from decimal import Decimal as D
from unittest import mock

from django.test import TestCase

from oscar.apps.checkout import calculators
from oscar.core import prices
from oscar.core.loading import get_class

SurchargeApplicator = get_class("checkout.applicator", "SurchargeApplicator")


class TestOrderTotalCalculator(TestCase):

    def setUp(self):
        self.calculator = calculators.OrderTotalCalculator()

    def test_returns_correct_totals_when_tax_is_not_known(self):
        basket = mock.Mock()
        basket.total_excl_tax = D('10.00')
        basket.is_tax_known = False

        shipping_charge = prices.Price(
            currency=basket.currency, excl_tax=D('5.00'))

        applicator = SurchargeApplicator()
        surcharges = applicator.get_applicable_surcharges(basket)

        total = self.calculator.calculate(basket, shipping_charge, surcharges)

        self.assertIsInstance(total, prices.Price)
        self.assertEqual(D('10.00') + D('5.00') + D('10.0'), total.excl_tax)
        self.assertFalse(total.is_tax_known)

    def test_returns_correct_totals_when_tax_is_known(self):
        basket = mock.Mock()
        basket.total_excl_tax = D('10.00')
        basket.total_incl_tax = D('12.00')
        basket.is_tax_known = True

        shipping_charge = prices.Price(
            currency=basket.currency, excl_tax=D('5.00'),
            tax=D('0.50'))

        applicator = SurchargeApplicator()
        surcharges = applicator.get_applicable_surcharges(basket)

        total = self.calculator.calculate(basket, shipping_charge, surcharges)

        self.assertIsInstance(total, prices.Price)
        self.assertEqual(D('10.00') + D('5.00') + D('20.0'), total.excl_tax)
        self.assertTrue(total.is_tax_known)
        self.assertEqual(D('12.00') + D('5.50') + D('22.00'), total.incl_tax)
        self.assertEqual(D('2.00') + D('0.50') + D('2.00'), total.tax)