from django.db.models import Q, Case, When, Value, IntegerField
from rest_framework import status
from rest_framework.authtoken.models import Token
from rest_framework.decorators import api_view, permission_classes
from rest_framework.permissions import AllowAny, IsAuthenticated
from rest_framework.response import Response

from .models import User, Place, Review
from .serializers import (
    UserSerializer,
    PlaceSerializer,
    PlaceDetailSerializer,
    AddReviewSerializer
)


@api_view(['POST'])
@permission_classes([AllowAny])
def register(request):
    """
    Register a new user with name and phone number.
    
    Request body:
    {
        "name": "John Doe",
        "phone": "1234567890"
    }
    
    Response:
    {
        "user": {
            "id": 1,
            "name": "John Doe",
            "phone": "1234567890"
        },
        "token": "your-auth-token"
    }
    """
    serializer = UserSerializer(data=request.data)
    
    if serializer.is_valid():
        user = serializer.save()
        token, _ = Token.objects.get_or_create(user=user)
        
        return Response({
            'user': serializer.data,
            'token': token.key
        }, status=status.HTTP_201_CREATED)
    
    return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)


@api_view(['POST'])
@permission_classes([AllowAny])
def login(request):
    """
    Login with phone number to get authentication token.
    
    Request body:
    {
        "phone": "1234567890"
    }
    
    Response:
    {
        "user": {
            "id": 1,
            "name": "John Doe",
            "phone": "1234567890"
        },
        "token": "your-auth-token"
    }
    """
    phone = request.data.get('phone')
    
    if not phone:
        return Response(
            {'error': 'Phone number is required'}, 
            status=status.HTTP_400_BAD_REQUEST
        )
    
    try:
        user = User.objects.get(phone=phone)
        token, _ = Token.objects.get_or_create(user=user)
        
        return Response({
            'user': UserSerializer(user).data,
            'token': token.key
        })
    except User.DoesNotExist:
        return Response(
            {'error': 'User with this phone number does not exist'}, 
            status=status.HTTP_404_NOT_FOUND
        )


@api_view(['POST'])
@permission_classes([IsAuthenticated])
def add_review(request):
    """
    Add a review for a place. Creates the place if it doesn't exist.
    
    Request body:
    {
        "place_name": "Joe's Pizza",
        "place_address": "123 Main St, New York, NY",
        "rating": 5,
        "review_text": "Best pizza in town!"
    }
    
    Response:
    {
        "message": "Review added successfully",
        "review": {
            "id": 1,
            "user_name": "John Doe",
            "rating": 5,
            "text": "Best pizza in town!",
            "created_at": "2024-01-01T12:00:00Z"
        }
    }
    """
    serializer = AddReviewSerializer(
        data=request.data,
        context={'request': request}
    )
    
    if serializer.is_valid():
        review = serializer.save()
        
        from .serializers import ReviewSerializer
        return Response({
            'message': 'Review added successfully',
            'review': ReviewSerializer(review).data
        }, status=status.HTTP_201_CREATED)
    
    return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def search_places(request):
    """
    Search for places by name and/or minimum rating.
    
    Query parameters:
    - name (optional): Search by place name (exact match first, then partial)
    - min_rating (optional): Filter by minimum average rating
    
    Example: /api/places/search/?name=pizza&min_rating=4
    
    Response:
    [
        {
            "id": 1,
            "name": "Joe's Pizza",
            "address": "123 Main St, New York, NY",
            "average_rating": 4.5
        }
    ]
    """
    name_query = request.query_params.get('name', '').strip()
    min_rating = request.query_params.get('min_rating', None)
    
    # Start with all places
    queryset = Place.objects.all()
    
    # Filter by name if provided
    if name_query:
        # Use Q objects to combine exact and partial matches
        # Annotate with priority: 1 for exact match, 2 for partial match
        queryset = queryset.annotate(
            match_priority=Case(
                When(name__iexact=name_query, then=Value(1)),
                When(name__icontains=name_query, then=Value(2)),
                default=Value(3),
                output_field=IntegerField()
            )
        ).filter(
            Q(name__iexact=name_query) | Q(name__icontains=name_query)
        ).order_by('match_priority', 'name')
    else:
        queryset = queryset.order_by('name')
    
    # Get all places and filter by rating in Python (since average is a property)
    places = list(queryset)
    
    if min_rating:
        try:
            min_rating_value = float(min_rating)
            places = [
                place for place in places 
                if place.average_rating is not None and place.average_rating >= min_rating_value
            ]
        except ValueError:
            return Response(
                {'error': 'Invalid min_rating value'}, 
                status=status.HTTP_400_BAD_REQUEST
            )
    
    serializer = PlaceSerializer(places, many=True)
    return Response(serializer.data)


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def place_detail(request, place_id):
    """
    Get detailed information about a place including all reviews.
    Current user's review appears first, followed by others sorted by newest.
    
    Response:
    {
        "id": 1,
        "name": "Joe's Pizza",
        "address": "123 Main St, New York, NY",
        "average_rating": 4.5,
        "reviews": [
            {
                "id": 1,
                "user_name": "John Doe",
                "rating": 5,
                "text": "Best pizza!",
                "created_at": "2024-01-01T12:00:00Z"
            }
        ]
    }
    """
    try:
        place = Place.objects.get(pk=place_id)
        serializer = PlaceDetailSerializer(
            place,
            context={'request': request}
        )
        return Response(serializer.data)
    except Place.DoesNotExist:
        return Response(
            {'error': 'Place not found'}, 
            status=status.HTTP_404_NOT_FOUND
        )