# Create your views here.
# billing/views.py
import os
from datetime import timedelta

import requests
from django.utils import timezone
from django.utils.timezone import localtime
from django_filters.rest_framework import DjangoFilterBackend
from rest_framework import generics, status
from rest_framework.response import Response

from api.mixins import StaffEditorPermissionMixin
from api.tasks import add_new_devices_to_omada
from apibase.env import BASE_DIR, env
from django.db.models import Prefetch
import logging
from .utils import calculate_total_new_price

from .models import Device, Payment, Topup, WalletTransaction
from .serializers import (
    PaymentSerializer,
    UpdatePaymentSerializer,
    TopupSerializer,
    WalletTransactionSerializer,
)
from .filters import PaymentFilter, TopupFilter, WalletTransactionFilter
from dataclasses import dataclass, asdict
from typing import Optional
from api.models import User
from api.omada import Omada

env.read_env(os.path.join(BASE_DIR, ".env"))

PAYMENT_BASE_URL = env("PAYMENT_BASE_URL", default="")  # type: ignore

logger = logging.getLogger(__name__)


@dataclass
class Transaction:
    ref: str
    sourceBank: str
    trxDate: str


@dataclass
class PaymentVerificationResponse:
    message: str
    success: bool
    transaction: Optional[Transaction] = None


class InsufficientFundsError(Exception):
    pass


class ListCreatePaymentView(StaffEditorPermissionMixin, generics.ListCreateAPIView):
    serializer_class = PaymentSerializer
    queryset = Payment.objects.all().select_related("user")
    filter_backends = [DjangoFilterBackend]
    filterset_fields = "__all__"
    filterset_class = PaymentFilter

    def get_queryset(self):
        unpaid_qs = Payment.objects.filter(paid=False).order_by("-created_at")
        device_qs = Device.objects.prefetch_related(
            Prefetch("payments", queryset=unpaid_qs, to_attr="unpaid_payments")
        )
        queryset = Payment.objects.select_related("user").prefetch_related(
            Prefetch("devices", queryset=device_qs)
        )

        if not self.request.user.is_superuser:
            queryset = queryset.filter(user=self.request.user)

        return queryset

    def create(self, request):
        data = request.data
        user = request.user
        number_of_months = data.get("number_of_months")
        number_of_devices = 0
        device_ids = data.get("device_ids", [])
        print(number_of_months, device_ids)
        current_time = timezone.now()
        expires_at = current_time + timedelta(minutes=10)
        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,
                )
            number_of_devices += 1
        if not number_of_months:
            return Response(
                {"message": "number_of_months is required."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if not device_ids:
            return Response(
                {"message": "device_ids are required."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        amount = calculate_total_new_price(
            number_of_devices=number_of_devices, number_of_months=number_of_months
        )
        payment = Payment.objects.create(
            amount=amount,
            number_of_months=number_of_months,
            paid=data.get("paid", False),
            user=user,
            expires_at=expires_at,
        )

        # Connect devices to payment
        devices = Device.objects.filter(id__in=device_ids, user=user)
        for device in devices:
            device.has_a_pending_payment = True
            device.save()
        payment.devices.set(devices)

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

    def list(self, request, *args, **kwargs):
        queryset = self.filter_queryset(self.get_queryset())
        all_payments = request.query_params.get("all_payments", "false").lower() in [
            "true",
            "1",
            "yes",
        ]
        if (
            request.user.is_authenticated
            and getattr(request.user, "is_admin")
            and bool(all_payments)
        ):
            pass
        else:
            queryset = queryset.filter(user=request.user)

        page = self.paginate_queryset(queryset)
        if page is not None:
            serializer = self.get_serializer(page, many=True)
            return self.get_paginated_response(serializer.data)

