// Bootstrap bootstraps the given environment. The supplied constraints are
// used to provision the instance, and are also set within the bootstrapped
// environment.
func Bootstrap(ctx environs.BootstrapContext, environ environs.Environ, args environs.BootstrapParams) error {
	cfg := environ.Config()
	if secret := cfg.AdminSecret(); secret == "" {
		return fmt.Errorf("environment configuration has no admin-secret")
	}
	if authKeys := ssh.SplitAuthorisedKeys(cfg.AuthorizedKeys()); len(authKeys) == 0 {
		// Apparently this can never happen, so it's not tested. But, one day,
		// Config will act differently (it's pretty crazy that, AFAICT, the
		// authorized-keys are optional config settings... but it's impossible
		// to actually *create* a config without them)... and when it does,
		// we'll be here to catch this problem early.
		return fmt.Errorf("environment configuration has no authorized-keys")
	}
	if _, hasCACert := cfg.CACert(); !hasCACert {
		return fmt.Errorf("environment configuration has no ca-cert")
	}
	if _, hasCAKey := cfg.CAPrivateKey(); !hasCAKey {
		return fmt.Errorf("environment configuration has no ca-private-key")
	}
	// Write out the bootstrap-init file, and confirm storage is writeable.
	if err := environs.VerifyStorage(environ.Storage()); err != nil {
		return err
	}
	logger.Debugf("environment %q supports service/machine networks: %v", environ.Name(), environ.SupportNetworks())
	logger.Infof("bootstrapping environment %q", environ.Name())
	return environ.Bootstrap(ctx, args)
}

// 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)
		}
	}
}

func (s *localJujuTestSuite) makeFakeUpstartScripts(c *gc.C, env environs.Environ,
) (mongoService *upstart.Service, machineAgent *upstart.Service) {
	upstartDir := c.MkDir()
	s.PatchValue(&upstart.InitDir, upstartDir)
	s.MakeTool(c, "start", `echo "some-service start/running, process 123"`)

	namespace := env.Config().AllAttrs()["namespace"].(string)
	mongoService = upstart.NewService(mongo.ServiceName(namespace))
	mongoConf := upstart.Conf{
		Service: *mongoService,
		Desc:    "fake mongo",
		Cmd:     "echo FAKE",
	}
	err := mongoConf.Install()
	c.Assert(err, gc.IsNil)
	c.Assert(mongoService.Installed(), jc.IsTrue)

	machineAgent = upstart.NewService(fmt.Sprintf("juju-agent-%s", namespace))
	agentConf := upstart.Conf{
		Service: *machineAgent,
		Desc:    "fake agent",
		Cmd:     "echo FAKE",
	}
	err = agentConf.Install()
	c.Assert(err, gc.IsNil)
	c.Assert(machineAgent.Installed(), jc.IsTrue)

	return mongoService, machineAgent
}

func assertEnvironDestroyed(c *gc.C, env environs.Environ, store configstore.Storage) {
	_, err := store.ReadInfo(env.Name())
	c.Assert(err, jc.Satisfies, errors.IsNotFound)

	_, err = env.Instances([]instance.Id{"invalid"})
	c.Assert(err, gc.ErrorMatches, "environment has been destroyed")
}

func assertEnvironNotDestroyed(c *gc.C, env environs.Environ, store configstore.Storage) {
	info, err := store.ReadInfo(env.Name())
	c.Assert(err, gc.IsNil)
	c.Assert(info.Initialized(), jc.IsTrue)

	_, err = environs.NewFromName(env.Name(), store)
	c.Assert(err, gc.IsNil)
}

func makeTestMetadata(c *gc.C, env environs.Environ, series, location string, im []*imagemetadata.ImageMetadata) {
	cloudSpec := simplestreams.CloudSpec{
		Region:   location,
		Endpoint: "https://management.core.windows.net/",
	}
	err := imagemetadata.MergeAndWriteMetadata(series, im, &cloudSpec, env.Storage())
	c.Assert(err, gc.IsNil)
}

func findInstanceTools(env environs.Environ, series, arch string) (*tools.Tools, error) {
	agentVersion, ok := env.Config().AgentVersion()
	if !ok {
		return nil, fmt.Errorf("no agent version set in environment configuration")
	}
	possibleTools, err := envtools.FindInstanceTools(env, agentVersion, series, &arch)
	if err != nil {
		return nil, err
	}
	return possibleTools[0], nil
}

