from django.shortcuts import render
from django.db import transaction
from django.contrib.auth import get_user_model
from rest_framework import viewsets, permissions, status, views
from rest_framework.renderers import TemplateHTMLRenderer
from rest_framework.response import Response
from rest_framework.decorators import action
from rest_framework.reverse import reverse
from rest_framework.decorators import renderer_classes

import json

from .models import *
from .serializers import *
from datetime import datetime
import uncloud_pay.stripe as uncloud_stripe

###
# Standard user views:

class BalanceViewSet(viewsets.ViewSet):
    # here we return a number
    # number = sum(payments) - sum(bills)

    #bills = Bill.objects.filter(owner=self.request.user)
    #payments = Payment.objects.filter(owner=self.request.user)

    # sum_paid = sum([ amount for amount payments..,.  ]) # you get the picture
    # sum_to_be_paid = sum([ amount for amount bills..,.  ]) # you get the picture
    pass


class BillViewSet(viewsets.ReadOnlyModelViewSet):
    serializer_class = BillSerializer
    permission_classes = [permissions.IsAuthenticated]

    def get_queryset(self):
        return Bill.objects.filter(owner=self.request.user)

class PaymentViewSet(viewsets.ReadOnlyModelViewSet):
    serializer_class = PaymentSerializer
    permission_classes = [permissions.IsAuthenticated]

    def get_queryset(self):
        return Payment.objects.filter(owner=self.request.user)

class OrderViewSet(viewsets.ReadOnlyModelViewSet):
    serializer_class = OrderSerializer
    permission_classes = [permissions.IsAuthenticated]

    def get_queryset(self):
        return Order.objects.filter(owner=self.request.user)

class UserViewSet(viewsets.ReadOnlyModelViewSet):
    serializer_class = UserSerializer
    permission_classes = [permissions.IsAuthenticated]

    def get_queryset(self):
        return get_user_model().objects.all()

class PaymentMethodViewSet(viewsets.ModelViewSet):
    permission_classes = [permissions.IsAuthenticated]

    def get_serializer_class(self):
        if self.action == 'create':
            return CreatePaymentMethodSerializer
        elif self.action == 'charge':
            return ChargePaymentMethodSerializer
        else:
            return PaymentMethodSerializer

    def get_queryset(self):
        return PaymentMethod.objects.filter(owner=self.request.user)

    # XXX: Handling of errors is far from great down there.
    @transaction.atomic
    def create(self, request):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        payment_method = PaymentMethod.objects.create(owner=request.user, **serializer.validated_data)

        if serializer.validated_data['source'] == "stripe":
            # Retrieve Stripe customer ID for user.
            customer_id  = uncloud_stripe.get_customer_id_for(request.user)
            if customer_id == None:
                return Response(
                    {'error': 'Could not resolve customer stripe ID.'},
                    status=status.HTTP_500_INTERNAL_SERVER_ERROR)

            # TODO: handle error
            setup_intent = uncloud_stripe.create_setup_intent(customer_id)
            payment_method = PaymentMethod.objects.create(
                    owner=request.user,
                    stripe_setup_intent_id=setup_intent['response_object']['id'],
                    **serializer.validated_data)

            # TODO: find a way to use reverse properly:
            # https://www.django-rest-framework.org/api-guide/reverse/
            query= "payment-method/{}/register-stripe-cc".format(
                    payment_method.uuid
                    )
            stripe_registration_url = reverse('api-root', request=request) + query
            return Response({'please_visit': stripe_registration_url})

        return Response(serializer.data)

    @action(detail=True, methods=['post'])
    def charge(self, request, pk=None):
        payment_method = self.get_object()
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        amount = serializer.validated_data['amount']
        try:
            payment = payment_method.charge(amount)
            output_serializer = PaymentSerializer(payment)
            return Response(output_serializer.data)
        except Exception as e:
            return Response({'error': str(e)}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)

    @action(detail=True, methods=['get'], url_path='register-stripe-cc', renderer_classes=[TemplateHTMLRenderer])
    def register_stripe_cc(self, request, pk=None):
        payment_method = self.get_object()
        setup_intent = uncloud_stripe.get_setup_intent(
                payment_method.stripe_setup_intent_id)

        # Render stripe card registration form.
        template_args = {
                'client_secret': setup_intent["response_object"]["client_secret"],
                'stripe_pk': uncloud_stripe.public_api_key
                }
        return Response(template_args, template_name='stripe-payment.html.j2')

    @action(detail=True, methods=['post'], url_path='register-stripe-cc')
    def register_stripe_cc(self, request, pk=None):
        payment_method = self.get_object()
        setup_intent = uncloud_stripe.get_setup_intent(
                payment_method.stripe_setup_intent_id)

        # Card had been registered, fetching payment method.
        payment_method_id = setup_intent["response_object"].payment_method
        if payment_method_id:
            payment_method.stripe_payment_method_id = payment_method_id
            payment_method.save()

            return Response({
                'uuid': payment_method.uuid,
                'activated': payment_method.active})
        else:
            error = 'Could not fetch payment method from stripe. Please try again.'
            return Response({'error': error})


###
# Admin views.

class AdminPaymentViewSet(viewsets.ModelViewSet):
    serializer_class = PaymentSerializer
    permission_classes = [permissions.IsAuthenticated]

    def get_queryset(self):
        return Payment.objects.all()

    def create(self, request):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        serializer.save(timestamp=datetime.now())

        headers = self.get_success_headers(serializer.data)
        return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)

class AdminBillViewSet(viewsets.ModelViewSet):
    serializer_class = BillSerializer
    permission_classes = [permissions.IsAuthenticated]

    def get_queryset(self):
        return Bill.objects.all()

    def unpaid(self, request):
        return Bill.objects.filter(owner=self.request.user, paid=False)

    def create(self, request):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        serializer.save(creation_date=datetime.now())

        headers = self.get_success_headers(serializer.data)
        return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)

class AdminOrderViewSet(viewsets.ModelViewSet):
    serializer_class = OrderSerializer
    permission_classes = [permissions.IsAuthenticated]

    def get_queryset(self):
        return Order.objects.all()