// FilterTLFEarlyExitError decides whether an error received while
// trying to create a TLF should result in showing the user an empty
// folder (exitEarly == true), or not.
func FilterTLFEarlyExitError(ctx context.Context, err error, log logger.Logger, name libkbfs.CanonicalTlfName) (
	exitEarly bool, retErr error) {
	switch err := err.(type) {
	case nil:
		// No error.
		return false, nil

	case libkbfs.WriteAccessError:
		// No permission to create TLF, so pretend it's still
		// empty.
		//
		// In theory, we need to invalidate this once the TLF
		// is created, but in practice, the Linux kernel
		// doesn't cache readdir results, and probably not
		// OSXFUSE either.
		log.CDebugf(ctx,
			"No permission to write to %s, so pretending it's empty",
			name)
		return true, nil

	case libkbfs.MDServerErrorWriteAccess:
		// Same as above; cannot fallthrough in type switch
		log.CDebugf(ctx,
			"No permission to write to %s, so pretending it's empty",
			name)
		return true, nil

	default:
		// Some other error.
		return true, err
	}
}

func tail(Log logger.Logger, filename string, numLines int) string {
	if filename == "" {
		return ""
	}

	f, err := os.Open(filename)
	if err != nil {
		Log.Warning("error opening log %q: %s", filename, err)
		return ""
	}
	b := rogReverse.NewScanner(f)
	b.Split(bufio.ScanLines)

	var lines []string
	for b.Scan() {
		lines = append(lines, b.Text())
		if len(lines) == numLines {
			break
		}
	}

	for left, right := 0, len(lines)-1; left < right; left, right = left+1, right-1 {
		lines[left], lines[right] = lines[right], lines[left]
	}

	return strings.Join(lines, "\n")
}

func NewUpdater(options keybase1.UpdateOptions, source sources.UpdateSource, config Config, log logger.Logger) *Updater {
	log.Debug("New updater with options: %#v", options)
	return &Updater{
		options: options,
		source:  source,
		config:  config,
		log:     log,
	}
}

// ShowStatus shows status info for a service
func ShowStatus(label string, log logger.Logger) error {
	service := NewService(label)
	service.SetLogger(log)
	status, err := service.LoadStatus()
	if err != nil {
		return err
	}
	if status != nil {
		log.Info("%s", status.Description())
	} else {
		log.Info("No service found with label: %s", label)
	}
	return nil
}

// WaitForServiceInfoFile tries to wait for a service info file, which should be
// written on successful service startup.
func WaitForServiceInfoFile(path string, label string, pid string, maxAttempts int, wait time.Duration, reason string, log logger.Logger) (*ServiceInfo, error) {
	if pid == "" {
		return nil, fmt.Errorf("No pid to wait for")
	}

	lookForServiceInfo := func() (*ServiceInfo, error) {
		if _, ferr := os.Stat(path); os.IsNotExist(ferr) {
			return nil, nil
		}
		dat, err := ioutil.ReadFile(path)
		if err != nil {
			return nil, err
		}
		var serviceInfo ServiceInfo
		err = json.Unmarshal(dat, &serviceInfo)
		if err != nil {
			return nil, err
		}

		// Make sure the info file is the pid we are waiting for, otherwise it is
		// still starting up.
		if pid != fmt.Sprintf("%d", serviceInfo.Pid) {
			return nil, nil
		}

		// PIDs match, the service has started up
		return &serviceInfo, nil
	}

	attempt := 1
	serviceInfo, lookErr := lookForServiceInfo()
	for attempt < maxAttempts && serviceInfo == nil {
		attempt++
		log.Debug("Waiting for service info file...")
		time.Sleep(wait)
		serviceInfo, lookErr = lookForServiceInfo()
	}

	// If no service info was found, let's return an error
	if serviceInfo == nil {
		if lookErr == nil {
			lookErr = fmt.Errorf("%s isn't running (expecting pid=%s)", label, pid)
		}
		return nil, lookErr
	}

	// We succeeded in finding service info
	log.Debug("Found service info: %#v", *serviceInfo)
	return serviceInfo, nil
}

func ctxWithRandomID(ctx context.Context, tagKey interface{},
	tagName string, log logger.Logger) context.Context {
	// Tag each request with a unique ID
	logTags := make(logger.CtxLogTags)
	logTags[tagKey] = tagName
	newCtx := logger.NewContextWithLogTags(ctx, logTags)
	id, err := MakeRandomRequestID()
	if err != nil {
		if log != nil {
			log.Warning("Couldn't generate a random request ID: %v", err)
		}
	} else {
		newCtx = context.WithValue(newCtx, tagKey, id)
	}
	return newCtx
}

// NewContextWithOpID adds a unique ID to this context, identifying
// a particular request.
func NewContextWithOpID(ctx context.Context,
	log logger.Logger) context.Context {
	if runtime.GOOS == "darwin" {
		// Timeout operations before they hit the osxfuse time limit,
		// so we don't hose the entire mount.  The timeout is 60
		// seconds, but it looks like sometimes it tries multiple
		// attempts within that 60 seconds, so let's go a little under
		// 60/3 to be safe.
		ctx, _ = context.WithTimeout(ctx, 19*time.Second)
	}
	id, err := libkbfs.MakeRandomRequestID()
	if err != nil {
		log.Errorf("Couldn't make request ID: %v", err)
		return ctx
	}
	return context.WithValue(ctx, CtxIDKey, id)
}

func (r *RemoteStatus) loop(ctx context.Context, log logger.Logger, config libkbfs.Config) {
	for {
		tctx, cancel := context.WithTimeout(ctx, 1*time.Second)
		st, ch, err := config.KBFSOps().Status(tctx)
		// No deferring inside loops, and no panics either here.
		cancel()
		if err != nil {
			log.Warning("KBFS Status failed: %v", err)
		}
		r.update(st)
		// Block on the channel or shutdown.
		select {
		case <-ctx.Done():
			return
		case <-ch:
		}
	}
}

