Use testify, write a couple more tests, and start a major refactor.

internal/mappingrules/rule_target_modeselect.go

@@ -0,0 +1,41 @@
+package mappingrules
+
+import (
+	"slices"
+
+	"git.annabunches.net/annabunches/joyful/internal/logger"
+	"github.com/holoplot/go-evdev"
+)
+
+type RuleTargetModeSelect struct {
+	RuleTargetBase
+	ModeSelect []string
+}
+
+func NewRuleTargetModeSelect(modes []string) *RuleTargetModeSelect {
+	return &RuleTargetModeSelect{
+		RuleTargetBase: NewRuleTargetBase("", nil, 0, false),
+		ModeSelect:     modes,
+	}
+}
+
+// RuleTargetModeSelect doesn't make sense as an input type
+func (target *RuleTargetModeSelect) NormalizeValue(value int32) int32 {
+	return -1
+}
+
+func (target *RuleTargetModeSelect) CreateEvent(value int32, mode *string) *evdev.InputEvent {
+	if value == 0 {
+		return nil
+	}
+
+	index := 0
+	if currentMode := slices.Index(target.ModeSelect, *mode); currentMode != -1 {
+		// find the next mode
+		index = (currentMode + 1) % len(target.ModeSelect)
+	}
+
+	*mode = target.ModeSelect[index]
+	logger.Logf("Mode changed to '%s'", *mode)
+	return nil
+}