import pytest

from django.core.exceptions import ImproperlyConfigured
from django.db import models
from django.test import override_settings

from psqlextra.manager import PostgresManager
from psqlextra.models import PostgresModel

from .fake_model import get_fake_model


@pytest.mark.parametrize(
    "databases",
    [
        {"default": {"ENGINE": "psqlextra.backend"}},
        {
            "default": {"ENGINE": "django.db.backends.postgresql"},
            "other": {"ENGINE": "psqlextra.backend"},
        },
        {
            "default": {"ENGINE": "psqlextra.backend"},
            "other": {"ENGINE": "psqlextra.backend"},
        },
    ],
)
def test_manager_backend_set(databases):
    """Tests that creating a new instance of :see:PostgresManager succeseeds
    without any errors if one or more databases are configured with
    `psqlextra.backend` as its ENGINE."""

    with override_settings(DATABASES=databases):
        assert PostgresManager()


def test_manager_backend_not_set():
    """Tests whether creating a new instance of
    :see:PostgresManager fails if no database
    has `psqlextra.backend` configured
    as its ENGINE."""

    with override_settings(
        DATABASES={"default": {"ENGINE": "django.db.backends.postgresql"}}
    ):
        with pytest.raises(ImproperlyConfigured):
            PostgresManager()


def test_manager_truncate():
    """Tests whether truncating a table works."""

    model = get_fake_model({"name": models.CharField(max_length=255)})

    model.objects.create(name="henk1")
    model.objects.create(name="henk2")

    assert model.objects.count() == 2
    model.objects.truncate()
    assert model.objects.count() == 0


@pytest.mark.django_db(transaction=True)
def test_manager_truncate_cascade():
    """Tests whether truncating a table with cascade works."""

    model_1 = get_fake_model({"name": models.CharField(max_length=255)})

    model_2 = get_fake_model(
        {
            "name": models.CharField(max_length=255),
            "model_1": models.ForeignKey(
                model_1, on_delete=models.CASCADE, null=True
            ),
        }
    )

    obj_1 = model_1.objects.create(name="henk1")
    model_2.objects.create(name="henk1", model_1_id=obj_1.id)

    assert model_1.objects.count() == 1
    assert model_2.objects.count() == 1

    model_1.objects.truncate(cascade=True)

    assert model_1.objects.count() == 0
    assert model_2.objects.count() == 0


def test_manager_truncate_quote_name():
    """Tests whether the truncate statement properly quotes the table name."""

    model = get_fake_model(
        {"name": models.CharField(max_length=255)},
        PostgresModel,
        {
            # without quoting, table names are always
            # lower-case, using a capital case table
            # name requires quoting to work
            "db_table": "MyTable"
        },
    )

    model.objects.create(name="henk1")
    model.objects.create(name="henk2")

    assert model.objects.count() == 2
    model.objects.truncate()
    assert model.objects.count() == 0