native functionality bridge

backend/mpmedia_mac.go

@@ -0,0 +1,161 @@
+//go:build darwin
+
+package backend
+
+/**
+* This file handles implementation of MacOS native controls via the native 'MediaPlayer' framework
+**/
+
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework Cocoa -framework MediaPlayer
+#include "mpmediabridge.h"
+*/
+import (
+	"C"
+)
+
+import (
+	"log"
+	"unsafe"
+
+	"github.com/dweymouth/supersonic/backend/mediaprovider"
+	"github.com/dweymouth/supersonic/player"
+)
+
+// os_remote_command_callback is called by Objective-C when incoming OS media commands are received.
+//
+//export os_remote_command_callback
+func os_remote_command_callback(command C.Command) {
+	switch command {
+	case C.PLAY:
+		mpMediaEventRecipient.OnCommandPlay()
+	case C.PAUSE:
+		mpMediaEventRecipient.OnCommandPause()
+	case C.STOP:
+		mpMediaEventRecipient.OnCommandStop()
+	case C.TOGGLE:
+		mpMediaEventRecipient.OnCommandTogglePlayPause()
+	case C.PREVIOUS_TRACK:
+		mpMediaEventRecipient.OnCommandPreviousTrack()
+	case C.NEXT_TRACK:
+		mpMediaEventRecipient.OnCommandNextTrack()
+	default:
+		log.Printf("unknown OS command received: %v", command)
+	}
+}
+
+// global recipient for Object-C callbacks from command center.
+// This is global so that it can be called from 'os_remote_command_callback' to avoid passing Go pointers into C.
+var mpMediaEventRecipient *MPMediaHandler
+
+// NewMPMediaHandler creates a new MPMediaHandler instances and sets it as the current recipient
+// for incoming system events.
+func NewMPMediaHandler(player *player.Player, playbackManager *PlaybackManager) *MPMediaHandler {
+	mp := &MPMediaHandler{
+		player:          player,
+		playbackManager: playbackManager,
+	}
+
+	// register remote commands and set callback target
+	mpMediaEventRecipient = mp
+	C.register_os_remote_commands()
+
+	mp.playbackManager.OnSongChange(func(track, _ *mediaprovider.Track) {
+		if track != nil && track.ID != "" {
+			var artURL string
+			if mp.ArtURLLookup != nil {
+				var err error
+				if artURL, err = mp.ArtURLLookup(track.CoverArtID); err != nil {
+					log.Printf("error fetching art url: %s", err.Error())
+				}
+			}
+
+			cTitle := C.CString(track.Name)
+			defer C.free(unsafe.Pointer(cTitle))
+
+			var artist string
+			if len(track.ArtistNames) > 0 {
+				artist = track.ArtistNames[0]
+			}
+
+			cArtist := C.CString(artist)
+			defer C.free(unsafe.Pointer(cArtist))
+
+			cArtURL := C.CString(artURL)
+			defer C.free(unsafe.Pointer(cArtURL))
+
+			C.set_os_now_playing_info(cTitle, cArtist, cArtURL)
+		}
+	})
+
+	mp.player.OnStopped(func() {
+		C.set_os_playback_state_stopped()
+	})
+
+	mp.player.OnPlaying(func() {
+		C.set_os_playback_state_playing()
+	})
+
+	mp.player.OnPaused(func() {
+		C.set_os_playback_state_paused()
+	})
+
+	return mp
+}
+
+/**
+* Handle incoming OS commands.
+**/
+
+// MPMediaHandler instance received OS command 'pause'
+func (mp *MPMediaHandler) OnCommandPause() {
+	if mp == nil || mp.player == nil {
+		return
+	}
+	mp.player.Pause()
+}
+
+// MPMediaHandler instance received OS command 'play'
+func (mp *MPMediaHandler) OnCommandPlay() {
+	if mp == nil || mp.player == nil {
+		return
+	}
+	mp.player.Continue()
+}
+
+// MPMediaHandler instance received OS command 'stop'
+func (mp *MPMediaHandler) OnCommandStop() {
+	if mp == nil || mp.player == nil {
+		return
+	}
+	mp.player.Stop()
+}
+
+// MPMediaHandler instance received OS command 'toggle'
+func (mp *MPMediaHandler) OnCommandTogglePlayPause() {
+	if mp == nil || mp.player == nil {
+		return
+	}
+	if mp.player.GetStatus().State == player.Playing {
+		mp.OnCommandPause()
+	} else {
+		mp.OnCommandPlay()
+	}
+}
+
+// MPMediaHandler instance received OS command 'next track'
+func (mp *MPMediaHandler) OnCommandNextTrack() {
+	if mp == nil || mp.player == nil {
+		return
+	}
+	mp.player.SeekNext()
+}
+
+// MPMediaHandler instance received OS command 'previous track'
+func (mp *MPMediaHandler) OnCommandPreviousTrack() {
+	if mp == nil || mp.player == nil {
+		return
+	}
+	mp.player.SeekBackOrPrevious()
+}