import pytz

from django.core.exceptions import ValidationError

from registrasion import models as rego
from registrasion.controllers.cart import CartController

from test_cart import RegistrationCartTestCase

UTC = pytz.timezone('UTC')


class EnablingConditionTestCases(RegistrationCartTestCase):

    @classmethod
    def add_product_enabling_condition(cls, mandatory=False):
        ''' Adds a product enabling condition: adding PROD_1 to a cart is
        predicated on adding PROD_2 beforehand. '''
        enabling_condition = rego.ProductEnablingCondition.objects.create(
            description="Product condition",
            mandatory=mandatory,
        )
        enabling_condition.save()
        enabling_condition.products.add(cls.PROD_1)
        enabling_condition.enabling_products.add(cls.PROD_2)
        enabling_condition.save()

    @classmethod
    def add_product_enabling_condition_on_category(cls, mandatory=False):
        ''' Adds a product enabling condition that operates on a category:
        adding an item from CAT_1 is predicated on adding PROD_3 beforehand '''
        enabling_condition = rego.ProductEnablingCondition.objects.create(
            description="Product condition",
            mandatory=mandatory,
        )
        enabling_condition.save()
        enabling_condition.categories.add(cls.CAT_1)
        enabling_condition.enabling_products.add(cls.PROD_3)
        enabling_condition.save()

    def add_category_enabling_condition(cls, mandatory=False):
        ''' Adds a category enabling condition: adding PROD_1 to a cart is
        predicated on adding an item from CAT_2 beforehand.'''
        enabling_condition = rego.CategoryEnablingCondition.objects.create(
            description="Category condition",
            mandatory=mandatory,
            enabling_category=cls.CAT_2,
        )
        enabling_condition.save()
        enabling_condition.products.add(cls.PROD_1)
        enabling_condition.save()

    def test_product_enabling_condition_enables_product(self):
        self.add_product_enabling_condition()

        # Cannot buy PROD_1 without buying PROD_2
        current_cart = CartController.for_user(self.USER_1)
        with self.assertRaises(ValidationError):
            current_cart.add_to_cart(self.PROD_1, 1)

        current_cart.add_to_cart(self.PROD_2, 1)
        current_cart.add_to_cart(self.PROD_1, 1)

    def test_product_enabled_by_product_in_previous_cart(self):
        self.add_product_enabling_condition()

        current_cart = CartController.for_user(self.USER_1)
        current_cart.add_to_cart(self.PROD_2, 1)
        current_cart.cart.active = False
        current_cart.cart.save()

        # Create new cart and try to add PROD_1
        current_cart = CartController.for_user(self.USER_1)
        current_cart.add_to_cart(self.PROD_1, 1)

    def test_product_enabling_condition_enables_category(self):
        self.add_product_enabling_condition_on_category()

        # Cannot buy PROD_1 without buying item from CAT_2
        current_cart = CartController.for_user(self.USER_1)
        with self.assertRaises(ValidationError):
            current_cart.add_to_cart(self.PROD_1, 1)

        current_cart.add_to_cart(self.PROD_3, 1)
        current_cart.add_to_cart(self.PROD_1, 1)

    def test_category_enabling_condition_enables_product(self):
        self.add_category_enabling_condition()

        # Cannot buy PROD_1 without buying PROD_2
        current_cart = CartController.for_user(self.USER_1)
        with self.assertRaises(ValidationError):
            current_cart.add_to_cart(self.PROD_1, 1)

        # PROD_3 is in CAT_2
        current_cart.add_to_cart(self.PROD_3, 1)
        current_cart.add_to_cart(self.PROD_1, 1)

    def test_product_enabled_by_category_in_previous_cart(self):
        self.add_category_enabling_condition()

        current_cart = CartController.for_user(self.USER_1)
        current_cart.add_to_cart(self.PROD_3, 1)
        current_cart.cart.active = False
        current_cart.cart.save()

        # Create new cart and try to add PROD_1
        current_cart = CartController.for_user(self.USER_1)
        current_cart.add_to_cart(self.PROD_1, 1)

    def test_multiple_non_mandatory_conditions(self):
        self.add_product_enabling_condition()
        self.add_category_enabling_condition()

        # User 1 is testing the product enabling condition
        cart_1 = CartController.for_user(self.USER_1)
        # Cannot add PROD_1 until a condition is met
        with self.assertRaises(ValidationError):
            cart_1.add_to_cart(self.PROD_1, 1)
        cart_1.add_to_cart(self.PROD_2, 1)
        cart_1.add_to_cart(self.PROD_1, 1)

        # User 2 is testing the category enabling condition
        cart_2 = CartController.for_user(self.USER_2)
        # Cannot add PROD_1 until a condition is met
        with self.assertRaises(ValidationError):
            cart_2.add_to_cart(self.PROD_1, 1)
        cart_2.add_to_cart(self.PROD_3, 1)
        cart_2.add_to_cart(self.PROD_1, 1)

    def test_multiple_mandatory_conditions(self):
        self.add_product_enabling_condition(mandatory=True)
        self.add_category_enabling_condition(mandatory=True)

        cart_1 = CartController.for_user(self.USER_1)
        # Cannot add PROD_1 until both conditions are met
        with self.assertRaises(ValidationError):
            cart_1.add_to_cart(self.PROD_1, 1)
        cart_1.add_to_cart(self.PROD_2, 1)  # Meets the product condition
        with self.assertRaises(ValidationError):
            cart_1.add_to_cart(self.PROD_1, 1)
        cart_1.add_to_cart(self.PROD_3, 1)  # Meets the category condition
        cart_1.add_to_cart(self.PROD_1, 1)

    def test_mandatory_conditions_are_mandatory(self):
        self.add_product_enabling_condition(mandatory=False)
        self.add_category_enabling_condition(mandatory=True)

        cart_1 = CartController.for_user(self.USER_1)
        # Cannot add PROD_1 until both conditions are met
        with self.assertRaises(ValidationError):
            cart_1.add_to_cart(self.PROD_1, 1)
        cart_1.add_to_cart(self.PROD_2, 1)  # Meets the product condition
        with self.assertRaises(ValidationError):
            cart_1.add_to_cart(self.PROD_1, 1)
        cart_1.add_to_cart(self.PROD_3, 1)  # Meets the category condition
        cart_1.add_to_cart(self.PROD_1, 1)