func makeBlockServer(config Config, serverInMemory bool, serverRootDir, bserverAddr string, log logger.Logger) (
	BlockServer, error) {
	if serverInMemory {
		// local in-memory block server
		return NewBlockServerMemory(config)
	}

	if len(serverRootDir) > 0 {
		// local persistent block server
		blockPath := filepath.Join(serverRootDir, "kbfs_block")
		return NewBlockServerLocal(config, blockPath)
	}

	if len(bserverAddr) == 0 {
		return nil, errors.New("Empty block server address")
	}

	log.Debug("Using remote bserver %s", bserverAddr)
	return NewBlockServerRemote(config, bserverAddr), nil
}

// ShowServices outputs keybase service info.
func ShowServices(filters []string, name string, log logger.Logger) (err error) {
	services, err := ListServices(filters)
	if err != nil {
		return
	}
	if len(services) > 0 {
		log.Info("%s %s:", name, libkb.Pluralize(len(services), "service", "services", false))
		for _, service := range services {
			log.Info(service.StatusDescription())
		}
		log.Info("")
	} else {
		log.Info("No %s services.\n", name)
	}
	return
}

func checkSystemUser(log logger.Logger) {
	if isAdminUser, match, _ := libkb.IsSystemAdminUser(); isAdminUser {
		log.Errorf("Oops, you are trying to run as an admin user (%s). This isn't supported.", match)
		os.Exit(int(keybase1.ExitCode_NOTOK))
	}
}

func warnNonProd(log logger.Logger, e *libkb.Env) {
	mode := e.GetRunMode()
	if mode != libkb.ProductionRunMode {
		log.Warning("Running in %s mode", mode)
	}
}

func FindPinentry(log logger.Logger) (string, error) {
	if !HasWindows() {
		return "", fmt.Errorf("Can't spawn gui window, not using pinentry")
	}
	bins := []string{
		// If you install MacTools you'll wind up with this pinentry
		"/usr/local/MacGPG2/libexec/pinentry-mac.app/Contents/MacOS/pinentry-mac",
	}

	extraPaths := []string{}

	log.Debug("+ FindPinentry()")

	cmds := []string{
		"pinentry-gtk-2",
		"pinentry-qt4",
		"pinentry",
	}

	checkFull := func(s string) bool {
		log.Debug("| Check fullpath %s", s)
		found := (canExec(s) == nil)
		if found {
			log.Debug("- Found: %s", s)
		}
		return found
	}

	for _, b := range bins {
		if checkFull(b) {
			return b, nil
		}
	}

	path := os.Getenv("PATH")
	for _, c := range cmds {
		log.Debug("| Looking for %s in standard PATH %s", c, path)
		fullc, err := exec.LookPath(c)
		if err == nil {
			log.Debug("- Found %s", fullc)
			return fullc, nil
		}
	}

	for _, ep := range extraPaths {
		for _, c := range cmds {
			full := filepath.Join(ep, c)
			if checkFull(full) {
				return full, nil
			}
		}
	}

	log.Debug("- FindPinentry: none found")
	return "", fmt.Errorf("No pinentry found, checked a bunch of different places")
}

func FindPinentry(log logger.Logger) (string, error) {

	//		// If you install GPG you'll wind up with this pinentry
	//		C:\Program Files (x86)\GNU\GnuPG\pinentry-gtk-2.exe
	//		C:\Program Files (x86)\GNU\GnuPG\pinentry-qt4.exe
	//		C:\Program Files (x86)\GNU\GnuPG\pinentry-w32.exe
	//		C:\Program Files (x86)\GNU\GnuPG\pinentry.exe

	k, err := registry.OpenKey(registry.LOCAL_MACHINE, `SOFTWARE\Wow6432Node\GNU\GnuPG`, registry.QUERY_VALUE)
	if err != nil {
		k, err = registry.OpenKey(registry.LOCAL_MACHINE, `SOFTWARE\GNU\GnuPG`, registry.QUERY_VALUE)
	}
	if err != nil {
		log.Debug("- FindPinentry: can't open registry")
	}
	defer k.Close()

	installDir, _, err := k.GetStringValue("Install Directory")
	if err != nil {
		log.Debug("- FindPinentry: can't get string from registry")
	}

	extraPaths := []string{}

	log.Debug("+ FindPinentry()")

	cmds := []string{
		"pinentry-gtk-2.exe",
		"pinentry-qt4.exe",
		"pinentry-w32.exe",
		"pinentry.exe",
	}

	// First, look where the registry points
	for _, c := range cmds {
		full := filepath.Join(installDir, c)
		log.Debug("| (registry) Looking for %s", full)
		_, err := exec.LookPath(full)
		if err == nil {
			return full, nil
		}
	}

	// Look in program files, just in case
	extraPaths = append(extraPaths, os.Getenv("ProgramFiles"))
	extraPaths = append(extraPaths, os.Getenv("ProgramFiles(x86)"))

	for _, ep := range extraPaths {
		for _, c := range cmds {
			full := filepath.Join(ep, "GNU", "GnuPG", c)
			log.Debug("| Looking for %s", full)
			_, err := exec.LookPath(full)
			if err == nil {
				return full, nil
			}
		}
	}

	log.Debug("- FindPinentry: none found")
	return "", fmt.Errorf("No pinentry found, checked a bunch of different places")
}

func Trace(log logger.Logger, msg string, f func() error) func() {
	log.Debug("+ %s", msg)
	return func() { log.Debug("- %s -> %s", msg, ErrToOk(f())) }
}