// handleBootstrapError cleans up after a failed bootstrap.
func handleBootstrapError(err error, ctx environs.BootstrapContext, inst instance.Instance, env environs.Environ) {
	if err == nil {
		return
	}

	logger.Errorf("bootstrap failed: %v", err)
	ch := make(chan os.Signal, 1)
	ctx.InterruptNotify(ch)
	defer ctx.StopInterruptNotify(ch)
	defer close(ch)
	go func() {
		for _ = range ch {
			fmt.Fprintln(ctx.GetStderr(), "Cleaning up failed bootstrap")
		}
	}()

	if inst != nil {
		fmt.Fprintln(ctx.GetStderr(), "Stopping instance...")
		if stoperr := env.StopInstances([]instance.Instance{inst}); stoperr != nil {
			logger.Errorf("cannot stop failed bootstrap instance %q: %v", inst.Id(), stoperr)
		} else {
			// set to nil so we know we can safely delete the state file
			inst = nil
		}
	}
	// We only delete the bootstrap state file if either we didn't
	// start an instance, or we managed to cleanly stop it.
	if inst == nil {
		if rmerr := bootstrap.DeleteStateFile(env.Storage()); rmerr != nil {
			logger.Errorf("cannot delete bootstrap state file: %v", rmerr)
		}
	}
}

// WaitDNSName is an implementation that the providers can use.  It builds on
// the provider's implementation of Instance.DNSName.
func WaitDNSName(inst instance.Instance) (string, error) {
	for a := LongAttempt.Start(); a.Next(); {
		name, err := inst.DNSName()
		if err == nil || err != instance.ErrNoDNSName {
			return name, err
		}
	}
	return "", fmt.Errorf("timed out trying to get DNS address for %v", inst.Id())
}

// instInfo returns the instance info for the given id
// and instance. If inst is nil, it returns a not-found error.
func (*aggregator) instInfo(id instance.Id, inst instance.Instance) (instanceInfo, error) {
	if inst == nil {
		return instanceInfo{}, errors.NotFoundf("instance %v", id)
	}
	addr, err := inst.Addresses()
	if err != nil {
		return instanceInfo{}, err
	}
	return instanceInfo{
		addr,
		inst.Status(),
	}, nil
}

func (manager *containerManager) DestroyContainer(instance instance.Instance) error {
	name := string(instance.Id())
	kvmContainer := KvmObjectFactory.New(name)
	if err := kvmContainer.Stop(); err != nil {
		logger.Errorf("failed to stop kvm container: %v", err)
		return err
	}
	return container.RemoveDirectory(name)
}

// assertInstanceId asserts that the machine has an instance id
// that matches that of the given instance. If the instance is nil,
// It asserts that the instance id is unset.
func assertInstanceId(c *gc.C, m *state.Machine, inst instance.Instance) {
	var wantId, gotId instance.Id
	var err error
	if inst != nil {
		wantId = inst.Id()
	}
	for a := waitAgent.Start(); a.Next(); {
		err := m.Refresh()
		c.Assert(err, gc.IsNil)
		gotId, err = m.InstanceId()
		if err != nil {
			c.Assert(err, jc.Satisfies, state.IsNotProvisionedError)
			if inst == nil {
				return
			}
			continue
		}
		break
	}
	c.Assert(err, gc.IsNil)
	c.Assert(gotId, gc.Equals, wantId)
}

// assertPorts retrieves the open ports of the instance and compares them
// to the expected.
func (s *FirewallerSuite) assertPorts(c *gc.C, inst instance.Instance, machineId string, expected []instance.Port) {
	s.BackingState.StartSync()
	start := time.Now()
	for {
		got, err := inst.Ports(machineId)
		if err != nil {
			c.Fatal(err)
			return
		}
		instance.SortPorts(got)
		instance.SortPorts(expected)
		if reflect.DeepEqual(got, expected) {
			c.Succeed()
			return
		}
		if time.Since(start) > coretesting.LongWait {
			c.Fatalf("timed out: expected %q; got %q", expected, got)
			return
		}
		time.Sleep(coretesting.ShortWait)
	}
}

// Bootstrap is a common implementation of the Bootstrap method defined on
// environs.Environ; we strongly recommend that this implementation be used
// when writing a new provider.
func Bootstrap(ctx environs.BootstrapContext, env environs.Environ, args environs.BootstrapParams) (err error) {
	// TODO make safe in the case of racing Bootstraps
	// If two Bootstraps are called concurrently, there's
	// no way to make sure that only one succeeds.

	var inst instance.Instance
	defer func() { handleBootstrapError(err, ctx, inst, env) }()

	// First thing, ensure we have tools otherwise there's no point.
	selectedTools, err := EnsureBootstrapTools(ctx, env, config.PreferredSeries(env.Config()), args.Constraints.Arch)
	if err != nil {
		return err
	}

	// Get the bootstrap SSH client. Do this early, so we know
	// not to bother with any of the below if we can't finish the job.
	client := ssh.DefaultClient
	if client == nil {
		// This should never happen: if we don't have OpenSSH, then
		// go.crypto/ssh should be used with an auto-generated key.
		return fmt.Errorf("no SSH client available")
	}

	privateKey, err := GenerateSystemSSHKey(env)
	if err != nil {
		return err
	}
	machineConfig := environs.NewBootstrapMachineConfig(privateKey)

	fmt.Fprintln(ctx.GetStderr(), "Launching instance")
	inst, hw, _, err := env.StartInstance(environs.StartInstanceParams{
		Constraints:   args.Constraints,
		Tools:         selectedTools,
		MachineConfig: machineConfig,
		Placement:     args.Placement,
	})
	if err != nil {
		return fmt.Errorf("cannot start bootstrap instance: %v", err)
	}
	fmt.Fprintf(ctx.GetStderr(), " - %s\n", inst.Id())
	machineConfig.InstanceId = inst.Id()
	machineConfig.HardwareCharacteristics = hw

	err = bootstrap.SaveState(
		env.Storage(),
		&bootstrap.BootstrapState{
			StateInstances: []instance.Id{inst.Id()},
		})
	if err != nil {
		return fmt.Errorf("cannot save state: %v", err)
	}
	return FinishBootstrap(ctx, client, inst, machineConfig)
}

func (manager *containerManager) DestroyContainer(instance instance.Instance) error {
	start := time.Now()
	name := string(instance.Id())
	lxcContainer := LxcObjectFactory.New(name)
	if useRestartDir() {
		// Remove the autostart link.
		if err := os.Remove(restartSymlink(name)); err != nil {
			logger.Errorf("failed to remove restart symlink: %v", err)
			return err
		}
	}
	if err := lxcContainer.Destroy(); err != nil {
		logger.Errorf("failed to destroy lxc container: %v", err)
		return err
	}

	err := container.RemoveDirectory(name)
	logger.Tracef("container %q stopped: %v", name, time.Now().Sub(start))
	return err
}

func (s *lxcBrokerSuite) lxcRemovedContainerDir(inst instance.Instance) string {
	return filepath.Join(s.RemovedDir, string(inst.Id()))
}

func (s *kvmBrokerSuite) kvmContainerDir(inst instance.Instance) string {
	return filepath.Join(s.ContainerDir, string(inst.Id()))
}