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_axis.go

@@ -0,0 +1,27 @@
+package mappingrules
+
+import "github.com/holoplot/go-evdev"
+
+// A Simple Mapping Rule can map a button to a button or an axis to an axis.
+type MappingRuleAxis struct {
+	MappingRuleBase
+	Input  *RuleTargetAxis
+	Output *RuleTargetAxis
+}
+
+func NewMappingRuleAxis(base MappingRuleBase, input *RuleTargetAxis, output *RuleTargetAxis) *MappingRuleAxis {
+	return &MappingRuleAxis{
+		MappingRuleBase: base,
+		Input:           input,
+		Output:          output,
+	}
+}
+
+func (rule *MappingRuleAxis) MatchEvent(device *evdev.InputDevice, event *evdev.InputEvent, mode *string) (*evdev.InputDevice, *evdev.InputEvent) {
+	if !rule.MappingRuleBase.modeCheck(mode) ||
+		!rule.Input.MatchEvent(device, event) {
+		return nil, nil
+	}
+
+	return rule.Output.Device, rule.Output.CreateEvent(rule.Input.NormalizeValue(event.Value), mode)
+}