Basic hat support. (#20)

Reviewed-on: #20
Co-authored-by: Anna Rose Wiggins <annabunches@gmail.com>
Co-committed-by: Anna Rose Wiggins <annabunches@gmail.com>

internal/mappingrules/rule_target_hat.go

@@ -0,0 +1,53 @@
+package mappingrules
+
+import (
+	"fmt"
+
+	"git.annabunches.net/annabunches/joyful/internal/configparser"
+	"git.annabunches.net/annabunches/joyful/internal/eventcodes"
+	"github.com/holoplot/go-evdev"
+)
+
+type RuleTargetHat struct {
+	Device   Device
+	Hat      evdev.EvCode
+	Inverted bool
+}
+
+func NewRuleTargetHatFromConfig(config configparser.RuleTargetConfigHat, devs map[string]Device) (*RuleTargetHat, error) {
+	dev, ok := devs[config.Device]
+	if !ok {
+		return nil, fmt.Errorf("device '%s' not found", config.Device)
+	}
+
+	code, err := eventcodes.ParseCode(config.Hat, eventcodes.CodePrefixAxis)
+	if err != nil {
+		return nil, err
+	}
+
+	return &RuleTargetHat{
+		Device:   dev,
+		Hat:      code,
+		Inverted: config.Inverted,
+	}, nil
+}
+
+func (target *RuleTargetHat) NormalizeValue(value int32) int32 {
+	if !target.Inverted {
+		return value
+	}
+
+	return value * -1
+}
+
+func (target *RuleTargetHat) CreateEvent(value int32, _ *string) *evdev.InputEvent {
+	return &evdev.InputEvent{
+		Type:  evdev.EV_ABS,
+		Code:  target.Hat,
+		Value: value,
+	}
+}
+
+func (target *RuleTargetHat) MatchEvent(device Device, event *evdev.InputEvent) bool {
+	return device == target.Device && event.Code == target.Hat
+}