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


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").prefetch_related("devices").all()
    serializer_class = UpdatePaymentSerializer
    lookup_field = "pk"

    def update(self, request, *args, **kwargs):
        instance = self.get_object()
        number_of_months = instance.number_of_months
        device_expire_date = timezone.now() + timedelta(days=30 * number_of_months)
        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=False, expiry_date=device_expire_date, has_a_pending_payment=False
        )
        return Response(serializer.data)


class VerifyPaymentView(StaffEditorPermissionMixin, generics.UpdateAPIView):
    serializer_class = PaymentSerializer
    queryset = Payment.objects.select_related("user").prefetch_related("devices").all()
    lookup_field = "pk"

    def update(self, request, *args, **kwargs):
        payment = self.get_object()
        devices = payment.devices.all()
        data = request.data
        user = request.user
        user_details = f"{user.first_name.capitalize() if user.first_name else ''} {user.last_name.capitalize() if user.last_name else ''} {user.mobile}"  # type: ignore
        omada_client = Omada()
        if payment.paid:
            return Response(
                {"message": "Payment has already been verified."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if payment.user != user and not user.is_superuser:
            return Response(
                {"message": "You are not authorized to verify this payment."},
                status=status.HTTP_403_FORBIDDEN,
            )
        method = data.get("method")
        if not method:
            return Response(
                {"message": "method is required. 'WALLET' or 'TRANSFER'"},
                status=status.HTTP_400_BAD_REQUEST,
            )

        if method == "WALLET":
            if user.wallet_balance < payment.amount:  # type: ignore
                return Response(
                    {"message": "Insufficient funds in wallet."},
                    status=status.HTTP_400_BAD_REQUEST,
                )
            else:
                self.process_wallet_payment(
                    user,  # type: ignore
                    payment,
                    devices,
                )
                device_list = []
                for device in devices:
                    device_list.append(
                        {
                            "mac": device.mac,
                            "name": f"{user_details} - {device.name}",
                        }
                    )
                    if device.registered:
                        omada_client.block_device(
                            mac_address=device.mac, operation="unblock"
                        )
                    if not device.registered:
                        # Add to omada
                        add_new_devices_to_omada.defer(new_devices=device_list)
                        device.registered = True
                        device.save()
                return Response(
                    {
                        "status": True,
                        "message": "Payment verified successfully using wallet.",
                    },
                    status=status.HTTP_200_OK,
                )
        if method == "TRANSFER":
            data = {
                "benefName": f"{user.first_name} {user.last_name}",  # type: ignore
                "accountNo": user.acc_no,  # type: ignore
                "absAmount": "{:.2f}".format(payment.amount),
                "time": localtime(payment.created_at).strftime("%Y-%m-%d %H:%M"),
            }
        payment_verification_response = self.verify_transfer_payment(data, payment)

        if payment_verification_response.success:
            expiry_date = timezone.now() + timedelta(days=30 * payment.number_of_months)
            devices.update(
                is_active=True,
                expiry_date=expiry_date,
                has_a_pending_payment=False,
            )
            payment.status = "PAID"
            payment.save()
            # add to omada if its a new device and not an existing device
            device_list = []
            for device in devices:
                device_list.append(
                    {
                        "mac": device.mac,
                        "name": f"{user_details} - {device.name}",
                    }
                )
                if device.registered:
                    omada_client.block_device(
                        mac_address=device.mac, operation="unblock"
                    )
                if not device.registered:
                    # Add to omada
                    add_new_devices_to_omada.defer(new_devices=device_list)
                    device.registered = True
                    device.save()

            return Response(
                {
                    "status": payment_verification_response.success,
                    "message": payment_verification_response.message,
                    "transaction": asdict(payment_verification_response.transaction)
                    if payment_verification_response.transaction
                    else None,
                },
                status=status.HTTP_200_OK,
            )
        else:
            return Response(
                {
                    "status": payment_verification_response.success,
                    "message": payment_verification_response.message
                    or "Topup payment verification failed.",
                },
                status=status.HTTP_400_BAD_REQUEST,
            )

