unit tests are good and v01cfg transforms input if players and user in players

src/device/input/button/v01.go

@@ -30,20 +30,10 @@ type (
 			Message string
 		}
 		Players []struct {
-			Buttons struct {
-				Up    string
-				Down  string
-				Left  string
-				Right string
-				L     string
-				R     string
-				A     string
-				B     string
-				X     string
-				Y     string
-			}
+			Transformation v01Transformation
 		}
 	}
+	v01Transformation map[string]string
 )
 
 func NewV01(src raw.Raw) V01 {
@@ -67,7 +57,33 @@ func (v01 V01) Read() []Button {
 		log.Printf("%v: %s", err, line)
 	}
 	v01.telemetry(msg)
-	return msg.buttons()
+
+	return v01.cfg.transform(msg).buttons()
+}
+
+func (cfg v01Cfg) transform(msg v01Msg) v01Msg {
+	if len(cfg.Players) == 0 {
+		return msg
+	}
+	user := cfg.Users[msg.U]
+	if user.Player < 1 {
+		msg.Y = ""
+		msg.N = ""
+		return msg
+	}
+	player := cfg.Players[user.Player-1]
+	msg.Y = player.Transformation.pipe(msg.Y)
+	msg.N = player.Transformation.pipe(msg.N)
+	return msg
+}
+
+func (t v01Transformation) pipe(s string) string {
+	for i := range s {
+		if v := t[s[i:i+1]]; v != "" {
+			s = s[:i] + v[:1] + s[i+1:]
+		}
+	}
+	return s
 }
 
 func (v01 V01) telemetry(msg v01Msg) {