1 files changed, 89 insertions, 3 deletions
diff --git a/pkg/controller/controller.go b/pkg/controller/controller.go
index b8d04e7..b982c56 100644
--- a/pkg/controller/controller.go
+++ b/pkg/controller/controller.go
@@ -22,17 +22,103 @@
 
 package controller
 
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/scgolang/midi"
+)
+
+const (
+	NOTE_OFFSET_BUTTON = byte(0x00)
+	NUM_BUTTONS        = 4
+
+	CC_LED          = byte(0xB0)
+	NOTE_OFFSET_LED = byte(0x00)
+	NUM_LEDS        = 4
+	LED_OFF         = byte(0x00)
+	LED_ON          = byte(0x01)
+	LED_TOGGLE      = byte(0x02)
+	LED_BLINK_MIN   = byte(0x03)
+	LED_BLINK_MAX   = byte(0x7f)
+)
+
 type Controller struct {
+	Dev *midi.Device
+}
+
+func openDevice(devices []*midi.Device, prefix string) (d *midi.Device, err error) {
+	for _, device := range devices {
+		if strings.HasPrefix(device.Name, prefix) {
+			d = device
+		}
+	}
+	if d == nil {
+		return nil, errors.New("could not find device with prefix: " + prefix)
+	}
+	return d, d.Open()
 }
 
 func NewController(c Config) (*Controller, error) {
-	return &Controller{}, nil
+	devices, err := midi.Devices()
+	if err != nil {
+		return nil, err
+	}
+
+	ctrl := &Controller{}
+	if ctrl.Dev, err = openDevice(devices, c.Dev); err != nil {
+		return nil, err
+	}
+	ctrl.Dev.QueueSize = 100
+
+	return ctrl, nil
+}
+
+func (c *Controller) Init() error {
+	return nil
 }
 
-func (m *Controller) Init() error {
+func (c *Controller) Shutdown() error {
+	if c.Dev != nil {
+		c.Dev.Close()
+	}
+	// TODO: also close all subscribed channels
+	//       terminate go-routine started by Init()
 	return nil
 }
 
-func (m *Controller) Shutdown() error {
+func (c *Controller) setLed(num byte, value byte) error {
+	if num >= NUM_LEDS {
+		return fmt.Errorf("this controller has only %d leds.", NUM_LEDS)
+	}
+
+	n, err := c.Dev.Write([]byte{CC_LED, NOTE_OFFSET_LED + num, value})
+	if err != nil {
+		// reopen device?
+		return err
+	}
+	if n != 3 {
+		return errors.New("sending LED command failed.")
+	}
 	return nil
 }
+
+func (c *Controller) LedOff(num byte) error {
+	return c.setLed(num, LED_OFF)
+}
+
+func (c *Controller) LedOn(num byte) error {
+	return c.setLed(num, LED_ON)
+}
+
+func (c *Controller) LedToggle(num byte) error {
+	return c.setLed(num, LED_TOGGLE)
+}
+
+func (c *Controller) LedBlink(num, wait byte) error {
+	if (wait + LED_BLINK_MIN) > LED_BLINK_MAX {
+		return fmt.Errorf("blink wait must be between 0 and %d.", LED_BLINK_MAX-LED_BLINK_MIN)
+	}
+	return c.setLed(num, wait+LED_BLINK_MIN)
+}