import multiprocessing
import sys
from io import StringIO
from unittest import skipIf

from django.apps import apps
from django.core import checks
from django.core.checks import Error, Warning
from django.core.checks.messages import CheckMessage
from django.core.checks.registry import CheckRegistry
from django.core.management import call_command
from django.core.management.base import CommandError
from django.db import models
from django.test import SimpleTestCase
from django.test.utils import isolate_apps, override_settings, override_system_checks

from .models import SimpleModel, my_check


class DummyObj:
    def __repr__(self):
        return "obj"


class SystemCheckFrameworkTests(SimpleTestCase):
    def test_register_and_run_checks(self):
        def f(**kwargs):
            calls[0] += 1
            return [1, 2, 3]

        def f2(**kwargs):
            return [4]

        def f3(**kwargs):
            return [5]

        calls = [0]

        # test register as decorator
        registry = CheckRegistry()
        registry.register()(f)
        registry.register("tag1", "tag2")(f2)
        registry.register("tag2", deploy=True)(f3)

        # test register as function
        registry2 = CheckRegistry()
        registry2.register(f)
        registry2.register(f2, "tag1", "tag2")
        registry2.register(f3, "tag2", deploy=True)

        # check results
        errors = registry.run_checks()
        errors2 = registry2.run_checks()
        self.assertEqual(errors, errors2)
        self.assertEqual(sorted(errors), [1, 2, 3, 4])
        self.assertEqual(calls[0], 2)

        errors = registry.run_checks(tags=["tag1"])
        errors2 = registry2.run_checks(tags=["tag1"])
        self.assertEqual(errors, errors2)
        self.assertEqual(sorted(errors), [4])

        errors = registry.run_checks(
            tags=["tag1", "tag2"], include_deployment_checks=True
        )
        errors2 = registry2.run_checks(
            tags=["tag1", "tag2"], include_deployment_checks=True
        )
        self.assertEqual(errors, errors2)
        self.assertEqual(sorted(errors), [4, 5])

    def test_register_no_kwargs_error(self):
        registry = CheckRegistry()
        msg = "Check functions must accept keyword arguments (**kwargs)."
        with self.assertRaisesMessage(TypeError, msg):

            @registry.register
            def no_kwargs(app_configs, databases):
                pass

    def test_register_run_checks_non_iterable(self):
        registry = CheckRegistry()

        @registry.register
        def return_non_iterable(**kwargs):
            return Error("Message")

        msg = (
            "The function %r did not return a list. All functions registered "
            "with the checks registry must return a list." % return_non_iterable
        )
        with self.assertRaisesMessage(TypeError, msg):
            registry.run_checks()


class MessageTests(SimpleTestCase):
    def test_printing(self):
        e = Error("Message", hint="Hint", obj=DummyObj())
        expected = "obj: Message\n\tHINT: Hint"
        self.assertEqual(str(e), expected)

    def test_printing_no_hint(self):
        e = Error("Message", obj=DummyObj())
        expected = "obj: Message"
        self.assertEqual(str(e), expected)

    def test_printing_no_object(self):
        e = Error("Message", hint="Hint")
        expected = "?: Message\n\tHINT: Hint"
        self.assertEqual(str(e), expected)

    def test_printing_with_given_id(self):
        e = Error("Message", hint="Hint", obj=DummyObj(), id="ID")
        expected = "obj: (ID) Message\n\tHINT: Hint"
        self.assertEqual(str(e), expected)

    def test_printing_field_error(self):
        field = SimpleModel._meta.get_field("field")
        e = Error("Error", obj=field)
        expected = "check_framework.SimpleModel.field: Error"
        self.assertEqual(str(e), expected)

    def test_printing_model_error(self):
        e = Error("Error", obj=SimpleModel)
        expected = "check_framework.SimpleModel: Error"
        self.assertEqual(str(e), expected)

    def test_printing_manager_error(self):
        manager = SimpleModel.manager
        e = Error("Error", obj=manager)
        expected = "check_framework.SimpleModel.manager: Error"
        self.assertEqual(str(e), expected)

    def test_equal_to_self(self):
        e = Error("Error", obj=SimpleModel)
        self.assertEqual(e, e)

