import time
from datetime import datetime, timedelta
from http import cookies

from django.http import HttpResponse
from django.test import SimpleTestCase
from django.test.utils import freeze_time
from django.utils.http import http_date
from django.utils.timezone import utc


class SetCookieTests(SimpleTestCase):

    def test_near_expiration(self):
        """Cookie will expire when a near expiration time is provided."""
        response = HttpResponse()
        # There's a timing weakness in this test; The expected result for
        # max-age requires that there be a very slight difference between the
        # evaluated expiration time and the time evaluated in set_cookie(). If
        # this difference doesn't exist, the cookie time will be 1 second
        # larger. The sleep guarantees that there will be a time difference.
        expires = datetime.utcnow() + timedelta(seconds=10)
        time.sleep(0.001)
        response.set_cookie('datetime', expires=expires)
        datetime_cookie = response.cookies['datetime']
        self.assertEqual(datetime_cookie['max-age'], 10)

    def test_aware_expiration(self):
        """set_cookie() accepts an aware datetime as expiration time."""
        response = HttpResponse()
        expires = (datetime.utcnow() + timedelta(seconds=10)).replace(tzinfo=utc)
        time.sleep(0.001)
        response.set_cookie('datetime', expires=expires)
        datetime_cookie = response.cookies['datetime']
        self.assertEqual(datetime_cookie['max-age'], 10)

    def test_create_cookie_after_deleting_cookie(self):
        """Setting a cookie after deletion clears the expiry date."""
        response = HttpResponse()
        response.set_cookie('c', 'old-value')
        self.assertEqual(response.cookies['c']['expires'], '')
        response.delete_cookie('c')
        self.assertEqual(response.cookies['c']['expires'], 'Thu, 01 Jan 1970 00:00:00 GMT')
        response.set_cookie('c', 'new-value')
        self.assertEqual(response.cookies['c']['expires'], '')

    def test_far_expiration(self):
        """Cookie will expire when a distant expiration time is provided."""
        response = HttpResponse()
        response.set_cookie('datetime', expires=datetime(2038, 1, 1, 4, 5, 6))
        datetime_cookie = response.cookies['datetime']
        self.assertIn(
            datetime_cookie['expires'],
            # assertIn accounts for slight time dependency (#23450)
            ('Fri, 01 Jan 2038 04:05:06 GMT', 'Fri, 01 Jan 2038 04:05:07 GMT')
        )

    def test_max_age_expiration(self):
        """Cookie will expire if max_age is provided."""
        response = HttpResponse()
        set_cookie_time = time.time()
        with freeze_time(set_cookie_time):
            response.set_cookie('max_age', max_age=10)
        max_age_cookie = response.cookies['max_age']
        self.assertEqual(max_age_cookie['max-age'], 10)
        self.assertEqual(max_age_cookie['expires'], http_date(set_cookie_time + 10))

    def test_httponly_cookie(self):
        response = HttpResponse()
        response.set_cookie('example', httponly=True)
        example_cookie = response.cookies['example']
        self.assertIn('; %s' % cookies.Morsel._reserved['httponly'], str(example_cookie))
        self.assertIs(example_cookie['httponly'], True)

    def test_unicode_cookie(self):
        """HttpResponse.set_cookie() works with Unicode data."""
        response = HttpResponse()
        cookie_value = '清風'
        response.set_cookie('test', cookie_value)
        self.assertEqual(response.cookies['test'].value, cookie_value)

    def test_samesite(self):
        response = HttpResponse()
        response.set_cookie('example', samesite='None')
        self.assertEqual(response.cookies['example']['samesite'], 'None')
        response.set_cookie('example', samesite='Lax')
        self.assertEqual(response.cookies['example']['samesite'], 'Lax')
        response.set_cookie('example', samesite='strict')
        self.assertEqual(response.cookies['example']['samesite'], 'strict')

    def test_invalid_samesite(self):
        msg = 'samesite must be "lax", "none", or "strict".'
        with self.assertRaisesMessage(ValueError, msg):
            HttpResponse().set_cookie('example', samesite='invalid')


class DeleteCookieTests(SimpleTestCase):

    def test_default(self):
        response = HttpResponse()
        response.delete_cookie('c')
        cookie = response.cookies['c']
        self.assertEqual(cookie['expires'], 'Thu, 01 Jan 1970 00:00:00 GMT')
        self.assertEqual(cookie['max-age'], 0)
        self.assertEqual(cookie['path'], '/')
        self.assertEqual(cookie['secure'], '')
        self.assertEqual(cookie['domain'], '')
        self.assertEqual(cookie['samesite'], '')

    def test_delete_cookie_secure_prefix(self):
        """
        delete_cookie() sets the secure flag if the cookie name starts with
        __Host- or __Secure- (without that, browsers ignore cookies with those
        prefixes).
        """
        response = HttpResponse()
        for prefix in ('Secure', 'Host'):
            with self.subTest(prefix=prefix):
                cookie_name = '__%s-c' % prefix
                response.delete_cookie(cookie_name)
                self.assertIs(response.cookies[cookie_name]['secure'], True)

    def test_delete_cookie_secure_samesite_none(self):
        # delete_cookie() sets the secure flag if samesite='none'.
        response = HttpResponse()
        response.delete_cookie('c', samesite='none')
        self.assertIs(response.cookies['c']['secure'], True)

    def test_delete_cookie_samesite(self):
        response = HttpResponse()
        response.delete_cookie('c', samesite='lax')
        self.assertEqual(response.cookies['c']['samesite'], 'lax')
