinct()
        )

        serializer = CalendarLocationSerializer(queryset, many=True)
        return Response(serializer.data)

    @action(detail=True, methods=['get'], url_path='additional-info')
    def additional_info(self, request, pk=None):
        """Get adventure with additional sunrise/sunset information."""
        adventure = self.get_object()
        user = request.user

        # Validate access permissions
        if not self._has_adventure_access(adventure, user):
            return Response(
                {"error": "User does not have permission to access this adventure"},
                status=status.HTTP_403_FORBIDDEN
            )

        # Get base adventure data
        serializer = self.get_serializer(adventure)
        response_data = serializer.data

        # Add sunrise/sunset data
        response_data['sun_times'] = self._get_sun_times(adventure, response_data.get('visits', []))
        
        return Response(response_data)
    
    # view to return location name and lat/lon for all locations a user owns for the golobal map
    @action(detail=False, methods=['get'], url_path='pins')
    def map_locations(self, request):
        """Get all locations with name and lat/lon for map display."""
        if not request.user.is_authenticated:
            return Response({"error": "User is not authenticated"}, status=400)

        locations = Location.objects.filter(user=request.user)
        serializer = MapPinSerializer(locations, many=True)
        return Response(serializer.data)

    # ==================== HELPER METHODS ====================

    def _validate_collection_update_permissions(self, instance, new_collections):
        """Validate collection permissions for updates, allowing collection owners to unlink locations."""
        current_collections = set(instance.collections.all())
        new_collections_set = set(new_collections)
        
        # Collections being added
        collections_to_add = new_collections_set - current_collections
        
        # Collections being removed
        collections_to_remove = current_collections - new_collections_set
        
        # Validate permissions for collections being added
        for collection in collections_to_add:
            # Standard validation for adding collections
            if collection.user != self.request.user:
                # Check if user has shared access to the collection
                if not collection.shared_with.filter(uuid=self.request.user.uuid).exists():
                    raise PermissionDenied(
                        f"You don't have permission to add location to collection '{collection.name}'"
                    )
        
        # For collections being removed, allow if:
        # 1. User owns the location, OR
        # 2. User owns the collection (even if they don't own the location)
        for collection in collections_to_remove:
            user_owns_location = instance.user == self.request.user
            user_owns_collection = collection.user == self.request.user
            
            if not (user_owns_location or user_owns_collection):
                # Check if user has shared access to the collection
                if not collection.shared_with.filter(uuid=self.request.user.uuid).exists():
                    raise PermissionDenied(
                        f"You don't have permission to remove this location from one of the collections it's linked to.'"
                    )
            else:
                # If the removal is permitted, also remove any itinerary items
                # in this collection that reference this Location instance.
                try:
                    ct = ContentType.objects.get_for_model(instance.__class__)
                    # Try deleting by native PK type first, then by string.
                    qs = CollectionItineraryItem.objects.filter(
                        collection=collection, content_type=ct, object_id=instance.pk
                    )
                    if qs.exists():
                        qs.delete()
                    else:
                        CollectionItineraryItem.objects.filter(
                            collection=collection, content_type=ct, object_id=str(instance.pk)
                        ).delete()
                except Exception:
                    # Don't raise on cleanup failures; deletion of itinerary items
                    # is best-effort and shouldn't block the update operation.
                    pass

    def _validate_collection_permissions(self, collections):
        """Validate permissions for all collections (used in create)."""
        for collection in collections:
            if collection.user != self.request.user:
                # Check if user has shared access to the collection
                if not collection.shared_with.filter(uuid=self.request.user.uuid).exists():
                    raise PermissionDenied(
                        f"You don't have permission to add location to collection '{collection.name}'"
                    )

    def _apply_visit_filtering(self, queryset, request):
        """Apply visit status filtering to queryset."""
        is_visited_param = request.query_params.get('is_visited')
        if is_visited_param is None:
            return queryset

        # Convert parameter to boolean
        if is_visited_param.lower() == 'true':
            is_visited_bool = True
        elif is_visited_param.lower() == 'false':
            is_visited_bool = False
        else:
            return queryset

        # Apply visit filtering
        now = timezone.now().date()
        if is_visited_bool:
            queryset = queryset.filter(visits__start_date__lte=now).distinct()
        else:
            queryset = queryset.exclude(visits__start_date__lte=now).distinct()

        return queryset

    def _has_adventure_access(self, adventure, user):
        """Check if user has access to adventure."""
        # Allow if public
        if adventure.is_public:
            return True

        # Check ownership
        if user.is_authenticated and adventure.user == user:
            return True

        # Check shared collection access
        if user.is_authenticated:
            for collection in adventure.collections.all():
                if collection.shared_with.filter(uuid=user.uuid).exists() or collection.user == user:
                    return True

        return False

    def _get_sun_times(self, adventure, visits):
        """Get sunrise/sunset times for adventure visits."""
        sun_times = []

        for visit in visits:
            date = visit.get('start_date')
            if not (date and adventure.longitude and adventure.latitude):
                continue

            api_url = (
                f'https://api.sunrisesunset.io/json?'
                f'lat={adventure.latitude}&lng={adventure.longitude}&date={date}'
            )
            
            try:
                response = requests.get(api_url)
                if response.status_code == 200:
                    data = response.json()
                    results = data.get('results', {})
                    
                    if results.get('sunrise') and results.get('sunset'):
                        sun_times.append({
                            "date": date,
                            "visit_id": visit.get('id'),
                            "sunrise": results.get('sunrise'),
                            "sunset": results.get('sunset')
                        })
            except requests.RequestException:
                # Skip this visit if API call fails
                continue

        return sun_times

    def paginate_and_respond(self, queryset, request):
        """Paginate queryset and return response."""
        paginator = self.pagination_class()
        page = paginator.paginate_queryset(queryset, request)
        
        if page is not None:
            serializer = self.get_serializer(page, many=True)
            return paginator.get_paginated_response(serializer.data)

        serializer = self.get_serializer(queryset, many=True)
        return Response(serializer.data)