"""A migration is logged where it runs (migrate_instance, in the job): the
mode it used on success, the error on failure."""

from unittest.mock import MagicMock, patch

from computes.models import Compute
from django.contrib.auth import get_user_model
from django.test import TestCase
from libvirt import libvirtError
from logs.models import Logs

from instances.models import Instance
from instances.utils import migrate_instance
from vrtManager import util


class MigrationLogTests(TestCase):
    def setUp(self):
        self.admin = get_user_model().objects.create_superuser("ml-admin", "ml@example.com", "pw")
        self.source = Compute.objects.create(name="ml-src", hostname="198.51.100.8", login="root", password="", type=2)
        self.dest = Compute.objects.create(name="ml-dst", hostname="198.51.100.9", login="root", password="", type=2)
        self.vm = Instance.objects.create(compute=self.source, name="vm", uuid="u-ml")

    def migrate(self, outcome, nvram=None, remove_nvram=True, **request):
        self.proxy = MagicMock()
        self.proxy.get_autostart.return_value = False
        self.proxy.get_nvram.return_value = nvram
        if isinstance(remove_nvram, Exception):
            self.proxy.remove_nvram.side_effect = remove_nvram
        else:
            self.proxy.remove_nvram.return_value = remove_nvram
        with patch.object(Compute, "status", True), \
             patch("instances.utils.wvmInstances") as instances, \
             patch("instances.utils.wvmInstance"), \
             patch.object(Instance, "proxy", self.proxy), \
             patch.object(Instance, "autostart", False):
            if isinstance(outcome, Exception):
                instances.return_value.moveto.side_effect = outcome
            else:
                instances.return_value.moveto.return_value = outcome
            return migrate_instance(self.dest, self.vm, self.admin, **request)

    def test_the_nvram_file_left_on_the_source_is_removed(self):
        self.migrate("live", nvram="/var/lib/libvirt/qemu/nvram/vm_VARS.fd", live=True)
        path, destination = self.proxy.remove_nvram.call_args[0]
        self.assertEqual(path, "/var/lib/libvirt/qemu/nvram/vm_VARS.fd")
        self.assertIsNotNone(destination)
        self.assertEqual(Logs.objects.get().message, "Instance is migrated(live) to 198.51.100.9")

    def test_a_vm_without_nvram_removes_nothing(self):
        self.migrate("live", live=True)
        self.assertFalse(self.proxy.remove_nvram.called)

    def test_a_failed_nvram_removal_is_logged_but_the_migration_stands(self):
        self.migrate("live", nvram="/var/lib/libvirt/qemu/nvram/vm_VARS.fd",
                     remove_nvram=libvirtError("cannot delete"), live=True)
        self.assertEqual(
            Logs.objects.get().message,
            "Instance is migrated(live) to 198.51.100.9; removing its NVRAM file "
            "/var/lib/libvirt/qemu/nvram/vm_VARS.fd on the source failed: cannot delete",
        )
        self.vm.refresh_from_db()
        self.assertEqual(self.vm.compute, self.dest)

    def test_any_nvram_removal_error_still_records_the_migration(self):
        self.migrate("live", nvram="/var/lib/libvirt/qemu/nvram/vm_VARS.fd",
                     remove_nvram=AttributeError("unexpected"), live=True)
        self.vm.refresh_from_db()
        self.assertEqual(self.vm.compute, self.dest)
        self.assertIn("on the source failed: unexpected", Logs.objects.get().message)

    def test_a_failed_migration_removes_nothing(self):
        with self.assertRaises(util.OperationError):
            self.migrate(util.OperationError("no"), nvram="/var/lib/libvirt/qemu/nvram/vm_VARS.fd", live=True)
        self.assertFalse(self.proxy.remove_nvram.called)

    def test_success_names_the_mode_used(self):
        self.migrate("non-live, compressed", live=False, compress=True)
        log = Logs.objects.get()
        self.assertEqual(log.message, "Instance is migrated(non-live, compressed) to 198.51.100.9")
        self.assertEqual((log.user, log.host, log.instance), ("ml-admin", "198.51.100.8", "vm"))

    def test_success_names_the_migration_address(self):
        self.dest.migration_address = "203.0.113.9"
        self.migrate("live", live=True)
        self.assertEqual(Logs.objects.get().message, "Instance is migrated(live) to 198.51.100.9 via 203.0.113.9")
        self.vm.compute = self.source
        self.vm.save()
        self.dest.migration_address = "198.51.100.9"  # the host name itself
        self.migrate("live", live=True)
        self.assertEqual(Logs.objects.latest("id").message, "Instance is migrated(live) to 198.51.100.9")

    def test_failure_is_logged_and_raised(self):
        with self.assertRaisesRegex(util.OperationError, "A shut-off VM cannot be migrated live"):
            self.migrate(util.OperationError("A shut-off VM cannot be migrated live"), live=True)
        self.assertEqual(
            Logs.objects.get().message,
            "Instance migration to 198.51.100.9 failed: A shut-off VM cannot be migrated live",
        )