from django.core.exceptions import ValidationError

from django.db import models

from django.test import SimpleTestCase, TestCase

from .models import Post

class TestCharField(TestCase):

    def test_max_length_passed_to_formfield(self):

        """

        CharField passes its max_length attribute to form fields created using

        the formfield() method.

        """

        cf1 = models.CharField()

        cf2 = models.CharField(max_length=1234)

        self.assertIsNone(cf1.formfield().max_length)

        self.assertEqual(1234, cf2.formfield().max_length)

    def test_lookup_integer_in_charfield(self):

        self.assertEqual(Post.objects.filter(title=9).count(), 0)

    def test_emoji(self):

        p = Post.objects.create(title="Smile 😀", body="Whatever.")

        p.refresh_from_db()

        self.assertEqual(p.title, "Smile 😀")

    def test_assignment_from_choice_enum(self):

        class Event(models.TextChoices):

            C = "Carnival!"

            F = "Festival!"

        p1 = Post.objects.create(title=Event.C, body=Event.F)

        p1.refresh_from_db()

        self.assertEqual(p1.title, "Carnival!")

        self.assertEqual(p1.body, "Festival!")

        self.assertEqual(p1.title, Event.C)

        self.assertEqual(p1.body, Event.F)

        p2 = Post.objects.get(title="Carnival!")

        self.assertEqual(p1, p2)

        self.assertEqual(p2.title, Event.C)

class TestMethods(SimpleTestCase):

    def test_deconstruct(self):

        field = models.CharField()

        *_, kwargs = field.deconstruct()

        self.assertEqual(kwargs, {})

        field = models.CharField(db_collation="utf8_esperanto_ci")

        *_, kwargs = field.deconstruct()

        self.assertEqual(kwargs, {"db_collation": "utf8_esperanto_ci"})

class ValidationTests(SimpleTestCase):

    class Choices(models.TextChoices):

        C = "c", "C"

    def test_charfield_raises_error_on_empty_string(self):

        f = models.CharField()

        msg = "This field cannot be blank."

        with self.assertRaisesMessage(ValidationError, msg):

            f.clean("", None)

    def test_charfield_cleans_empty_string_when_blank_true(self):

        f = models.CharField(blank=True)

        self.assertEqual("", f.clean("", None))

    def test_charfield_with_choices_cleans_valid_choice(self):

        f = models.CharField(max_length=1, choices=[("a", "A"), ("b", "B")])

        self.assertEqual("a", f.clean("a", None))

    def test_charfield_with_choices_raises_error_on_invalid_choice(self):

        f = models.CharField(choices=[("a", "A"), ("b", "B")])

        msg = "Value 'not a' is not a valid choice."

        with self.assertRaisesMessage(ValidationError, msg):

            f.clean("not a", None)

    def test_enum_choices_cleans_valid_string(self):

        f = models.CharField(choices=self.Choices.choices, max_length=1)

        self.assertEqual(f.clean("c", None), "c")

    def test_enum_choices_invalid_input(self):

        f = models.CharField(choices=self.Choices.choices, max_length=1)

        msg = "Value 'a' is not a valid choice."

        with self.assertRaisesMessage(ValidationError, msg):

            f.clean("a", None)

    def test_charfield_raises_error_on_empty_input(self):

        f = models.CharField(null=False)

        msg = "This field cannot be null."

        with self.assertRaisesMessage(ValidationError, msg):

            f.clean(None, None)