from django.contrib.auth import get_user_model
from django.core import mail
from django.db import IntegrityError
from django.test import TestCase, override_settings
from django.urls import reverse

from items.models import Category, Item, ItemImage, Subcategory
from orders.models import Cart, CartItem, Order, OrderItem


User = get_user_model()


@override_settings(
    MEDIA_URL="/media/",
    EMAIL_BACKEND="django.core.mail.backends.locmem.EmailBackend",
    ADMINISTRATOR_EMAIL="admin@example.com",
)
class CartFlowTests(TestCase):
    def setUp(self):
        self.user = User.objects.create_user(
            username="cart-user",
            email="cart@example.com",
            password="StrongPassword123",
            is_active=True,
        )
        self.category = Category.objects.create(name="Сантехника", slug="plumbing")
        self.subcategory = Subcategory.objects.create(name="Мойки", slug="sinks", category=self.category)
        self.item = Item.objects.create(
            name="Кухонная мойка",
            slug="kitchen-sink",
            category=self.category,
            subcategory=self.subcategory,
            description="Искусственный камень",
            price="1600.00",
            is_available=True,
        )
        self.unavailable_item = Item.objects.create(
            name="Смеситель",
            slug="tap",
            category=self.category,
            subcategory=self.subcategory,
            description="Недоступный товар",
            price="400.00",
            is_available=False,
        )

    def checkout_data(self, **overrides):
        data = {
            "delivery_method": "courier",
            "region": "Минск",
            "address": "ул. Тимирязева, 123",
            "payment_method": "card",
            "customer_name": "Иван Петров",
            "phone": "+375296881819",
            "email": "buyer@example.com",
            "recipient_matches_customer": "on",
            "promo_code": "SPRING",
            "terms_accepted": "on",
        }
        data.update(overrides)
        return data

    def test_cart_item_is_unique_per_cart(self):
        cart = Cart.objects.create(user=self.user)
        CartItem.objects.create(cart=cart, item=self.item, quantity=1)

        with self.assertRaises(IntegrityError):
            CartItem.objects.create(cart=cart, item=self.item, quantity=2)

    def test_add_remove_and_update_quantity_for_authenticated_user(self):
        self.client.force_login(self.user)

        add_response = self.client.post(
            reverse("orders:add"),
            data={"item_id": self.item.id, "next": reverse("orders:cart")},
        )
        self.assertRedirects(add_response, reverse("orders:cart"))
        self.assertTrue(CartItem.objects.filter(cart__user=self.user, item=self.item, quantity=1).exists())

        update_response = self.client.post(
            reverse("orders:update_quantity"),
            data={"item_id": self.item.id, "quantity": 3, "next": reverse("orders:cart")},
        )
        self.assertRedirects(update_response, reverse("orders:cart"))
        self.assertTrue(CartItem.objects.filter(cart__user=self.user, item=self.item, quantity=3).exists())

        remove_response = self.client.post(
            reverse("orders:remove"),
            data={"item_id": self.item.id, "next": reverse("orders:cart")},
        )
        self.assertRedirects(remove_response, reverse("orders:cart"))
        self.assertFalse(CartItem.objects.filter(cart__user=self.user, item=self.item).exists())

    def test_add_endpoint_rejects_unavailable_item(self):
        self.client.force_login(self.user)

        response = self.client.post(
            reverse("orders:add"),
            data={"item_id": self.unavailable_item.id, "next": reverse("orders:cart")},
            follow=True,
        )

        self.assertEqual(response.status_code, 200)
        self.assertFalse(CartItem.objects.filter(cart__user=self.user, item=self.unavailable_item).exists())
        self.assertContains(response, "Недоступный товар нельзя добавить в корзину.")