// EnsureNotBootstrapped returns nil if the environment is not
// bootstrapped, and an error if it is or if the function was not able
// to tell.
func EnsureNotBootstrapped(env environs.Environ) error {
	_, err := LoadState(env.Storage())
	// If there is no error loading the bootstrap state, then we are
	// bootstrapped.
	if err == nil {
		return fmt.Errorf("environment is already bootstrapped")
	}
	if err == environs.ErrNotBootstrapped {
		return nil
	}
	return err
}

func publicAttrs(e environs.Environ) map[string]interface{} {
	cfg := e.Config()
	secrets, err := e.Provider().SecretAttrs(cfg)
	if err != nil {
		panic(err)
	}
	attrs := cfg.AllAttrs()
	for attr := range secrets {
		delete(attrs, attr)
	}
	return attrs
}

// NewConn returns a new Conn that uses the
// given environment. The environment must have already
// been bootstrapped.
func NewConn(environ environs.Environ) (*Conn, error) {
	info, _, err := environ.StateInfo()
	if err != nil {
		return nil, err
	}
	password := environ.Config().AdminSecret()
	if password == "" {
		return nil, fmt.Errorf("cannot connect without admin-secret")
	}
	err = environs.CheckEnvironment(environ)
	if err != nil {
		return nil, err
	}

	info.Password = password
	opts := state.DefaultDialOpts()
	st, err := state.Open(info, opts, environs.NewStatePolicy())
	if errors.IsUnauthorized(err) {
		logger.Infof("authorization error while connecting to state server; retrying")
		// We can't connect with the administrator password,;
		// perhaps this was the first connection and the
		// password has not been changed yet.
		info.Password = utils.UserPasswordHash(password, utils.CompatSalt)

		// We try for a while because we might succeed in
		// connecting to mongo before the state has been
		// initialized and the initial password set.
		for a := redialStrategy.Start(); a.Next(); {
			st, err = state.Open(info, opts, environs.NewStatePolicy())
			if !errors.IsUnauthorized(err) {
				break
			}
		}
		if err != nil {
			return nil, err
		}
		if err := st.SetAdminMongoPassword(password); err != nil {
			return nil, err
		}
	} else if err != nil {
		return nil, err
	}
	conn := &Conn{
		Environ: environ,
		State:   st,
	}
	if err := conn.updateSecrets(); err != nil {
		conn.Close()
		return nil, fmt.Errorf("unable to push secrets: %v", err)
	}
	return conn, nil
}

func environAPIInfo(environ environs.Environ) (*api.Info, error) {
	_, info, err := environ.StateInfo()
	if err != nil {
		return nil, err
	}
	info.Tag = "user-admin"
	password := environ.Config().AdminSecret()
	if password == "" {
		return nil, fmt.Errorf("cannot connect without admin-secret")
	}
	info.Password = password
	return info, nil
}

// validateUploadAllowed returns an error if an attempt to upload tools should
// not be allowed.
func validateUploadAllowed(env environs.Environ, toolsArch *string, forceVersion bool) error {
	if !forceVersion {
		// First, check that there isn't already an agent version specified.
		if _, hasAgentVersion := env.Config().AgentVersion(); hasAgentVersion {
			return fmt.Errorf(noToolsNoUploadMessage)
		}
	}
	// Now check that the architecture for which we are setting up an
	// environment matches that from which we are bootstrapping.
	hostArch := arch.HostArch()
	// We can't build tools for a different architecture if one is specified.
	if toolsArch != nil && *toolsArch != hostArch {
		return fmt.Errorf("cannot build tools for %q using a machine running on %q", *toolsArch, hostArch)
	}
	// If no architecture is specified, ensure the target provider supports instances matching our architecture.
	supportedArchitectures, err := env.SupportedArchitectures()
	if err != nil {
		return fmt.Errorf(
			"no packaged tools available and cannot determine environment's supported architectures: %v", err)
	}
	archSupported := false
	for _, arch := range supportedArchitectures {
		if hostArch == arch {
			archSupported = true
			break
		}
	}
	if !archSupported {
		envType := env.Config().Type()
		return fmt.Errorf(
			"environment %q of type %s does not support instances running on %q", env.Name(), envType, hostArch)
	}
	return nil
}

