import unittest
from functools import wraps

from django.db import models
from django.db.models import Manager

from parler.models import TranslatableModel, TranslatedFields

from .testapp.models import (
    CharModel,
    DoubleModel,
    Level1,
    Level2,
    ManualModel,
    ManualModelTranslations,
    ProxyBase,
    ProxyModel,
    RegularModel,
    SimpleModel,
)
from .utils import AppTestCase


def clear_app_registry(func):
    """
    Decorator for unit tests that corrupt the global app registry, and therefore need a reset.
    """

    @wraps(func)
    def _clearing_dec(*args, **kwargs):
        from django.apps import apps

        try:
            func(*args, **kwargs)
        finally:
            # TODO: this doens't yet work.
            apps.clear_cache()

    return _clearing_dec


class ModelConstructionTests(AppTestCase):
    """
    Test model construction
    """

    def test_manual_model(self):
        """
        Test the metaclass of the model.
        """
        # Test whether the link has taken place
        self.assertIsInstance(ManualModel().translations, Manager)  # RelatedManager class
        self.assertIs(ManualModel().translations.model, ManualModelTranslations)
        self.assertIs(ManualModel._parler_meta.root_model, ManualModelTranslations)

    def test_simple_model(self):
        """
        Test the simple model syntax.
        """
        self.assertIs(SimpleModel().translations.model, SimpleModel._parler_meta.root_model)

    def test_inherited_model(self):
        """
        Test the inherited model syntax.
        """
        # First level has 1 ParlerMeta object
        self.assertEqual(Level1._parler_meta.root.rel_name, "l1_translations")
        self.assertEqual(Level1._parler_meta.root.model.__name__, "Level1Translation")
        self.assertEqual(len(Level1._parler_meta), 1)

        # Second level has 2 ParlerMeta objects.
        self.assertEqual(len(Level2._parler_meta), 2)
        self.assertEqual(Level2._parler_meta[0].rel_name, "l1_translations")
        self.assertEqual(Level2._parler_meta[1].rel_name, "l2_translations")
        self.assertEqual(Level2._parler_meta[1].model.__name__, "Level2Translation")

        # Level 2 root attributes should point to the top-level object (Level1)
        self.assertEqual(Level2._parler_meta.root_model.__name__, "Level1Translation")
        self.assertEqual(Level2._parler_meta.root_rel_name, "l1_translations")
        self.assertEqual(Level2._parler_meta.root, Level1._parler_meta.root)

    def test_proxy_model(self):
        """
        Test whether proxy models can get new translations
        """
        # First level has 1 ParlerMeta object
        self.assertEqual(ProxyBase._parler_meta.root.rel_name, "base_translations")
        self.assertEqual(len(ProxyBase._parler_meta), 1)

        # Second level has 2 ParlerMeta objects
        self.assertEqual(len(ProxyModel._parler_meta), 2)
        self.assertEqual(ProxyModel._parler_meta[0].rel_name, "base_translations")
        self.assertEqual(ProxyModel._parler_meta[1].rel_name, "proxy_translations")

        self.assertEqual(ProxyModel._parler_meta[0].model.__name__, "ProxyBaseTranslation")
        self.assertEqual(ProxyModel._parler_meta[1].model.__name__, "ProxyModelTranslation")

        # Second inheritance level attributes should point to the top-level object (ProxyBase)
        self.assertEqual(ProxyModel._parler_meta.root_model.__name__, "ProxyBaseTranslation")
        self.assertEqual(ProxyModel._parler_meta.root_rel_name, "base_translations")
        self.assertEqual(ProxyModel._parler_meta.root, ProxyBase._parler_meta.root)

    def test_double_translation_table(self):
        """
        Test how assigning two translation tables works.
        """
        self.assertIsNone(
            DoubleModel._parler_meta.base
        )  # Should call .add_meta() instead of overwriting/chaining it.
        self.assertEqual(len(DoubleModel._parler_meta), 2)
        self.assertEqual(DoubleModel._parler_meta[0].rel_name, "base_translations")
        self.assertEqual(DoubleModel._parler_meta[1].rel_name, "more_translations")

    def test_model_with_different_pks(self):
        """
        Test that TranslatableModels works with different types of pks
        """
        self.assertIsInstance(SimpleModel.objects.create(tr_title="Test"), SimpleModel)
        self.assertIsInstance(CharModel.objects.create(pk="test", tr_title="Test"), CharModel)