fix percentage calculation

internal/light/file.go

@@ -12,13 +12,15 @@ const (
 )
 
 type Light interface {
-	SetBrightness(percentage int) error
-	GetBrightness() (percentage int, err error)
+	// SetBrightness sets the brightness of this light as a percentage in range [0..1]
+	SetBrightness(percentage float64) error
+	// GetBrightness returns the brightness of this light as a percentage in range [0..1]
+	GetBrightness() (percentage float64, err error)
 }
 
 type light struct {
 	path          string
-	maxBrightness int
+	maxBrightness float64
 }
 
 func NewLight(path string) Light {
@@ -30,17 +32,17 @@ func NewLight(path string) Light {
 
 	return &light{
 		path:          path,
-		maxBrightness: m,
+		maxBrightness: float64(m),
 	}
 }
 
-func (f *light) GetBrightness() (percentage int, err error) {
+func (f *light) GetBrightness() (percentage float64, err error) {
 	rawBrightness, err := util.ReadIntFromFile(f.path + string(os.PathSeparator) + Brightness)
-	mappedToPercentage := int(math.Round(float64(rawBrightness) / float64(f.maxBrightness)))
+	mappedToPercentage := math.Round(float64(rawBrightness) / float64(f.maxBrightness))
 	return mappedToPercentage, err
 }
 
-func (f *light) SetBrightness(percentage int) (err error) {
-	mappedToRange := int(math.Round(float64(percentage) * (float64(f.maxBrightness) / 100)))
+func (f *light) SetBrightness(percentage float64) (err error) {
+	mappedToRange := int(math.Round((percentage * 100) * (float64(f.maxBrightness) / 100)))
 	return util.WriteIntToFile(mappedToRange, f.path+string(os.PathSeparator)+Brightness)
 }

internal/service/service.go

@@ -30,12 +30,17 @@ var (
 )
 
 type KbdService struct {
-	initialized      bool
-	idleTimeout      time.Duration
-	light            light.Light
-	targetBrightness int
-	userIdle         bool
-	userIdleTimer    *time.Timer
+	initialized bool
+	// idleTimeout specified the time to wait before assuming that the user is idle
+	idleTimeout time.Duration
+	// light the light instance to control through this KbdService instance
+	light light.Light
+	// targetBrightness the currant target brightness
+	targetBrightness float64
+	// userIdle true if the user is currently idling for at least the duration of idleTimeout
+	userIdle bool
+	// idleUserTimer timer instance used to toggle userIdle flag
+	userIdleTimer *time.Timer
 }
 
 func NewKbdService(c config.Configuration, l light.Light) *KbdService {
@@ -51,9 +56,9 @@ func (s *KbdService) Run() {
 
 	b, err := s.light.GetBrightness()
 	if err != nil || b <= 0 {
-		b = 255
+		b = 1
 	}
-	s.targetBrightness = b * 255
+	s.targetBrightness = b
 
 	ctx, cancel := context.WithCancel(context.Background())