    def process_wallet_payment(self, user: User, payment: Payment, devices=None):
        print("processing wallet payment...")
        print(user, payment.amount)
        # Use passed devices or fetch if not provided
        if devices is None:
            devices = payment.devices.all()

        payment.paid = True
        payment.paid_at = timezone.now()
        payment.method = "WALLET"
        payment.status = "PAID"
        expiry_date = timezone.now() + timedelta(days=30 * payment.number_of_months)
        devices.update(
            is_active=True,
            expiry_date=expiry_date,
            has_a_pending_payment=False,
        )
        payment.save()

        user.deduct_wallet_funds(
            payment.amount, "Wallet payment for devices", payment.id
        )
        user.save()
        return True

    def verify_transfer_payment(self, data, payment) -> PaymentVerificationResponse:
        if not PAYMENT_BASE_URL:
            raise ValueError(
                "PAYMENT_BASE_URL is not set. Please set it in your environment variables."
            )
        response = requests.post(
            f"{PAYMENT_BASE_URL}/verify-payment",
            json=data,
            headers={"Content-Type": "application/json"},
        )
        logger.info("MIB Verification Response -> ", response)
        try:
            response.raise_for_status()
        except requests.exceptions.HTTPError as e:
            logger.error(f"HTTPError: {e}")
            return PaymentVerificationResponse(
                message="Payment verification failed.", success=False, transaction=None
            )
        mib_resp = response.json()
        logger.info("MIB Verification Response ->", mib_resp)
        if not response.json().get("success"):
            return PaymentVerificationResponse(
                message=mib_resp["message"],
                success=mib_resp["success"],
                transaction=None,
            )
        else:
            payment.paid = True
            payment.paid_at = timezone.now()
            payment.method = "TRANSFER"
            payment.mib_reference = mib_resp["transaction"]["ref"] or ""
            payment.save()
            return PaymentVerificationResponse(
                message=mib_resp["message"],
                success=mib_resp["success"],
                transaction=Transaction(
                    ref=payment.mib_reference,
                    sourceBank=mib_resp["transaction"]["sourceBank"],
                    trxDate=mib_resp["transaction"]["trxDate"],
                ),
            )


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

    def update(self, request, *args, **kwargs):
        instance = self.get_object()
        user = request.user
        if instance.status == "CANCELLED":
            return Response(
                {"message": "Payment has already been cancelled."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if instance.user != user and not user.is_superuser:
            return Response(
                {"message": "You are not authorized to cancel this payment."},
                status=status.HTTP_403_FORBIDDEN,
            )
        if instance.paid:
            return Response(
                {"message": "Paid payments cannot be cancelled."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        devices = instance.devices.all()
        instance.status = "CANCELLED"
        instance.save()
        devices.update(is_active=False, expiry_date=None, has_a_pending_payment=False)
        return super().update(request, *args, **kwargs)


class ListCreateTopupView(StaffEditorPermissionMixin, generics.ListCreateAPIView):
    queryset = Topup.objects.all().prefetch_related("user")
    serializer_class = TopupSerializer
    filter_backends = [DjangoFilterBackend]
    filterset_fields = "__all__"
    filterset_class = TopupFilter

    def create(self, request, *args, **kwargs):
        data = request.data
        user = request.user
        current_time = timezone.now()
        expires_at = current_time + timedelta(minutes=10)  # Topup expires in 10 minutes
        amount = data.get("amount")
        if not amount:
            return Response(
                {"message": "amount is required."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        topup = Topup.objects.create(amount=amount, user=user, expires_at=expires_at)
        serializer = TopupSerializer(topup)
        return Response(serializer.data, status=status.HTTP_201_CREATED)

    def get_queryset(self):
        queryset = super().get_queryset()
        if getattr(self.request.user, "is_admin") or self.request.user.is_superuser:
            return queryset
        return queryset.filter(user=self.request.user)

    def list(self, request, *args, **kwargs):
        queryset = self.filter_queryset(self.get_queryset())
        all_topups = request.query_params.get("all_topups", "false").lower() in [
            "true",
            "1",
            "yes",
        ]
        if (
            request.user.is_authenticated
            and getattr(request.user, "is_admin")
            and bool(all_topups)
        ):
            pass
        else:
            queryset = queryset.filter(user=request.user)

        page = self.paginate_queryset(queryset)
        if page is not None:
            serializer = self.get_serializer(page, many=True)
            return self.get_paginated_response(serializer.data)

