Big Refactor (#2)

Refactor Everything.

Co-authored-by: Anna Rose Wiggins <annabunches@gmail.com>
Co-committed-by: Anna Rose Wiggins <annabunches@gmail.com>

internal/mappingrules/mapping_rule_button_latched.go

@@ -0,0 +1,46 @@
+package mappingrules
+
+import "github.com/holoplot/go-evdev"
+
+type MappingRuleButtonLatched struct {
+	MappingRuleBase
+	Input  *RuleTargetButton
+	Output *RuleTargetButton
+	State  bool
+}
+
+func NewMappingRuleButtonLatched(
+	base MappingRuleBase,
+	input *RuleTargetButton,
+	output *RuleTargetButton) *MappingRuleButtonLatched {
+
+	return &MappingRuleButtonLatched{
+		MappingRuleBase: base,
+		Input:           input,
+		Output:          output,
+		State:           false,
+	}
+}
+
+func (rule *MappingRuleButtonLatched) MatchEvent(device *evdev.InputDevice, event *evdev.InputEvent, mode *string) (*evdev.InputDevice, *evdev.InputEvent) {
+	if !rule.MappingRuleBase.modeCheck(mode) {
+		return nil, nil
+	}
+
+	if device != rule.Input.Device ||
+		event.Code != rule.Input.Button ||
+		rule.Input.NormalizeValue(event.Value) == 0 {
+		return nil, nil
+	}
+
+	// Input is pressed, so toggle state and emit event
+	var value int32
+	rule.State = !rule.State
+	if rule.State {
+		value = 1
+	} else {
+		value = 0
+	}
+
+	return rule.Output.Device, rule.Output.CreateEvent(value, mode)
+}