    def test_equal_to_same_constructed_check(self):
        e1 = Error("Error", obj=SimpleModel)
        e2 = Error("Error", obj=SimpleModel)
        self.assertEqual(e1, e2)

    def test_not_equal_to_different_constructed_check(self):
        e1 = Error("Error", obj=SimpleModel)
        e2 = Error("Error2", obj=SimpleModel)
        self.assertNotEqual(e1, e2)

    def test_not_equal_to_non_check(self):
        e = Error("Error", obj=DummyObj())
        self.assertNotEqual(e, "a string")

    def test_invalid_level(self):
        msg = "The first argument should be level."
        with self.assertRaisesMessage(TypeError, msg):
            CheckMessage("ERROR", "Message")


def simple_system_check(**kwargs):
    simple_system_check.kwargs = kwargs
    return []


def tagged_system_check(**kwargs):
    tagged_system_check.kwargs = kwargs
    return [checks.Warning("System Check")]


tagged_system_check.tags = ["simpletag"]


def deployment_system_check(**kwargs):
    deployment_system_check.kwargs = kwargs
    return [checks.Warning("Deployment Check")]


deployment_system_check.tags = ["deploymenttag"]


class CheckCommandTests(SimpleTestCase):
    def setUp(self):
        simple_system_check.kwargs = None
        tagged_system_check.kwargs = None
        self.old_stdout, self.old_stderr = sys.stdout, sys.stderr
        sys.stdout, sys.stderr = StringIO(), StringIO()

    def tearDown(self):
        sys.stdout, sys.stderr = self.old_stdout, self.old_stderr

    @override_system_checks([simple_system_check, tagged_system_check])
    def test_simple_call(self):
        call_command("check")
        self.assertEqual(
            simple_system_check.kwargs, {"app_configs": None, "databases": None}
        )
        self.assertEqual(
            tagged_system_check.kwargs, {"app_configs": None, "databases": None}
        )

    @override_system_checks([simple_system_check, tagged_system_check])
    def test_given_app(self):
        call_command("check", "auth", "admin")
        auth_config = apps.get_app_config("auth")
        admin_config = apps.get_app_config("admin")
        self.assertEqual(
            simple_system_check.kwargs,
            {"app_configs": [auth_config, admin_config], "databases": None},
        )
        self.assertEqual(
            tagged_system_check.kwargs,
            {"app_configs": [auth_config, admin_config], "databases": None},
        )

    @override_system_checks([simple_system_check, tagged_system_check])
    def test_given_tag(self):
        call_command("check", tags=["simpletag"])
        self.assertIsNone(simple_system_check.kwargs)
        self.assertEqual(
            tagged_system_check.kwargs, {"app_configs": None, "databases": None}
        )

    @override_system_checks([simple_system_check, tagged_system_check])
    def test_invalid_tag(self):
        msg = 'There is no system check with the "missingtag" tag.'
        with self.assertRaisesMessage(CommandError, msg):
            call_command("check", tags=["missingtag"])

    @override_system_checks([simple_system_check])
    def test_list_tags_empty(self):
        call_command("check", list_tags=True)
        self.assertEqual("\n", sys.stdout.getvalue())

    @override_system_checks([tagged_system_check])
    def test_list_tags(self):
        call_command("check", list_tags=True)
        self.assertEqual("simpletag\n", sys.stdout.getvalue())

    @override_system_checks(
        [tagged_system_check], deployment_checks=[deployment_system_check]
    )
    def test_list_deployment_check_omitted(self):
        call_command("check", list_tags=True)
        self.assertEqual("simpletag\n", sys.stdout.getvalue())

    @override_system_checks(
        [tagged_system_check], deployment_checks=[deployment_system_check]
    )
    def test_list_deployment_check_included(self):
        call_command("check", deploy=True, list_tags=True)
        self.assertEqual("deploymenttag\nsimpletag\n", sys.stdout.getvalue())

    @override_system_checks(
        [tagged_system_check], deployment_checks=[deployment_system_check]
    )
    def test_tags_deployment_check_omitted(self):
        msg = 'There is no system check with the "deploymenttag" tag.'
        with self.assertRaisesMessage(CommandError, msg):
            call_command("check", tags=["deploymenttag"])

