Remove IsActive() from Timer interface - factories return nil instead

Timer implementations now control their activation by returning nil from their factory functions when not configured, eliminating the need for the IsActive() method in the Timer interface.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: hollesse

timer/localtimer/localtimer.go

@@ -15,6 +15,9 @@ import (
 
 func init() {
 	timer.Register(func(configuration config.Configuration) timer.Timer {
+		if !configuration.TimerLocal {
+			return nil
+		}
 		return NewProcessLocalTimer(configuration)
 	})
 }
@@ -28,10 +31,6 @@ func NewProcessLocalTimer(configuration config.Configuration) ProcessLocalTimer
 	return ProcessLocalTimer{configuration: configuration}
 }
 
-func (t ProcessLocalTimer) IsActive() bool {
-	return t.configuration.TimerLocal
-}
-
 func (t ProcessLocalTimer) StartTimer(minutes int) error {
 	timeoutInSeconds := minutes * 60
 	if err := ExecuteCommandsInBackgroundProcess(

timer/timer.go

@@ -13,12 +13,12 @@ import (
 
 // Timer abstracts timer functionality so different implementations can be used.
 type Timer interface {
-	IsActive() bool
 	StartTimer(minutes int) error
 	StartBreakTimer(minutes int) error
 }
 
 // Factory creates a Timer for the given configuration.
+// Returns nil if the timer should not be active.
 type Factory func(configuration config.Configuration) Timer
 
 var factories []Factory
@@ -29,12 +29,12 @@ func Register(f Factory) {
 	factories = append(factories, f)
 }
 
-// GetTimers returns all registered timers that report themselves as active.
+// GetTimers returns all registered timers that are active for the given configuration.
 func GetTimers(configuration config.Configuration) []Timer {
 	var active []Timer
 	for _, f := range factories {
 		t := f(configuration)
-		if t.IsActive() {
+		if t != nil {
 			active = append(active, t)
 		}
 	}
@@ -48,9 +48,8 @@ func RunTimer(timerInMinutes string, configuration config.Configuration) error {
 		return err
 	}
 
-	timeoutInSeconds := timeoutInMinutes * 60
 	timeOfTimeout := time.Now().Add(time.Minute * time.Duration(timeoutInMinutes)).Format("15:04")
-	say.Debug(fmt.Sprintf("Starting timer at %s for %d minutes = %d seconds (parsed from user input %s)", timeOfTimeout, timeoutInMinutes, timeoutInSeconds, timerInMinutes))
+	say.Debug(fmt.Sprintf("Starting timer at %s for %d minutes (parsed from user input %s)", timeOfTimeout, timeoutInMinutes, timerInMinutes))
 
 	timers := GetTimers(configuration)
 	if len(timers) == 0 {
@@ -76,9 +75,8 @@ func RunBreakTimer(timerInMinutes string, configuration config.Configuration) er
 		return err
 	}
 
-	timeoutInSeconds := timeoutInMinutes * 60
 	timeOfTimeout := time.Now().Add(time.Minute * time.Duration(timeoutInMinutes)).Format("15:04")
-	say.Debug(fmt.Sprintf("Starting break timer at %s for %d minutes = %d seconds (parsed from user input %s)", timeOfTimeout, timeoutInMinutes, timeoutInSeconds, timerInMinutes))
+	say.Debug(fmt.Sprintf("Starting break timer at %s for %d minutes (parsed from user input %s)", timeOfTimeout, timeoutInMinutes, timerInMinutes))
 
 	timers := GetTimers(configuration)
 	if len(timers) == 0 {

timer/webtimer/webtimer.go

@@ -11,6 +11,9 @@ import (
 
 func init() {
 	timer.Register(func(configuration config.Configuration) timer.Timer {
+		if configuration.TimerRoom == "" {
+			return nil
+		}
 		return NewWebTimer(configuration)
 	})
 }
@@ -32,10 +35,6 @@ func NewWebTimer(configuration config.Configuration) WebTimer {
 	}
 }
 
-func (t WebTimer) IsActive() bool {
-	return t.room != ""
-}
-
 func (t WebTimer) StartTimer(minutes int) error {
 	if err := httpPutTimer(minutes, t.room, t.timerUser, t.timerUrl, t.timerInsecure); err != nil {
 		return fmt.Errorf("remote timer couldn't be started: %w", err)