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


class TopupDetailAPIView(StaffEditorPermissionMixin, generics.RetrieveAPIView):
    queryset = Topup.objects.all()
    serializer_class = TopupSerializer
    lookup_field = "pk"

    def get_queryset(self):
        queryset = super().get_queryset()
        if getattr(self.request.user, "is_admin") or self.request.user.is_superuser:
            return queryset
        return queryset.filter(user=self.request.user)


class VerifyTopupPaymentAPIView(StaffEditorPermissionMixin, generics.UpdateAPIView):
    queryset = Topup.objects.all()
    serializer_class = TopupSerializer
    lookup_field = "pk"

    def verify_transfer_topup(self, data, topup) -> PaymentVerificationResponse:
        if not PAYMENT_BASE_URL:
            raise ValueError(
                "PAYMENT_BASE_URL is not set. Please set it in your environment variables."
            )
        logger.info(data)
        response = requests.post(
            f"{PAYMENT_BASE_URL}/verify-payment",
            json=data,
            headers={"Content-Type": "application/json"},
        )
        try:
            response.raise_for_status()
        except requests.exceptions.HTTPError as e:
            logger.error(f"HTTPError: {e}")
            return PaymentVerificationResponse(
                message="Payment verification failed.", success=False, transaction=None
            )
        mib_resp = response.json()
        print(mib_resp)
        if not response.json().get("success"):
            return PaymentVerificationResponse(
                message=mib_resp["message"],
                success=mib_resp["success"],
                transaction=None,
            )
        else:
            topup.paid = True
            topup.mib_reference = mib_resp["transaction"]["ref"] or ""
            topup.paid_at = mib_resp["transaction"]["trxDate"]
            topup.save()
            return PaymentVerificationResponse(
                message=mib_resp["message"],
                success=mib_resp["success"],
                transaction=Transaction(
                    ref=topup.mib_reference,
                    sourceBank=mib_resp["transaction"]["sourceBank"],
                    trxDate=mib_resp["transaction"]["trxDate"],
                ),
            )

    def update(self, request, *args, **kwargs):
        topup_instance = self.get_object()
        user = request.user

        if topup_instance.paid:
            return Response(
                {"message": "Payment has already been verified."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if topup_instance.user != user and not user.is_superuser:
            return Response(
                {"message": "You are not allowed to pay for this topup."},
                status=status.HTTP_403_FORBIDDEN,
            )
        data = {
            "benefName": f"{user.first_name} {user.last_name}",  # type: ignore
            "accountNo": user.acc_no,  # type: ignore
            "absAmount": "{:.2f}".format(topup_instance.amount),
            "time": localtime(topup_instance.created_at).strftime("%Y-%m-%d %H:%M"),
        }
        logger.info(
            f"Verifying topup payment created at {localtime(topup_instance.created_at)}  with data: {data}"
        )
        topup_verification_response = self.verify_transfer_topup(data, topup_instance)
        print("Topup verification response:", topup_verification_response)
        if topup_verification_response.success:
            user.add_wallet_funds(  # type: ignore
                topup_instance.amount,
                f"Topup of {topup_instance.amount} MVR",
                topup_instance.id,
            )
            user.save()
            topup_instance.status = "PAID"
            topup_instance.save()
            return Response(
                {
                    "status": topup_verification_response.success,
                    "message": topup_verification_response.message,
                    "transaction": asdict(topup_verification_response.transaction)
                    if topup_verification_response.transaction
                    else None,
                },
                status=status.HTTP_200_OK,
            )
        else:
            return Response(
                {
                    "status": topup_verification_response.success,
                    "message": topup_verification_response.message
                    or "Topup payment verification failed.",
                },
                status=status.HTTP_400_BAD_REQUEST,
            )


