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_combo.go

@@ -0,0 +1,62 @@
+package mappingrules
+
+import "github.com/holoplot/go-evdev"
+
+// A Combo Mapping Rule can require multiple physical button presses for a single output button
+type MappingRuleButtonCombo struct {
+	MappingRuleBase
+	Inputs []*RuleTargetButton
+	Output *RuleTargetButton
+	State  int
+}
+
+func NewMappingRuleButtonCombo(
+	base MappingRuleBase,
+	inputs []*RuleTargetButton,
+	output *RuleTargetButton) *MappingRuleButtonCombo {
+
+	return &MappingRuleButtonCombo{
+		MappingRuleBase: base,
+		Inputs:          inputs,
+		Output:          output,
+		State:           0,
+	}
+}
+
+func (rule *MappingRuleButtonCombo) MatchEvent(device *evdev.InputDevice, event *evdev.InputEvent, mode *string) (*evdev.InputDevice, *evdev.InputEvent) {
+	if !rule.MappingRuleBase.modeCheck(mode) {
+		return nil, nil
+	}
+
+	// Check each of the inputs, and if we find a match, proceed
+	var match *RuleTargetButton
+	for _, input := range rule.Inputs {
+		if input.MatchEvent(device, event) {
+			match = input
+			break
+		}
+	}
+
+	if match == nil {
+		return nil, nil
+	}
+
+	// Get the value and add/subtract it from State
+	inputValue := match.NormalizeValue(event.Value)
+	oldState := rule.State
+	if inputValue == 0 {
+		rule.State = max(rule.State-1, 0)
+	}
+	if inputValue == 1 {
+		rule.State++
+	}
+	targetState := len(rule.Inputs)
+
+	if oldState == targetState-1 && rule.State == targetState {
+		return rule.Output.Device, rule.Output.CreateEvent(1, mode)
+	}
+	if oldState == targetState && rule.State == targetState-1 {
+		return rule.Output.Device, rule.Output.CreateEvent(0, mode)
+	}
+	return nil, nil
+}