from django.db import NotSupportedError
from django.db.models import F, Value
from django.db.models.functions import JSONObject, Lower
from django.test import TestCase
from django.test.testcases import skipIfDBFeature, skipUnlessDBFeature
from django.utils import timezone

from ..models import Article, Author


@skipUnlessDBFeature('has_json_object_function')
class JSONObjectTests(TestCase):
    @classmethod
    def setUpTestData(cls):
        Author.objects.create(name='Ivan Ivanov', alias='iivanov')

    def test_empty(self):
        obj = Author.objects.annotate(json_object=JSONObject()).first()
        self.assertEqual(obj.json_object, {})

    def test_basic(self):
        obj = Author.objects.annotate(json_object=JSONObject(name='name')).first()
        self.assertEqual(obj.json_object, {'name': 'Ivan Ivanov'})

    def test_expressions(self):
        obj = Author.objects.annotate(json_object=JSONObject(
            name=Lower('name'),
            alias='alias',
            goes_by='goes_by',
            salary=Value(30000.15),
            age=F('age') * 2,
        )).first()
        self.assertEqual(obj.json_object, {
            'name': 'ivan ivanov',
            'alias': 'iivanov',
            'goes_by': None,
            'salary': 30000.15,
            'age': 60,
        })

    def test_nested_json_object(self):
        obj = Author.objects.annotate(json_object=JSONObject(
            name='name',
            nested_json_object=JSONObject(
                alias='alias',
                age='age',
            ),
        )).first()
        self.assertEqual(obj.json_object, {
            'name': 'Ivan Ivanov',
            'nested_json_object': {
                'alias': 'iivanov',
                'age': 30,
            },
        })

    def test_nested_empty_json_object(self):
        obj = Author.objects.annotate(json_object=JSONObject(
            name='name',
            nested_json_object=JSONObject(),
        )).first()
        self.assertEqual(obj.json_object, {
            'name': 'Ivan Ivanov',
            'nested_json_object': {},
        })

    def test_textfield(self):
        Article.objects.create(
            title='The Title',
            text='x' * 4000,
            written=timezone.now(),
        )
        obj = Article.objects.annotate(json_object=JSONObject(text=F('text'))).first()
        self.assertEqual(obj.json_object, {'text': 'x' * 4000})


@skipIfDBFeature('has_json_object_function')
class JSONObjectNotSupportedTests(TestCase):
    def test_not_supported(self):
        msg = 'JSONObject() is not supported on this database backend.'
        with self.assertRaisesMessage(NotSupportedError, msg):
            Author.objects.annotate(json_object=JSONObject()).get()
