from __future__ import unicode_literals

from django.contrib.auth.checks import check_user_model
from django.contrib.auth.models import AbstractBaseUser
from django.core import checks
from django.db import models
from django.test import (
    SimpleTestCase, override_settings, override_system_checks,
)
from django.test.utils import isolate_apps

from .models import CustomUserNonUniqueUsername


@isolate_apps('auth_tests', attr_name='apps')
@override_system_checks([check_user_model])
class UserModelChecksTests(SimpleTestCase):
    @override_settings(AUTH_USER_MODEL='auth_tests.CustomUserNonListRequiredFields')
    def test_required_fields_is_list(self):
        """REQUIRED_FIELDS should be a list."""
        class CustomUserNonListRequiredFields(AbstractBaseUser):
            username = models.CharField(max_length=30, unique=True)
            date_of_birth = models.DateField()

            USERNAME_FIELD = 'username'
            REQUIRED_FIELDS = 'date_of_birth'

        errors = checks.run_checks(app_configs=self.apps.get_app_configs())
        self.assertEqual(errors, [
            checks.Error(
                "'REQUIRED_FIELDS' must be a list or tuple.",
                obj=CustomUserNonListRequiredFields,
                id='auth.E001',
            ),
        ])

    @override_settings(AUTH_USER_MODEL='auth_tests.CustomUserBadRequiredFields')
    def test_username_not_in_required_fields(self):
        """USERNAME_FIELD should not appear in REQUIRED_FIELDS."""
        class CustomUserBadRequiredFields(AbstractBaseUser):
            username = models.CharField(max_length=30, unique=True)
            date_of_birth = models.DateField()

            USERNAME_FIELD = 'username'
            REQUIRED_FIELDS = ['username', 'date_of_birth']

        errors = checks.run_checks(self.apps.get_app_configs())
        self.assertEqual(errors, [
            checks.Error(
                "The field named as the 'USERNAME_FIELD' for a custom user model "
                "must not be included in 'REQUIRED_FIELDS'.",
                obj=CustomUserBadRequiredFields,
                id='auth.E002',
            ),
        ])

    @override_settings(AUTH_USER_MODEL='auth_tests.CustomUserNonUniqueUsername')
    def test_username_non_unique(self):
        """
        A non-unique USERNAME_FIELD should raise an error only if we use the
        default authentication backend. Otherwise, an warning should be raised.
        """
        errors = checks.run_checks()
        self.assertEqual(errors, [
            checks.Error(
                "'CustomUserNonUniqueUsername.username' must be "
                "unique because it is named as the 'USERNAME_FIELD'.",
                obj=CustomUserNonUniqueUsername,
                id='auth.E003',
            ),
        ])
        with self.settings(AUTHENTICATION_BACKENDS=['my.custom.backend']):
            errors = checks.run_checks()
            self.assertEqual(errors, [
                checks.Warning(
                    "'CustomUserNonUniqueUsername.username' is named as "
                    "the 'USERNAME_FIELD', but it is not unique.",
                    hint='Ensure that your authentication backend(s) can handle non-unique usernames.',
                    obj=CustomUserNonUniqueUsername,
                    id='auth.W004',
                ),
            ])