initial implementation of Windows SMTC integration

backend/app.go

@@ -12,6 +12,7 @@ import (
 	"reflect"
 	"runtime"
 	"slices"
+	"strings"
 	"time"
 
 	"github.com/dweymouth/supersonic/backend/ipc"
@@ -45,6 +46,7 @@ type App struct {
 	LocalPlayer     *mpv.Player
 	UpdateChecker   UpdateChecker
 	MPRISHandler    *MPRISHandler
+	WinSMTC         *SMTC
 	ipcServer       ipc.IPCServer
 
 	// UI callbacks to be set in main
@@ -165,11 +167,14 @@ func StartupApp(appName, displayAppName, appVersion, appVersionTag, latestReleas
 	}
 
 	// OS media center integrations
+	// Linux MPRIS
 	a.setupMPRIS(displayAppName)
+	// MacOS MPNowPlayingInfoCenter
 	InitMPMediaHandler(a.PlaybackManager, func(id string) (string, error) {
 		a.ImageManager.GetCoverThumbnail(id) // ensure image is cached locally
 		return a.ImageManager.GetCoverArtUrl(id)
 	})
+	// Windows SMTC is initialized from main once we have a window HWND.
 
 	a.startConfigWriter(a.bgrndCtx)
 
@@ -331,6 +336,50 @@ func (a *App) setupMPRIS(mprisAppName string) {
 	a.MPRISHandler.Start()
 }
 
+func (a *App) SetupWindowsSMTC(hwnd uintptr) {
+	smtc, err := InitSMTCForWindow(hwnd)
+	if err != nil {
+		log.Printf("error initializing SMTC: %d", err)
+		return
+	}
+	a.WinSMTC = smtc
+
+	smtc.OnButtonPressed(func(btn SMTCButton) {
+		switch btn {
+		case SMTCButtonPlay:
+			a.PlaybackManager.Continue()
+		case SMTCButtonPause:
+			a.PlaybackManager.Pause()
+		case SMTCButtonNext:
+			a.PlaybackManager.SeekNext()
+		case SMTCButtonPrevious:
+			a.PlaybackManager.SeekBackOrPrevious()
+		case SMTCButtonStop:
+			a.PlaybackManager.Stop()
+		}
+	})
+	smtc.OnSeek(func(millis int) {
+		a.PlaybackManager.SeekSeconds(float64(millis) / 1000)
+	})
+
+	a.PlaybackManager.OnSongChange(func(nowPlaying mediaprovider.MediaItem, _ *mediaprovider.Track) {
+		if nowPlaying == nil {
+			smtc.UpdateMetadata("", "")
+			return
+		}
+		artist := strings.Join(nowPlaying.Metadata().Artists, ", ")
+		smtc.UpdateMetadata(nowPlaying.Metadata().Name, artist)
+		smtc.UpdatePosition(0, nowPlaying.Metadata().Duration*1000)
+	})
+	a.PlaybackManager.OnSeek(func() {
+		dur := a.PlaybackManager.NowPlaying().Metadata().Duration
+		smtc.UpdatePosition(int(a.PlaybackManager.CurrentPlayer().GetStatus().TimePos*1000), dur*1000)
+	})
+	a.PlaybackManager.OnPlaying(func() { smtc.UpdatePlaybackState(SMTCPlaybackStatePlaying) })
+	a.PlaybackManager.OnPaused(func() { smtc.UpdatePlaybackState(SMTCPlaybackStatePaused) })
+	a.PlaybackManager.OnStopped(func() { smtc.UpdatePlaybackState(SMTCPlaybackStateStopped) })
+}
+
 func (a *App) LoginToDefaultServer(string) error {
 	serverCfg := a.ServerManager.GetDefaultServer()
 	if serverCfg == nil {
@@ -370,6 +419,9 @@ func (a *App) Shutdown() {
 		a.ipcServer.Shutdown(a.bgrndCtx)
 	}
 	a.MPRISHandler.Shutdown()
+	if a.WinSMTC != nil {
+		a.WinSMTC.Shutdown()
+	}
 	a.PlaybackManager.DisableCallbacks()
 	a.PlaybackManager.Stop() // will trigger scrobble check
 	a.cancel()

