from django.contrib.auth import get_user_model
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


User = get_user_model()


@override_settings(MEDIA_URL="/media/")
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 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, "1600,00 руб.")
        self.assertContains(response, "3200,00 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"])