housekeeping: Refactored API to separate packages

translation/midi.go

@@ -0,0 +1,39 @@
+package translation
+
+import (
+	"gitlab.com/gomidi/midi/v2"
+	"gitlab.com/gomidi/midi/v2/drivers"
+	_ "gitlab.com/gomidi/midi/v2/drivers/rtmididrv"
+)
+
+// A MidiInput represents a MIDI input and provides a channel to read incoming
+// Messages, as well as a Stop function to terminate the connection.
+type MidiInput struct {
+	input drivers.In
+	Messages chan midi.Message
+	Stop func()
+}
+
+// NewMidiInput initialises a MidiInput object connected to the MIDI port specified
+// by portName. Retuns an error if the connection fails.
+func NewMidiInput(portName string) (*MidiInput, error) {
+	input, err := midi.FindInPort(portName)
+	if err != nil {
+		return nil, err
+	}
+
+	messages := make(chan midi.Message)
+
+	midiListener := func(msg midi.Message, timestampMs int32) {
+		if msg.IsOneOf(midi.NoteOnMsg, midi.NoteOffMsg, midi.ControlChangeMsg) {
+			messages <- msg
+		}
+	}
+
+	stopFunc, err := midi.ListenTo(input, midiListener, midi.UseSysEx())
+	if err != nil {
+		return nil, err
+	}
+
+	return &MidiInput{input, messages, stopFunc}, nil
+}