class CancelTopupView(StaffEditorPermissionMixin, generics.UpdateAPIView):
    queryset = Topup.objects.all().select_related("user")
    serializer_class = TopupSerializer
    lookup_field = "pk"

    def update(self, request, *args, **kwargs):
        instance = self.get_object()
        user = request.user
        if instance.status == "CANCELLED":
            return Response(
                {"message": "Topup has already been cancelled."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if instance.is_expired:
            return Response(
                {"message": "Expired topups cannot be cancelled."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if (
            instance.user != user
            and getattr(user, "is_admin")
            and not user.is_superuser
        ):
            return Response(
                {"message": "You are not authorized to delete this topup."},
                status=status.HTTP_403_FORBIDDEN,
            )
        if instance.paid:
            return Response(
                {"message": "Paid topups cannot be deleted."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        instance.status = "CANCELLED"
        instance.save()
        return super().update(request, *args, **kwargs)


class AdminTopupCreateView(StaffEditorPermissionMixin, generics.CreateAPIView):
    queryset = Topup.objects.all().select_related("user")
    serializer_class = TopupSerializer

    def create(self, request, *args, **kwargs):
        data = request.data
        user_id = data.get("user_id")
        amount = data.get("amount")
        topup_description = ""
        admin_description = data.get("description", "")
        if not getattr(request.user, "is_admin", False):
            return Response(
                {"message": "You are not authorized to perform this action."},
                status=status.HTTP_403_FORBIDDEN,
            )
        if not user_id:
            return Response(
                {"message": "user_id is required."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        if not amount:
            return Response(
                {"message": "amount is required."},
                status=status.HTTP_400_BAD_REQUEST,
            )
        user = User.objects.filter(id=user_id).first()
        if not user:
            return Response(
                {"message": "User not found."},
                status=status.HTTP_404_NOT_FOUND,
            )
        topup = Topup.objects.create(
            amount=amount,
            user=user,
            paid=True,
            paid_at=timezone.now(),
            payment_type="CASH",
            status="PAID",
        )
        default_description = f"Topup of {amount} MVR (Cash)"
        if admin_description and admin_description.strip() != "":
            topup_description = admin_description.strip()
        else:
            topup_description = default_description
        user.add_wallet_funds(amount, topup_description, topup.id)
        serializer = TopupSerializer(topup)
        return Response(serializer.data, status=status.HTTP_201_CREATED)


class ListWalletTransactionView(StaffEditorPermissionMixin, generics.ListAPIView):
    serializer_class = WalletTransactionSerializer
    queryset = WalletTransaction.objects.all().select_related("user")
    filter_backends = [DjangoFilterBackend]
    filterset_fields = "__all__"
    filterset_class = WalletTransactionFilter

    def get_queryset(self):
        queryset = super().get_queryset()
        if getattr(self.request.user, "is_admin") or self.request.user.is_superuser:
            return queryset
        return queryset.filter(user=self.request.user)

    def list(self, request, *args, **kwargs):
        queryset = self.filter_queryset(self.get_queryset())
        all_transations = request.query_params.get(
            "all_transations", "false"
        ).lower() in [
            "true",
            "1",
            "yes",
        ]
        if (
            request.user.is_authenticated
            and getattr(request.user, "is_admin")
            and bool(all_transations)
        ):
            pass
        else:
            queryset = queryset.filter(user=request.user)

        page = self.paginate_queryset(queryset)
        if page is not None:
            serializer = self.get_serializer(page, many=True)
            return self.get_paginated_response(serializer.data)

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