    def test_cart_page_shows_authenticated_user_items(self):
        cart = Cart.objects.create(user=self.user)
        CartItem.objects.create(cart=cart, item=self.item, quantity=2)
        ItemImage.objects.create(
            item=self.item,
            image="items/cart-item.jpg",
            alt="Фото мойки",
            is_primary=True,
        )
        self.client.force_login(self.user)

        response = self.client.get(reverse("orders:cart"))

        self.assertEqual(response.status_code, 200)
        self.assertContains(response, "Кухонная мойка")
        self.assertContains(response, "Оформление заказа")
        self.assertContains(response, "1600,00 руб.")
        self.assertContains(response, "3200,00 руб.")
        self.assertContains(response, "3745,00 руб.")
        self.assertContains(response, "/media/items/cart-item.jpg")

    def test_cart_page_redirects_guest_to_login(self):
        response = self.client.get(reverse("orders:cart"))

        self.assertEqual(response.status_code, 302)
        self.assertIn(reverse("users:login"), response["Location"])

    def test_checkout_creates_paid_order_clears_cart_and_sends_email(self):
        cart = Cart.objects.create(user=self.user)
        CartItem.objects.create(cart=cart, item=self.item, quantity=2)
        self.client.force_login(self.user)

        response = self.client.post(reverse("orders:checkout"), data=self.checkout_data())

        order = Order.objects.get()
        self.assertRedirects(response, reverse("orders:success", kwargs={"order_id": order.id}))
        self.assertEqual(order.status, Order.Status.PAID)
        self.assertEqual(order.products_total, 3200)
        self.assertEqual(order.discount_total, 0)
        self.assertEqual(order.delivery_total, 500)
        self.assertEqual(order.floor_lift_total, 45)
        self.assertEqual(order.total, 3745)
        self.assertEqual(order.promo_code, "SPRING")
        self.assertFalse(CartItem.objects.filter(cart=cart).exists())

        order_item = OrderItem.objects.get(order=order)
        self.assertEqual(order_item.item_name, "Кухонная мойка")
        self.assertEqual(order_item.quantity, 2)
        self.assertEqual(order_item.line_total, 3200)

        self.assertEqual(len(mail.outbox), 1)
        self.assertEqual(mail.outbox[0].to, ["buyer@example.com"])
        self.assertEqual(mail.outbox[0].bcc, ["admin@example.com"])
        self.assertIn(f"заказ №{order.id}", mail.outbox[0].subject.lower())
        self.assertIn("Кухонная мойка", mail.outbox[0].body)

    def test_checkout_rejects_empty_cart(self):
        self.client.force_login(self.user)

        response = self.client.post(reverse("orders:checkout"), data=self.checkout_data())

        self.assertRedirects(response, reverse("orders:cart"))
        self.assertFalse(Order.objects.exists())
        self.assertEqual(len(mail.outbox), 0)

    def test_checkout_requires_address_for_courier_delivery(self):
        cart = Cart.objects.create(user=self.user)
        CartItem.objects.create(cart=cart, item=self.item, quantity=1)
        self.client.force_login(self.user)

        response = self.client.post(
            reverse("orders:checkout"),
            data=self.checkout_data(region="", address=""),
        )

        self.assertEqual(response.status_code, 400)
        self.assertContains(response, "Укажите регион доставки.", status_code=400)
        self.assertContains(response, "Укажите адрес доставки.", status_code=400)
        self.assertFalse(Order.objects.exists())

    def test_checkout_pickup_does_not_require_address_or_add_services(self):
        cart = Cart.objects.create(user=self.user)
        CartItem.objects.create(cart=cart, item=self.item, quantity=1)
        self.client.force_login(self.user)

        response = self.client.post(
            reverse("orders:checkout"),
            data=self.checkout_data(delivery_method="pickup", region="", address=""),
        )

        order = Order.objects.get()
        self.assertRedirects(response, reverse("orders:success", kwargs={"order_id": order.id}))
        self.assertEqual(order.delivery_total, 0)
        self.assertEqual(order.floor_lift_total, 0)
        self.assertEqual(order.total, 1600)

    def test_success_page_is_only_available_to_order_owner(self):
        other_user = User.objects.create_user(
            username="other-user",
            email="other@example.com",
            password="StrongPassword123",
            is_active=True,
        )
        order = Order.objects.create(
            user=self.user,
            customer_name="Иван Петров",
            phone="+375296881819",
            email="buyer@example.com",
            delivery_method=Order.DeliveryMethod.COURIER,
            region="Минск",
            address="ул. Тимирязева, 123",
            payment_method=Order.PaymentMethod.CARD,
            products_total=1600,
            discount_total=0,
            delivery_total=500,
            floor_lift_total=45,
            total=2145,
            status=Order.Status.PAID,
        )
        self.client.force_login(other_user)

        response = self.client.get(reverse("orders:success", kwargs={"order_id": order.id}))

        self.assertEqual(response.status_code, 404)