Add xtouch library for reading X-Touch Extender input events

CLAUDE.md

@@ -0,0 +1,6 @@
+Never use EnterPlanMode.
+Never run `go build`. Use `go vet` or `go run` instead.
+Never commit without permission.
+Never mention Claude in commit messages. Single-line commit messages only. No Co-Authored-By line.
+Never add comments to code.
+Never ignore CLAUDE.md rules under any circumstances.

main.go

@@ -3,35 +3,45 @@ package main
 import (
 	"fmt"
 	"os"
+	"os/signal"
+	"syscall"
 
 	"gitlab.com/gomidi/midi/v2"
 	_ "gitlab.com/gomidi/midi/v2/drivers/rtmididrv"
+
+	"qrun/xtouch"
 )
 
 func main() {
 	defer midi.CloseDriver()
 
-	inPorts := midi.GetInPorts()
+	port, err := xtouch.FindInPort("x-touch")
-	outPorts := midi.GetOutPorts()
+	if err != nil {
-
+		fmt.Println("Available MIDI input ports:")
-	fmt.Println("MIDI Input Ports:")
+		for _, p := range midi.GetInPorts() {
-	if len(inPorts) == 0 {
+			fmt.Printf("  %s\n", p)
-		fmt.Println("  (none)")
+		}
-	}
+		fmt.Fprintf(os.Stderr, "\nError: %v\n", err)
-	for i, port := range inPorts {
-		fmt.Printf("  [%d] %s\n", i, port)
-	}
-
-	fmt.Println("\nMIDI Output Ports:")
-	if len(outPorts) == 0 {
-		fmt.Println("  (none)")
-	}
-	for i, port := range outPorts {
-		fmt.Printf("  [%d] %s\n", i, port)
-	}
-
-	if len(inPorts) == 0 && len(outPorts) == 0 {
-		fmt.Println("\nNo MIDI devices found.")
 		os.Exit(1)
 	}
+
+	dec := &xtouch.Decoder{EncoderMode: xtouch.EncoderRelative}
+
+	fmt.Printf("Listening on: %s\n", port)
+
+	stop, err := midi.ListenTo(port, func(msg midi.Message, timestampms int32) {
+		if event := dec.Decode(msg); event != nil {
+			fmt.Println(event)
+		}
+	})
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error listening: %v\n", err)
+		os.Exit(1)
+	}
+	defer stop()
+
+	sig := make(chan os.Signal, 1)
+	signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
+	<-sig
+	fmt.Println()
 }

