// NewSignalService creates a new SignalService with the appropriate logger etc.
func NewSignalService(name string, log *logrus.Logger, action func() (err error), signals ...os.Signal) (service *SignalService, err error) {
	entry := log.WithFields(map[string]any{logFieldService: serviceTypeSignals, serviceTypeSignals: name})
	event := make(chan os.Signal, 1)
	done := make(chan struct{}, 1)

	signal.Notify(event, signals...)

	return &SignalService{
		name:   name,
		log:    entry,
		event:  event,
		done:   done,
		action: action,
	}, nil
}


// SignalService is a Service that listens to operating system signals.
type SignalService struct {
	name string
	log  *logrus.Entry

	event  chan os.Signal
	done   chan struct{}
	action func() (err error)
}

// ServiceType returns the service type for this service, which is always 'watcher'.
func (service *SignalService) ServiceType() string {
	return serviceTypeSignals
}

// ServiceName returns the individual name for this service.
func (service *SignalService) ServiceName() string {
	return service.name
}

// Run the FileWatcherService.
func (service *SignalService) Run() (err error) {
	defer func() {
		if r := recover(); r != nil {
			service.log.WithError(recoverErr(r)).Error("Critical error caught (recovered)")
		}
	}()

	service.log.Debug("Signals Service Started")

	for {
		select {
		case <-service.event:
			if err := service.action(); err != nil {
				return err
			}
		case <-service.done:
			return nil
		}
	}
}

// Shutdown the FileWatcherService.
func (service *SignalService) Shutdown() {
	service.done <- struct{}{}

	close(service.event)
	close(service.done)
}

// Log returns the *logrus.Entry of the FileWatcherService.
func (service *SignalService) Log() *logrus.Entry {
	return service.log
}

func svcSignalLogRotateFunc(ctx *CmdCtx) (service Service) {
	action := func() (err error) {
		// TODO: Add logging logic here.

		return nil
	}

	var err error

	if service, err = NewSignalService("log rotate", ctx.log, action, syscall.SIGUSR1); err != nil {
		ctx.log.WithError(err).Fatal("Create Signal Service (log rotate) returned error")
	}

	return service
}