from django.contrib.auth import views as auth_views


url(r"^accounts/password_change/$",
    auth_views.PasswordChangeView.as_view(),
    name="password_change"),
url(r"^accounts/password_change/done/$",
    auth_views.PasswordChangeDoneView.as_view(),
    name="password_change_done"),
url(r"^accounts/password_reset/$",
    auth_views.PasswordResetView.as_view(email_template_name="app/email/accounts/password_reset_email.html",
                                         success_url=reverse_lazy("app:password_reset_done"),
                                         subject_template_name="app/email/accounts/password_reset_subject.html"),
    name="password_reset"),
url(r"^accounts/password_reset/done/$",
    auth_views.PasswordResetDoneView.as_view(),
    name="password_reset_done"),
url(r"^accounts/reset/(?P<uidb64>[0-9A-Za-z_-]+)/(?P<token>[0-9A-Za-z]{1,13}-[0-9A-Za-z]{1,20})/$",
    auth_views.PasswordResetConfirmView.as_view(
        success_url=reverse_lazy("app:password_reset_complete"),
        form_class=CustomSetPasswordForm),
    name="password_reset_confirm"),
url(r"^accounts/reset/complete/$",
    auth_views.PasswordResetCompleteView.as_view(),
    name="password_reset_complete"),

import re
from django.urls import reverse, NoReverseMatch
from django.test import TestCase, Client
from django.core import mail
from django.test.utils import override_settings
from django.contrib.auth import authenticate

VALID_USER_NAME = "username"
USER_OLD_PSW = "oldpassword"
USER_NEW_PSW = "newpassword"
PASSWORD_RESET_URL = reverse("app:password_reset")

def PASSWORD_RESET_CONFIRM_URL(uidb64, token):
    try:
        return reverse("app:password_reset_confirm", args=(uidb64, token))
    except NoReverseMatch:
        return f"/accounts/reset/invaliduidb64/invalid-token/"


def utils_extract_reset_tokens(full_url):
    return re.findall(r"/([w-]+)",
                      re.search(r"^http://.+$", full_url, flags=re.MULTILINE)[0])[3:5]


@override_settings(EMAIL_BACKEND="anymail.backends.test.EmailBackend")
class PasswordResetTestCase(TestCase):
    @classmethod
    def setUpClass(cls):
        super().setUpClass()
        cls.myclient = Client()

    def test_password_reset_ok(self):
        # ask for password reset
        response = self.myclient.post(PASSWORD_RESET_URL,
                                      {"email": VALID_USER_NAME},
                                      follow=True)

        # extract reset token from email
        self.assertEqual(len(mail.outbox), 1)
        msg = mail.outbox[0]
        uidb64, token = utils_extract_reset_tokens(msg.body)

        # change the password
        response = self.myclient.post(PASSWORD_RESET_CONFIRM_URL(uidb64, token),
                                      {"new_password1": USER_NEW_PSW,
                                       "new_password2": USER_NEW_PSW},
                                      follow=True)

        self.assertIsNone(authenticate(username=VALID_USER_NAME,password=USER_OLD_PSW))

def test_password_reset_ok(self):
        # ask for password reset
        response = self.myclient.post(PASSWORD_RESET_URL,
                                      {"email": VALID_USER_NAME},
                                      follow=True)

        # extract reset token from email
        self.assertEqual(len(mail.outbox), 1)
        msg = mail.outbox[0]
        uidb64, token = utils_extract_reset_tokens(msg.body)

        # change the password
        self.myclient.get(PASSWORD_RESET_CONFIRM_URL(uidb64, token), follow=True)
        response = self.myclient.post(PASSWORD_RESET_CONFIRM_URL(uidb64, "set-password"),
                                      {"new_password1": USER_NEW_PSW,
                                       "new_password2": USER_NEW_PSW},
                                      follow=True)

        self.assertIsNone(authenticate(username=VALID_USER_NAME,password=USER_OLD_PSW))

INTERNAL_RESET_URL_TOKEN = 'set-password'
INTERNAL_RESET_SESSION_TOKEN = '_password_reset_token'

@method_decorator(sensitive_post_parameters())
@method_decorator(never_cache)
def dispatch(self, *args, **kwargs):
    assert 'uidb64' in kwargs and 'token' in kwargs

    self.validlink = False
    self.user = self.get_user(kwargs['uidb64'])

    if self.user is not None:
        token = kwargs['token']
        if token == INTERNAL_RESET_URL_TOKEN:
            session_token = self.request.session.get(INTERNAL_RESET_SESSION_TOKEN)
            if self.token_generator.check_token(self.user, session_token):
                # If the token is valid, display the password reset form.
                self.validlink = True
                return super().dispatch(*args, **kwargs)
        else:
            if self.token_generator.check_token(self.user, token):
                # Store the token in the session and redirect to the
                # password reset form at a URL without the token. That
                # avoids the possibility of leaking the token in the
                # HTTP Referer header.
                self.request.session[INTERNAL_RESET_SESSION_TOKEN] = token
                redirect_url = self.request.path.replace(token, INTERNAL_RESET_URL_TOKEN)
                return HttpResponseRedirect(redirect_url)

    # Display the "Password reset unsuccessful" page.
    return self.render_to_response(self.get_context_data())