From 91206f6037cfd843ebd67651c6e09c7b39bb9187 Mon Sep 17 00:00:00 2001
From: Joel Wetzell <git@jwetzell.com>
Date: Sat, 30 May 2026 09:06:07 -0500
Subject: [PATCH] add tod control packet

---
 artnet.go          | 10 ++++++
 todcontrol.go      | 88 ++++++++++++++++++++++++++++++++++++++++++++++
 todcontrol_test.go | 30 ++++++++++++++++
 3 files changed, 128 insertions(+)
 create mode 100644 todcontrol.go
 create mode 100644 todcontrol_test.go

diff --git a/artnet.go b/artnet.go
index f01bb00..d091f6c 100644
--- a/artnet.go
+++ b/artnet.go
@@ -185,6 +185,16 @@ func Decode(bytes []byte) (ArtNetPacket, error) {
 		}
 
 		return &artTodRequest, nil
+	case OpTodControl:
+		artTodControl := ArtTodControl{}
+
+		err := artTodControl.UnmarshalBinary(bytes)
+
+		if err != nil {
+			return nil, err
+		}
+
+		return &artTodControl, nil
 	default:
 		return nil, fmt.Errorf("unhandled opcode: %#x", opCode)
 	}
diff --git a/todcontrol.go b/todcontrol.go
new file mode 100644
index 0000000..802a096
--- /dev/null
+++ b/todcontrol.go
@@ -0,0 +1,88 @@
+package artnet
+
+import (
+	"encoding/binary"
+	"errors"
+	"slices"
+)
+
+type TodControlCommand uint8
+
+const (
+	AtcNone   TodControlCommand = 0x00
+	AtcFlush  TodControlCommand = 0x01
+	AtcEnd    TodControlCommand = 0x02
+	AtcIncOn  TodControlCommand = 0x03
+	AtcIncOff TodControlCommand = 0x04
+)
+
+type ArtTodControl struct {
+	filler1 uint8
+	filler2 uint8
+	spare1  uint8
+	spare2  uint8
+	spare3  uint8
+	spare4  uint8
+	spare5  uint8
+	spare6  uint8
+	spare7  uint8
+	Net     uint8
+	Command TodControlCommand
+	Address uint8
+}
+
+func (adr *ArtTodControl) GetOpCode() uint16 {
+	return OpTodRequest
+}
+
+func (adr *ArtTodControl) UnmarshalBinary(data []byte) error {
+
+	if len(data) < 24 {
+		return errors.New("ArtTodControl packet must be at least 24 bytes long")
+	}
+
+	if !slices.Equal(ArtNetID[:], data[0:8]) {
+		return errors.New("ID does not match Art-Net ID")
+	}
+
+	opCode := binary.LittleEndian.Uint16(data[8:10])
+	if opCode != OpTodRequest {
+		return errors.New("packet does not have the correct OpCode for an ArtTodControl packet")
+	}
+
+	offset := 12
+	adr.filler1 = data[offset]
+	adr.filler2 = data[offset+1]
+	adr.spare1 = data[offset+2]
+	adr.spare2 = data[offset+3]
+	adr.spare3 = data[offset+4]
+	adr.spare4 = data[offset+5]
+	adr.spare5 = data[offset+6]
+	adr.spare6 = data[offset+7]
+	adr.spare7 = data[offset+8]
+	adr.Net = data[offset+9]
+	adr.Command = TodControlCommand(data[offset+10])
+	adr.Address = data[offset+11]
+	return nil
+}
+
+func (adr *ArtTodControl) MarshalBinary() ([]byte, error) {
+	data := make([]byte, 8+16)
+	copy(data[0:8], ArtNetID[:])
+	binary.LittleEndian.PutUint16(data[8:10], OpTodRequest)
+	data[10] = 0
+	data[11] = 14
+	data[12] = adr.filler1
+	data[13] = adr.filler2
+	data[14] = adr.spare1
+	data[15] = adr.spare2
+	data[16] = adr.spare3
+	data[17] = adr.spare4
+	data[18] = adr.spare5
+	data[19] = adr.spare6
+	data[20] = adr.spare7
+	data[21] = adr.Net
+	data[22] = uint8(adr.Command)
+	data[23] = adr.Address
+	return data, nil
+}
diff --git a/todcontrol_test.go b/todcontrol_test.go
new file mode 100644
index 0000000..b95b633
--- /dev/null
+++ b/todcontrol_test.go
@@ -0,0 +1,30 @@
+package artnet_test
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/jwetzell/artnet-go"
+)
+
+func TestGoodArtTodControlUnmarshal(t *testing.T) {
+	tests := []struct {
+		Name     string
+		Data     []byte
+		Expected *artnet.ArtTodControl
+	}{}
+
+	for _, test := range tests {
+		t.Run(test.Name, func(t *testing.T) {
+			got := &artnet.ArtTodControl{}
+
+			err := got.UnmarshalBinary(test.Data)
+			if err != nil {
+				t.Fatalf("failed to Unmarshal ArtTodControl: %s", err)
+			}
+			if !reflect.DeepEqual(got, test.Expected) {
+				t.Fatalf("ArtTodControl does not match got: %+v expected: %+v", got, test.Expected)
+			}
+		})
+	}
+}