backend/smtc.go

@@ -0,0 +1,159 @@
+//go:build windows
+
+package backend
+
+/*
+#cgo CFLAGS: -I .
+void btn_callback_cgo(int in);
+void seek_callback_cgo(int in);
+*/
+import "C"
+
+import (
+	"errors"
+	"fmt"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+type SMTCPlaybackState int
+type SMTCButton int
+
+const (
+	// constants from smtc.h in github.com/supersonic-app/smtc-dll
+	SMTCPlaybackStateStopped SMTCPlaybackState = 2
+	SMTCPlaybackStatePlaying SMTCPlaybackState = 3
+	SMTCPlaybackStatePaused  SMTCPlaybackState = 4
+
+	SMTCButtonPlay     SMTCButton = 0
+	SMTCButtonPause    SMTCButton = 1
+	SMTCButtonStop     SMTCButton = 2
+	SMTCButtonPrevious SMTCButton = 4
+	SMTCButtonNext     SMTCButton = 5
+)
+
+type SMTC struct {
+	dll *windows.DLL
+
+	onButtonPressed func(SMTCButton)
+	onSeek          func(int)
+}
+
+var smtcInstance *SMTC
+
+func InitSMTCForWindow(hwnd uintptr) (*SMTC, error) {
+	dll, err := windows.LoadDLL("smtc.dll")
+	if err != nil {
+		return nil, err
+	}
+
+	proc, err := dll.FindProc("InitializeForWindow")
+	if err != nil {
+		return nil, err
+	}
+
+	hr, _, _ := proc.Call(hwnd, uintptr(unsafe.Pointer(C.btn_callback_cgo)), uintptr(unsafe.Pointer(C.seek_callback_cgo)))
+	if hr < 0 {
+		return nil, fmt.Errorf("InitializeForWindow failed with HRESULT=%d", hr)
+	}
+
+	smtcInstance = &SMTC{dll: dll}
+	return smtcInstance, nil
+}
+
+func (s *SMTC) OnButtonPressed(f func(SMTCButton)) {
+	s.onButtonPressed = f
+}
+
+func (s *SMTC) OnSeek(f func(millis int)) {
+	s.onSeek = f
+}
+
+func (s *SMTC) Shutdown() {
+	if s.dll == nil {
+		return
+	}
+	proc, err := s.dll.FindProc("Destroy")
+	if err == nil {
+		proc.Call()
+	}
+
+	s.dll.Release()
+	s.dll = nil
+	smtcInstance = nil
+}
+
+func (s *SMTC) UpdatePlaybackState(state SMTCPlaybackState) error {
+	if s.dll == nil {
+		return errors.New("SMTC DLL not available")
+	}
+
+	proc, err := s.dll.FindProc("UpdatePlaybackState")
+	if err != nil {
+		return err
+	}
+
+	if hr, _, _ := proc.Call(uintptr(state)); hr < 0 {
+		return fmt.Errorf("UpdatePlaybackState failed with HRESULT=%d", hr)
+	}
+	return nil
+}
+
+func (s *SMTC) UpdateMetadata(title, artist string) error {
+	if s.dll == nil {
+		return errors.New("SMTC DLL not available")
+	}
+
+	utfTitle, err := windows.UTF16PtrFromString(title)
+	if err != nil {
+		return err
+	}
+
+	utfArtist, err := windows.UTF16PtrFromString(artist)
+	if err != nil {
+		return err
+	}
+
+	proc, err := s.dll.FindProc("UpdateMetadata")
+	if err != nil {
+		return err
+	}
+
+	hr, _, _ := proc.Call(uintptr(unsafe.Pointer(utfTitle)), uintptr(unsafe.Pointer(utfArtist)))
+	if hr < 0 {
+		return fmt.Errorf("UpdateMetadata failed with HRESULT=%d", hr)
+	}
+	return nil
+}
+
+func (s *SMTC) UpdatePosition(positionMillis, durationMillis int) error {
+	if s.dll == nil {
+		return errors.New("SMTC DLL not available")
+	}
+
+	proc, err := s.dll.FindProc("UpdatePosition")
+	if err != nil {
+		return err
+	}
+
+	hr, _, _ := proc.Call(uintptr(positionMillis), uintptr(durationMillis))
+	if hr < 0 {
+		return fmt.Errorf("UpdatePosition failed with HRESULT=%d", hr)
+	}
+	return nil
+}
+
+//export btnCallback
+func btnCallback(in int) {
+	if smtcInstance != nil && smtcInstance.onButtonPressed != nil {
+		smtcInstance.onButtonPressed(SMTCButton(in))
+	}
+}
+
+//export seekCallback
+func seekCallback(millis int) {
+	if smtcInstance != nil && smtcInstance.onSeek != nil {
+		smtcInstance.onSeek(millis)
+	}
+}

