# Create your views here.
# billing/views.py
from datetime import datetime, timedelta
from django.utils import timezone

import requests
from decouple import config
from rest_framework import generics, status
from rest_framework.response import Response

from api.mixins import StaffEditorPermissionMixin

from .models import Device, Payment
from .serializers import PaymentSerializer, UpdatePaymentSerializer


class InsufficientFundsError(Exception):
    pass


class ListCreatePaymentView(StaffEditorPermissionMixin, generics.ListCreateAPIView):
    serializer_class = PaymentSerializer
    queryset = Payment.objects.all().select_related("user")

    def get_queryset(self):
        queryset = super().get_queryset()
        if self.request.user.is_superuser:
            return queryset
        return queryset.filter(user=self.request.user)

    def create(self, request):
        data = request.data
        user = request.user
        amount = data.get("amount")
        number_of_months = data.get("number_of_months")
        device_ids = data.get("device_ids", [])
        print(amount, number_of_months, device_ids)

        for device_id in device_ids:
            device = Device.objects.filter(id=device_id, user=user).first()
            print("DEVICE", device)
            if not device:
                return Response(
                    {"message": f"Device with id {device_id} not found."},
                    status=status.HTTP_400_BAD_REQUEST,
                )
        if not amount or not number_of_months:
            return Response(
                {"message": "amount and number_of_months are required."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if not device_ids:
            return Response(
                {"message": "device_ids are required."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        # Create payment
        payment = Payment.objects.create(
            amount=amount,
            number_of_months=number_of_months,
            paid=data.get("paid", False),
            user=user,
        )

        # Connect devices to payment
        devices = Device.objects.filter(id__in=device_ids, user=user)
        payment.devices.set(devices)

        serializer = PaymentSerializer(payment)
        return Response(serializer.data, status=status.HTTP_201_CREATED)


class PaymentDetailAPIView(StaffEditorPermissionMixin, generics.RetrieveAPIView):
    queryset = Payment.objects.select_related("user").all()
    serializer_class = PaymentSerializer
    lookup_field = "pk"


class UpdatePaymentAPIView(StaffEditorPermissionMixin, generics.UpdateAPIView):
    queryset = Payment.objects.select_related("user").all()
    serializer_class = UpdatePaymentSerializer
    lookup_field = "pk"

    def update(self, request, *args, **kwargs):
        number_of_months = request.data.get("number_of_months")

        if not number_of_months:
            return Response(
                {"message": "number_of_months is required."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if not isinstance(number_of_months, int):
            return Response(
                {"message": "number_of_months must be an integer."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        device_expire_date = timezone.now() + timedelta(days=30 * number_of_months)
        instance = self.get_object()
        devices = instance.devices.all()
        serializer = self.get_serializer(instance, data=request.data, partial=False)
        serializer.is_valid(raise_exception=True)
        self.perform_update(serializer)
        devices.update(is_active=True, expiry_date=device_expire_date)
        return Response(serializer.data)


class VerifyPaymentView(StaffEditorPermissionMixin, generics.UpdateAPIView):
    serializer_class = PaymentSerializer
    queryset = Payment.objects.all()

    def update(self, request, *args, **kwargs):
        data = request.data
        user = request.user
        print(user)
        method = data.get("method")
        payment_id = data.get("payment_id")
        abs_amount = data.get("abs_amount")
        if not method:
            return Response(
                {"message": "method is required. 'WALLET' or 'TRANSFER'"},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if not payment_id:
            return Response(
                {"message": "payment_id is required."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if not abs_amount:
            return Response(
                {"message": "abs_amount is required."},
                status=status.HTTP_400_BAD_REQUEST,
            )

        try:
            payment = Payment.objects.get(id=payment_id)
            devices = payment.devices.all()

            if data["type"] == "WALLET":
                print("processing WALLET payment")
                self.process_wallet_payment(user, payment, float(data["abs_amount"]))
            elif data["type"] == "TRANSFER":
                self.verify_external_payment(data, payment)

            # Update devices
            expiry_date = datetime.now() + timedelta(days=30 * payment.number_of_months)
            devices.update(is_active=True, expiry_date=expiry_date)

            return Response({"message": "Payment verified successfully."})

        except Payment.DoesNotExist:
            return Response(
                {"message": "Payment not found."}, status=status.HTTP_404_NOT_FOUND
            )
        except InsufficientFundsError:
            return Response(
                {"message": "Insufficient funds in wallet."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        except Exception as e:
            return Response(
                {"message": str(e)}, status=status.HTTP_500_INTERNAL_SERVER_ERROR
            )

    def process_wallet_payment(self, user, payment, amount):
        print("processing wallet payment")
        print(user, amount)
        if user.wallet_balance < amount:
            return Response(
                {"message": "Insufficient funds in wallet."},
                status=status.HTTP_400_BAD_REQUEST,
            )

        payment.paid = True
        payment.paid_at = datetime.now()
        payment.method = "WALLET"
        payment.save()

        user.wallet_balance -= amount
        user.save()

    def verify_external_payment(self, data, payment):
        response = requests.post(
            f"{config('PAYMENT_VERIFY_BASE_URL')}/verify-payment",
            json=data,
            headers={"Content-Type": "application/json"},
        )
        response.raise_for_status()
        print(response.json())
        if not response.json().get("success"):
            raise Exception("Payment verification failed.")