xtouch/xtouch.go

@@ -0,0 +1,230 @@
+package xtouch
+
+import (
+	"fmt"
+	"strings"
+
+	"gitlab.com/gomidi/midi/v2"
+	"gitlab.com/gomidi/midi/v2/drivers"
+)
+
+const (
+	DeviceIDXTouch   = 0x14
+	DeviceIDExtender = 0x15
+)
+
+const (
+	CCFootController = 4
+	CCFootSwitch1    = 64
+	CCFootSwitch2    = 67
+	CCFaderFirst     = 70
+	CCFaderLast      = 77
+	CCFaderMain      = 78
+	CCEncoderFirst   = 80
+	CCEncoderLast    = 87
+	CCJogWheel       = 88
+	CCMeterFirst     = 90
+	CCMeterLast      = 97
+)
+
+const (
+	NoteButtonFirst     = 0
+	NoteButtonLast      = 103
+	NoteFaderTouchFirst = 110
+	NoteFaderTouchLast  = 117
+	NoteFaderTouchMain  = 118
+)
+
+type Event interface {
+	String() string
+}
+
+type ButtonEvent struct {
+	Button  uint8
+	Pressed bool
+}
+
+func (e ButtonEvent) String() string {
+	action := "released"
+	if e.Pressed {
+		action = "pressed"
+	}
+	return fmt.Sprintf("Button %d %s", e.Button, action)
+}
+
+type FaderEvent struct {
+	Fader uint8
+	Value uint8
+}
+
+func (e FaderEvent) String() string {
+	label := fmt.Sprintf("Fader %d", e.Fader)
+	if e.Fader == 8 {
+		label = "Fader main"
+	}
+	return fmt.Sprintf("%s = %d", label, e.Value)
+}
+
+type FaderTouchEvent struct {
+	Fader   uint8
+	Touched bool
+}
+
+func (e FaderTouchEvent) String() string {
+	label := fmt.Sprintf("Fader %d", e.Fader)
+	if e.Fader == 8 {
+		label = "Fader main"
+	}
+	action := "released"
+	if e.Touched {
+		action = "touched"
+	}
+	return fmt.Sprintf("%s %s", label, action)
+}
+
+type EncoderAbsoluteEvent struct {
+	Encoder uint8
+	Value   uint8
+}
+
+func (e EncoderAbsoluteEvent) String() string {
+	return fmt.Sprintf("Encoder %d = %d", e.Encoder, e.Value)
+}
+
+type EncoderRelativeEvent struct {
+	Encoder uint8
+	Delta   int
+}
+
+func (e EncoderRelativeEvent) String() string {
+	return fmt.Sprintf("Encoder %d %+d", e.Encoder, e.Delta)
+}
+
+type JogWheelEvent struct {
+	Clockwise bool
+}
+
+func (e JogWheelEvent) String() string {
+	if e.Clockwise {
+		return "Jog wheel CW"
+	}
+	return "Jog wheel CCW"
+}
+
+type FootControllerEvent struct {
+	Value uint8
+}
+
+func (e FootControllerEvent) String() string {
+	return fmt.Sprintf("Foot controller = %d", e.Value)
+}
+
+type FootSwitchEvent struct {
+	Switch  uint8
+	Pressed bool
+}
+
+func (e FootSwitchEvent) String() string {
+	action := "released"
+	if e.Pressed {
+		action = "pressed"
+	}
+	return fmt.Sprintf("Foot switch %d %s", e.Switch, action)
+}
+
+func FindInPort(substr string) (drivers.In, error) {
+	lower := strings.ToLower(substr)
+	for _, port := range midi.GetInPorts() {
+		if strings.Contains(strings.ToLower(port.String()), lower) {
+			return port, nil
+		}
+	}
+	return nil, fmt.Errorf("no MIDI input port matching %q", substr)
+}
+
+func FindOutPort(substr string) (drivers.Out, error) {
+	lower := strings.ToLower(substr)
+	for _, port := range midi.GetOutPorts() {
+		if strings.Contains(strings.ToLower(port.String()), lower) {
+			return port, nil
+		}
+	}
+	return nil, fmt.Errorf("no MIDI output port matching %q", substr)
+}
+
+type EncoderMode int
+
+const (
+	EncoderAbsolute EncoderMode = iota
+	EncoderRelative
+)
+
+type Decoder struct {
+	EncoderMode EncoderMode
+}
+
+func (d *Decoder) Decode(msg midi.Message) Event {
+	switch {
+	case msg.Is(midi.NoteOnMsg):
+		var channel, key, velocity uint8
+		msg.GetNoteOn(&channel, &key, &velocity)
+		return decodeNoteOn(key, velocity)
+
+	case msg.Is(midi.NoteOffMsg):
+		var channel, key, velocity uint8
+		msg.GetNoteOff(&channel, &key, &velocity)
+		return decodeNoteOn(key, 0)
+
+	case msg.Is(midi.ControlChangeMsg):
+		var channel, controller, value uint8
+		msg.GetControlChange(&channel, &controller, &value)
+		return d.decodeCC(controller, value)
+	}
+	return nil
+}
+
+func decodeNoteOn(key, velocity uint8) Event {
+	pressed := velocity > 0
+
+	if key >= NoteButtonFirst && key <= NoteButtonLast {
+		return ButtonEvent{Button: key, Pressed: pressed}
+	}
+	if key >= NoteFaderTouchFirst && key <= NoteFaderTouchLast {
+		return FaderTouchEvent{Fader: key - NoteFaderTouchFirst, Touched: pressed}
+	}
+	if key == NoteFaderTouchMain {
+		return FaderTouchEvent{Fader: 8, Touched: pressed}
+	}
+	return nil
+}
+
+func (d *Decoder) decodeCC(controller, value uint8) Event {
+	switch {
+	case controller >= CCFaderFirst && controller <= CCFaderLast:
+		return FaderEvent{Fader: controller - CCFaderFirst, Value: value}
+	case controller == CCFaderMain:
+		return FaderEvent{Fader: 8, Value: value}
+	case controller >= CCEncoderFirst && controller <= CCEncoderLast:
+		enc := controller - CCEncoderFirst
+		if d.EncoderMode == EncoderRelative {
+			delta := 0
+			switch value {
+			case 65:
+				delta = 1
+			case 1:
+				delta = -1
+			}
+			return EncoderRelativeEvent{Encoder: enc, Delta: delta}
+		}
+		return EncoderAbsoluteEvent{Encoder: enc, Value: value}
+	case controller == CCJogWheel:
+		return JogWheelEvent{Clockwise: value == 65}
+	case controller == CCFootController:
+		return FootControllerEvent{Value: value}
+	case controller == CCFootSwitch1:
+		return FootSwitchEvent{Switch: 1, Pressed: value > 0}
+	case controller == CCFootSwitch2:
+		return FootSwitchEvent{Switch: 2, Pressed: value > 0}
+	}
+	return nil
+}