backend/smtc_cfuncs.go

@@ -0,0 +1,16 @@
+//go:build windows
+
+package backend
+
+/*
+void btn_callback_cgo(int in) {
+	void btnCallback(int);
+	btnCallback(in);
+}
+
+void seek_callback_cgo(int in) {
+	void seekCallback(int);
+	seekCallback(in);
+}
+*/
+import "C"

backend/smtc_unsupported.go

@@ -0,0 +1,32 @@
+//go:build !windows
+
+package backend
+
+import "errors"
+
+type SMTCPlaybackState int
+
+const (
+	SMTCPlaybackStateStopped SMTCPlaybackState = 0
+	SMTCPlaybackStatePlaying SMTCPlaybackState = 1
+	SMTCPlaybackStatePaused  SMTCPlaybackState = 2
+)
+
+type SMTC struct{}
+
+var smtcUnsupportedErr = errors.New("SMTC is not supported on this platformo")
+
+func InitSMTCForWindow(hwnd uintptr) (*SMTC, error) {
+	return nil, smtcUnsupportedErr
+}
+
+func (s *SMTC) UpdatePlaybackState(state SMTCPlaybackState) error {
+	return smtcUnsupportedErr
+}
+
+func (s *SMTC) UpdateMetadata(title, artist string) error {
+	return smtcUnsupportedErr
+}
+
+func (s *SMTC) Shutdown() {
+}

main.go

@@ -10,6 +10,8 @@ import (
 	"sync"
 	"time"
 
+	"golang.org/x/sys/windows"
+
 	"github.com/dweymouth/supersonic/backend"
 	"github.com/dweymouth/supersonic/res"
 	"github.com/dweymouth/supersonic/ui"
@@ -87,27 +89,33 @@ func main() {
 		}
 	}()
 
-	// slightly hacky workaround for https://github.com/fyne-io/fyne/issues/4964
-	if runtime.GOOS == "linux" {
-		workaroundWindowSize := sync.OnceFunc(func() {
-			go func() {
-				isWayland := false
-				mainWindow.Window.(driver.NativeWindow).RunNative(func(ctx any) {
-					_, isWayland = ctx.(*driver.WaylandWindowContext)
-				})
-				if !isWayland {
+	startupOnceTasks := sync.OnceFunc(func() {
+		mainWindow.Window.(driver.NativeWindow).RunNative(func(ctx any) {
+			// intialize Windows SMTC
+			if runtime.GOOS == "windows" {
+				if maj, _, _ := windows.RtlGetNtVersionNumbers(); maj >= 10 {
+					// SMTC is only available from Windows 10 (10.0.10240) onward
+					hwnd := ctx.(driver.WindowsWindowContext).HWND
+					myApp.SetupWindowsSMTC(hwnd)
+				}
+			}
+
+			// slightly hacky workaround for https://github.com/fyne-io/fyne/issues/4964
+			_, isWayland := ctx.(*driver.WaylandWindowContext)
+			if runtime.GOOS == "linux" && !isWayland {
+				go func() {
 					time.Sleep(50 * time.Millisecond)
 					s := mainWindow.DesiredSize()
 					mainWindow.Window.Resize(s.Subtract(fyne.NewSize(4, 0)))
 					time.Sleep(50 * time.Millisecond)
 					mainWindow.Window.Resize(s) // back to desired size
-				}
-			}()
+				}()
+			}
 		})
-		fyneApp.Lifecycle().SetOnEnteredForeground(func() {
-			workaroundWindowSize()
-		})
-	}
+	})
+	fyneApp.Lifecycle().SetOnEnteredForeground(func() {
+		startupOnceTasks()
+	})
 
 	mainWindow.ShowAndRun()