// EnsureToolsAvailability verifies the tools are available. If no tools are
// found, it will automatically synchronize them.
func EnsureToolsAvailability(ctx environs.BootstrapContext, env environs.Environ, series string, toolsArch *string) (coretools.List, error) {
	cfg := env.Config()
	var vers *version.Number
	if agentVersion, ok := cfg.AgentVersion(); ok {
		vers = &agentVersion
	}

	logger.Debugf(
		"looking for bootstrap tools: series=%q, arch=%v, version=%v",
		series, toolsArch, vers,
	)
	params := envtools.BootstrapToolsParams{
		Version: vers,
		Arch:    toolsArch,
		Series:  series,
		// If vers.Build>0, the tools may have been uploaded in this session.
		// Allow retries, so we wait until the storage has caught up.
		AllowRetry: vers != nil && vers.Build > 0,
	}
	toolsList, err := envtools.FindBootstrapTools(env, params)
	if err == nil {
		return toolsList, nil
	} else if !errors.IsNotFound(err) {
		return nil, err
	}

	// Only automatically upload tools for dev versions.
	if !version.Current.IsDev() {
		return nil, fmt.Errorf("cannot upload bootstrap tools: %v", noToolsNoUploadMessage)
	}

	// No tools available so our only hope is to build locally and upload.
	logger.Warningf("no prepackaged tools available")
	uploadSeries := SeriesToUpload(cfg, nil)
	if series != "" {
		uploadSeries = append(uploadSeries, series)
	}
	if err := UploadTools(ctx, env, toolsArch, false, uploadSeries...); err != nil {
		logger.Errorf("%s", noToolsMessage)
		return nil, fmt.Errorf("cannot upload bootstrap tools: %v", err)
	}
	// TODO(axw) have uploadTools return the list of tools in the target, and use that.
	params.AllowRetry = true
	if toolsList, err = envtools.FindBootstrapTools(env, params); err != nil {
		return nil, fmt.Errorf("cannot find bootstrap tools: %v", err)
	}
	return toolsList, nil
}

// Destroy is a common implementation of the Destroy method defined on
// environs.Environ; we strongly recommend that this implementation be
// used when writing a new provider.
func Destroy(env environs.Environ) error {
	logger.Infof("destroying environment %q", env.Name())
	instances, err := env.AllInstances()
	switch err {
	case nil:
		if err := env.StopInstances(instances); err != nil {
			return err
		}
		fallthrough
	case environs.ErrNoInstances:
		return env.Storage().RemoveAll()
	}
	return err
}

// StartInstanceWithConstraintsAndNetworks is a test helper function that
// starts an instance with the given networks, and a plausible but invalid
// configuration, and returns the result of Environ.StartInstance.
func StartInstanceWithConstraintsAndNetworks(
	env environs.Environ, machineId string, cons constraints.Value,
	includeNetworks, excludeNetworks []string,
) (
	instance.Instance, *instance.HardwareCharacteristics, []network.Info, error,
) {
	series := config.PreferredSeries(env.Config())
	agentVersion, ok := env.Config().AgentVersion()
	if !ok {
		return nil, nil, nil, fmt.Errorf("missing agent version in environment config")
	}
	possibleTools, err := tools.FindInstanceTools(env, agentVersion, series, cons.Arch)
	if err != nil {
		return nil, nil, nil, err
	}
	machineNonce := "fake_nonce"
	stateInfo := FakeStateInfo(machineId)
	apiInfo := FakeAPIInfo(machineId)
	machineConfig := environs.NewMachineConfig(
		machineId, machineNonce,
		includeNetworks, excludeNetworks,
		stateInfo, apiInfo)
	return env.StartInstance(environs.StartInstanceParams{
		Constraints:   cons,
		Tools:         possibleTools,
		MachineConfig: machineConfig,
	})
}

// StateInfo is a reusable implementation of Environ.StateInfo, available to
// providers that also use the other functionality from this file.
func StateInfo(env environs.Environ) (*state.Info, *api.Info, error) {
	st, err := bootstrap.LoadState(env.Storage())
	if err != nil {
		return nil, nil, err
	}
	config := env.Config()
	if _, hasCert := config.CACert(); !hasCert {
		return nil, nil, fmt.Errorf("no CA certificate in environment configuration")
	}
	// Wait for the DNS names of any of the instances
	// to become available.
	logger.Debugf("waiting for DNS name(s) of state server instances %v", st.StateInstances)
	var hostnames []string
	for a := LongAttempt.Start(); len(hostnames) == 0 && a.Next(); {
		insts, err := env.Instances(st.StateInstances)
		if err != nil && err != environs.ErrPartialInstances {
			logger.Debugf("error getting state instances: %v", err.Error())
			return nil, nil, err
		}
		hostnames = getDNSNames(insts)
	}

	if len(hostnames) == 0 {
		return nil, nil, fmt.Errorf("timed out waiting for mgo address from %v", st.StateInstances)
	}

	stateInfo, apiInfo := getStateInfo(config, hostnames)
	return stateInfo, apiInfo, nil
}

