from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import status
from .models import UserData, AIKey, AppVersion, Contact
from django.shortcuts import get_object_or_404
from .serializers import ContactSerializer, ExpenseRequestSerializer
from rest_framework.generics import CreateAPIView, GenericAPIView
import uuid
from .models import ExpenseLog
from django.apps import apps
import re


class UserDataPostView(APIView):
    def post(self, request):
        user_id = request.data.get("user_id")
        if not user_id:
            return Response(
                {"error": "user_id is required"},
                status=status.HTTP_400_BAD_REQUEST,
            )

        obj, created = UserData.objects.get_or_create(user_id=user_id)

        # Always regenerate backup key
        obj.data_backup_key = str(uuid.uuid4())

        updated = False
        for key in ["expenses", "salary", "category", "user_data"]:
            if key in request.data and getattr(obj, key) != request.data[key]:
                setattr(obj, key, request.data[key])
                updated = True

        obj.save()  # Save once after changes

        # AI key logic
        if obj.has_ai_access:
            AI_KEY = get_object_or_404(AIKey, isActive=True).aikey
        else:
            AI_KEY = None

        return Response(
            {
                "message": (
                    "Data created successfully"
                    if created
                    else "Data updated successfully" if updated else "No changes made"
                ),
                "app_version": get_object_or_404(AppVersion, isActive=True).version,
                "has_music_url_access": obj.has_music_url_access,
                "has_ai_access": obj.has_ai_access,
                "ai_key": AI_KEY,
                "data_backup_key": obj.data_backup_key,
            },
            status=status.HTTP_201_CREATED if created else status.HTTP_200_OK,
        )


class GetFieldView(APIView):
    def get(self, request, field, identifier):
        # identifier can be user_id OR data_backup_key
        obj = (
            UserData.objects.filter(user_id=identifier).first()
            or UserData.objects.filter(data_backup_key=identifier).first()
        )

        if not obj:
            return Response({"error": "User not found"}, status=404)

        if field == "all":
            data = {
                "userData": obj.user_data,
                "expenseData": obj.expenses,
                "categoryData": obj.category,
                "salaryData": obj.salary,
            }
            return Response(data)
        if hasattr(obj, field):
            return Response({field: getattr(obj, field)})
        return Response({"error": "Invalid field"}, status=status.HTTP_400_BAD_REQUEST)


class ContactList1(CreateAPIView):
    queryset = Contact.objects.all()
    serializer_class = ContactSerializer

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)

        if serializer.is_valid():
            serializer.save()
            return Response(
                {"message": "Contact saved successfully"},
                status=status.HTTP_201_CREATED,
            )

        return Response(
            {"message": "Validation failed", "errors": serializer.errors},
            status=status.HTTP_400_BAD_REQUEST,
        )


class CategorizeExpenseView(GenericAPIView):
    # 2. Assign the serializer class to automatically populate the Swagger schema
    serializer_class = ExpenseRequestSerializer

    def post(self, request):
        # 3. Validate input using the serializer
        serializer = self.get_serializer(data=request.data)
        if not serializer.is_valid():
            return Response(serializer.errors, status=400)

        expense_text = serializer.validated_data["text"]

        # 4. Extract Amount using Regex
        # Matches formats like 150, 1,500, 150.50, 1,500.50
        amount_match = re.search(r"\d+(?:,\d+)*(?:\.\d+)?", expense_text)
        extracted_amount = (
            float(amount_match.group().replace(",", "")) if amount_match else None
        )

        # 5. Use the safe Django app registry to fetch the pre-loaded AI model
        api_config = apps.get_app_config("api")

        result = api_config.classifier(
            expense_text,
            candidate_labels=api_config.categories,
            hypothesis_template="This expense is for {}.",
        )

        top_category = result["labels"][0]
        confidence_score = result["scores"][0]

        # 6. Save to database
        ExpenseLog.objects.create(
            text=expense_text,
            amount=extracted_amount,
            predicted_category=top_category,
            confidence_score=confidence_score,
        )

        return Response(
            {
                "expense": expense_text,
                "amount": extracted_amount,
                "category": top_category,
                "confidence": round(confidence_score * 100, 2),
            }
        )