housekeeping: Refactored API to separate packages

translation/controller.go

@@ -0,0 +1,83 @@
+package translation
+
+import (
+	"github.com/charmbracelet/log"
+	"gitlab.com/gomidi/midi/v2"
+	"github.com/bendahl/uinput"
+)
+
+// A ControllerList is a list of controllers. Duh.
+type ControllerList []*Controller
+
+// Stop iterates over all Controller objects and Stops their update loops and MIDI connections.
+// Always call this for a clean shutdown. Meant to be deferred.
+func (cl ControllerList) Stop() {
+	for _, controller := range cl {
+		controller.Stop()
+	}
+}
+
+// A Controller object manages the translation from MIDI to uinput.
+type Controller struct {
+	midiInput *MidiInput
+	mappings []Mapping
+	abortChan chan interface{}
+	virtGamepad uinput.Gamepad
+}
+
+// NewController builds a new Controller object reading from the MIDI port specified by portName,
+// and registers a virtual uinput-Gamepad using vendorID and productID.
+func NewController(portName string, vendorID, productID uint16) (*Controller, error) {
+	if vendorID == 0 && productID == 0 {
+		// if no IDs were defined, imitate XBox 360 controller
+		vendorID = 0x45e
+		productID = 0x285
+	}
+	midiInput, err := NewMidiInput(portName)
+	if err != nil {
+		return nil, err
+	}
+
+	virtGamepad, err := uinput.CreateGamepad("/dev/uinput", []byte(portName), vendorID, productID)
+	if err != nil {
+		return nil, err
+	}
+
+	abortChan := make(chan interface{})
+
+	controller := &Controller{midiInput, nil, abortChan, virtGamepad}
+
+	go func() {
+		for {
+			select {
+			case midiMessage := <-midiInput.Messages:
+				controller.update(midiMessage)
+			case <-abortChan:
+				return
+			}
+		}
+	}()
+
+	return controller, nil
+}
+
+// AddMapping adds a mapping to the Controller.
+func (c *Controller) AddMapping(mapping Mapping) {
+	c.mappings = append(c.mappings, mapping)
+}
+
+// Stop quits the update loop and terminates all corresponding connections.
+func (c Controller) Stop() {
+	c.midiInput.Stop()
+	c.abortChan <- struct{}{}
+	c.virtGamepad.Close()
+}
+
+func (c Controller) update(msg midi.Message) {
+	for _, mapping := range c.mappings {
+		err := mapping.TriggerIfMatch(msg, c.virtGamepad)
+		if err != nil {
+			log.Errorf("Error in Mapping \"%s\": %v", mapping.Comment(), err)
+		}
+	}
+}