// SetBootstrapTools returns the newest tools from the given tools list,
// and updates the agent-version configuration attribute.
func SetBootstrapTools(environ environs.Environ, possibleTools coretools.List) (coretools.List, error) {
	if len(possibleTools) == 0 {
		return nil, fmt.Errorf("no bootstrap tools available")
	}
	var newVersion version.Number
	newVersion, toolsList := possibleTools.Newest()
	logger.Infof("newest version: %s", newVersion)
	cfg := environ.Config()
	if agentVersion, _ := cfg.AgentVersion(); agentVersion != newVersion {
		cfg, err := cfg.Apply(map[string]interface{}{
			"agent-version": newVersion.String(),
		})
		if err == nil {
			err = environ.SetConfig(cfg)
		}
		if err != nil {
			return nil, fmt.Errorf("failed to update environment configuration: %v", err)
		}
	}
	bootstrapVersion := newVersion
	// We should only ever bootstrap the exact same version as the client,
	// or we risk bootstrap incompatibility. We still set agent-version to
	// the newest version, so the agent will immediately upgrade itself.
	if !isCompatibleVersion(newVersion, version.Current.Number) {
		compatibleVersion, compatibleTools := findCompatibleTools(possibleTools, version.Current.Number)
		if len(compatibleTools) == 0 {
			logger.Warningf(
				"failed to find %s tools, will attempt to use %s",
				version.Current.Number, newVersion,
			)
		} else {
			bootstrapVersion, toolsList = compatibleVersion, compatibleTools
		}
	}
	logger.Infof("picked bootstrap tools version: %s", bootstrapVersion)
	return toolsList, nil
}

// 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)
}

// UploadTools uploads tools for the specified series and any other relevant series to
// the environment storage, after which it sets the agent-version. If forceVersion is true,
// we allow uploading even when the agent-version is already set in the environment.
func UploadTools(ctx environs.BootstrapContext, env environs.Environ, toolsArch *string, forceVersion bool, bootstrapSeries ...string) error {
	logger.Infof("checking that upload is possible")
	// Check the series are valid.
	for _, series := range bootstrapSeries {
		if _, err := ubuntu.SeriesVersion(series); err != nil {
			return err
		}
	}
	// See that we are allowed to upload the tools.
	if err := validateUploadAllowed(env, toolsArch, forceVersion); err != nil {
		return err
	}

	// Make storage interruptible.
	interrupted := make(chan os.Signal, 1)
	interruptStorage := make(chan struct{})
	ctx.InterruptNotify(interrupted)
	defer ctx.StopInterruptNotify(interrupted)
	defer close(interrupted)
	go func() {
		defer close(interruptStorage) // closing interrupts all uploads
		if _, ok := <-interrupted; ok {
			ctx.Infof("cancelling tools upload")
		}
	}()
	stor := newInterruptibleStorage(env.Storage(), interruptStorage)

	cfg := env.Config()
	explicitVersion := uploadVersion(version.Current.Number, nil)
	uploadSeries := SeriesToUpload(cfg, bootstrapSeries)
	ctx.Infof("uploading tools for series %s", uploadSeries)
	tools, err := sync.Upload(stor, &explicitVersion, uploadSeries...)
	if err != nil {
		return err
	}
	cfg, err = cfg.Apply(map[string]interface{}{
		"agent-version": tools.Version.Number.String(),
	})
	if err == nil {
		err = env.SetConfig(cfg)
	}
	if err != nil {
		return fmt.Errorf("failed to update environment configuration: %v", err)
	}
	return nil
}

// GenerateSystemSSHKey creates a new key for the system identity. The
// authorized_keys in the environment config is updated to include the public
// key for the generated key.
func GenerateSystemSSHKey(env environs.Environ) (privateKey string, err error) {
	logger.Debugf("generate a system ssh key")
	// Create a new system ssh key and add that to the authorized keys.
	privateKey, publicKey, err := ssh.GenerateKey(config.JujuSystemKey)
	if err != nil {
		return "", fmt.Errorf("failed to create system key: %v", err)
	}
	authorized_keys := config.ConcatAuthKeys(env.Config().AuthorizedKeys(), publicKey)
	newConfig, err := env.Config().Apply(map[string]interface{}{
		config.AuthKeysConfig: authorized_keys,
	})
	if err != nil {
		return "", fmt.Errorf("failed to create new config: %v", err)
	}
	if err = env.SetConfig(newConfig); err != nil {
		return "", fmt.Errorf("failed to set new config: %v", err)
	}
	return privateKey, nil
}