    @override_system_checks(
        [tagged_system_check], deployment_checks=[deployment_system_check]
    )
    def test_tags_deployment_check_included(self):
        call_command("check", deploy=True, tags=["deploymenttag"])
        self.assertIn("Deployment Check", sys.stderr.getvalue())

    @override_system_checks([tagged_system_check])
    def test_fail_level(self):
        with self.assertRaises(CommandError):
            call_command("check", fail_level="WARNING")


def custom_error_system_check(app_configs, **kwargs):
    return [Error("Error", id="myerrorcheck.E001")]


def custom_warning_system_check(app_configs, **kwargs):
    return [Warning("Warning", id="mywarningcheck.E001")]


class SilencingCheckTests(SimpleTestCase):
    def setUp(self):
        self.old_stdout, self.old_stderr = sys.stdout, sys.stderr
        self.stdout, self.stderr = StringIO(), StringIO()
        sys.stdout, sys.stderr = self.stdout, self.stderr

    def tearDown(self):
        sys.stdout, sys.stderr = self.old_stdout, self.old_stderr

    @override_settings(SILENCED_SYSTEM_CHECKS=["myerrorcheck.E001"])
    @override_system_checks([custom_error_system_check])
    def test_silenced_error(self):
        out = StringIO()
        err = StringIO()
        call_command("check", stdout=out, stderr=err)
        self.assertEqual(
            out.getvalue(), "System check identified no issues (1 silenced).\n"
        )
        self.assertEqual(err.getvalue(), "")

    @override_settings(SILENCED_SYSTEM_CHECKS=["mywarningcheck.E001"])
    @override_system_checks([custom_warning_system_check])
    def test_silenced_warning(self):
        out = StringIO()
        err = StringIO()
        call_command("check", stdout=out, stderr=err)
        self.assertEqual(
            out.getvalue(), "System check identified no issues (1 silenced).\n"
        )
        self.assertEqual(err.getvalue(), "")


class CheckFrameworkReservedNamesTests(SimpleTestCase):
    @isolate_apps("check_framework", kwarg_name="apps")
    @override_system_checks([checks.model_checks.check_all_models])
    def test_model_check_method_not_shadowed(self, apps):
        class ModelWithAttributeCalledCheck(models.Model):
            check = 42

        class ModelWithFieldCalledCheck(models.Model):
            check = models.IntegerField()

        class ModelWithRelatedManagerCalledCheck(models.Model):
            pass

        class ModelWithDescriptorCalledCheck(models.Model):
            check = models.ForeignKey(
                ModelWithRelatedManagerCalledCheck, models.CASCADE
            )
            article = models.ForeignKey(
                ModelWithRelatedManagerCalledCheck,
                models.CASCADE,
                related_name="check",
            )

        errors = checks.run_checks(app_configs=apps.get_app_configs())
        expected = [
            Error(
                "The 'ModelWithAttributeCalledCheck.check()' class method is "
                "currently overridden by 42.",
                obj=ModelWithAttributeCalledCheck,
                id="models.E020",
            ),
            Error(
                "The 'ModelWithFieldCalledCheck.check()' class method is "
                "currently overridden by %r." % ModelWithFieldCalledCheck.check,
                obj=ModelWithFieldCalledCheck,
                id="models.E020",
            ),
            Error(
                "The 'ModelWithRelatedManagerCalledCheck.check()' class method is "
                "currently overridden by %r."
                % ModelWithRelatedManagerCalledCheck.check,
                obj=ModelWithRelatedManagerCalledCheck,
                id="models.E020",
            ),
            Error(
                "The 'ModelWithDescriptorCalledCheck.check()' class method is "
                "currently overridden by %r." % ModelWithDescriptorCalledCheck.check,
                obj=ModelWithDescriptorCalledCheck,
                id="models.E020",
            ),
        ]
        self.assertEqual(errors, expected)


@skipIf(
    multiprocessing.get_start_method() == "spawn",
    "Spawning reimports modules, overwriting my_check.did_run to False, making this "
    "test useless.",
)
class ChecksRunDuringTests(SimpleTestCase):
    databases = "__all__"

    def test_registered_check_did_run(self):
        self.assertTrue(my_check.did_run)