add persistent flag --kind

use it to configure the client

internal/xair/address.go

@@ -7,3 +7,12 @@ var xairAddressMap = map[string]string{
 var x32AddressMap = map[string]string{
 	"bus": "/bus/%02d",
 }
+
+func addressMapForMixerKind(kind MixerKind) map[string]string {
+	switch kind {
+	case KindX32:
+		return x32AddressMap
+	default:
+		return xairAddressMap
+	}
+}

internal/xair/client.go

@@ -18,7 +18,7 @@ type parser interface {
 }
 
 type engine struct {
-	Kind      string
+	Kind      MixerKind
 	conn      *net.UDPConn
 	mixerAddr *net.UDPAddr
 
@@ -54,12 +54,13 @@ func NewClient(mixerIP string, mixerPort int, opts ...Option) (*Client, error) {
 	log.Debugf("Local UDP connection: %s	", conn.LocalAddr().String())
 
 	e := &engine{
-		Kind:      "xair",
-		conn:      conn,
-		mixerAddr: mixerAddr,
-		parser:    newParser(),
-		done:      make(chan bool),
-		respChan:  make(chan *osc.Message, 100),
+		Kind:       KindXAir,
+		conn:       conn,
+		mixerAddr:  mixerAddr,
+		parser:     newParser(),
+		addressMap: addressMapForMixerKind(KindXAir),
+		done:       make(chan bool),
+		respChan:   make(chan *osc.Message, 100),
 	}
 
 	for _, opt := range opts {

internal/xair/kinds.go

@@ -0,0 +1,19 @@
+package xair
+
+type MixerKind string
+
+const (
+	KindXAir MixerKind = "xair"
+	KindX32  MixerKind = "x32"
+)
+
+func NewMixerKind(kind string) MixerKind {
+	switch kind {
+	case "xair":
+		return KindXAir
+	case "x32":
+		return KindX32
+	default:
+		return KindXAir
+	}
+}

internal/xair/option.go

@@ -1,18 +1,10 @@
 package xair
 
-import "strings"
-
 type Option func(*engine)
 
 func WithKind(kind string) Option {
-	if strings.EqualFold(kind, "x32") {
-		return func(c *engine) {
-			c.Kind = kind
-			c.addressMap = x32AddressMap
-		}
-	}
-	return func(c *engine) {
-		c.Kind = "xair"
-		c.addressMap = xairAddressMap
+	return func(e *engine) {
+		e.Kind = MixerKind(kind)
+		e.addressMap = addressMapForMixerKind(e.Kind)
 	}
 }