import datetime
import pytz

from decimal import Decimal
from django.contrib.auth.models import User
from django.core.exceptions import ValidationError
from django.test import TestCase
from django.utils import timezone

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

from test_cart import RegistrationCartTestCase

UTC = pytz.timezone('UTC')

class CeilingsTestCases(RegistrationCartTestCase):

    def test_add_to_cart_ceiling_limit(self):
        self.make_ceiling("Limit ceiling", limit=9)
        self.__add_to_cart_test()

    def test_add_to_cart_ceiling_category_limit(self):
        self.make_category_ceiling("Limit ceiling", limit=9)
        self.__add_to_cart_test()

    def __add_to_cart_test(self):

        current_cart = CartController.for_user(self.USER_1)

        # User should not be able to add 10 of PROD_1 to the current cart
        # because it is affected by limit_ceiling
        with self.assertRaises(ValidationError):
            current_cart.add_to_cart(self.PROD_2, 10)

        # User should be able to add 5 of PROD_1 to the current cart
        current_cart.add_to_cart(self.PROD_1, 5)

        # User should not be able to add 6 of PROD_2 to the current cart
        # because it is affected by CEIL_1
        with self.assertRaises(ValidationError):
            current_cart.add_to_cart(self.PROD_2, 6)

        # User should be able to add 5 of PROD_2 to the current cart
        current_cart.add_to_cart(self.PROD_2, 4)


    def test_add_to_cart_ceiling_date_range(self):
        self.make_ceiling("date range ceiling",
            start_time=datetime.datetime(2015, 01, 01, tzinfo=UTC),
            end_time=datetime.datetime(2015, 02, 01, tzinfo=UTC)
        )

        current_cart = CartController.for_user(self.USER_1)

        # User should not be able to add whilst we're before start_time
        self.set_time(datetime.datetime(2014, 01, 01, tzinfo=UTC))
        with self.assertRaises(ValidationError):
            current_cart.add_to_cart(self.PROD_1, 1)

        # User should be able to add whilst we're during date range
        # On edge of start
        self.set_time(datetime.datetime(2015, 01, 01, tzinfo=UTC))
        current_cart.add_to_cart(self.PROD_1, 1)
        # In middle
        self.set_time(datetime.datetime(2015, 01, 15, tzinfo=UTC))
        current_cart.add_to_cart(self.PROD_1, 1)
        # On edge of end
        self.set_time(datetime.datetime(2015, 02, 01, tzinfo=UTC))
        current_cart.add_to_cart(self.PROD_1, 1)

        # User should not be able to add whilst we're after date range
        self.set_time(datetime.datetime(2014, 01, 01, minute=01, tzinfo=UTC))
        with self.assertRaises(ValidationError):
            current_cart.add_to_cart(self.PROD_1, 1)


    def test_add_to_cart_ceiling_limit_reserved_carts(self):
        self.make_ceiling("Limit ceiling", limit=1)

        self.set_time(datetime.datetime(2015, 01, 01, tzinfo=UTC))

        first_cart = CartController.for_user(self.USER_1)
        second_cart = CartController.for_user(self.USER_2)

        first_cart.add_to_cart(self.PROD_1, 1)

        # User 2 should not be able to add item to their cart
        # because user 1 has item reserved, exhausting the ceiling
        with self.assertRaises(ValidationError):
            second_cart.add_to_cart(self.PROD_1, 1)

        # User 2 should be able to add item to their cart once the
        # reservation duration is elapsed
        self.add_timedelta(self.RESERVATION + datetime.timedelta(seconds=1))
        second_cart.add_to_cart(self.PROD_1, 1)

        # User 2 pays for their cart
        second_cart.cart.active = False
        second_cart.cart.save()

        # User 1 should not be able to add item to their cart
        # because user 2 has paid for their reserved item, exhausting
        # the ceiling, regardless of the reservation time.
        self.add_timedelta(self.RESERVATION * 20)
        with self.assertRaises(ValidationError):
            first_cart.add_to_cart(self.PROD_1, 1)


    def test_validate_cart_fails_product_ceilings(self):
        self.make_ceiling("Limit ceiling", limit=1)
        self.__validation_test()

    def test_validate_cart_fails_product_discount_ceilings(self):
        self.make_discount_ceiling("Limit ceiling", limit=1)
        self.__validation_test()

    def __validation_test(self):
        self.set_time(datetime.datetime(2015, 01, 01, tzinfo=UTC))

        first_cart = CartController.for_user(self.USER_1)
        second_cart = CartController.for_user(self.USER_2)

        # Adding a valid product should validate.
        first_cart.add_to_cart(self.PROD_1, 1)
        first_cart.validate_cart()

        # Cart should become invalid if lapsed carts are claimed.
        self.add_timedelta(self.RESERVATION + datetime.timedelta(seconds=1))

        # Unpaid cart within reservation window
        second_cart.add_to_cart(self.PROD_1, 1)
        with self.assertRaises(ValidationError):
            first_cart.validate_cart()

        # Paid cart outside the reservation window
        second_cart.cart.active = False
        second_cart.cart.save()
        self.add_timedelta(self.RESERVATION + datetime.timedelta(seconds=1))
        with self.assertRaises(ValidationError):
            first_cart.validate_cart()