from decimal import Decimal

from django.db.models.deletion import ProtectedError
from django.utils.text import gettext_lazy as _
from django.shortcuts import get_object_or_404
from django.db import transaction

from rest_framework.viewsets import ModelViewSet
from rest_framework.exceptions import ValidationError
from rest_framework.permissions import IsAdminUser

from shop.api.v1.filters import ProductFilter
from shop.api.v1.serializers import (
    ProductSerializer,
    ProductPriceSerializer,
    CustomerSerializer,
    TaxSerializer,
    OrderSerializer,
    OrderLineSerializer,
    ProviderSerializer,
    ProductBatchSerializer,
    CreateProductSerializer,
    CreateProductPriceSerializer,
    TagSerializer,
    ListProductSerializer,
    UpdateProductSerializer,
    BrandSerializer,
)
from shop.models import (
    Product,
    ProductPrice,
    Customer,
    Tax,
    Order,
    OrderLine,
    Provider,
    ProductBatch,
    Tag,
    Brand,
)

from shop.api.v1.permissions import ProductPermissions, ProductPricePermissions
from shop.utils import delete_product_batch


class ProductViewSet(ModelViewSet):
    serializer_class = ProductSerializer
    queryset = (
        Product.objects.prefetch_related("prices")
        .prefetch_related("tags")
        .prefetch_related("images")
        .all()
    )
    permission_classes = (
        IsAdminUser,
        ProductPermissions,
    )
    search_fields = ("name",)
    filterset_class = ProductFilter

    def get_serializer_class(self):
        if self.action == "create":
            return CreateProductSerializer
        elif self.action == "list":
            return ListProductSerializer
        elif self.action in ("update", "partial_update"):
            return UpdateProductSerializer
        return self.serializer_class

    def perform_destroy(self, instance):
        try:
            super().perform_destroy(instance)
        except ProtectedError:
            raise ValidationError(_("No se puede borrar el producto"))


class ProductPriceViewSet(ModelViewSet):
    serializer_class = ProductPriceSerializer
    queryset = ProductPrice.objects.all()
    permission_classes = (
        IsAdminUser,
        ProductPricePermissions,
    )

    def get_queryset(self):
        return super().get_queryset().filter(product_id=self.kwargs.get("product_id"))

    def get_serializer_class(self):
        if self.action == "create":
            return CreateProductPriceSerializer
        return self.serializer_class

    def perform_create(self, serializer):
        product = get_object_or_404(Product, pk=self.kwargs.get("product_id"))
        product.prices.all().update(current=False)
        serializer.save(product=product, current=True)


class ProductBatchViewSet(ModelViewSet):
    serializer_class = ProductBatchSerializer
    queryset = ProductBatch.objects.all()
    permission_classes = (IsAdminUser,)

    def perform_create(self, serializer):
        instance = serializer.save()
        product = instance.product
        product.stock += instance.quantity
        product.save()

    def perform_destroy(self, instance):
        delete_product_batch(instance)

    def perform_update(self, serializer):
        instance = self.get_object()
        product = instance.product
        product.stock -= instance.quantity

        updated_batch = serializer.save()
        product.stock += updated_batch.quantity
        product.save()


class CustomerViewSet(ModelViewSet):
    serializer_class = CustomerSerializer
    queryset = Customer.objects.all()
    permission_classes = (IsAdminUser,)


class ProviderViewSet(ModelViewSet):
    serializer_class = ProviderSerializer
    queryset = Provider.objects.all()
    permission_classes = (IsAdminUser,)


class TaxViewSet(ModelViewSet):
    serializer_class = TaxSerializer
    queryset = Tax.objects.all()
    permission_classes = (IsAdminUser,)
    search_fields = ("code",)


class OrderViewSet(ModelViewSet):
    serializer_class = OrderSerializer
    queryset = Order.objects.all()
    lookup_field = "uuid"


class OrderLineViewSet(ModelViewSet):
    serializer_class = OrderLineSerializer
    queryset = OrderLine.objects.all()

    def perform_create(self, serializer):
        with transaction.atomic():
            order = get_object_or_404(Order, uuid=self.kwargs.get("order_id"))
            product = serializer.validated_data.get("product")
            price = product.prices.last()
            tax = price.tax.value
            quantity = serializer.validated_data.get("quantity")
            base_total = quantity * price.price
            taxes = base_total * (tax / Decimal("100"))
            total = base_total + taxes

            instance = serializer.save(
                order=order,
                price=price.price,
                base_total=base_total,
                tax_value=tax,
                taxes=taxes,
                total=total,
            )

            order.base_total += instance.base_total
            order.total += instance.total
            order.save()

    def perform_destroy(self, instance):
        order = instance.order

        with transaction.atomic():
            order.base_total -= instance.base_total
            order.total -= instance.total
            instance.delete()
            order.save()

    def get_queryset(self):
        return (
            super()
            .get_queryset()
            .select_related("order")
            .filter(order__uuid=self.kwargs.get("order_id"))
        )


class TagViewSet(ModelViewSet):
    serializer_class = TagSerializer
    queryset = Tag.objects.all()
    permission_classes = (IsAdminUser,)


class BrandViewSet(ModelViewSet):
    serializer_class = BrandSerializer
    queryset = Brand.objects.all()
    permission_classes = (IsAdminUser,)
    search_fields = ("name",)